JP2009302960A - Video signal processing apparatus, program and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a video signal processing apparatus, a program and a method capable of enhancing image quality by reducing white-out or black-out, and controlling an extent of image quality enhancement. <P>SOLUTION: The video signal processing apparatus is adopted which includes: a gradation converting unit 106 for applying gradation conversion to a video signal; a specific region detecting unit 107 for detecting a specific region having luminance equal to or higher than a specified first threshold or lower than or equal to a specified second threshold from a current video signal after gradation conversion; a past data storage unit 110 storing past video signals in which information of a distance to a subject is made corresponding to gradation information for each pixel or for each predetermined region; and a gradation correcting unit 108 for detecting a region of a past video signal corresponding to the specific region on the basis of the distance information, extracting from the past data storage unit 110 past gradation information indicating gradation information of the region, and correcting a gradation width of the specific region in the current video signal using the past gradation information. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a video signal processing apparatus, a program, and a method for performing gradation conversion processing on a video signal.

  In the gradation conversion process, a luminance region in which the gradation width is expanded or compressed is generated along with the conversion. In the luminance range to be compressed, the contrast of the image is lowered, and in particular, a problem in image quality such as whiteout in a high luminance part and blackout in a low luminance part occurs.

A technique for separating the obtained video signal into a luminance signal and a color difference signal and compressing the luminance signal and the color difference signal based on a reference gradation conversion curve and a non-reference gradation conversion curve. Is disclosed (for example, see Patent Document 1). In addition, a technique for generating a signal with a wide dynamic range with a wider gradation width by combining a plurality of images having different exposure amounts is disclosed (for example, see Patent Document 2).
JP 2005-191711 A JP 2001-238128 A

  However, according to the technique disclosed in Patent Document 1, since the video signal is separated into a luminance signal and a color difference signal and compressed based on a plurality of gradation conversion curves, gradation discontinuity occurs. There is a possibility that. In addition, according to the technique disclosed in Patent Document 2, in order to synthesize a plurality of images with different exposure amounts, it is necessary to adjust the exposure amount and perform imaging multiple times. There is an inconvenience that application to a signal is difficult.

  The present invention has been made in view of the above circumstances, and provides a video signal processing apparatus, program, and method capable of improving image quality by reducing overexposure and blackout, and controlling the degree of image quality improvement. With the goal.

In order to solve the above problems, the present invention employs the following means.
According to a first aspect of the present invention, a gradation conversion unit that performs gradation conversion on a video signal, and a current video signal after gradation conversion are equal to or greater than a predetermined first threshold value or a predetermined second threshold value. A region detection unit for detecting a specific region having the following luminance, and a storage unit storing a past video signal in which distance information to a subject and gradation information are associated with each pixel or for each predetermined region; A past gradation information extraction unit that detects a region of a past video signal corresponding to the specific region based on the distance information, and extracts past gradation information indicating the gradation information of the region from the storage unit; A video signal processing apparatus comprising: a gray level correction unit that corrects a gray level width of the specific area of the current video signal using the past gray level information.

According to this aspect, the region detection unit detects, for example, a specific region that is overexposed from the current video signal after the gradation conversion, and the past gradation information extraction unit detects the distance information to the subject and the floor. The gradation information of the past video signal area corresponding to the specific area is extracted from the storage unit storing the past video signal associated with the key information, and the current video signal is extracted using the gradation information of the area. The gradation width of the specific area is corrected by the gradation correction unit.
As a result, the specific area of the current video signal that is overexposed is corrected for the gradation width using the gradation information of the area of the past video signal having the same distance information. Even when a scene having a large influence on the brightness of an object is imaged, a high-quality video signal can be obtained while maintaining a sense of perspective.

  According to a second aspect of the present invention, a gradation conversion unit that performs gradation conversion on a video signal, and a current video signal after gradation conversion are equal to or higher than a predetermined first threshold value or a predetermined second threshold value. An area detection unit for detecting a specific area having the following luminance, and peripheral gradation information for detecting a peripheral area of the specific area from the current video signal and extracting peripheral gradation information indicating gradation information of the peripheral area A video signal processing apparatus comprising: an extraction unit; and a gray level correction unit that corrects a gray level width of the specific area of the current video signal using the peripheral gray level information.

According to this aspect, for example, a specific region that is overexposed is extracted from the current video signal after gradation conversion by the region detection unit, and the peripheral region of the specific region of the current video signal is extracted by the peripheral gradation information extraction unit. Gradation information is extracted, and the gradation width of the specific area of the current video signal is corrected by the gradation correction unit using the gradation information of the peripheral area.
As a result, the specific area of the current video signal that is overexposed is corrected for the gradation width using the gradation information of the peripheral area, so the influence on the brightness of the object is great depending on the distance relationship with the illumination. Even when a scene is imaged, a high-quality video signal can be obtained while maintaining a sense of perspective.

  According to a third aspect of the present invention, a gradation conversion process for performing gradation conversion on a video signal, and a current video signal after gradation conversion, a predetermined first threshold value or a predetermined second threshold value. Based on the distance information from a past video signal in which the distance information to the subject and the gradation information are associated with each other or for each predetermined area and area detection processing for detecting a specific area having the following luminance A past gradation information extracting process for detecting a past video signal area corresponding to the specific area and extracting past gray scale information indicating the gray scale information of the area; and A video signal processing program that causes a computer to execute gradation correction processing for correcting the gradation width of the specific area of a video signal.

  According to a fourth aspect of the present invention, a gradation conversion process for performing gradation conversion on a video signal, and a current video signal after gradation conversion, a predetermined first threshold value or a predetermined second threshold value. Area detection processing for detecting a specific area having the following luminance, and peripheral gradation information for detecting a peripheral area of the specific area from the current video signal and extracting peripheral gradation information indicating gradation information of the peripheral area A video signal processing program causing a computer to execute an extraction process and a gradation correction process for correcting a gradation width of the specific area of the current video signal using the peripheral gradation information.

  According to a fifth aspect of the present invention, there is provided a gradation conversion step for performing gradation conversion on a video signal, and a current video signal after gradation conversion based on a predetermined first threshold value or a predetermined second threshold value. Based on the distance information from an area detection step for detecting a specific area having the following luminance and a past video signal in which distance information to the subject and gradation information are associated with each pixel or for each predetermined area. A past gradation information extraction step of detecting a past video signal region corresponding to the specific region and extracting past gradation information indicating the gradation information of the region; and using the past gradation information, the current gradation information is extracted. And a tone correction step of correcting the tone width of the specific area of the video signal.

  According to a sixth aspect of the present invention, there is provided a gradation conversion step for performing gradation conversion on a video signal, and a current video signal after gradation conversion that is equal to or greater than a predetermined first threshold value or a predetermined second threshold value. A region detecting step for detecting a specific region having the following luminance; and peripheral gradation information for detecting a peripheral region of the specific region from the current video signal and extracting peripheral gradation information indicating gradation information of the peripheral region A video signal processing method comprising: an extraction step; and a tone correction step of correcting a tone width of the specific region of the current video signal using the peripheral tone information.

  According to the present invention, a high-quality video signal can be provided.

[First Embodiment]
A video signal processing apparatus according to a first embodiment of the present invention will be described below with reference to the drawings. Note that the video signal processing apparatus according to the present embodiment is mounted on an electronic device such as a digital camera or a digital video camera. This equipment is equipment that relies on current or electromagnetic fields to operate correctly.
FIG. 1 is a configuration diagram of a video signal processing apparatus according to the present embodiment.
The video signal processing apparatus according to the present embodiment includes a lens system 100, a diaphragm 101, a CCD 102, a Gain 103, an A / D 104, a buffer unit 105, a gradation conversion unit (gradation conversion unit) 106, a specific region detection unit (region detection unit). ) 107, gradation correction unit (gradation correction unit) 108, output unit 109, past data storage unit (storage unit) 110, infrared sensor 111, distance information acquisition unit 112, control unit 113, external I / F unit 114, And a ROM 115.

  The lens system 100 is connected in order of an aperture 101, a CCD 102, a Gain 103, an A / D 104, and a buffer unit 105. The buffer unit 105 is connected to the gradation conversion unit 106 and the gradation correction unit 108. The gradation conversion unit 106 is connected to the output unit 109 via the specific area detection unit 107 and the gradation correction unit 108. The specific area detection unit 107 is connected to the output unit 109. The infrared sensor 111 is connected to the gradation correction unit 108 via the distance information acquisition unit 112 and the past data storage unit 110. The output unit 109 is connected to the past data storage unit 110. The ROM 115 is connected to the gradation conversion unit 106, the specific area detection unit 107, the gradation correction unit 108, and the distance information acquisition unit 112. The control unit 113 includes a gain 103, an A / D 104, a buffer unit 105, a gradation conversion unit 106, a specific area detection unit 107, a gradation correction unit 108, an output unit 109, a past data storage unit 110, an infrared sensor 111, and distance information acquisition. Unit 112, ROM 115 and external I / F unit 114 are connected bidirectionally.

The flow of the video signal in the video signal processing apparatus having the above configuration will be described.
When a moving image capturing button (not shown) is pressed through the external I / F unit 114, video signals captured in time series through the lens system 100, the aperture 101, the CCD 102, and the Gain 103 are converted into a known correlated double. By sampling, an analog signal is continuously output at predetermined time intervals. Here, it is assumed that the time interval is 1/30 second. The CCD 102 is assumed to be a three-plate CCD with RGB primary color filters arranged on the front surface. Hereinafter, a plurality of video signals that are continuously output are simply referred to as a video signal, and one video signal is referred to as one frame.

  The analog signal is amplified by a predetermined amount by Gain 103, converted to a digital signal by A / D 104, and transferred to buffer unit 105. The buffer unit 105 can record a video signal of one frame and is overwritten sequentially as the image is taken. In this embodiment, it is assumed that the video signal is a three-plate CCD configured by arranging R, G, and B primary color filters in front of each other. However, a single-plate or two-plate CCD is also supported. Is possible.

  Based on the control of the control unit 113, the gradation conversion unit 106 extracts γ characteristic data suitable for the display device corresponding to the output unit 109 from the ROM 115 for the video signal transferred from the buffer unit 105, and performs gradation conversion processing. I do. Here, as shown in FIG. 2, description will be made assuming that normal gradation conversion processing is performed. Then, the processed video signal is transferred to the specific area detection unit 107 under the control of the control unit 113.

  Based on the control of the control unit 113, the specific area detection unit 107 has a luminance that is higher than a predetermined first threshold or lower than a predetermined second threshold, such as overexposure or blackout in a transferred video signal. Detect whether there is an area. Here, in the present embodiment, description will be made assuming that only overexposure is detected. The specific area detection unit 107 transfers the video signal to the output unit 109 when the specific area is not detected. On the other hand, when the specific area is detected, information on the specific area and the video signal are transferred to the gradation correction unit 108 based on the control of the control unit 113. The specific area may be detected by using an area occupied by a pixel whose luminance is equal to or higher than a predetermined first threshold value or lower than a predetermined second threshold value, or the count number of the pixel. It is good also as detecting combining both count numbers. A specific method for detecting the specific area will be described later.

  The distance information acquisition unit 112 measures distance information indicating the distance to the subject when the current video signal is acquired from the infrared sensor 111 for each frame, and transfers the measured distance information to the past data storage unit 110. The past data storage unit 110 stores a past video signal after gradation correction in which distance information and gradation information are associated with each other. When the specific area exists, the past data storage unit 110 transfers the past video signal, the current video signal, and the distance information of the past video signal to the gradation correction unit 108 based on the control of the control unit 113. A specific method for acquiring the distance information will be described later.

Based on the control of the control unit 113, the gradation correction unit 108 stores the specific area in the current video signal transferred from the specific area detection unit 107 and the past data stored in the past data storage unit 110 corresponding to the specific area. Compare with the area in the video signal. Then, an area in the past video signal having the same distance and the same color as the specific area in the current video signal is detected, and the gradation width of the specific area in the current video signal is corrected using the gradation information of the area. To do. That is, the gradation correction unit 108 detects a past video signal region corresponding to the specific region based on the distance information, and extracts past gradation information indicating the gradation information of the region from the past data storage unit 110. The gradation width of the specific area of the current video signal is corrected using the past gradation information. A specific method for extracting past gradation information and a specific method for correcting the gradation width of a specific area will be described later.
Here, the video signal of the part other than the specific area is not corrected. Then, the corrected video signal of the specific area and the video signal other than the specific area are combined and transferred to the output unit 109. Here, the same distance described above does not have to be exactly the same distance. For example, if the difference between the distance in the current video signal and the distance in the past video signal is within a predetermined range, the same distance means Point to. This predetermined range may be set in advance and stored in the ROM 115, or may be set by the user.

Hereinafter, a specific method for detecting a specific area will be described.
FIG. 3 shows an example of the configuration of the specific area detection 107.
As shown in FIG. 3, the gradation conversion unit 106 is connected to the gradation correction unit 108 and the output unit 109 via the luminance signal conversion unit 301 and the specific luminance range detection unit 302. The ROM 115 is connected to the specific luminance area detection unit 302. The control unit 113 is bi-directionally connected to the luminance signal conversion unit 301 and the specific luminance range detection unit 302.

In the present embodiment, the luminance signal conversion unit 301 calculates a pixel value for each pixel from the RGB video signal according to the following equation (1).
K _ij = A1 × R _ij + A2 × G _ij + A3 × B _ij (1)
In the above equation (1), K _ij is a pixel value, A1, A2 and A3 are constants, R _ij is an R signal, G _ij is a G signal, B _ij is a B signal, and i and j are coordinate values of a video signal. Show.

FIG. 4 shows an example of the configuration of the specific luminance range detection unit 302.
As shown in FIG. 4, the luminance signal conversion unit 301 is connected to the gradation correction unit 108 and the output unit 109 via the γ characteristic data extraction unit 3021, the high luminance range threshold detection unit 3022, and the high luminance range determination unit 3023. is doing. The ROM 115 is connected to the γ characteristic data extraction unit 3021, the high luminance range threshold detection unit 3022, and the high luminance range determination unit 3023. The control unit 113 is bi-directionally connected to the γ characteristic data extraction unit 3021, the high luminance range threshold detection unit 3022, and the high luminance range determination unit 3023.

  Here, the video signal processing apparatus according to the present embodiment improves the phenomenon that an area that is not overexposure before gradation processing becomes overexposed after gradation conversion using gamma characteristic data. It is aimed. As shown in FIG. 2A, the cause of the overexposure is that the curve change of the curve representing the γ characteristic data corresponding to the gradation characteristic of the high luminance part becomes almost horizontal, The change in shading of the corresponding video signal disappears after the tone conversion and becomes overexposed. Therefore, in order to improve the gradation characteristics of the video signal in the high luminance part, first, it is necessary to detect a threshold value for identifying the high luminance region.

  The specific luminance area detection unit 302 determines whether a high luminance video signal exists for the video signal transferred from the buffer unit 105 based on a predetermined threshold. If the calculated pixel value is larger than the threshold value, it is determined that the corresponding pixel is a high luminance video signal. Further, when the number of pixels determined to be a high luminance video signal is greater than a predetermined value in all images, it is determined that the high luminance signal exists in the image. If a high luminance signal exists, the determination result and the video signal are transferred to the gradation correction unit 108. On the other hand, when there is no high luminance signal, the video signal is transferred to the output unit 109.

  The threshold may be set freely by the user through the external I / F unit 114, or the user may designate one of a plurality of thresholds prepared in the ROM 115 through the external I / F unit 114. Good. When the threshold value is automatically designated, γ characteristic data is extracted from the ROM 115, and the threshold value is calculated based on the γ characteristic data. Here, a description will be given assuming that a plurality of types of γ characteristic data are stored in the ROM 115 and the threshold value is automatically designated based on the γ characteristic data.

When the threshold value is automatically designated, for example, when gradation conversion processing is performed from an 8-bit video signal to an 8-bit video signal, the γ characteristic data has 255 points, the input level is 255 points, and the output level is 255 points. is there. In the ascending order, as shown in the following formula (2), when the slope ΔH corresponding to the γ characteristic data of 255 points is first smaller than the angle that is recognized as overexposure, the input value corresponding to that point is A threshold value (STh in FIG. 2) is set. Here, the angle that is recognized as overexposed is stored in the ROM 115.
ΔH = tan ⁻¹ ((H255o−Hxo) / (255−Hxi) (2)
Here, H255o indicates an output level corresponding to the maximum input level 255, Hxo indicates an output level corresponding to the xth input level, and Hxi indicates an xth input level.

It should be noted that information on the slope ΔH composed of the above input levels and output levels corresponding to the γ characteristic data may be stored in the ROM 115 in advance. When the threshold value is automatically designated, if an inclination smaller than the angle that is recognized as an overexposure is read for the first time by reading each inclination ΔH information from the ROM 115 in ascending order, the input value corresponding to the inclination ΔH is set as the threshold value.
In addition, a threshold value corresponding to γ characteristic data corresponding to a different display device may be stored in advance in the ROM 115 and a threshold value corresponding to γ characteristic data corresponding to a predetermined display device may be extracted when the video signal is processed. is there.

Here, a modified example of the process when detecting the specific area will be described below.
When overexposure and underexposure exist simultaneously, for example, as shown in FIG. 2B, the curve change of the γ characteristic data corresponding to the gradation characteristic of the high luminance part and the gradation characteristic of the low luminance part Becomes substantially horizontal, and the change in shading of the video signal corresponding to that portion disappears after the gradation conversion, the video signal in the high-luminance portion is overexposed, and the video signal in the low-luminance portion is obscured. Therefore, in order to improve the gradation characteristics of the video signals of the high luminance part and the low luminance part, first, it is necessary to detect the threshold values of the high luminance area and the low luminance area for identifying the high luminance area and the low luminance area. is there. Although the calculation of the threshold value for the high luminance region is the same as that in the above-described embodiment, the threshold value for the low luminance region is calculated by the following equation (3).
ΔL = tan ⁻¹ (Lxo / Lxi) (3)
Here, Lxo represents the output level corresponding to the xth input level, and Lxi represents the xth input level.

  In FIG. 4, the γ characteristic data extraction unit 3021 extracts the γ characteristic data from the ROM 115 and transfers it to the high luminance area threshold value detection unit 3022. The high brightness area threshold value detection unit 3022 extracts angle data that is recognized as being overexposed from the ROM 115, detects the threshold value (ST) as shown in the equation (2), and detects the detected threshold value and the video signal in the high brightness area. The data is transferred to the determination unit 3023. The high luminance area determination unit 3023 counts the high luminance video signal with respect to all the video signals based on the transferred threshold value. The high luminance determination unit 3023 determines that the high luminance signal exists when the count number of the high luminance video signals of all the images is larger than the predetermined threshold value read from the ROM 115, and when the number is small, the image Determines that there is no high luminance signal. Based on the control of the control unit 113, the high brightness determination unit 3023 transfers the video signal to the output unit 109 when there is no high brightness signal. The high luminance determination unit 3023 transfers the high luminance signal information and the video signal to the gradation correction unit 108 when there is a high luminance signal.

Below, the specific method at the time of acquiring distance information is demonstrated.
FIG. 5 shows an example of the configuration of the distance information acquisition unit 112, and the distance information acquisition unit 112 includes an area division unit 201 and a distance measurement unit 202. The gradation conversion unit 106 is connected to the past data storage unit 110 via the region division unit 201 and the distance measurement unit 202. The infrared sensor 111 is connected to the distance measuring unit 202. The ROM 115 is connected to the area dividing unit 201. The control unit 113 is bi-directionally connected to the area dividing unit 201 and the distance measuring unit 202.

  In FIG. 5, an area dividing unit 201 performs an area dividing process on the video signal transferred from the gradation converting unit 106 with a predetermined size, for example, a 3 × 3 pixel block for each frame, and the divided video signal (Hereinafter referred to as “divided video signal”) is transferred to the distance measuring unit 202. The distance measuring unit 202 measures distance information using the distance measuring sensor 111 for each divided video signal transferred from the region dividing unit 201. Then, the distance measurement unit 202 transfers the distance information of each divided video signal, that is, the distance information for each region, to the past data storage unit 110 based on the control of the control unit 113.

  Here, in the area division processing, it is possible to measure distance information for each pixel, but as shown in FIG. 6A, M × N (M, N> = 2). It is also possible to divide the video by area and measure the distance information of each area. In this case, distance information of each region is measured for each pixel, and the distance information for each region is calculated by averaging the measured distance information for each pixel. Here, since a video signal of a medical endoscope that requires precision is assumed, distance information is measured for each pixel. In addition, as shown in FIG. 6B, it is possible to divide the area into the area focused by AF and the other areas. In this case, distance information set so that the contrast is maximized by determining the in-focus position is calculated. Then, the distance information is transferred to the past data storage unit 110 under the control of the control unit 113. In the present embodiment, the past data storage unit 110 can record the distance information of the current video signal and the distance information of the past video signal and are sequentially overwritten as the image is taken.

Hereinafter, a specific method for extracting past gradation information and a specific method for correcting the gradation width of a specific area will be described.
FIG. 7 shows an example of the configuration of the gradation correction unit 108, and the gradation correction unit 108 includes a corresponding region extraction unit (past gradation information extraction unit) 401 and a target region correction unit 402. The buffer unit 105, the specific area detection unit 107, and the past data storage unit 110 are connected to the corresponding area detection unit 401. The corresponding area detection unit 401 is connected to the output unit 109 via the target area correction unit 402. The ROM 115 is connected to the target area correction unit 402. The control unit 113 is bi-directionally connected to the corresponding region extraction unit 401 and the target region correction unit 402.

  Based on the control of the control unit 113, the corresponding region extraction 401 is the same distance from the past video signal transferred from the past data storage unit 110 with respect to the video signal of the specific region transferred from the specific region detection unit 107. A video signal having is extracted. The corresponding area extraction 401 also extracts a video signal in the same area as the specific area from the video signal before gradation conversion that has been transferred from the buffer unit 105. The extracted two types of video signals and the video signals after the gradation conversion process are transferred to the target area correction unit 402. The target area correction unit 402 performs gradation correction processing on a specific area of the current video signal using past video signal information having the same distance, and transfers the video signal after the gradation correction processing to the output unit 109. .

  FIG. 8 shows an example of the configuration of the corresponding area extraction unit 401. The corresponding area extraction unit 401 includes an equidistant detection unit 4011 and a similar color extraction unit (brightness signal extraction unit, color signal extraction unit) 4012. ing. The specific area detection unit 107 and the past data storage unit 110 are connected to the target area correction unit 402 via the equidistance detection unit 4011 and the similar color extraction unit 4012. The buffer unit 105 is connected to the similar color extraction unit 4012. The control unit 113 is bi-directionally connected to the equidistance detection unit 4011 and the similar color extraction unit 4012.

  The equidistant detection unit 4011 extracts a past video signal having the same distance as the specific region and not overexposed based on the video signal transferred from the specific region detection unit 107 and information on the specific region. Then, based on the control of the control unit 113, the information on the specific area, the information on the extracted video signal, and the video signal are transferred to the similar color extraction unit 4012.

Under the control of the control unit 113, the similar color extraction unit 4012 starts from the buffer 105 for each pixel as shown in the following formula (4) based on the information regarding the specific area transferred from the equidistance detection unit 4011. A color difference signal of a specific area in which the transferred current video signal before gradation conversion is overexposed after gradation conversion processing is calculated. Next, a color difference signal is calculated for each pixel of the past video signal that has the same distance as the specific region and is not overexposed. At the same time, the luminance signal of the specific area before gradation conversion and the corresponding luminance signal of the past video signal having the same distance are also calculated using equation (1).
Cr _ij = b1 × R _ij + b2 × G _ij + b3 × B _ij
Cb _ij = b4 × R _ij + b5 × G _ij + b6 × B _ij (4)
Here, Cb _ij and Cr _ij are pixel color difference values, b1 to b6 are constants, R _ij is an R signal, G _ij is a G signal, B _ij is a B signal, and i and j are coordinate values of the video signal. .

In the present embodiment, as shown in FIG. 9, the similar color extraction unit 4012 divides the color space equally into six color division regions, and in the specific region that is overexposed after the gradation conversion process. On the other hand, it is determined for each pixel which color division region the color difference signal calculated in the equation (4) is included in. Similarly, a determination is also made for a past video signal that has the same distance as the specific area and is not overexposed. Specifically, it is determined to which color division region the following formulas (5) and (6) are used.
Angle _ij = arctg (Cb _ij / Cr _ij ) (5)
Here, arctg is a function that returns an arc tangent.
T1 <Angle _ij <T2 (6)
Here, T1 and T2 are angle threshold values of a certain color division area.

Then, based on the control of the control unit 113, the similar color extraction unit 4012 transfers information regarding the affiliation of the color division region, the luminance and color difference signals of the specific region, and the video signal to the target region correction unit 402.
As described above, the similar color extraction unit 4012 has the same color difference signal as the specific region in the current video signal before gradation conversion from the past video signal after gradation correction stored in the past data storage unit 110. The luminance signal of the area is extracted for each color signal. In the present embodiment, the area is divided in the Cr and Cb color spaces. However, the area may be divided in another color space such as a Lab color space.

  FIG. 10 shows an example of the configuration of the target region correction unit 402. The target region correction unit 402 includes a target histogram detection unit 4021, a past histogram detection unit 4022, a histogram correction unit (histogram correction unit) 4023, and an image composition unit. (Video signal synthesis unit) 4024. The corresponding area extraction unit 401 is connected to the target histogram detection unit 4021, the past histogram detection unit 4022, and the image composition unit 4024. The target histogram detection unit 4021 and the past histogram detection unit 4022 are connected to the output unit 109 via the histogram correction unit 4023 and the image composition unit 4024. The ROM 115 is connected to the image composition unit 4024. The control unit 113 is bi-directionally connected to the target histogram detection unit 4021, the past histogram detection unit 4022, the histogram correction unit 4023, and the image composition unit 4024.

  The target histogram detection unit 4021 verifies whether or not a color difference signal of a specific region exists in each color division region, using the information regarding the affiliation of the color division region transferred from the target region detection unit 401. If a color difference signal exists, a histogram of the luminance signal before gradation conversion processing in a specific area is formed. Then, the information on the formed luminance histogram and the corresponding color difference signal are transferred to the histogram correction unit 4023.

  Based on the control of the control unit 113, the past histogram detection unit 4022 forms a luminance histogram of past video signals corresponding to specific regions in which color difference signals are in the same color division region and having the same distance. Then, the information on the formed luminance histogram and the corresponding color difference signal are transferred to the histogram correction unit 4023.

Based on the control of the control unit 113, the histogram correction unit 4023 has been transferred from the past histogram detection unit 4022 for the luminance signal before gradation conversion processing corresponding to the specific area transferred from the target histogram detection unit 4021. Using the luminance histogram information of the past video signal corresponding to the specific area, for example, a known histogram accumulation process such as an equalization process is performed to uniformize the histogram distribution. When the number of pixels of the past video signal having the same distance as the number of pixels in the specific region does not match in each color division region, the correction magnification is calculated using the following equation (7).
N _k = S _k / O _k (7)
Here, N _k is the correction magnification, S _k is the number of pixels in the specific area, O _k is the number of pixels in the past video signal, and K is the number of the color division area.

Next, when the accumulation process is performed, the luminance value of the luminance histogram of the past video signal and the accumulated number are multiplied for each pixel using the correction magnification described above. A known accumulation process is performed based on the luminance histogram of the past video signal after the multiplication process. After the luminance histogram accumulation processing in all the color division regions is completed, the following equation (8) is used for each pixel with respect to the color difference signal before the gradation conversion processing and the luminance signal after the accumulation processing in the specific region. Convert to RGB video signal. Based on the control of the control unit 113, the converted RGB video signal is transferred to the image composition unit 4024.
R _ij = Q1 × K _ij + Q2 × Cr _ij + Q3 × Cb _ij
G _ij = Q4 × K _ij + Q5 × Cr _ij + Q6 × Cb _ij (8)
B _ij = Q7 × K _ij + Q8 × Cr _ij + Q9 × Cb _ij
Here, Q1 to Q9 indicate constants.

  Based on the control of the control unit 113, the image composition unit 4024 uses the video signal of the corrected specific area transferred from the histogram correction unit 4023, and the specific area after gradation conversion processing from the corresponding area extraction 401 is performed. Performs composition processing with the video signal. It is possible to simply replace the specific area after gradation correction with the specific area before gradation correction, but in order to maintain the continuity of the video signal, the specific area that is overexposed to the video signal after gradation correction is used. These video signals may be combined at a predetermined ratio. Then, the image synthesis unit 4024 transfers the video signal after the synthesis process to the output unit 109.

  As described above, according to the video signal processing apparatus according to the present embodiment, the color difference signal before gradation conversion of the specific area is calculated for each pixel, and it is determined to which color division area it belongs. Further, based on the luminance histogram of the past video signal having the same distance and belonging to the same color division region, the cumulative processing of the luminance histogram of the specific region of the current video signal is performed. Thus, by correcting the gradation for each color division area, it is possible to improve overexposure in a specific area and to prevent misuse of information on different color division areas. Further, by using the distance information, for example, in a field such as an endoscope that greatly affects the brightness of an object due to a distance relationship with illumination, a high-quality video signal can be obtained while maintaining perspective.

In the present embodiment, the color space is equally divided into six color division regions, but it is not necessary to be limited to such a configuration. In order to obtain a video signal with higher image quality, the color space can be equally divided into twelve. Further, it is possible to divide an important color area frequently and to divide other color areas greatly as necessary. For example, in the field of endoscopy, yellow and red are important color regions. Therefore, in the yellow and red regions, the color division region equally divided into six is further divided into two divisions, four divisions, etc. The color area may be equally divided into six.
Further, a plurality of past video signals after gradation correction may be stored in the past data storage unit 110, and the past gradation information may be extracted from the plurality of past video signals. The past video signal stored in the past data storage unit 110 may be a video signal before gradation correction.

  Further, the video signal processing in the present embodiment described above is realized by hardware, but need not be limited to such a configuration. For example, a signal from the CCD 102 is recorded as raw (RAW) data on a recording medium such as a memory card, and information (ISO sensitivity, white balance coefficient, etc.) and distance information at the time of shooting from the control unit 113 are recorded. It is also possible to record distance information from the acquisition unit 112 as header information on a recording medium, and cause a computer to execute a video signal processing program, which is separate software, so that the information on the recording medium is read by the computer and processed. It is. The transfer of various types of information to the computer is not limited to being performed via a recording medium, and may be performed via a communication line or the like.

FIG. 11 is a flowchart showing processing by the video signal processing program in the present embodiment.
When this process is started, first, at Step 1, the video signal, distance information, the header information, and the like are read, and information such as gradation characteristic data provided in advance is also read, and the process proceeds to Step 2. This process corresponds to a process of acquiring a video signal obtained by photographing a subject in a video signal processing apparatus that is an imaging apparatus.
Next, at Step 2, gradation conversion processing is performed on the video signal based on the provided gradation characteristic data, and the process proceeds to Step 3.
Subsequently, at Step 3, a high-luminance video signal is detected in the video signal, and the process proceeds to Step 4.

  Next, in Step 4, it is determined whether or not a high-luminance video signal exists in the video signal based on the detection result in Step 3. If it is determined that a high-luminance video signal exists, distance information corresponding to the high-luminance video signal is extracted at Step 5 and the process proceeds to Step 6. Then, in Step 6, based on the distance information, a video signal in a region corresponding to the high luminance video signal in the current video signal is extracted from the past video signal, gradation correction processing is performed, and the process proceeds to Step 7 and Step 8. On the other hand, if it is determined that there is no high-luminance video signal, it is determined that there is no need to perform gradation correction processing, and the process proceeds to Step 7 and Step 8.

  Next, at Step 7, the video signal is output and displayed on the display device or stored in a memory card or the like, and then this process ends. Simultaneously with the processing of Step 7, at Step 8, the video signal after the tone correction processing is stored in the memory as the past video signal for the tone correction processing of the next frame.

Next, detailed processing at the time of detecting a specific area in Step 3 of FIG. 11 (high luminance video signal detection processing) will be described using the flowchart shown in FIG. The process shown in FIG. 12 corresponds to the process performed in the specific luminance range detection unit 302.
When this process is started, first, in Step 101, γ characteristic data corresponding to a predetermined display device is extracted, and the process proceeds to Step 102.

In Step 102, if the slope ΔH corresponding to the γ characteristic data is smaller than the predetermined angle that is recognized as overexposure for the first time, as shown in FIG. The input value to be set is set as a threshold value (STh in FIG. 2), and the process proceeds to Step 103.
Subsequently, in Step 103, the luminance values of all the pixels included in the image are compared with a high luminance threshold value, and the number of pixels having a luminance value larger than the high luminance threshold value (pixels determined to be a high luminance video signal) is counted. And it progresses to Step104.

  Then, in Step 104, the count number of the high luminance video signal is compared with a predetermined threshold value, and if it is larger than the predetermined threshold value, it is determined that the high luminance signal exists in the image. On the other hand, when the count number of the high luminance video signal is smaller than the predetermined threshold value, it is determined that the high luminance signal does not exist in the image, and the gradation correction process is not performed as described above. When the process of Step 104 is completed, the process returns to the process shown in FIG.

Next, detailed processing of the gradation correction processing in Step 6 of FIG. 11 will be described using the flowchart shown in FIG. The process shown in FIG. 13 corresponds to the process performed in the gradation correction unit 108.
When this process is started, first, in Step 201, based on the distance information, an area in the past video signal corresponding to the high-luminance video signal area is extracted, and the process proceeds to Step 202.
Next, in Step 202, the gradation of the high luminance video signal is corrected based on the past video signal. When the process of Step 202 is completed, the process returns to the process shown in FIG.

Next, detailed processing of the corresponding region extraction processing in Step 201 of FIG. 13 will be described using the flowchart shown in FIG. The process shown in FIG. 14 corresponds to the process performed in the corresponding area extraction unit 401.
When this process is started, first, in step 211, based on the distance information, a past video signal corresponding to the high-intensity video signal and having the same distance but not overexposed is extracted, and the process proceeds to step 212.

  Next, in Step 212, first, based on the equation (4), the color difference signal of the video signal before gradation conversion of the high luminance video signal is calculated. Next, a color difference signal is calculated for each pixel of the past video signal that has the same distance as the specific region and is not overexposed. At the same time, the luminance signal of the specific area before gradation conversion and the corresponding luminance signal of the past video signal having the same distance are also calculated using equation (1). Then, as shown in FIG. 9, the color space is equally divided into six color division regions, and the current video signal before gradation conversion is overexposed to a specific region after gradation change processing. On the other hand, it is verified in which color division region the color difference signal calculated in the equation (4) is included for each pixel. Similarly, color difference verification processing is performed on past video signals that have the same distance as the specific area and are not overexposed. Then, by using the equations (5) and (6), it is determined which color division region belongs. When the process of Step 212 is completed, the process returns to the process shown in FIG.

Next, detailed processing of the target region correction processing in Step 202 of FIG. 13 will be described using the flowchart shown in FIG. The process shown in FIG. 15 corresponds to the process performed in the target area correction unit 402.
When this process is started, first, in Step 221, it is verified whether or not there is a color difference signal in the high luminance area in each color division area. If a color difference signal exists, a histogram of the luminance signal before gradation conversion processing in the high luminance region is formed, and the process proceeds to Step 223. At the same time, in Step 222, a luminance histogram of the past video signal corresponding to the high luminance region in which the color difference signal of the video signal is in the same color division region and having the same distance is formed, and the process proceeds to Step 223.

  Next, in Step 223, the luminance signal before gradation conversion processing corresponding to the high luminance area in each color division area is used for the luminance signal information of the past video signal in the same color division area by using publicly known luminance histogram information. A histogram accumulation process is performed to correct the luminance signal histogram. Next, based on the equation (8), the luminance signal and the color difference signal after correction are converted into RGB signals, and the process proceeds to Step 224.

  Finally, in Step 224, in the high luminance region, the video signal after gradation correction and the video signal after gradation conversion processing are combined. In a region other than the high luminance region, a video signal after gradation conversion processing is used. When the process of Step 224 is completed, the process returns to the process shown in FIG.

[Second Embodiment]
Next, a second embodiment of the present invention will be described below.
The basic configuration is the same as that of the first embodiment, and description of points that are the same as those of the first embodiment will be omitted, and different portions will be mainly described. Also, the same functions as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.
In the moving image capturing processing apparatus according to the present embodiment, first, a signal flow in the gradation correction unit 108 shown in FIG. 16 will be described.

  FIG. 16 shows an example of the configuration of the gradation correction unit 108, and the gradation correction unit 108 includes a corresponding region extraction unit (peripheral gradation information extraction unit) 411 and a target region correction unit 412. The buffer unit 105, the specific region detection unit 107, and the past data storage unit 110 are connected to the corresponding region extraction unit 411. The corresponding area extraction unit 411 is connected to the output unit 109 via the target area correction unit 412. The ROM 115 is connected to the target area correction unit 412. The control unit 113 is bidirectionally connected to the corresponding region extraction unit 411 and the target region correction unit 412.

In FIG. 16, the corresponding area extraction unit 411 is based on the control of the control unit 113, and with respect to the video signal of the specific area transferred from the specific area detection unit 107, the corresponding area extraction unit 411 A video signal having the same distance is extracted from the video signal. Further, the video signal in the peripheral area of the specific area is also extracted from the current video signal before gradation conversion processing transferred from the buffer unit 105. Then, the two types of extracted video signals and the video signal after the gradation correction process are transferred to the target area correction unit 412.
The target area correction unit 412 performs gradation correction processing on the specific area using past video signal information having the same distance. The video signal after the gradation correction processing is transferred to the output unit 109.

  FIG. 17 shows an example of the configuration of the corresponding region extraction unit 411. The corresponding region extraction unit 411 includes an equidistant detection unit 4011, a similar color extraction unit 4012, a neighborhood detection unit (periphery detection unit) 4013, and a neighborhood similar color extraction. Part (peripheral luminance signal extraction unit, peripheral color signal extraction unit) 4014. The specific area detection unit 107 is connected to the equidistant detection unit 4011 and the proximity detection unit 4013. The equidistant detection unit 4011 is connected to the target region correction unit 412 via the similar color extraction unit 4012. The neighborhood detection unit 4013 is connected to the target region correction unit 412 via the neighborhood similar color extraction unit 4014. The buffer unit 105 is connected to the similar color extracting unit 4012 and the neighboring similar color extracting unit 4014. The past data storage unit 110 is connected to the equidistance detection unit 4011 and the similar color extraction unit 4012. The control unit 113 is bidirectionally connected to the equidistant detection unit 4011, the similar color extraction unit 4012, the neighborhood detection unit 4013, and the neighborhood similar color extraction unit 4014.

In FIG. 17, the processing in the equidistance detection unit 4011 and the similar color extraction unit 4012 is the same as that in FIG.
Based on the control of the control unit 113, the neighborhood detection unit 4013 detects a peripheral region of the specific region as a neighborhood region using the video signal of the specific region and the video signal after gradation conversion from the specific region detection 107. Specifically, as shown in FIG. 18, the area is uniformly expanded with a predetermined width in the vertical and horizontal directions with respect to the specific area, and a portion between the specific area and the extended area is set as a neighboring area. The peripheral gradation information indicating the gradation information of the area corresponding to the neighboring area is detected and transferred to the neighboring similar color extracting unit 4014 together with the video signal of the specific area and the video signal after the gradation conversion process.

The neighborhood similar color extraction unit 4014 performs gradation conversion transferred from the buffer 105 for each pixel based on the information on the specific area transferred from the neighborhood detection unit 4013 and the expression (4) under the control of the control unit 113. A color difference signal of a specific area in which the previous current video signal is overexposed after gradation conversion processing is calculated. Similarly, a color difference signal for each pixel is calculated from the video signal in the neighboring area. At the same time, the luminance signal of the specific area before gradation conversion and the luminance signal of the video signal of the neighboring area are also calculated using the equation (1). In other words, the neighborhood similar color extraction unit 4014 extracts the color difference signal from the neighborhood area detected by the neighborhood detection unit 4013, and obtains the luminance signal of the neighborhood area having the same color difference signal as the specific area from the current video signal for each color signal. Extract.
In the present embodiment, as shown in FIG. 9, the color space is equally divided into six color division regions, and the current video signal before gradation conversion is overexposed after gradation conversion processing. With respect to the specific area, it is verified which color division area the color difference signal calculated in the equation (4) is included for each pixel. The same verification is performed on the video signal in the neighboring area. It is determined to which color division area the formula (5) and (6) belong.

Then, based on the control of the control unit 113, the neighborhood similar color extraction unit 4014, information on the affiliation of the color division region, the luminance and color difference signal of the specific region, the luminance and color difference signal of the neighboring region, the video signal after the gradation conversion process Is transferred to the target area correction unit 412.
In the present embodiment, the area is divided in the Cr and Cb color spaces. However, the area may be divided in another color space such as a Lab color space.

  FIG. 19 shows an example of the configuration of the target region correction unit 412. The target region correction unit 412 includes a target histogram detection unit 4021, a past histogram detection unit 4022, a histogram 4023, an image composition unit (composition unit) 4124, and a neighborhood. A histogram detection unit 4025 and a neighborhood histogram correction unit 4028 are included.

  The similar color extraction unit 4012 is connected to the target histogram detection unit 4021, the past histogram detection unit 4022, and the image composition unit 4124. The target histogram detection unit 4012 is connected to the neighborhood histogram correction unit 4026. The target histogram detection unit 4021 and the past histogram detection unit 4022 are connected to the output unit 109 via the histogram 4023 and the image composition unit 4124. The ROM 115 is connected to the image composition unit 4124. The neighborhood similar color extraction unit 4014 is connected to the image composition unit 4124 via the neighborhood histogram detection unit 4025 and the neighborhood histogram correction unit 4026. The control unit 113 is bi-directionally connected to the target histogram detection unit 4021, the past histogram detection unit 4022, the histogram 4023 image composition unit 4124, the neighborhood histogram detection unit 4025, and the neighborhood histogram correction unit 4028.

Here, the processing in the target region histogram detection unit 4021, the past histogram detection unit 4022, and the histogram 4023 is the same as the processing in the first embodiment, and thus description thereof is omitted.
Based on the control of the control unit 113, the neighborhood histogram detection unit 4025 uses the information related to the color division region affiliation from the neighborhood similar color extraction unit 4014 to form a luminance histogram in each color division region of the neighborhood region. Then, the formed histogram information is transferred to the neighborhood histogram correction unit 4026 together with each video signal from the neighborhood similar color extraction 4014 and information regarding the affiliation of the color division region.

  The neighborhood histogram correction unit 4026 is transferred from the neighborhood histogram detection unit 4025 with respect to the luminance signal before gradation conversion processing corresponding to the specific area transferred from the target histogram detection unit 4021 based on the control of the control unit 113. A known histogram accumulation process is performed using the luminance histogram information of the neighboring area. In each color division area, when the number of pixels in the specific area portion and the number of pixels of the video signal in the neighboring area portion do not match, the correction magnification is calculated using equation (7).

  Next, when performing the accumulation process, the luminance value of the luminance histogram of the neighboring region and the accumulated number are multiplied for each pixel using the correction magnification described above. A known accumulation process is performed based on the luminance histogram of the video signal in the neighboring area after the multiplication process. After the luminance histogram accumulation processing in all the color division regions is completed, the luminance signal after the accumulation processing in the specific region is converted into an RGB video signal for each pixel using equation (8). Based on the control of the control unit 113, the converted RGB video signal is transferred to the image composition unit 4124.

  Based on the control of the control unit 113, the image composition unit 4124 corrects the specific region with the past video signal from the histogram 4023 and the video signal corrected with the neighborhood region video signal from the neighborhood histogram correction unit 4026. Is used to perform the composition process at a predetermined ratio. Regarding the composition ratio, the composition ratio of both video signals is basically 100%, but it is possible to set 100% for one video signal and 0% for the other video signal. In an area other than the specific area, a video signal after gradation conversion processing is used. The combined video signal is transferred to the output unit 109.

  When correcting a specific area using past video signals based on distance information, past video signals having the same distance may not be sufficient. In addition, when there is an overexposed area from the beginning, there is no past video signal, so it is possible that gradation correction cannot be performed. On the other hand, when the gradation of the specific area is corrected using the neighboring area video signal, there is a possibility that the neighboring area video signal is not sufficient, or the neighboring area includes a color blur. On the other hand, according to the video signal processing apparatus according to the present embodiment, the video signal corrected with the past video signal based on the distance information and the video signal corrected with the video signal in the neighboring area are synthesized, A tone-corrected video signal with high image quality is obtained.

  The video signal processing in the present embodiment described above is realized by hardware, but need not be limited to such a configuration. Here, a flowchart showing processing by the video signal processing program in the present embodiment example, a flowchart showing details of detecting a specific area (high luminance video signal detection processing), and a flowchart showing details of the gradation correction processing are as follows: Since it is the same as that of the first embodiment, description thereof is omitted here, and different portions will be mainly described.

  FIG. 20 is a flowchart showing details of the corresponding area extraction processing in Step 201 of FIG. The process shown in FIG. 20 corresponds to the process performed in the corresponding area extraction unit 411 in FIG. Since the equidistant detection process and the similar color extraction process are the same as the process contents shown in FIG. 14 of the first embodiment, the description of the process contents of these two parts is omitted, and the neighbor detection process and the neighbor similarity process are omitted. The color extraction process will be described.

When this process is started, first, in Step 231, a neighboring area of the high luminance video signal area is detected, and the process proceeds to Step 232.
Next, in Step 232, based on the equation (4), the color difference signal of the video signal before gradation conversion of the high luminance video signal is calculated. Next, the color difference signal for each pixel is calculated in the same manner from the video signal in the neighboring area. At the same time, the luminance signal of the specific area before gradation conversion and the luminance signal of the video signal of the neighboring area are also calculated using the equation (1). As shown in FIG. 9, the color space is equally divided into six color division areas, and the current video signal before gradation conversion is overexposed to a specific area that is overexposed after gradation change processing. For each pixel, it is verified which color division region the color difference signal calculated in the equation (4) is in. The same verification is performed on the video signal in the neighboring area. It is determined to which color division area the formula (5) and (6) belong. When the process of Step 232 is completed, the process returns to the process shown in FIG.

  FIG. 21 is a flowchart showing details of the target area correction processing in Step 202 of FIG. The process shown in FIG. 21 corresponds to the process performed in the target area correction unit 412 in FIG. Since the target histogram detection process and the histogram correction process are the same as the process contents shown in FIG. 15, the description of the process contents of these two parts is omitted.

  When this process is started, first, in Step 241, it is verified whether or not there is a color difference signal in the high luminance area in each color division area. If a color difference signal exists, a luminance histogram of a neighboring region corresponding to the high luminance region portion is formed, and the process proceeds to Step 242.

  Next, in Step 242, a known histogram accumulation process is performed on the luminance signal before the gradation conversion process corresponding to the specific area using the luminance histogram information of the neighboring area. In each color division area, when the number of pixels in the specific area does not match the number of pixels in the video signal in the neighboring area, the correction magnification is calculated using equation (7). Next, when performing the accumulation process, the luminance value of the luminance histogram of the neighboring region and the accumulated number are multiplied for each pixel using the correction magnification described above. A known accumulation process is performed based on the luminance histogram of the video signal in the neighboring area after the multiplication process. After the luminance histogram accumulation processing in all the color division regions is completed, the luminance signal after the accumulation processing in the specific region is converted into an RGB video signal for each pixel using Equation (8), and the process proceeds to Step 244.

  Finally, in Step 224, in the high luminance region, the video signal after gradation correction and the video signal after gradation conversion processing are combined. In a region other than the high luminance region, a video signal after gradation conversion processing is used. When the process of Step 224 is completed, the process returns to the process shown in FIG.

As mentioned above, although each embodiment of the present invention has been described in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and includes design changes and the like without departing from the gist of the present invention. .
For example, in each of the above-described embodiments, one example of the past video signal after gradation correction stored in the past data storage unit 110 has been shown. However, the present invention is not limited to this. Good.

It is a functional block diagram of the video imaging device concerning a 1st embodiment. It is a graph which shows (gamma) characteristic data, Comprising: (a) is a graph which shows the gamma characteristic data of this embodiment, (b) is a graph which shows the gamma characteristic data of a modification. It is a functional block diagram of the specific area | region detection part of FIG. FIG. 4 is a functional block diagram of a specific luminance area detection unit in FIG. 3. It is a functional block diagram of the distance information acquisition part of FIG. It is a figure explaining the image | video division | segmentation method for distance measurement, Comprising: (a) is a figure explaining the division | segmentation method of this embodiment, (b) is a figure explaining the division | segmentation method of a modification. FIG. 2 is a functional block diagram of a gradation correction unit in FIG. 1. FIG. 8 is a functional block diagram of a corresponding area extraction unit in FIG. 7. It is a figure explaining the method of color area division. FIG. 8 is a functional block diagram of a target area correction unit in FIG. 7. It is a flowchart of the video signal processing program which concerns on 1st Embodiment. It is a flowchart of the detection process of the high-intensity video signal of FIG. It is a flowchart of the gradation correction process of FIG. It is a flowchart of the corresponding | compatible area | region process of FIG. It is a flowchart of the object area | region correction process of FIG. It is a functional block diagram of the gradation correction | amendment part which concerns on 2nd Embodiment. FIG. 17 is a functional block diagram of a corresponding area extraction unit in FIG. 16. It is a figure explaining the method of neighborhood detection. FIG. 17 is a functional block diagram of a target area correction unit in FIG. 16. It is a flowchart of the corresponding | compatible area process which concerns on 2nd Embodiment. It is a flowchart of the object area | region correction process which concerns on 2nd Embodiment.

Explanation of symbols

106 gradation conversion unit 107 specific region detection unit 108 gradation correction unit 109 output unit 110 past data storage unit 111 infrared sensor 112 distance information acquisition unit 113 control unit 201 region division unit 202 distance measurement unit 301 luminance signal conversion unit 302 specific luminance Area detection unit 401 Corresponding region extraction unit 402 Target region correction unit 411 Corresponding region extraction unit 412 Target region correction unit 4011 Equal distance detection unit 4012 Similar color extraction unit 4013 Neighborhood detection unit 4014 Neighborhood similar color extraction unit 4021 Target histogram detection unit 4022 Past Histogram detection unit 4023 Histogram correction unit 4024 Image composition unit 4025 Neighborhood histogram detection unit 4026 Neighborhood histogram correction unit 4124 Image composition unit

Claims (20)

A gradation conversion unit that performs gradation conversion on the video signal;
An area detection unit for detecting a specific area having a luminance equal to or higher than a predetermined first threshold value or lower than a predetermined second threshold value from the current video signal after gradation conversion;
A storage unit storing a past video signal in which distance information to a subject and gradation information are associated with each other or for each predetermined region;
A past gradation information extraction unit that detects a region of a past video signal corresponding to the specific region based on the distance information, and extracts past gradation information indicating gradation information of the region from the storage unit;
A video signal processing apparatus comprising: a gray level correction unit that corrects a gray level width of the specific area of the current video signal using the past gray level information. A gradation conversion unit that performs gradation conversion on the video signal;
An area detection unit for detecting a specific area having a luminance equal to or higher than a predetermined first threshold value or lower than a predetermined second threshold value from the current video signal after gradation conversion;
A peripheral gradation information extracting unit for detecting a peripheral area of the specific area from the current video signal and extracting peripheral gradation information indicating gradation information of the peripheral area;
A video signal processing apparatus comprising: a gray level correction unit that corrects a gray level width of the specific area of the current video signal using the peripheral gray level information. A peripheral gradation information extraction unit that detects a peripheral region of the specific region detected by the region detection unit and extracts peripheral gradation information indicating gradation information of the peripheral region from the current video signal;
The video signal processing apparatus according to claim 1, wherein the gradation correction unit corrects a gradation width of the specific area of the current video signal using the past gradation information and the peripheral gradation information. . The past gradation information extraction unit
4. The video signal processing apparatus according to claim 1, wherein the past gradation information is extracted from a past video signal after gradation correction stored in the storage unit. The past gradation information extraction unit
A luminance signal extraction unit that extracts a luminance signal of a region of a past video signal corresponding to the specific region of the current video signal from the storage unit;
The gradation correction unit
5. The video signal processing apparatus according to claim 1, wherein a gradation width of the specific area of the current video signal is corrected using the luminance signal. 6. The past gradation information extraction unit
A color signal extraction unit that extracts a color signal of a region of a past video signal corresponding to the specific region of the current video signal from the storage unit;
The gradation correction unit
6. The video signal processing apparatus according to claim 5, wherein a gradation width of the specific area of the current video signal is corrected using the color signal and the luminance signal. The storage unit stores, for each pixel or predetermined area, past video signals before or after gradation correction in which distance information to the subject and gradation information are associated with each other,
The color signal extraction unit includes:
A luminance signal of an area having the same color signal as that of the specific area in the current video signal before gradation conversion from a past video signal before or after gradation correction stored in the storage unit is a color signal. Extract every
The gradation correction unit
The video signal processing apparatus according to claim 6, wherein a gradation width of the specific area of the current video signal is corrected for each color signal using the luminance signal extracted by the color signal extraction unit. The gradation correction unit
A histogram correction unit that corrects a histogram of a luminance signal of the specific area of the current video signal for each color signal based on a histogram of a past video signal;
The histogram correction unit
The video signal processing apparatus according to claim 7, wherein the gradation width of the specific area of the current video signal is corrected by performing accumulation processing of the histogram.   9. The video signal processing apparatus according to claim 1, further comprising a video signal synthesis unit that synthesizes the current video signal corrected by the gradation correction unit and the current video signal before correction. The peripheral gradation information extraction unit
A peripheral detection unit for detecting a peripheral region of the specific region of the current video signal;
A peripheral luminance signal extraction unit that extracts a luminance signal from the peripheral region detected by the peripheral detection unit;
The gradation correction unit
4. The video signal processing apparatus according to claim 2, wherein a gradation width of the specific area of the current video signal is corrected using a luminance signal of the peripheral area. The peripheral gradation information extraction unit
A peripheral color signal extraction unit that extracts a color signal from the peripheral region detected by the peripheral detection unit;
The gradation correction unit
The video signal processing apparatus according to claim 10, wherein a gradation width of the specific area of the current video signal is corrected using a color signal and a luminance signal of the peripheral area. The peripheral color signal extraction unit
Extracting the luminance signal of the peripheral area having the same color signal as the specific area from the current video signal for each color signal,
The gradation correction unit
12. The video according to claim 11, wherein the gradation width of the specific area of the current video signal is corrected for each color signal using the luminance signal of the peripheral area extracted by the peripheral color signal extraction unit. Signal processing device.   4. The video according to claim 3, further comprising: a synthesis unit that synthesizes the current video signal corrected by using the past gradation information and the current video signal corrected by using the peripheral gradation information by the gradation correction unit. Signal processing device. The region detection unit
The identification is performed using at least one of the area occupied by the pixels having the luminance equal to or higher than the predetermined first threshold or lower than the predetermined second threshold from the current video signal after the gradation conversion, and the count number of the pixels. 14. The video signal processing apparatus according to claim 1, wherein the video signal processing apparatus detects an area. The region detection unit
15. The video signal processing apparatus according to claim 1, wherein an area where the slope of the curve indicating the gamma characteristic of the current video signal after gradation conversion is equal to or less than a predetermined value is detected as a specific area. Gradation conversion processing for performing gradation conversion on the video signal;
An area detection process for detecting a specific area having a luminance equal to or higher than a predetermined first threshold value or lower than a predetermined second threshold value from a current video signal after gradation conversion;
A past video signal region corresponding to the specific region is detected based on the distance information from a past video signal in which distance information to the subject and gradation information are associated with each other or for each predetermined region. Past gradation information extraction processing for extracting past gradation information indicating gradation information of the area;
A video signal processing program for causing a computer to execute gradation correction processing for correcting the gradation width of the specific area of the current video signal using the past gradation information. Gradation conversion processing for performing gradation conversion on the video signal;
An area detection process for detecting a specific area having a luminance equal to or higher than a predetermined first threshold value or lower than a predetermined second threshold value from a current video signal after gradation conversion;
A peripheral gradation information extraction process for detecting a peripheral area of the specific area from the current video signal and extracting peripheral gradation information indicating gradation information of the peripheral area;
A video signal processing program for causing a computer to execute a gradation correction process for correcting a gradation width of the specific area of the current video signal using the peripheral gradation information.   An electronic apparatus comprising the video signal processing device according to claim 1. A gradation conversion step for performing gradation conversion on the video signal;
A region detecting step for detecting a specific region having a luminance equal to or higher than a predetermined first threshold value or equal to or lower than a predetermined second threshold value from the current video signal after gradation conversion;
A past video signal region corresponding to the specific region is detected based on the distance information from a past video signal in which distance information to the subject and gradation information are associated with each other or for each predetermined region. A past gradation information extracting step of extracting past gradation information indicating gradation information of the area;
A gradation correction step of correcting a gradation width of the specific area of the current image signal using the past gradation information. A gradation conversion step for performing gradation conversion on the video signal;
A region detecting step for detecting a specific region having a luminance equal to or higher than a predetermined first threshold value or equal to or lower than a predetermined second threshold value from the current video signal after gradation conversion;
A peripheral gradation information extracting step of detecting a peripheral area of the specific area from the current video signal and extracting peripheral gradation information indicating gradation information of the peripheral area;
And a gradation correction step of correcting a gradation width of the specific area of the current video signal using the peripheral gradation information.

Images