JP2009044362A - Camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a camera capable of obtaining a composite image having appropriate exposure regardless of the number of images to be composited. <P>SOLUTION: The camera is adopted, where it includes an imaging apparatus for acquiring an image having minus exposure by photographing the image of an object, and an image processor for generating an image having appropriate exposure by compositing a plurality of images acquired by the imaging apparatus. The image processor multiplies the luminance information of the acquired image or the composited image by the reciprocal of the ratio of the exposure information of the composited image to that of an image having appropriate exposure when compositing a plurality of images acquired by the imaging apparatus. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a camera that performs a composition process of a plurality of images.

  2. Description of the Related Art Conventionally, a technique is known in which a predetermined number of images are selected from a plurality of images based on preset conditions, and the selected predetermined number of images are synthesized (see, for example, Patent Document 1). The purpose of this technique is to improve the image quality of a composite image by creating a composite image using only images that satisfy preset conditions.

By the way, for example, when a plurality of images are shot by continuous shooting, each image often cannot obtain a sufficient exposure time, and there are cases where a darkly shot image is synthesized to obtain an image with proper exposure. In this case, there is a known technique for correcting and displaying the brightness of a single composite image for the purpose of confirming the composition and focus of the composite image after the start of image capture and before the composition of the image is completed. (For example, refer to Patent Document 2).
JP 2006-246309 A JP 2006-54698 A

  However, in the above technique, the brightness correction is performed only for confirming the composition, focus, and the like of the composite image before the completion of the composition of the image. A predetermined number of composite images are required. Therefore, for example, when the number of images to be combined is less than a predetermined number, there is a disadvantage that a combined image cannot be obtained or only an underexposed composite image can be obtained.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a camera that can obtain a composite image with appropriate exposure regardless of the number of composite images.

In order to solve the above problems, the present invention employs the following means.
The present invention includes an imaging device that captures an image of a subject and obtains a negative exposure image, and an image processing device that synthesizes a plurality of images acquired by the imaging device to generate an image with appropriate exposure. The reciprocal of the ratio of the exposure information of the composite image to the exposure information of the proper exposure image when the image processing device combines a plurality of images acquired by the imaging device is obtained image or the composite image A camera that multiplies the luminance information is used.

  According to the present invention, the image processing apparatus multiplies the luminance information of the acquired image or the composite image by the inverse of the ratio of the exposure information of the composite image to the exposure information of the image of the proper exposure, thereby combining the proper exposure. An image can be generated. That is, for example, in continuous shooting, even when continuous shooting is completed with a number smaller than the planned number of images, image processing is performed at a ratio according to the exposure information of the combined image obtained by combining the smaller number of images. Since the brightness of the pre-combination image or the composite image is amplified by the apparatus, a composite image with proper exposure can be generated.

  Here, by synthesizing the negative exposure image obtained by increasing the shutter speed, a clear and proper exposure image without blurring can be obtained. Further, by combining the negative exposure image obtained by reducing the aperture, it is possible to obtain an appropriate exposure image having a deep depth of field. Furthermore, by combining the negative exposure image obtained by reducing the sensitivity, it is possible to obtain a proper exposure image with less noise.

In the above invention, the image number setting unit for setting a required number of images required for combining the images with the appropriate exposure, and the imaging based on the required number set by the image number setting unit. You may provide the exposure adjustment part which adjusts the exposure of an apparatus.
In this way, when the required number of images is set by the image number setting unit, the exposure adjustment unit adjusts the exposure of the imaging device so that the exposure of the composite image obtained by combining the required number of images becomes an appropriate exposure. Is done. Therefore, if a required number of images are acquired in continuous shooting, these images can be combined to easily generate a composite image with proper exposure. When an image less than the required number is acquired, it can be amplified to obtain a composite image with proper exposure.

In the above invention, the exposure information of the composite image when combining a plurality of images acquired by the imaging device is the number of images actually acquired by the imaging device, and The exposure information may be a necessary number of images set by the image number setting unit.
In this way, the image processing apparatus multiplies the ratio between the required number of set images and the number of actually acquired images by the luminance information of the pre-combination image or the composite image, thereby more easily. A composite image with proper exposure can be generated.

Further, in the above invention, exposure information of a composite image when combining a plurality of images acquired by the imaging device is a sum of average luminance values of the images actually acquired by the imaging device, The exposure information of the image with proper exposure may be a preset average luminance value.
By doing in this way, the ratio of the average luminance value of the image with the appropriate exposure set in advance and the total of the average luminance value of each image actually acquired by the image processing device is the image before synthesis or the synthesized image. Can be multiplied by the brightness information, and a composite image with proper exposure can be generated. Further, by using the average luminance value as the exposure information, a composite image with proper exposure can be obtained even when the average luminance value of the composite image becomes larger than the average luminance value of an image with proper exposure.

  According to the present invention, it is possible to obtain a composite image with appropriate exposure regardless of the number of composite images.

A camera according to an embodiment of the present invention will be described below with reference to the drawings.
As shown in FIGS. 1 and 2, a camera 1 according to the present embodiment includes a camera body 3 formed in a substantially rectangular parallelepiped shape, and an imaging device 5 that is provided on the front surface of the camera body 3 and captures an image of a subject. A shutter operation unit 7 that is provided on the upper surface of the camera body 3 and operates the imaging device 5 and a display unit 109 that is a display device such as a rear liquid crystal display, for example.

  As shown in FIG. 3, the camera body 3 includes an image number setting unit 130 for setting a necessary number of images necessary for synthesizing images with appropriate exposure, and exposure of an image acquired by the imaging device 5. An exposure adjusting unit 6 for adjusting, an image processing device 10 for processing an image acquired by the imaging device 5, an external memory 112 that is a recording medium for recording an image processed by the image processing device 10, and the like. And a control unit 4 for controlling.

  The imaging device 5 includes an optical system 120 such as a lens and an imaging unit 107 such as a CCD. The imaging unit 107 performs AD conversion on an image acquired by the optical system 120 and outputs the image to the SDRAM 110. It has become.

  The exposure adjustment unit 6 uses the AE sensor 121 that detects the brightness of the subject, the brightness information from the AE sensor 121, and the required number of images from the image number setting unit 130 to set the exposure setting value of the imaging device 5. And an AE unit 106 for determination. The AE unit 106 outputs the determined exposure setting value to the control unit 4.

  The shutter operation unit 7 includes a shutter button 123 that can be pushed in the vertical direction with respect to the upper end surface of the camera body 3, and a shutter button determination unit 101 that determines that the shutter button 123 has been pushed a predetermined amount. The shutter button determination unit 101 outputs to the control unit 4 that the shutter button 123 has been pressed by a predetermined amount. The shutter button determination unit 101 is configured to continue output to the control unit 4 while the shutter button 123 is depressed by a predetermined amount.

  The control unit 4 controls the imaging device 5 and the exposure adjustment unit 6 based on information from the shutter button determination unit 101. Specifically, when the shutter button 123 is pushed in by a predetermined amount from the shutter button determination unit 101, the control unit 4 instructs the exposure adjustment unit 6 to determine the exposure setting value. It has become. Further, when the shutter button 123 is further pushed in by a predetermined amount, the control unit 4 sets the exposure setting value determined by the exposure adjustment unit 6 to the imaging device 5. To instruct the acquisition of images. Further, when it is continuously input from the shutter button determination unit 101 that the shutter button 123 has been depressed by a predetermined amount, the control unit 4 maintains the imaging device 5 in the continuous shooting state. .

  The image processing apparatus 10 includes an SDRAM 110 that temporarily stores an image input from the imaging unit 107, an image processing unit 108 that performs image processing by reading the image temporarily stored in the SDRAM 110, and an image input from the imaging unit 107. Using the number of shots counting unit 102 that counts the number of images, the number of images counted by the number of shots counting unit 102, and the required number of images set by the image number setting unit 130, the gain of the luminance information of the image before composition Is calculated by multiplying the gain calculated by the gain calculating unit 103 and the luminance information of the image processed by the image processing unit 108, thereby adjusting the luminance information of the image before synthesis. An image that combines the adjustment unit 126 and a plurality of images whose luminance information has been adjusted by the luminance information adjustment unit 126 And a generation unit 127.

The SDRAM 110 temporarily stores an image input from the imaging unit 107.
The image processing unit 108 reads an image temporarily stored in the SDRAM 110, performs image processing such as three-plate processing and correction, and outputs the image subjected to the image processing to the luminance adjustment unit 126.

The shooting number counting unit 102 counts the number of images input from the imaging unit 107 and outputs the counted result to the gain calculation unit 103.
The gain calculation unit 103 calculates the reciprocal of the ratio of the number of images counted by the number-of-photographing counting unit 102 to the required number of images set by the image number setting unit 130, and uses the calculated value as a gain to adjust the luminance information adjustment unit It outputs to 126.

The luminance information adjustment unit 126 adjusts the luminance information of the image before synthesis by multiplying the gain calculated by the gain calculation unit 103 and the luminance information of the image processed by the image processing unit 108, and the luminance information is The adjusted image is output to the image composition unit 127.
The image combining unit 127 combines a plurality of images whose luminance information is adjusted by the luminance information adjusting unit 126 and outputs the combined image to the external memory 112.

The external memory 112 records the composite image output from the image composition unit 127.
The display unit 109 reads the composite image from the external memory 112 and performs format conversion so as to be visible to the user.

The operation of the camera according to the present embodiment configured as described above will be described below using a specific example with reference to FIGS. 3 and 4.
When the camera 1 according to the present embodiment is activated, the image of the subject illustrated in FIG. 4 is acquired by the optical system 120 and formed on the imaging surface of the imaging unit 107. When the user presses the shutter button 123 a predetermined amount, the shutter button determination unit 101 outputs the information to the control unit 4, and the control unit 4 outputs an exposure adjustment instruction to the AE unit 106.

When the exposure adjustment instruction from the control unit 4 is input, the AE unit 106 combines the brightness information of the subject from the AE sensor 121 and an image with appropriate exposure preset in the image number setting unit 130. The exposure setting value is determined based on the required number of images required for this purpose. Here, it is assumed that the required number of images is four and is preset in the image number setting unit 130. Accordingly, the exposure setting value is determined by the AE unit 106 as 1/4 of the appropriate exposure value.
The exposure setting value determined as described above is output to the imaging device 5 via the control unit 4, and the imaging device 5 is controlled so that the image acquired by the control unit 4 has a set exposure.

The subject image acquired by the imaging device 5 controlled in this way is acquired by the imaging unit 107 in accordance with an instruction from the control unit 4 and output to the SDRAM 110 when the shutter button 123 is further pushed by a predetermined amount. .
In addition, while the shutter button 123 is depressed by a predetermined amount, the subject image acquired by the imaging device 5 is continuously acquired by the imaging unit 107 and temporarily stored in the SDRAM 110.
Examples of images A, B, and C in FIG. 4 are illustrated as images that are continuously shot as described above. It is assumed that the image D has not been shot due to shooting time or the like.

The image temporarily stored in the SDRAM 110 is subjected to image processing by the image processing unit 108 while the number of images is counted by the number-of-photographing number counting unit 102.
Further, the gain calculation unit 103 calculates the reciprocal (gain) of the ratio of the number of images counted by the shooting number counting unit 102 to the required number of images set by the image number setting unit 130.
That is, in the example of FIG. 4, the number of images taken is counted by the number-of-photographing counting unit 102, and the required number of images is set as 4 in the image number setting unit 130 as described above, so that the gain is 4 / 3 is calculated.

Then, the luminance information adjustment unit 126 multiplies the gain calculated by the gain calculation unit 103 and the luminance information of the image processed by the image processing unit 108 to adjust the luminance information.
In this way, the luminance information of the images A, B, and C is multiplied by 4/3, respectively, so that gain-up images A ′, B ′, and C ′ are obtained.

The images A ′, B ′, and C ′ whose luminance information has been gained up by the luminance information adjusting unit 126 are combined by the image combining unit 127, and the combined images are output to the external memory 112 and recorded.
The composite image recorded in the external memory 112 in this way is read out by the display unit 109 and displayed so as to be visible to the user.

  Here, the images A ′, B ′, and C ′ are images obtained by gaining up the luminance information of the images A, B, and C, respectively. Therefore, the combined images obtained by combining the images A ′, B ′, and C ′. Will have luminance information equivalent to a properly exposed composite image obtained by combining images A, B, C, and D.

  As described above, according to the camera according to the present embodiment, the image processing apparatus 10 determines the reciprocal of the ratio of the exposure information of the composite image to the exposure information of the image with the proper exposure as the luminance of the acquired image or the composite image. By multiplying the information, a composite image with proper exposure can be generated. That is, for example, in continuous shooting, even when continuous shooting is completed with a number smaller than the planned number of images, image processing is performed at a ratio according to the exposure information of the combined image obtained by combining the smaller number of images. Since the brightness of the pre-combination image or the composite image is amplified by the apparatus 10, a composite image with proper exposure can be generated.

  Here, the pre-combination image is an image shot with a negative exposure. For example, by combining a negative exposure image obtained by increasing the shutter speed, a clear and proper exposure without blurring can be obtained. An image can be obtained. Further, by combining the negative exposure image obtained by reducing the aperture, it is possible to obtain an appropriate exposure image having a deep depth of field. Furthermore, by combining the negative exposure image obtained by reducing the sensitivity, it is possible to obtain a proper exposure image with less noise.

In addition, according to the camera of the present embodiment, when the required number of images is set by the image number setting unit 130, the exposure of the combined image obtained by combining the required number of images by the exposure adjusting unit 6 becomes an appropriate exposure. The exposure of the imaging device 5 is adjusted. Therefore, if a required number of images are acquired in continuous shooting, these images can be combined to easily generate a composite image with proper exposure. When an image less than the required number is acquired, it can be amplified to obtain a composite image with proper exposure.
Further, by using the number of images as exposure information, it is possible to generate a composite image with appropriate exposure more easily.

  In the present embodiment, the gain calculated by the gain calculation unit 103 has been described as being constant for each image before synthesis. However, for example, the noise amount of each image before synthesis is calculated and the noise is calculated. You may calculate the gain according to quantity respectively. As a result, the image quality of the composite image can be improved by increasing the gain of an image with a relatively small amount of noise larger than the gain of an image with a relatively large amount of noise.

  Further, in the present embodiment, it has been described that the gain is applied to the pre-combine image. However, the luminance adjustment unit 126 may be provided at the subsequent stage of the image composition unit 127 and the gain may be multiplied to the composite image. Good. As a result, a composite image with appropriate exposure can be generated more easily.

  In this embodiment, the image processing apparatus is premised on processing by hardware, but is not limited to such a configuration. For example, a configuration in which processing is performed separately by software is also possible. In this case, the image processing apparatus may include a main storage device such as a CPU and a RAM, and a computer-readable recording medium in which a program for realizing all or part of the above processing is recorded. Then, the CPU reads out the program recorded in the storage medium and executes information processing / calculation processing, whereby the same processing as the above-described image processing apparatus can be realized. Here, the computer-readable recording medium means a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, a semiconductor memory, or the like.

Specific processing by the above software will be described below based on the flowchart shown in FIG.
First, the user sets the number N of images necessary for generating one composite image (S1).
When the shutter button is pressed by the user and shooting is started in the continuous shooting mode (S2), the count value M of the number of shots is reset (S3), and the pre-combination is performed based on the required number N set in S1. The exposure of the image is set (S4).
An image photographed by the imaging unit is temporarily stored in a storage means such as SDRAM (S5), subjected to predetermined image processing (S6), and the number of photographed images is counted (S7).

  Then, it is determined whether or not the number M of photographed images has reached the necessary number N (S8). If the number M of photographed images has reached the necessary number N, the process proceeds to S11 to be described later. If the number M of images that have been taken is smaller than the required number N, it is determined whether or not the shutter button has been released (S9). If the pressing of the shutter button has not been released, the process returns to S5 and the processing is continued. If the pressing of the shutter button has been released, the image to be synthesized is multiplied by an N / M gain (S10). ).

Next, the image multiplied by the gain is synthesized (S11), and the synthesized image is output to an external memory and recorded (S12).
The reference image and the composite image recorded in the external memory as described above are displayed as thumbnail images on the display unit, and the continuous shooting is finished (S13).

Further, as a modification of the image processing apparatus and the camera according to the present embodiment, as shown in FIG. 6, a luminance extraction unit 140 that extracts the average luminance value of the pre-combination image is provided instead of the number-of-photographing-number counting unit 102. May be.
According to the camera according to this modification, the luminance extraction unit 140 extracts the average luminance value of each actually acquired image, and the gain calculation unit 103 determines the average luminance value of the image with the appropriate exposure set in advance. A ratio with the sum of the average luminance values of the images extracted by the luminance extraction unit 140 is calculated. Then, the luminance adjustment unit 126 multiplies the ratio calculated by the gain calculation unit 103 by the luminance information of the pre-combination image or the composite image, so that a composite image with appropriate exposure can be generated. In addition, by using the average luminance value as the exposure information, even when the average luminance value of the composite image becomes larger than the average luminance value of the image of appropriate exposure, by multiplying by a gain smaller than 1, A composite image of exposure can be obtained.

  Note that the gain calculation unit 103 may change the gain for each image according to the average luminance value of each image extracted by the luminance extraction unit 140. Specifically, for example, an average value of average luminance values of each image may be obtained, and gains may be calculated so that the average luminance value of each image becomes the average value.

It is a top view of the camera concerning one embodiment of the present invention. It is a rear view of the camera shown in FIG. It is the functional block diagram which expanded and showed the function with which the camera shown in FIG. 1 is provided. It is a figure explaining the specific operation | movement of the camera shown in FIG. It is a flowchart which shows the process sequence of the camera which concerns on one Embodiment of this invention. It is the functional block diagram which expanded and showed the function with which the camera which concerns on the modification of this invention is provided.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Camera 3, 30 Camera main body 4 Control part 5 Imaging device 6 Exposure adjustment part 7 Shutter operation part 10,20 Image processing apparatus 102 Image | photographing number count part 103 Gain calculation part 108 Image processing part 109 Display part 110 SDRAM
112 External memory 126 Brightness adjustment unit 127 Image composition unit 130 Image number setting unit 140 Luminance extraction unit

Claims (4)

An imaging device for capturing an image of a subject to obtain a negative exposure image;
An image processing device that combines a plurality of images acquired by the imaging device to generate an image with appropriate exposure,
When the image processing device combines a plurality of images acquired by the imaging device, the reciprocal of the ratio of the exposure information of the composite image to the exposure information of the image of the proper exposure is obtained. A camera that multiplies luminance information. An image number setting unit for setting a required number of images required for synthesizing the images with appropriate exposure;
2. The camera according to claim 1, further comprising an exposure adjusting unit that adjusts an exposure of the imaging device based on a required number of images set by the image number setting unit. The exposure information of the composite image when combining a plurality of images acquired by the imaging device is the number of images actually acquired by the imaging device,
The camera according to claim 2, wherein the exposure information of the image with the proper exposure is a necessary number of images set by the image number setting unit. Exposure information of a composite image when combining a plurality of images acquired by the imaging device is a sum of average luminance values of the images actually acquired by the imaging device;
The camera according to claim 2, wherein the exposure information of the image with the proper exposure is a preset average luminance value.

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