JP2005129998A - Method for stabilizing output value of ccd camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for stabilizing the output value of a CCD camera by correcting variations in the output value caused by colors, defects and a temporal change of CCD elements and reducing variations in the sensitivity among pixels. <P>SOLUTION: The method includes: acquiring image data representing the sensitivity of the CCD elements; selecting a region with a prescribed size from an output image on the basis of the image data; setting a plurality of kinds of number of pixels to obtain an average value; obtaining a plurality of data, one of data being an average by each of the number of pixels set respectively; determining the set number of pixels of a plurality of data whose variation is a prescribed value or below among variations of the average values of a plurality of the data obtained respectively as an optimum number of averaged pixels; and outputting the determined average value of the number of averaged pixels as one data. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention suppresses, for example, the sensitivity variation for each pixel of a CCD element of a CCD camera by averaging the output values of a plurality of adjacent pixels, and stabilizes the output value of the CCD camera. It is about.

Normally, when using a CCD camera, there are variations in the sensitivity of the CCD device (depending on brightness and color), defects in the CCD device, and variations with time, such as fixed pattern noise and random noise. To do.
For this reason, even if a uniform light source is actually input to the CCD element, a uniform output result cannot be obtained due to these variations.
Therefore, a method for suppressing variation using an output result obtained from an image measured by a CCD camera is required.

In order to suppress such variation in sensitivity of the CCD element, a conventional solid-state imaging device includes a solid-state imaging element having a characteristic that an output voltage naturally changes logarithmically with respect to the amount of received light, and is obtained from imaging data of a subject. By subtracting the imaging data at the time of uniform light irradiation, the sensitivity non-uniformity between the pixels is corrected (see, for example, Patent Document 1).
Another conventional solid-state imaging device is a natural logarithmic solid-state imaging device that corrects variations in output for each pixel together with variations in pixel sensitivity, and also corrects variations due to transistors, voltage-charge conversion elements, and the like. As a result, an imaging output with extremely small variation for each pixel is obtained (for example, see Patent Document 2).

Further, another method for correcting the imaging output is a method of acquiring a plurality of correction data in advance before imaging exposure and having a high S / N ratio by performing an averaging operation or the like from the plurality of correction data. 2 correction data is acquired, and element values such as circuit system temperature, imaging exposure time, and dark output that affect the output of the image sensor during imaging exposure are acquired as parameters, and correction coefficients are acquired from the parameters. Further, third correction data is obtained from the second correction data and the correction coefficient. Then, at the time of imaging exposure, when the imaging output of the imaging device is corrected, the imaging output is added without adding a noise component by using the third correction data reflecting the element at this time. Thus, an image output having a high S / N ratio can be obtained with certainty. (For example, refer to Patent Document 3).
JP-A-5-30350 JP-A-5-167848 JP-A-11-177891

The pixel sensitivity variation correction method using the conventional solid-state imaging device described in Patent Documents 1 and 2 corrects the sensitivity variation of the CCD element and the variation of the circuit system. However, this correction only considers the effect of brightness, and in reality, there are variations due to color, defects, and temporal changes, and these variations cannot be corrected. It was.
In addition, the conventional imaging output correction method described in Patent Document 3 has a problem in that although individual pixel variations are corrected, variations between pixels are not corrected.
Therefore, the present invention has been made to solve such a problem, and by averaging the output values of a plurality of adjacent pixels, it is possible to correct variations caused by the color, defect, and time change of the CCD element. An object of the present invention is to obtain a CCD camera output value stabilization method that reduces variations in sensitivity between pixels and stabilizes the output value of the CCD camera.

  In order to solve the above problems, the present invention obtains image data representing the sensitivity of a CCD element, selects a region having a predetermined size from an output image based on the image data, and obtains an average value. A plurality of types are set, and a plurality of data each having an average value for each set number of pixels as one data is obtained from the area, and among the variations of the average values in the obtained data, the variation is predetermined. It is characterized in that the set number of pixels of a plurality of data as described below is determined as an optimal averaged pixel number, and the average value of the determined averaged pixel number is output as one data.

According to the present invention, an area having a predetermined size is selected from an output image based on image data representing the sensitivity of a CCD element, and an average value for each number of pixels set from the area is set as a plurality of data. The average number of pixels determined is determined by determining the set number of pixels of the plurality of data whose variation is equal to or less than a predetermined value among the variations of the average values of the plurality of data, and determining the average number of pixels determined Is output as one data, the output data has as little variation in sensitivity as possible, and color information can be extracted with reduced variation in sensitivity.
In addition, by determining the set number of pixels of a plurality of data whose variation is equal to or less than a predetermined average as the number of average pixels, an optimal average corresponding to the sensitivity variation finally obtained for each CCD camera or each measurement situation The number of pixels can be determined.

  Further, the present invention acquires image data representing the sensitivity of the CCD element, selects a region having a predetermined size from an output image based on the image data, sets a plurality of types of pixels for obtaining an average value, A plurality of data, each having an average value for each set number of pixels as one data, is obtained from the region, and the variation of the average value in each of the obtained data is obtained from the standard deviation. The number of set pixels of a plurality of data having the above is determined as the optimal averaged pixel number, and the average value of the determined averaged pixel number is output as one data.

According to the present invention, an area having a predetermined size is selected from an output image based on image data representing the sensitivity of a CCD element, and an average value for each number of pixels set from the area is set as a plurality of data. For each of the obtained data, each of the obtained average data variation of the average value is determined from the standard deviation, respectively, the set number of pixels of the plurality of data having a standard deviation of a predetermined value or less is determined as the optimal averaged pixel number, Since the average value of the determined average number of pixels is output as one data, the output data has as little sensitivity variation as possible based on the standard deviation, and color information is extracted with reduced sensitivity variation. Became possible.
Further, by determining the set number of pixels of a plurality of data having a standard deviation whose variation is not more than a predetermined value as an optimal average number of pixels, it is based on the standard deviation finally obtained for each CCD camera or each measurement situation thereof. It is possible to determine the optimum average number of pixels according to the sensitivity variation.

Also, in the output value stabilization method of the CCD camera of the present invention, the desired number of pixels to be averaged by the CCD elements in the region are respectively cut out, and the average value of the output of the desired number of cut out pixels is respectively set as one data. When obtaining, compare the output value of each cut-out pixel with a threshold value indicating a preset defect, and substitute the value calculated in the surrounding pixels for pixels outside the threshold value. Yes.
By doing so, when there is a defect in the pixels cut out to obtain the average value, the average value can be obtained unless it is a large defect.

Further, in the output value stabilization method of the CCD camera of the present invention, among the optimum averaged pixel number, the one corresponding to the desired resolution of the output image is finally determined as the optimum averaged pixel number. Yes.
By doing this, the optimal average pixel count corresponding to the resolution required for the product is determined from among the set average pixel counts of the plurality of data having a standard deviation with a variation equal to or less than a predetermined value. can do.

Further, in the output value stabilization method of the CCD camera of the present invention, light having different brightness is measured by the CCD camera, the optimum number of average pixels for each brightness is determined, and the optimum average pixel of each brightness is determined. The number of average pixels from the maximum value is determined as the final optimum number of average pixels.
As described above, since the maximum number of the optimum average number of pixels for each brightness is set as the final optimum average number of pixels, the variation in sensitivity increases as the brightness increases. This is because, if the average pixel number that suppresses bright and large variations in sensitivity is matched, it is possible to cover pixels that are smaller in brightness and have smaller variations in sensitivity.

Further, in the output value stabilization method of the CCD camera of the present invention, an optimum average number of pixels for each wavelength is determined for a CCD element that captures light having different wavelengths, and the maximum number of pixels from the optimum average number of pixels for each wavelength is determined. The average number of pixels of the value is determined as the final optimum average number of pixels.
In this way, since the variation in sensitivity varies depending on the wavelength by setting the maximum number of the optimum averaged number of pixels for each wavelength as the final optimum number of averaged pixels, the wavelength having a large variation in sensitivity. This is because a pixel having a wavelength with less sensitivity variation can be covered if the average pixel number that suppresses the pixel is matched.

Further, in the output value stabilization method of the CCD camera of the present invention, an optimum average number of pixels per hour is determined for a CCD element that images light at a fixed time interval, and the optimum average number of pixels per time is determined. The maximum average number of pixels is finally determined as the optimum average number of pixels.
This is because, for example, if the fixed time interval is the time interval between when the product is completed and when it is used, the variation in sensitivity usually increases with the passage of time. This is because it is sufficient to match the number of averaged pixels.

Furthermore, in the CCD camera output value stabilization method of the present invention, for the CCD elements each picking up light with different brightness, the finally optimum average number of pixels determined by the method according to claim 3; 5. For CCD elements each picking up light with different wavelengths, for the CCD elements picking up light at regular time intervals, and finally with the optimum average number of pixels determined by the method of claim 4. When the final optimum average number of pixels determined by the method described above is obtained, the maximum value or the average value of these final optimum average pixel numbers is corrected. The number of pixels to be averaged is determined.
In this way, the optimum number of average pixels is determined from the viewpoints of different factors such as brightness, light having different wavelengths, and fixed time intervals, and the maximum value or average value of these is averaged for correction. If the number is determined as a number, it is possible to cover a factor with a smaller sensitivity variation if it is matched with the average number of pixels that suppresses a factor with a large sensitivity variation.
The reason why these values are averaged is that there is actually no problem in terms of sensitivity variations if they are between those having a large sensitivity variation and those having a small sensitivity variation.

According to the output value stabilization method of the CCD camera of the present invention, an area having a predetermined size is selected from an output image based on image data representing the sensitivity of the CCD element, and an average for each number of pixels set in plural types from the area is selected. A plurality of data with a value of 1 data is obtained, and among the variations of the average value in the plurality of data, the set number of pixels of the plurality of data whose variation is equal to or less than a predetermined value is determined as the optimal averaged pixel number. Since the average value of the averaged number of pixels is output as one data, the output data has as little sensitivity variation as possible, and color information can be extracted with reduced sensitivity variation. is there.
In addition, by determining the set number of pixels of a plurality of data whose variation is equal to or less than a predetermined average as the number of average pixels, an optimal average corresponding to the sensitivity variation finally obtained for each CCD camera or each measurement situation The number of pixels can be determined.

Embodiment 1.
FIG. 1 is a block diagram showing the configuration of an apparatus for carrying out the output value stabilization method for a CCD camera according to Embodiment 1 of the present invention, FIG. 2 is a flowchart showing the operation of the output value stabilization method for the CCD camera, and FIG. Is an explanatory diagram showing the averaging method of the output value stabilization method of the CCD camera, FIG. 4 is a graph showing the relationship between the number of average pixels and the standard deviation in the output value stabilization method of the CCD camera, and FIG. It is explanatory drawing which shows the relationship between the average pixel number and the resolution in the output value stabilization method of a CCD camera.
In FIG. 1, 1 is an organic EL panel that is a color panel, 3 is a pattern generator that outputs various patterns to the organic EL panel 1, and 4 is a CCD camera that captures an image of the organic EL panel 1. A CCD element having a resolution higher than the resolution is mounted.
Reference numeral 5 denotes a computer device which is an arithmetic means for controlling the pattern generator 3 and performs image processing picked up by the CCD camera 4, and 6 is a display device connected to the computer device 5.

Next, a method for stabilizing the output value of the CCD camera according to the first embodiment of the present invention will be described with reference to the flowcharts of FIGS.
First, the CCD camera 4 captures a uniform light image having a predetermined brightness of the organic EL panel 1 illuminated by the backlight, and the computer device 5 acquires image data representing the sensitivity captured by the CCD camera 4. (Step S1).
In order to grasp the sensitivity variation of the CCD element, it is necessary to measure a uniform light source. However, since there is no uniform light source at present, first, image data is acquired in a light-shielded state in order to measure the characteristics of only the CCD element, which is affected by variations in the light source.

Next, the computer device 5 selects an area of 60 × 60 (3600 CCD pixels) from the center of the image in order to derive the number of CCD pixels (step S2).
In this way, the center area of the image is selected because it is easy to handle in terms of data because the lens system has a lens system and the area near the center is not easily affected by the light of the lens system and there is little variation. Because I know. Therefore, a lens that does not have a lens system may not be the central region of the image.
The reason why the size of the region is 60 × 60 (3600 CCD pixels) is that this size is reflected as variations in the entire image.

Then, an image selected from an area of 60 × 60 (3600 CCD pixels) from the center of the image is set as an output image for averaging (step S3).
Thereafter, when 25 (5 × 5) data is created from the output image, the number of CCD elements to be averaged per data is set (step S4).
For example, as shown in FIG. 3 (a), there are 100 pixels of CCD elements, and when 25 data is created from that, if one pixel per data is set as shown in FIG. 3 (b) (1 25 pixels is obtained if there are 25 pixels.
Further, as shown in FIG. 3C, if 4 pixels per data (4 pixels / 1 data), 25 data can be obtained if 100 pixels.
The above is an explanation of obtaining 25 data when the pixels to be averaged are 1 and 4 from the pixels of 100 CCD elements. Usually, 100 data is usually obtained. The numbers are also 1 (1 pixel / 1 data), 4 (4 pixels / 1 data), 9 (9 pixels / 1 data), 16 (16 pixels / 1 data), 25 (25 pixels / 1 data), 36 (36 100 data is obtained as (pixel / 1 data).

Next, an average value of the output values for the average number of pixels set from the output image of the selected area is obtained by calculation (step S5).
In step S5, when the average value of the output values for the average number of pixels set from the output image of the selected area is obtained by calculation, the output value of each cut out pixel and the preset defect are determined. Is compared with a threshold value representing the value of the pixel, and the value calculated for the neighboring pixels is substituted for a pixel outside the threshold value.
By doing so, it is possible to obtain the average value of the output values if there is a defect in the pixels that are cut out in order to obtain the average value, as long as there is no large defect.

Thereafter, for 100 data, a standard deviation is obtained from the average value data of the output values corresponding to the set number of averaged pixels (for the number of divisions) (step S6).
The graph of FIG. 4 shows the relationship between the obtained standard deviation and the average pixel count.
Next, of the standard deviations, for example, a standard deviation is set such that a variation required for each CCD camera is equal to or less than a predetermined value, for example, 1 or less, and an optimal average number of pixels is determined based on the standard deviation where the set variation is equal to or less than a predetermined value. Determine (steps S7 and S8).

Thus, since the average value of the output values of the determined average number of pixels is output as one data, the output data has as little sensitivity variation as possible based on the standard deviation, and the sensitivity variation. Color information can be extracted with reduced color.
Further, by determining the set number of pixels of a plurality of data having a standard deviation whose variation is not more than a predetermined value as an optimal average number of pixels, it is based on the standard deviation finally obtained for each CCD camera or each measurement situation thereof. It is possible to determine the optimum average number of pixels according to the sensitivity variation.
In the above description, the optimum average number of pixels is determined based on the standard deviation. However, the optimum average number of pixels can be determined by empirical rules without using the standard deviation. Needless to say, it can be done.

In Steps S7 and S8, when, for example, a standard deviation of 1 or less is set and the optimum number of pixels to be averaged is determined based on the standard deviation whose set variation is a predetermined value or less, the number of data to be averaged, that is, the average When the number of pixels increases, the accuracy of suppressing sensitivity variations increases, but the resolution decreases.
FIG. 5 shows the relationship between the number of averaged pixels and the resolution, and it can be seen from FIG. 5 that the resolution becomes worse as the number of averaged pixels increases.
Here, the resolution of 2000 means that when the number of CCD elements for taking one pixel of the organic EL panel is 8000 (40 × 200), the average number of pixels 4 is 2 × 2, so 20 divisions. This means 100 divisions and 2000 divisions (20 × 100). Further, the resolution of 500 means that the average number of pixels 16 is 4 × 4, which means 500 divisions (10 × 50) of 10 divisions and 50 divisions.
Therefore, the resolution increases as the number of divisions increases for a certain area.
Therefore, in determining the optimal number of average pixels, it is necessary to consider the resolution in addition to the standard deviation.

Therefore, among the optimum average number of pixels determined based on the standard deviation, the one corresponding to the desired resolution of the output image is finally determined as the optimum average number of pixels.
By doing this, the optimal average pixel count corresponding to the resolution required for the product is determined from among the set average pixel counts of the plurality of data having a standard deviation with a variation equal to or less than a predetermined value. can do.

In the above description, in step S1, the CCD camera 4 captures a uniform light image having a predetermined brightness of the organic EL panel 1, and the computer device 5 acquires the image data captured by the CCD camera 4, Through steps S2 to S6, the optimum average number of pixels is determined based on the standard deviation and resolution. However, when the brightness is different, the variation in sensitivity is different. There is a tendency for variations in sensitivity to increase.
Therefore, an optimum average number of pixels for each brightness is determined for CCD elements that have captured light of different brightness, and the maximum average number of pixels is determined from the optimum average number of pixels for each brightness. The optimum number of averaged pixels is used.
In this way, by setting the maximum average number of pixels from the optimal average number of pixels for each brightness to the final optimal average number of pixels, the variation in sensitivity increases as the brightness increases. For this reason, if the number of pixels is adjusted to an average number of pixels that suppresses bright and large variations in sensitivity, it is possible to cover pixels having a smaller brightness and smaller variations in sensitivity.

Embodiment 2.
FIG. 6 is a flowchart showing the operation of the output value stabilization method of the CCD camera according to the second embodiment of the present invention, and FIG. 7 is an explanation showing the value of the standard deviation with respect to the averaged data number of the output value stabilization method of the CCD camera. FIG. 8 is a graph showing the relationship between the average output value of R, G and B and the standard deviation of the output value stabilization method of the CCD camera, and FIG. 9 is the luminance value and standard of the output value stabilization method of the CCD camera. It is a graph which shows the relationship of deviation.
In the second embodiment, variation in sensitivity of the CCD element with respect to light having different wavelengths, that is, color, is grasped, variation in luminance in the plane is small, and temporal luminance variation is stable. Color (red, green, blue) LED backlights were used. The specifications of each LED backlight are as follows.
When the color is red, the peak wavelength is 660 nm, green is the peak wavelength 525 nm, and blue is the peak wavelength 470 nm.
The organic EL panel 1 emits light in a state where R, G, and B are alternately arranged. The CCD camera 4 is a 3CCD camera.
Furthermore, grasping the variation of all the CCD elements (1344 × 1024 × 3) has a huge amount of data processing, so the area at the center of the CCD element is determined, converted from image information to numerical information, and evaluation of the variation Like to do. Further, this area is the number of CCD elements necessary for taking in one pixel of the organic EL panel 1.

Next, the operation of the output value stabilization method for the CCD camera according to the second embodiment of the present invention will be described with reference to the flowchart shown in FIG.
First, the 3CCD camera 4 captures R, G, and B light images of the backlit illuminated organic EL panel 1, and the computer device 5 acquires image data representing the sensitivity captured by the 3CCD camera 4 (step S11). ).
In this case as well, the image data is actually acquired in a light-shielded state in order to measure the characteristics of only the CCD element without being affected by variations in the light source.

Next, the computer device 5 selects an area of 10 × 24 (240 CCD pixels) from the center of the image in order to derive the number of CCD pixels (step S12).
The reason why the center area of the image is selected in this way is that it is known from experience that it is easy to handle data because the vicinity of the center of the image is hardly affected by light and there is little variation. The reason why the size of the region is 20 × 40 (240 CCD pixels) is that this size is reflected as variations in the entire image.

Then, an R output image for averaging an image in which an area of 10 × 24 (240 CCD pixels) is selected from the center of the image is set (step S13).
Thereafter, when 100 data is created from the R output image, the number of pixels of the CCD elements to be averaged per data is set (step S14).
In this case, the number of pixels to be averaged is also 1 (1 pixel / 1 data), 4 (4 pixels / 1 data), 9 (9 pixels / 1 data), 16 (16 pixels / 1 data), 25 (25 pixels) / 1 data) and 36 (36 pixels / 1 data), 100 data is obtained.

Next, an average value of output values for the number of average pixels set from the R output image of the selected area is obtained by calculation (step S15).
In step S15, when the average value of the output values for the average number of pixels set from the output image of the selected area is obtained by calculation, the output value of each cut-out pixel and a preset defect are obtained. Is compared with a threshold value representing the value of the pixel, and the value calculated for the neighboring pixels is substituted for a pixel outside the threshold value.
By doing so, it is possible to obtain the average value of the output values if there is a defect in the pixels that are cut out in order to obtain the average value, as long as there is no large defect.

Thereafter, for 100 data, a standard deviation is obtained from the average value data of the output values corresponding to the set number of averaged pixels (for the number of divisions) (step S6).
Next, of the standard deviations, for example, a standard deviation is set such that a variation required for each CCD camera is equal to or less than a predetermined value, for example, 1 or less. Determine (steps S17 and S18).
Also, for the G output image, the optimum average number of pixels is determined through steps S13 to S28 having the same contents as the R output image.
Further, for the B output image, the optimum average number of pixels is determined through steps S33 to S38 having the same contents as the R output image.
Next, among the averaged pixel numbers determined for the RGB output values, the maximum value is set as the final averaged pixel number (step S39).

As described above, the sensitivity variation varies depending on the wavelength by setting the maximum average pixel count from the optimal average pixel count for each wavelength of RGB to the final optimal average pixel count. This is because, if the number of average pixels is suppressed so as to suppress a pixel having a large wavelength, it is possible to cover a pixel having a smaller sensitivity variation.
Then, since the average value of the determined optimum averaged number of pixels is output as one data, the output data has as little sensitivity variation as possible based on the standard deviation, and the sensitivity variation is reduced. Color information can be extracted.

FIG. 7 shows the results when the average brightness and standard deviation of R, D, and G are obtained from 100 data and the brightness of green is changed (red and blue LEDs). Are omitted because the trend is close). FIG. 8 is a graph showing the relationship between the average value and standard deviation for R, D, and G for each set average pixel number from 100 data.
From the results shown in FIGS. 7 and 8, the standard deviation value decreases as the number of averaged CCD pixels per data increases. Therefore, it has been found that increasing the number of CCD pixels to be averaged has the effect of numerically suppressing variations in CCD elements.

Next, color information (luminance) was converted based on RGB output values, and the degree of influence was actually calculated. The conversion to luminance is derived from the RGB output value of the green LED, and the result of conversion is shown in FIG. Since the conversion is a linear operation, the relationship between the standard deviation and the luminance value approximates the relationship with the RGB average output value. The current average of 25 to 36 CCD pixels per data at 300 cd / m 2 shows a standard deviation of 1 or less.
Therefore, in order to suppress spatial and temporal variations in CCD elements, it is considered that a method of averaging with 25 to 36 CCD pixels per data is optimal. In addition, when 36 CCD pixels are used, it is about 3 divisions per pixel of organic EL panel. In addition, when considering human eyes as a reference, it is reasonable to average 25-36 CCDs per data because it is possible to see one pixel in approximately three divisions for calculation. The conclusion has been reached.

Embodiment 3.
In the third embodiment, for example, an optimal average number of pixels per hour is determined for a CCD element that captures light of a predetermined brightness at regular time intervals, and among the optimal average number of pixels per time, The one with the larger number of averaged pixels is finally determined as the optimum number of averaged pixels.
This is because, for example, if the fixed time interval is the time interval between when the product is completed and when it is used, the variation in sensitivity usually increases with the passage of time. This is because it is sufficient to match the number of averaged pixels.

Embodiment 4.
In the fourth embodiment, for the CCD elements that pick up images of light with different brightness, the optimum average number of pixels determined by the method described in the first embodiment and the light with different wavelengths are respectively used. As for the CCD element that has been imaged, the optimum average number of pixels determined by the method described in the second embodiment and the CCD element that has captured light at a predetermined time interval have been described in the third embodiment. When the final optimal average pixel number determined by the method is obtained, the maximum value or the average value of these final optimal average pixel numbers is corrected for correction. Is determined as the average number of pixels.

In this way, the optimum number of average pixels is determined from the viewpoint that the factors such as brightness, light (color) having different wavelengths, and constant time intervals are different, and the maximum value or the average value of these is corrected. If it is determined as the number of averaged pixels, it is possible to cover factors with less sensitivity variation than the averaged number of pixels that suppresses factors with large sensitivity variations. .
Further, the reason why these values are averaged is that there is no practical problem in terms of sensitivity variations if they are between those having a large sensitivity variation and those having a small sensitivity variation.

In the above embodiment, the organic EL panel 1 is described as a color panel picked up by the CCD camera 4. However, the present invention can also be applied to display body parts such as a liquid crystal panel, a plasma display, and a DMD (digital mirror device). .
The output value stabilization method of the CCD camera described in the above embodiment is a correction method of random noise caused by each CCD element of the CCD camera 4, and the averaging determined by the output value stabilization method of the CCD camera is used. When the output of the average value of the number of pixels as one data is actually used, the fixed pattern noise correction processing described in the conventional example is performed.

  The output value stabilization method of the CCD camera according to the present invention described above is applied to the local region of the output image, but is not limited to the local region of the output image, and the entire image taking into account the variation of the lens system Application to the correction method is also possible.

It is a block diagram which shows the structure of the apparatus which implements the output value stabilization method of the CCD camera of Embodiment 1 of this invention. It is a flowchart which shows operation | movement of the output value stabilization method of the CCD camera. It is explanatory drawing which shows the averaging method of the output value stabilization method of the CCD camera. It is a graph which shows the relationship between the average pixel number and the standard deviation in the output value stabilization method of the CCD camera. It is explanatory drawing which shows the relationship between the average pixel number and the resolution in the output value stabilization method of the CCD camera. It is a flowchart which shows operation | movement of the output value stabilization method of the CCD camera of Embodiment 2 of this invention. It is explanatory drawing which shows the value of the standard deviation with respect to the average data number of the output value stabilization method of the CCD camera. It is a graph which shows the relationship between the average output value of R, G, B of the output value stabilization method of the CCD camera, and a standard deviation. It is a graph which shows the relationship between the luminance value and standard deviation of the output value stabilization method of the CCD camera.

Explanation of symbols

1 organic EL panel, 3 pattern generator, 4 CCD camera, 5 computer device.

Claims (8)

Obtain image data representing the sensitivity of the CCD element, select a region of a predetermined size from the output image based on the image data,
Set multiple types of pixels to find the average value,
A plurality of data each having an average value for each set number of pixels as one data is obtained from the area,
Of the variation of the average value in each of the obtained data, determine the set number of pixels of the plurality of data whose variation is less than or equal to a predetermined average pixel number,
An output value stabilization method for a CCD camera, wherein the average value of the determined average number of pixels is output as one data. Obtain image data representing the sensitivity of the CCD element, select a region of a predetermined size from the output image based on the image data,
Set multiple types of pixels to find the average value,
A plurality of data each having an average value for each set number of pixels as one data is obtained from the area,
The variation of the average value in each of the obtained plurality of data is obtained from the standard deviation, and the set number of pixels of the plurality of data having the standard deviation equal to or less than the predetermined value is determined as the optimum average number of pixels,
An output value stabilization method for a CCD camera, wherein the average value of the determined average number of pixels is output as one data.   When the desired number of pixels to be averaged by the CCD elements in the region are respectively cut out, and the average value of the output of the desired number of cut out pixels is obtained as one data each, the output value of each cut out pixel is determined in advance. 3. A method of stabilizing an output value of a CCD camera according to claim 1, wherein a threshold value representing a set defect is compared, and a value calculated in a peripheral pixel is substituted for a pixel outside the threshold value. .   4. The CCD camera according to claim 2, wherein among the optimum average number of pixels, a pixel corresponding to a desired resolution of the output image is finally determined as the optimum average number of pixels. Output value stabilization method.   Measure light with different brightness with a CCD camera, determine the optimal number of average pixels for each brightness, and finally determine the maximum number of average pixels from the optimal average number of pixels for each brightness. 5. The method of stabilizing an output value of a CCD camera according to claim 1, wherein the number of averaged pixels is used.   For CCD elements that pick up light with different wavelengths, determine the optimal number of average pixels for each wavelength, and finally calculate the maximum number of average pixels from the optimal average number of pixels for each wavelength. 5. The method for stabilizing an output value of a CCD camera according to claim 1, wherein the output value is a number.   Determines the optimal average number of pixels per hour for CCD elements that capture light at regular time intervals, and finally optimizes the maximum average number of pixels from the optimal average number of pixels per hour. 5. The method for stabilizing an output value of a CCD camera according to claim 1, wherein the number of pixels is determined. Finally, an optimal average number of pixels determined by the method of claim 3 for each CCD element that images light of different brightness,
Finally, the optimum number of averaged pixels determined by the method of claim 4 for each CCD element that images light of different wavelengths,
Finally, the optimum number of averaged pixels determined by the method of claim 5 for a CCD device that images light at regular time intervals;
Of the final optimal average number of pixels, the maximum value of these or the average value of these is determined as the average number of pixels for correction. To stabilize the output value of a CCD camera.

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