JP2005260453A - Infrared ray image correction apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an infrared ray image correction apparatus detecting a blinking defect with high accuracy without being affected by lens shading correction deviation, offset correction deviation and sensitivity correction deviation. <P>SOLUTION: An infrared ray solid-state imaging element images an object the temperature of which is almost constant for an imaging time by closing or opening a shutter so that the temperature is almost constant for the imaging time, an image memory stores a plurality of frames of outputs from the infrared ray solid-state imaging element, a blinking defect detection means calculates an average and a standard deviation of outputs of the infrared ray solid-state imaging element over a plurality of frames for pixels configuring the infrared ray solid-state imaging element, calculates an absolute value subtracting the average from the output of the infrared ray solid-state imaging element by each frame, and regards a blinking defect to be caused in the pixels wherein the absolute value is greater than a constant number multiple of the standard deviation because of the discrimination that the output variation from the average is considerably greater and the output is momentarily fluctuated. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a blinking defect detection method for accurately detecting a blinking defect pixel generated in a solid-state imaging device, and an infrared ray using an image correction method including defect correction for the blinking pixel specified and detected by the blinking defect detection method. The present invention relates to an image correction apparatus.

As described in Japanese Patent Application Laid-Open No. 2003-298949 (FIG. 6), in an infrared imaging apparatus using a conventional solid-state imaging device, processing such as offset correction, sensitivity correction, and defect correction has been performed on the output of the solid-state imaging device. An infrared imaging device 12 that includes an infrared solid-state imaging device 10 as an imaging device for imaging a subject in an infrared region and performs image correction by an infrared image correction device 14. In a state in which the shutter 22 placed in front of the infrared solid-state image sensor 10 is open, light rays that mainly belong to the infrared region out of the light rays coming from the subject pass through the lens 16 and are captured by the infrared solid-state image sensor 10. Although not shown, the infrared solid-state imaging device 10 is composed of a large number of pixels arranged two-dimensionally, and each pixel exhibits an output corresponding to the received light intensity of infrared rays. For each pixel output, the infrared image correction device 14 performs correction processing in the order of offset correction, sensitivity correction, and defect correction (see, for example, Patent Document 1).
JP 2003-298949 A

  The operation of the conventional infrared image correction device 14 will be described below. First, an output value shift (output offset) may occur between pixels. When the data indicating the output offset is arranged according to the 10-pixel arrangement of the infrared solid-state imaging device, it can be seen what pattern the output offset between the pixels has on the pixel arrangement. A pattern that the output offset has on the pixel array is called an offset pattern. The offset pattern can be obtained, for example, from the output of the infrared solid-state imaging device 10 when imaging is performed using an object having a uniform temperature over almost the entire angle of view of the infrared imaging device 12 as a subject.

  The offset correction process is a process for removing or suppressing the output offset between pixels from the imaging output of the infrared solid-state imaging device 10 during normal use according to the offset pattern stored in advance in the image memory 20. Performed by means 18. The offset pattern used for the offset correction process is called an offset correction pattern. Further, the above-described processing for capturing an image of a uniform temperature subject and storing the offset correction pattern obtained as a result in the image memory 20 is called calibration. The shutter 22 can be used as a uniform temperature subject for calibration. That is, the offset correction pattern may be obtained by capturing an image with the shutter 22 closed. Providing the shutter 22 is advantageous because calibration can be performed at an arbitrary time.

  A sensitivity difference between pixels remains in each pixel imaging output that has undergone the offset correction processing. In order to realize uniform output characteristics over the entire screen (all pixels), a sensitivity correction process of multiplying each pixel imaging output that has passed through the offset correction unit 18 by a sensitivity correction coefficient ΔVave / ΔV (x, y) is a sensitivity correction unit 24. It is executed by. (X, y) is a pixel position, ΔV (x, y) is an output change due to temperature, that is, an offset difference value, and ΔVave is an average value of the entire screen of ΔV (x, y). Note that ΔV (x, y) can be obtained from, for example, an offset pattern when an object having an arbitrary temperature T is a subject and an offset pattern when another object having an arbitrary temperature T + ΔT is a subject. . ΔVave can be obtained by averaging ΔV (x, y) thus obtained over the entire screen (all pixels). The process of deriving ΔV (x, y), ΔVave and further the sensitivity correction coefficient is executed by the sensitivity coefficient calculation fixed defect detection means 26 prior to the process by the sensitivity correction means 24. The sensitivity correction coefficient obtained as a result is written in the sensitivity coefficient defect information storage means 28.

  Each pixel imaging output that has undergone the offset correction processing and sensitivity correction processing is further subjected to defect correction processing by the defect correction means 30. The defective pixel includes a fixed defective pixel that constantly outputs the same abnormal luminance and a blinking defective pixel that outputs the abnormal luminance irregularly. For a fixed defective pixel, a replacement value is supplied to the subsequent stage instead of the output (abnormal output) of the pixel, and the (average) output of the pixels surrounding the defective pixel can be used as the replacement value. .

  In order to perform this process, it is necessary to identify and detect defective pixels. Sensitivity coefficient calculation fixed defect detection means 26 detects a pixel having a sensitivity correction coefficient ΔVave / ΔV (x, y) obtained for each pixel position (x, y) exceeding a predetermined threshold, and has a defect having abnormal sensitivity. It is specified as a pixel. For blinking defective pixels, an image of a subject having a substantially uniform temperature over the entire angle of view of the solid-state image sensor is picked up by the solid-state image sensor, and the image output obtained as a result is output between pixels in the solid-state image sensor. The process of correcting the offset and the sensitivity difference is repeatedly executed over a plurality of frames, and the luminance comparator 36 identifies a pixel whose output value variation or frequency in the plurality of frames exceeds a determination criterion as a blinking defective pixel. To do. The sensitivity coefficient defect information storage means 28 stores the position (x, y) of the defective pixel specified in this way. The defect correction unit 30 executes the above-described defect correction process for the pixel at the position (x, y) stored as the defective pixel position in the sensitivity coefficient defect information storage unit 28.

  However, in the above-described method, when a blinking defective pixel is specified among defective pixels, it is necessary to capture a subject having a substantially uniform temperature over almost the entire angle of view of a solid-state imaging device such as the shutter 22. Actually, the subject such as the shutter 22 is not necessarily at a substantially uniform temperature due to internal heat generation or the like. Further, even if the object outside the infrared imaging device 12 can be set to a substantially uniform temperature, it is affected by shading due to the lens 16 being broken in the process of imaging the infrared solid-state imaging device 10 through the lens 16. For this reason, in the output of the defect correction means 30, level unevenness may occur over the entire screen.

  Further, since the output of the defect correction means 30 passes through the offset correction means 18 and the sensitivity correction means 24, the offset is offset by the influence of errors at the time of acquisition of the image memory (offset correction pattern) 20 and the sensitivity coefficient defect information storage means 28. A correction deviation may occur with respect to the correction means 18 and the sensitivity correction means 24, and the output level may become non-uniform throughout the screen. For this reason, there is a problem that the blinking defect may not be identified with high accuracy in the above-described method of separately detecting the blinking defect on the premise of level uniformity in the entire screen in the output of the defect correction means 30.

  The invention described in the present application has been made in order to solve this problem, that is, when a blinking defective pixel is specified among defective pixels in a solid-state image sensor used in an infrared imaging device. An infrared image correction apparatus that does not need to be a subject having a substantially uniform temperature over almost the entire angle of view and that can be suitably specified and detected even when the output level of the entire solid-state imaging device is nonuniform is configured. For the purpose.

  An infrared image correction apparatus according to the present invention includes an offset correction unit that removes an output offset between pixels configured from the solid-state image sensor for an image sensor output of a solid-state image sensor that captures at least an infrared region, and after the offset correction. Sensitivity correction means for correcting the sensitivity variation between the pixels with respect to the output, defect correction means for correcting the defective pixel with respect to the output after the sensitivity correction, and a video signal on the monitor for the output after the defect correction. In the infrared image correction apparatus comprising: a video signal generating means for outputting; an image sensor output output from the solid-state image sensor is stored with a predetermined image memory over a plurality of image frames; For each pixel composed of the elements, the average value and the standard deviation of the output values of the imaging elements over the plurality of imaging frames. The absolute value obtained by subtracting the average value from the output value of each imaging device for each imaging frame is calculated, and the pixel whose absolute value exceeds a predetermined constant multiple of the standard deviation value flashes. The pixel is detected as a defective pixel.

  Infrared solid-state imaging device for the flashing interval of the non-steady output blinking pixel, the variation due to noise or the like that is output in a non-flashing state and the non-steady flashing state Therefore, for each pixel constituting the infrared solid-state imaging device, there is a variation in noise that is steadily output as a non-flashing state, a variation in non-steady output as a flashing state, and an infrared ray. If the blinking interval of the blinking pixel of the solid-state imaging device is known in advance, the flashing output characteristic of the infrared solid-state imaging device is appropriate for the number of frames N and the threshold value α that compensate for the blinking interval as an externally set blinking defect detection condition Can be set to As a result, the blinking defect detection means can accurately identify and detect blinking defective pixels.

  Preferred embodiments of the present invention will be described below with reference to the drawings. In addition, the same code | symbol is attached | subjected to the structure similar to the prior art shown in FIG. 6, and duplication description is abbreviate | omitted. Furthermore, the same code | symbol is mutually attached to the same structure in embodiment, and duplication description is abbreviate | omitted.

Embodiment 1 FIG.
FIG. 1 is a block diagram for explaining an infrared imaging device having an infrared image correction device 14a according to Embodiment 1 of the present invention. Hereinafter, the infrared image correction device 14a will be described in detail, and the infrared imaging device 12 of the first embodiment will be described.

  In this embodiment, the shutter 22 used for specifying and detecting the position of the blinking defective pixel does not need to be at a substantially uniform temperature over almost the entire angle of view of the solid-state imaging device 10. It is also possible to use. At that time, the influence of the shading of the lens 16 and the influence of the offset correction deviation and the sensitivity correction deviation due to the influence of the error of the image memory (offset pattern) 20 and the sensitivity coefficient defect information storage means 28 in the offset correction means 18 and the sensitivity correction means 24. It is possible to identify and detect the position of the blinking defective pixel without receiving.

  This is because the output of the infrared solid-state imaging device 10 at the time of imaging is stored in the image memory 20 over a plurality of frames, and the flashing defect detection means 38 uses the stored solid-state output from the infrared solid-state imaging device 10 over the plurality of frames. The blinking defect is detected by observing the output fluctuation of the image sensor for each frame of each pixel constituting the element 10, so that it is not necessary to make the frame output of the infrared solid-state image sensor 10 uniform. On the other hand, imaging of a uniform temperature subject and the result of offset correction etc. are repeated over a sufficiently long number of frames, etc., to uniformize the steady output on the entire screen, and flashing as a defect that exhibits abnormal brightness irregularly This is because the defect is completely different from the conventional method in which the defect can be separated and detected in the form of instantaneous output fluctuation or the like.

  When the blinking defect detection means 36 identifies and detects blinking defective pixels, the shutter 22 is in a state where the temperature is substantially constant with respect to the imaged time, or the shutter 22 is opened and the temperature is approximately equal to the imaged time. In a state where a fixed subject is imaged, imaging is performed on the infrared solid-state image sensor 10 by external blinking defect detection setting, and outputs from the infrared solid-state image sensor 10 are output to a plurality of frames F1, F2,. . . , FN are stored in the image memory 20 for each frame Fk (k = 1,..., N). As long as the temperature of the subject is within the dynamic range of the infrared imaging device 12, an arbitrary temperature can be used, and a subject that becomes an arbitrary still image can be used.

  In the blinking defect detection means 38, the output from the infrared solid-state imaging device 10 stored in the image memory 20 is repeatedly taken every frame Fk (k = 1,..., N), and a plurality of frames F1, F2,. . . , FN, the pixels (k1, k2) (k1 = 1,..., N1), (k2 = 1,..., N1) constituting the infrared solid-state image sensor 10 are used. , n2) for a plurality of frames F1, F2,. . . , FN, the average value Vave (k1, k2) and standard deviation Vσ (k1, k2) of the output of the infrared solid-state imaging device 10 are obtained. For each pixel (k1, k2) constituting the infrared solid-state image sensor 10, the average value Vave (k1) is calculated from the image sensor output Vk (k1, k2) for each frame Fk (k = 1,..., N). , K2) minus the absolute value | Vk (k1, k2) −Vave (k1, k2) |, and the value is in a certain frame Fl: Fuel (1 <l: L <N) among a plurality of frames. When it becomes larger than the standard deviation Vσ (k1, k2) * α, the output Vl (k1, k2) of the infrared solid-state image sensor 10 at that time is compared with the outputs of the infrared solid-state image sensor 10 in other plural frames. Thus, it can be determined that the output variation from the average value Vave (k1, k2) is remarkably large and the output fluctuates instantaneously. At this time, the pixel (k1, k2) can be regarded as a blinking pixel.

  α is a variation due to noise or the like that is regularly output as a non-flashing state for the flashing pixel of the infrared solid-state imaging device 10 in order to specify the frame Fl at the time of flashing output, and when it is output as a non-steady flashing state It is a threshold value that is adjusted and determined in consideration of the variation of. The threshold value α and the number N of frames required for imaging by the infrared solid-state imaging device 10 are simultaneously set as the flashing defect detection condition setting when acquiring the flashing pixel defect detection data from the outside.

  Infrared solid-state imaging device for the blinking interval of blinking pixels that are output non-steadily, and the variation due to noise that is output in a non-flashing state and the variation when the flashing pixels are output as a non-steady blinking state Since there are many things that depend on 10, each pixel (k 1, k 2) that constitutes the infrared solid-state imaging device 10 is output in a non-steady state as a variation in noise or the like that is steadily output as a non-flashing state and a flashing state. If the variation and the blinking interval of the blinking pixel of the infrared solid-state image pickup device 10 are known in advance, the infrared solid state with respect to the number of frames N and the threshold value α to compensate for the blinking interval detection condition set from the outside. The blinking output characteristics of the image sensor 10 can be set appropriately. As a result, the blinking defect detection means 36 can identify and detect blinking defective pixels with high accuracy.

Embodiment 2. FIG.
FIG. 2 is a block diagram for explaining an infrared imaging apparatus having an infrared image correction apparatus 14b according to Embodiment 2 of the present invention. Hereinafter, the infrared image correction device 14b will be described in detail, and the infrared imaging device 12 of the first embodiment will be described.
In this embodiment, a blinking defect characteristic detecting unit 40 and a blinking defect characteristic display unit 42 are added to the first embodiment.

  In the first embodiment, the blinking defect characteristic detection unit 40 cannot set the blinking defect detection condition corresponding to the blinking output characteristic of the infrared solid-state image sensor 10 from the outside because the blinking output characteristic of the infrared solid-state image sensor 10 is unknown in the first embodiment. In addition, the detection is performed to detect the output characteristics of the blinking pixels of the infrared solid-state imaging device 10, and the imaging is performed by closing the shutter 22 where the temperature is substantially constant with respect to the imaging time or opening the shutter 22. Setting of the number of imaging frames N ′ and the threshold value α ′ for detecting a blinking defect candidate as the blinking defect characteristic detection condition when setting the blinking defect characteristic detection from the outside in a state where an object whose temperature is substantially constant with respect to time is imaged Is carried out. N ′ is a sufficiently large value for the blinking period in which a blinking pixel appears in the infrared solid-state imaging device 10 and the blinking pixel is assumed to blink, and α ′ is a non-flashing state for the blinking pixel of the infrared solid-state imaging device 10. Assuming variations in noise or the like that is steadily output, and variations when output as a non-steady blinking state, respectively.

  First, the infrared solid-state image sensor 10 is imaged, and the output from the infrared solid-state image sensor 10 is converted into a plurality of frames F1, F2,. . . , FN ′ are stored in the image memory 20. In the blinking defect characteristic detection 40, the output from the infrared solid-state imaging device 10 stored in the image memory 20 is taken for each frame Fk (k = 1,..., N ′), and each frame Fk (k = 1,. , N ′), the output value V for each pixel (k1, k2) (k1 = 1,..., N1), (k2 = 1,..., N2) constituting the infrared solid-state imaging device 10. Store (k, k1, k2) and repeat for all frames. Further, for each pixel (k1, k2) constituting the infrared solid-state imaging device 10, a plurality of frames F1, F2,. . . , FN ′, the plurality of frames F1, F2,. . . , FN ′, the average value Vave (k1, k2) of the output of the image sensor and the standard deviation Vσ (k1, k2) are calculated and stored.

  For each pixel (k1, k2) constituting the infrared solid-state image sensor 10, the average value Vave () is obtained from the output Vk (k1, k2) of the image sensor for each frame Fk (k = 1,..., N ′). The absolute value | Vk (k1, k2) −Vave (k1, k2) | obtained by subtracting k1, k2) is calculated, and the value is a certain frame Fl: F (1 <l: L <N ′) among a plurality of frames. ) Becomes larger than the standard deviation Vσ (k1, k2) * α ′, the output Vl (k1, k2) of the infrared solid-state image sensor 10 in the corresponding frame becomes the output of the infrared solid-state image sensor 10 in other plural frames. As compared with the above, the output variation from the average value Vave (k1, k2) is remarkably large, and it can be determined that the output fluctuated instantaneously. Therefore, the pixel (k1, k2) is regarded as a blinking defective pixel candidate. Te, for the pixel (k1, k2), each frame Fk (k = 1, ..., N ') output value for (k, k1, k2), a plurality of frames F1, F2,. . . , FN ′, the average value Vave (k1, k2) and standard deviation Vσ (k1, k2) of the output of the image sensor are transferred to the blinking defect characteristic display means 42 as blinking defect characteristic detection information.

  The blinking defect characteristic display means 42 displays the blinking defect characteristic detection information obtained from the blinking defect detection means 40 so that the user can easily visually check the characteristics of the blinking defect candidate of the infrared solid-state imaging device 10. The flashing defect characteristic detection information that has been processed and displayed is superimposed on the video signal generation means 32 and displayed on the television monitor 34.

In the blinking defect characteristic display means 42, blinking defect candidates (k 1, k 2) (k 1 = 1,..., N 3), (k 1 = 1,...) Of the infrared solid-state imaging device 10 detected by the blinking defect characteristic detection means 40. , N4), the blinking defect characteristic is displayed in a graph.
FIG. 3 is a block diagram for explaining an infrared imaging apparatus having an infrared image correction apparatus according to Embodiment 2 of the present invention. Specifically, as shown in FIG. 3, for each blinking defect candidate (k1, k2), the horizontal axis is set to the number of imaging frames N ′ when setting blinking defect characteristic detection from the outside, and the vertical axis is set. Output values (k, k1, k2) for each frame Fk (k = 1,..., N ′) and a plurality of frames F1, F2,. . . , FN ′, the average value Vave (k1, k2), the standard deviation Vσ (k1, k2), and the average value Vave (k1, k2) of the output of the frame Fl determined to be remarkably large. The value and the threshold value α ′ set by the outside are displayed.

  Further, the blinking defect candidate (k1, k2) is switched to the remaining blinking defect candidate (k1, k2) sequentially detected by the blinking defect display switching setting from the outside, and the switched blinking defect candidate (k1, k2) is switched to. The corresponding flashing defect characteristics are displayed in the same graph. When all the remaining blinking defect candidates (k1, k2) are switched, the display returns to the first displayed blinking defect candidate (k1, k2) and the above is repeated. If there is no blinking defect candidate, a display indicating that there is no blinking defect candidate is displayed.

Thus, for the detected blinking defect candidate (k1, k2), the user can easily confirm the observation result of the variation at the blinking output and the output interval at the blinking output, and from the observation result, Since the user can set the number of frames N and the threshold value α to compensate for the blinking interval from the outside appropriately according to the blinking output characteristics of the infrared solid-state imaging device 10, the blinking defect detection means 36 can specify the blinking defective pixel with high accuracy. Detection is possible.
If there is no blinking defect candidate or the blinking defect candidate is specified but the output interval at the time of blinking output is not obtained, that is, when the blinking output is performed only once, the output interval at the time of blinking output Therefore, there is a possibility that the number of imaging frames N ′ for obtaining the image quality is not satisfied. Therefore, it is necessary to increase the number of imaging frames N ′ from the outside and detect the blinking defect characteristic again.

Embodiment 3 FIG.
FIG. 4 is a block diagram for explaining an infrared imaging device having an infrared image correction device 14c according to Embodiment 3 of the present invention. Hereinafter, the infrared image correction device 14c will be described in detail, and the infrared imaging device 12 of the third embodiment will be described.
In this embodiment, a blinking defect characteristic detection availability unit 44 and a blinking defect detection availability unit 46 are added to the second embodiment.

The blinking defect characteristic detection enable / disable means 44 observes the output from the infrared solid-state imaging device 10 in the blinking defect characteristic detection in the second embodiment, and determines whether or not the blinking defect characteristic can be detected with accuracy, and closes the shutter 22. Or when the shutter 22 is opened and the subject is imaged to detect blinking defect characteristics from the outside. First, the infrared solid-state imaging device 10 is imaged, and the output from the infrared solid-state imaging device 10 is converted into a plurality of frames F1, F2,. . . , FN ′ are stored in the image memory 20.

  The blinking defect characteristic detection enable / disable means captures the output from the infrared solid-state imaging device 10 stored in the image memory 20 for each frame, and for each frame Fk (k = 1,..., N ′), the infrared solid-state imaging device 10. The output value V (k, k1, k2) for each pixel (k1, k2) (k1 = 1,..., N1), (k2 = 1,. Repeat for all frames. For each pixel (k1, k2) constituting the infrared solid-state imaging device 10, a plurality of frames F1, F2,. . . , FN ′, the plurality of frames F1, F2,. . . , FN ′, the average value Vave (k1, k2) of the output of the image sensor and the standard deviation Vσ (k1, k2) are calculated and stored.

  Here, when the upper limit and the lower limit of the allowable output of the infrared solid-state imaging device 10 are Sh (high, hereinafter abbreviated as h) and Sl (low, hereinafter abbreviated as l), Vave (k1, k2) is Vave (k1, k2). When k1, k2)> Sh or Vave (k1, k2) <Sl, the set temperature of the shutter 22 or the subject is out of the dynamic range of the infrared solid-state imaging device 12, and the output of the infrared solid-state imaging device 10 is constantly allowed. Since it exceeds the output range and is considered to be an error factor when the blinking defect characteristic is detected, if the condition is met, the blinking defect characteristic detection unit 40 is not implemented and the blinking defect characteristic display unit 42 is “Infrared solid-state image sensor output error” is displayed.

  In addition, when the standard deviation Vσ (k1, k2) is larger than a threshold value S set in advance in consideration of noise that is constantly output as a non-flashing state, the shutter 22 or Since the output fluctuation due to the temperature change is dominant and varies with respect to the noise that the output of the infrared solid-state imaging device 10 steadily outputs due to a change in the temperature of the subject, etc. Even if they match, the blinking defect characteristic detection means 40 is not implemented, and “abnormality of infrared solid-state image sensor output” is displayed on the blinking defect characteristic display means 42.

  However, the fixed defective pixels are constantly output with abnormal brightness, and are thus excluded from the determination targets based on the above two conditions. As a result, the shutter 22 or the subject blinks due to the influence when the set temperature is out of the dynamic range of the infrared solid-state imaging device 12 and when the shutter 22 or the subject has a temperature change during the imaging of the infrared solid-state imaging device 10. It is possible to prevent erroneous detection of defect characteristics and to prompt the user that the output of the infrared solid-state imaging device 10 is abnormal and the blinking defect characteristics cannot be detected.

The blinking defect detection enable / disable means 46 is for observing the output from the infrared solid-state imaging device 10 in the blinking defect detection in the second embodiment and determining whether or not the blinking defect can be detected accurately. Alternatively, the shutter 22 is opened and an image of the subject is imaged, and this is performed when setting blinking defect detection from the outside. First, the infrared solid-state imaging device 10 is imaged, and the output from the infrared solid-state imaging device 10 is converted into a plurality of frames F1, F2,. . . , FN are stored in the image memory 20.

The blinking defect characteristic detection enable / disable means captures the output from the infrared solid-state imaging device 10 stored in the image memory 20 for each frame, and for each frame Fk (k = 1,..., N), The output value V (k, k1, k2) for each pixel (k1, k2) (k1 = 1,..., N1), (k2 = 1,. Repeat for all frames. For each pixel (k1, k2) constituting the infrared solid-state imaging device 10, a plurality of frames F1, F2,. . . , FN, and the plurality of frames F1, F2,. . . , FN, the average value Vave (k1, k2) of the output of the image sensor and the standard deviation Vσ (k1, k2) are calculated and stored.

Here, when the upper limit and the lower limit of the allowable output of the infrared solid-state imaging device 10 are Sh and Sl, respectively, Vave (k1, k2)> Sh or Vave (k1, k2) <Sl for the Vave (k1, k2). Sometimes, the set temperature of the shutter 22 or subject is out of the dynamic range of the infrared solid-state imaging device 12, and the output of the infrared solid-state imaging device 10 regularly exceeds the allowable output range, which is considered as an error factor when detecting a blinking defect. Therefore, if the condition is met, the blinking defect detecting means 38 is not executed, and “infrared solid-state image sensor output abnormality” is displayed on the blinking defect characteristic display means 42.

In addition, when the standard deviation Vσ (k1, k2) is larger than a threshold value S set in advance in consideration of noise that is constantly output as a non-flashing state, the shutter 22 or The output fluctuation due to the temperature change is dominant with respect to the noise that the output of the infrared solid-state imaging device 10 outputs steadily due to the temperature change of the subject, etc. In this case, the blinking defect detection means 38 is not implemented, and the blinking defect characteristic display means 42 displays “infrared solid-state image sensor output abnormality”.

However, the fixed defective pixels are constantly output with abnormal brightness, and are thus excluded from the determination targets based on the above two conditions. As a result, the shutter 22 or the subject blinks due to the influence when the set temperature is out of the dynamic range of the infrared solid-state imaging device 12 and when the shutter 22 or the subject has a temperature change during the imaging of the infrared solid-state imaging device 10. It is possible to prevent erroneous detection of defects and to prompt the user that the output of the infrared solid-state imaging device 10 is abnormal and that the blinking defect cannot be detected.

Embodiment 4 FIG.
FIG. 5 is a block diagram for explaining an infrared imaging device having the infrared image correction device 14d according to the first embodiment of the present invention. Hereinafter, the infrared image correction device 14d will be described in detail, and the infrared imaging device 12 of the first embodiment will be described.
In this embodiment, a blinking defect detection condition storage unit 48 and a blinking defect detection condition internal / external switching unit 50 are added to the third embodiment.

The blinking defect detection condition storage means 48 stores the number of imaging frames N set by the outside and the threshold value α for detecting the blinking defect as the blinking defect detection condition when the blinking defect detection is set by the outside. The stored value is updated and stored whenever the external setting is made. The blinking defect detection condition external / internal switching means 50 is an externally set blinking defect detection condition based on the setting of an external blinking defect detection external / internal condition as a blinking defect detection condition used at the time of external blinking defect detection setting. Alternatively, the stored blinking defect detection condition is selected and used.

Accordingly, since the user uses the infrared imaging device 12 for the first time, the visual confirmation by the television monitor 34 of the detection result of the blinking defect characteristic is the first time, and the blinking defect corresponding to the output of the infrared solid-state imaging device 10 set when the blinking defect detection is set. When the detection condition is set for the first time, it is necessary to use the external setting based on the external setting of the flashing defect detection. However, the flashing defect detection condition of the infrared imaging device 12 is almost reproduced every time the power is turned on. Since the blinking defect detection condition corresponding to the output of the solid-state imaging device 10 is stored in the blinking defect detection condition storage means 48, when the infrared imaging device 12 is used after the next time, it is not necessary to set the blinking defect detection condition by the outside. Thus, the burden on the user's operation can be reduced.

It is a block diagram for demonstrating the infrared imaging device which has the infrared image correction apparatus by Embodiment 1 of this invention. It is a block diagram for demonstrating the infrared imaging device which has the infrared image correction apparatus by Embodiment 2 of this invention. It is a figure for demonstrating the blink defect display means by Embodiment 2 of this invention. It is a block diagram for demonstrating the infrared imaging device which has the infrared image correction apparatus by Embodiment 3 of this invention. It is a block diagram for demonstrating the infrared imaging device which has the infrared image correction apparatus by Embodiment 4 of this invention. It is a block diagram which shows an example of the infrared imaging device using the solid-state imaging device concerning a prior art.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Infrared solid-state image sensor, 12 Infrared imaging device, 14 Infrared image correction apparatus, 16 Lens, 18 Offset correction means, 20 Image memory, 22 Shutter, 24 Sensitivity correction means, 26 Sensitivity coefficient calculation, Fixed defect detection means, 28 Sensitivity coefficient Defect information storage means, 30 Defect correction means, 32 Video signal generation means, 34 TV monitor, 36 Luminance comparator, 38 Flashing defect detection means, 40 Flashing defect characteristic detection means, 42 Flashing defect characteristic display means, 44 Flashing defect characteristic detection Availability means, 46 blinking defect detection availability judgment means, 48 blinking defect detection condition storage means, 50 blinking defect detection condition external / internal switching means.

Claims (4)

For an image sensor output of a solid-state image sensor that captures at least an infrared region, an image memory that stores in advance an output offset between each pixel composed of the solid-state image sensor, and an image sensor output of the solid-state image sensor during normal use Offset correction means for removing the output offset between the pixels stored in the image memory, sensitivity coefficient for correcting sensitivity variations between the pixels, and sensitivity coefficient calculation for detecting defective pixel position information that is a fixed defect Fixed defect detection means, a luminance comparator for detecting defective pixel position information that is a blinking defect, sensitivity coefficient defect information storage means for storing the detected sensitivity coefficient and defective pixel position information of the fixed defect and blinking defect, A sensitivity correction method for correcting variations in sensitivity among the pixels using the sensitivity coefficient with respect to the output after the offset correction. And a defect correction means for correcting the defective pixel based on the defective pixel position information of the fixed defect and the blinking defect with respect to the output after the sensitivity correction, and a video signal generation for outputting the output after the correction of the defective pixel as a video signal. And an infrared image correction apparatus comprising:
The imaging device output output from the solid-state imaging device is stored in the image memory over a plurality of imaging frames, and for each pixel configured from the solid-state imaging device, the output of each imaging device over the plurality of imaging frames An average value and a standard deviation value are calculated, and an absolute value obtained by subtracting the average value from an output value of each imaging element for each imaging frame is calculated, and this absolute value is a predetermined constant of the standard deviation value. An infrared image correction apparatus comprising: a blinking defect detection unit configured to detect a pixel exceeding twice as a blinking defective pixel. Furthermore, a blinking defect characteristic detecting means for detecting a blinking defect output characteristic output from the solid-state imaging device, and a blinking defect characteristic display means for displaying the blinking defect characteristic detection information are provided.
By appropriately setting the value of the number of frames to be imaged and the constant value to be multiplied by a constant set by the user visually observing with the monitor device and setting for specific detection of the blinking defective pixel based on the observed output characteristics 2. The infrared image correction apparatus according to claim 1, wherein a blinking defective pixel is detected with high accuracy. Furthermore, the image sensor output value output from the solid-state image sensor is observed, and a blinking defect characteristic detection availability determining unit for determining whether or not the blinking defect characteristic can be detected is provided.
When the abnormality is determined, the infrared imaging output abnormality is displayed on the monitor device to prompt the user to detect the infrared imaging output abnormality, and the blinking defect detection and the blinking defect output characteristic are not detected. 3. The infrared image correction apparatus according to claim 1, wherein the detection of the blinking defect or the erroneous detection of the blinking defect output characteristic due to the influence of the abnormality of the imaging element output is prevented beforehand. Further, when the defect detection setting for flashing is set externally, the flashing defect detection condition storage means for storing the flashing defect detection condition, and the flashing defect detection condition set by the outside as the flashing defect detection condition used when setting the flashing defect detection, or A blinking defect detection condition external / internal switching means for selecting one of the blinking defect detection conditions stored in the blinking defect detection condition storage means;
About the blinking defect detection condition at the time of the above-mentioned blinking defect detection, after the user sets appropriately based on the output, the infrared image correction device stores it internally so that the user can use the infrared image correction device from the next time onward. 4. The infrared image correction apparatus according to claim 3, wherein the user's operation burden is reduced by making the setting of the blinking defect detection condition unnecessary.

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