KR20090127171A - Method and device for detecting chromatic aberration in imaging device - Google Patents

Abstract

A chart on which a first and a second imaging pattern having different luminance values are alternately arranged is imaged to detect intersections of the first and the second imaging patterns in S411. Then, S412 to S416 detect an edge position of the first and the second imaging pattern around the intersections of each of RGB colors. Subsequently, S417 obtains a difference between the detected edge positions of the R and B with respect to G. The differences are detected as chromatic aberrations ΔR and ΔB.

Description

Chromatic aberration detection method and chromatic aberration detection device in the image pickup device {METHOD AND DEVICE FOR DETECTING CHROMATIC ABERRATION IN IMAGING DEVICE}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chromatic aberration amount detecting method and chromatic aberration amount detecting device for detecting a chromatic aberration amount of a lens using an image signal obtained through an imaging element such as a CCD in an imaging device.

Background Art [0002] Conventionally, in an imaging device such as a digital camera, as shown in Fig. 1 (a), it is known that image shift on the CCD occurs for each color component of RGB due to the magnification chromatic aberration of the lens. And with the imaging shift | offset | difference, there existed a problem that the edge part of an image appears as a color shift | offset | difference and deteriorates the quality of image quality.

Therefore, the image pickup device is configured to detect the chromatic aberration amount according to the distance from the reference position in the color image based on the color image signal obtained by the imaging, and to correct the chromatic aberration to the color image signal based on the detected chromatic aberration amount. There is. At this time, there is an image pickup apparatus that detects an effective edge in a color image and detects an amount of chromatic aberration according to a distance from a reference position based on the edge position. As shown in Fig. 1B, a horizontal scanning area and a vertical scanning area are provided in the center of the screen, and the vertical aberration can be ignored in the horizontal scanning area in the screen center. The aberration amount in the horizontal direction is calculated, and the aberration amount in the vertical direction is negligible in the scanning area in the vertical direction at the center of the screen. There is a detection method that calculates and calculates the amount of aberration based on the amount of aberration in the horizontal direction and the vertical direction of the screen center orthogonal to (see Patent Document 1, for example).

[Patent Document 1: Japanese Patent Publication 2002-320237]

However, according to the conventional method for detecting chromatic aberration, the aberration amount in the vertical direction can be ignored in the scanning area in the horizontal direction at the center of the screen, and the horizontal aberration amount can be ignored in the vertical operation area in the center of the screen. In order to increase the detection accuracy of the aberration amount, there is room for improvement. That is, in an image region other than the center region, the image region is scanned without actually detecting the aberration amount and calculated using the aberration amounts in the horizontal and vertical directions in the center region. There is a possibility that an error may occur, and there was room for improvement to eliminate this error.

Accordingly, an object of the present invention is to provide a chromatic aberration amount detecting method and a chromatic aberration amount detecting device capable of accurately detecting chromatic aberration amount over the entire screen based on image data output through an imaging element.

The invention according to claim 1 made to attain such an object comprises a chart in which the first and second imaging shapes having different luminance are alternately arranged in a method of detecting chromatic aberration in the imaging device, and the chart image. An imaging lens leading to the imaging element and a plurality of photoelectric conversion elements are arranged in a matrix, and the chart image drawn through the imaging lens is photoelectrically converted to correspond to each of the photoelectric conversion elements to correspond to each of the photoelectric conversion elements. An edge detection step of detecting edge positions of the first imaging shape and the second imaging shape for each of the plurality of colors based on the output of the pixel signal, using the imaging device for outputting the? A chromatic aberration amount detecting step of obtaining a difference between the plurality of colors with respect to the edge position detected at It characterized.

According to the method for detecting chromatic aberration in the imaging device according to claim 1, the chart includes a chart in which the first and second imaging patterns having different luminance are alternately arranged, and the first and second imaging images are provided. An edge detection step of detecting an edge position of each of the plurality of colors, and a chromatic aberration amount of obtaining a difference between the plurality of colors with respect to the detected edge position in the edge detection step, and detecting the difference as a chromatic aberration amount. Since the detection step is provided, the chromatic aberration amount can be detected on the basis of the plurality of edges formed by the first and second image capturing shapes, and further, based on the image data output through the image pickup device, The aberration amount of chromatic aberration can be detected with high precision. In addition, according to the method for detecting chromatic aberration in the imaging device according to claim 1, since the first imaging pattern and the second imaging pattern are arranged in a matrix shape, the chromatic aberration amount can be detected in correspondence with the edge position of the matrix shape. It becomes a thing superior in utility.

Next, the invention described in claim 2 is characterized in that, in the method for detecting chromatic aberration in the imaging device according to claim 1, the first imaging mode and the above-described directions are directed in two directions, the vertical direction being perpendicular to each other and the horizontal direction. A plurality of second imaging patterns are alternately arranged in parallel, and based on the output values of the plurality of pixel signals output from the imaging element, the first and second imaging images adjacent to each other in the vertical direction and the first and second in the vertical direction are arranged. An intersection detection step of detecting an intersection in four imaging modes consisting of second and first imaging shapes adjacent to the imaging shape in the left and right directions is provided, wherein the edge detection step is performed based on the plurality of intersections. In each of the two directions, the luminance signal for each predetermined pixel column is detected to detect the edge position, and the chromatic aberration amount detecting step includes the color number at each of the plurality of intersection positions. Characterized by detecting the amount.

According to the method for detecting chromatic aberration in the imaging device according to claim 2, an intersection detection step for detecting intersections in four imaging modes adjacent to the top, bottom, left, and right sides is provided, and the edge detection step is based on a plurality of intersections. Then, in each of the two directions, the luminance signal for each predetermined pixel column is detected to detect the edge position, and the chromatic aberration amount detecting step detects the chromatic aberration amount at each of the plurality of intersection positions, thereby causing the pixel position to be the intersection point. The amount of chromatic aberration can be detected in correspondence with the coordinate of.

Next, in the invention according to claim 3, in the chromatic aberration amount detection method in the imaging device according to claim 2, the chromatic aberration amount detecting step is an edge extending in the vertical direction from the intersection point. The chromatic aberration in the left and right directions is detected by averaging the chromatic aberration in the position, and the chromatic aberration in the vertical direction is detected by averaging the chromatic aberration in the edge positions extending in the left and right directions.

According to the chromatic aberration amount detecting method in the imaging device according to claim 3, the chromatic aberration amount detecting step detects the chromatic aberration amount in the left and right direction by averaging the chromatic aberration amount at the edge position extending in the vertical direction from the intersection point. In addition, by detecting the chromatic aberration in the vertical direction by averaging the chromatic aberration in the edge position extending in the left and right direction, the chromatic aberration in the vertical direction and the left and right direction at the intersection position can be detected with high accuracy.

Next, the invention described in claim 4 is based on the arrangement of the photoelectric conversion element in the imaging device in the method for detecting chromatic aberration in the imaging device according to any one of claims 1 to 3. On the other hand, the arrangement of the first and second imaging shapes is inclined.

According to the chromatic aberration amount detection method in the imaging device of Claim 4, even when the 1st, 2nd image pick-up form is inclined, aberration amount can be detected with high precision. In detail, as shown in Fig. 6 (a), for the chart in which the imaging pattern P1 is inclined α with respect to the horizontal direction X, edges for each RGB are detected from the intersection Int, for example, with respect to the edge in the vertical direction. As shown in Fig. 6 (b) (only the edge of R is shown in Fig. 6 (b)), the line is fitted to the edge of R, and similarly to R and G, B is also fitted to the edge, respectively. The chromatic aberration in the horizontal direction can be detected by obtaining a line and detecting the distance between three lines of RGB.

In addition, according to the method for detecting chromatic aberration in the imaging device according to claim 4, since the chromatic aberration amount can be measured even on a chart inclined, the chart is horizontally perpendicular to the imaging device (for example, a camera). There is no need to install, and the measurement efficiency of chromatic aberration is improved with the advantage of being easy to measure. In addition, there is an advantage that the chromatic aberration amount can be measured using this algorithm even for a lens having a large distortion aberration.

Next, in the method for detecting chromatic aberration in the imaging device according to any one of claims 2 to 4, as in the invention according to claim 5, the edge detection step is performed by the plurality of intersections. Each pixel is sampled for each of a predetermined number of first pixels in the left and right directions and a predetermined number of second pixels in an up and down direction from the positions of the intersections, and pixel values obtained for the plurality of colors are obtained and obtained by the sampling. Based on the values, the edges of the first image and the second image can be detected with high precision by detecting the sampling position at which the amount of change in the pixel value is the greatest as the edge position, and furthermore, the amount of chromatic aberration can be detected with high precision. have.

Next, the invention according to claim 6 is a chromatic aberration detection apparatus comprising: a chart in which the first and second imaging patterns having different luminance are alternately arranged; an imaging lens for guiding the chart image to an imaging device; A plurality of photoelectric conversion elements are arranged in a matrix form, the image pickup element for photoelectric conversion of the chart image drawn through the imaging lens, and outputs a plurality of color pixel signals corresponding to each of the photoelectric conversion elements; On the basis of the output of the pixel signal, edge detection means for detecting the edge positions of the first imaging pattern and the second imaging pattern for each of the plurality of colors, and for the edge positions detected by the edge detection means. And chromatic aberration amount detecting means for obtaining a difference between the plurality of colors and detecting the difference as a chromatic aberration amount.

According to the chromatic aberration amount detecting device according to claim 6, the chromatic aberration amount can be detected on the basis of a plurality of edges formed by the first and second image capturing shapes, as in the invention according to claim 1. Based on the image data output through the imaging element, the aberration amount of chromatic aberration can be detected with high accuracy over the entire screen. In addition, according to the chromatic aberration amount detecting device in the imaging device according to claim 6, since the first imaging form and the second imaging form are arranged in a matrix form, the chromatic aberration amount can be detected in correspondence with the edge position of the matrix form. It becomes a thing superior in utility.

Next, in the invention according to claim 7, the first and second images are taken in the? Chromatic aberration amount detection device according to claim 6 in a vertical direction perpendicular to each other and a? 2 direction in a left and right direction. A plurality of columns are alternately arranged alternately and based on the output values of the plurality of pixel signals output from the imaging device, the first and second imaging shapes adjacent in the vertical direction and the first and second imaging shapes in the vertical direction. Intersection detection means for detecting an intersection in four imaging modes including the second and first imaging modes adjacent in the left and right directions is provided, and the edge detection means is configured in the two directions in the two or more intersections as a starting point. Each of them detects a luminance signal for each predetermined pixel column to detect the edge position, and the chromatic aberration amount detecting means sets the chromatic aberration amount at each of the plurality of intersection positions. And configured to detect.

According to the chromatic aberration amount detecting apparatus according to claim 7, according to the invention according to claim 2, two or more directions are detected by detecting intersections in four imaging modes adjacent to each other vertically, up, down, left, and right. Detects the luminance position for each predetermined pixel column by detecting the edge position, and detects the chromatic aberration amount at each of the plurality of intersection positions, thereby detecting the chromatic aberration amount in correspondence with the coordinates of the pixel position at the intersection. can do.

Next, in the invention according to claim 8, in the chromatic aberration amount detecting apparatus according to claim 7, the chromatic aberration at the edge position in which the chromatic aberration amount detecting means extends in the vertical direction from the intersection point. And averaging the amounts and detecting the chromatic aberrations in the left and right directions, and averaging the chromatic aberrations in the edge positions extending in the left and right directions to detect the chromatic aberrations in the vertical direction.

According to the chromatic aberration amount detecting device according to claim 8, the chromatic aberration amount in the left and right directions is averaged by averaging the chromatic aberration amounts at edge positions extending in the vertical direction from the intersection as in the invention described in claim 3. In addition, by detecting the chromatic aberration in the vertical direction by averaging the chromatic aberration in the edge positions extending in the left and right directions, the chromatic aberration in the vertical direction and the left and right directions at the intersection positions can be detected with high accuracy.

Next, the invention according to claim 9 is the chromatic aberration amount detecting device according to any one of claims 6 to 8, wherein the arrangement of the photoelectric conversion element in the image pickup device is performed. The 1st, 2nd imaging pattern arrangement is provided inclined, It is characterized by the above-mentioned.

According to the chromatic aberration amount detecting device according to claim 9, the aberration amount can be detected with high accuracy even when the first and second imaging patterns are inclined, as in the invention according to claim 4, and the chart Does not need to be provided in the horizontal and vertical direction with respect to the imaging device (for example, a camera), has the advantage of being easy to measure, and improves the detection efficiency of the chromatic aberration amount. In addition, there is an advantage that the chromatic aberration amount can be measured using this algorithm even for a lens having a large distortion aberration.

Next, in the chromatic aberration amount detecting device according to any one of claims 7 to 9, as in the invention according to claim 10, the edge detecting means is used for each of the plurality of intersections. Based on the pixel values obtained by the sampling by sampling the predetermined number of first pixels in the left and right directions and the predetermined number of second pixels in the vertical direction at the intersection positions, and obtaining the pixel values for each of the plurality of colors. By detecting the sampling position at which the amount of change in the pixel value is the greatest, as the edge position, the edges of the first image and the second image can be detected with high accuracy, and the chromatic aberration can be detected with high accuracy. have.

According to the chromatic aberration amount detecting method and chromatic aberration amount detecting device in the imaging device of the present invention, the first and second image capturing patterns having different luminance are provided in parallel with each other. The edge position is detected for each of a plurality of colors, and the difference between the plurality of colors is determined for the detected edge position, and the difference is detected as the chromatic aberration amount. Therefore, based on the plurality of edges formed by the first and second imaging modes, Therefore, the chromatic aberration amount can be detected, and furthermore, based on the image data output through the imaging element, the aberration amount of the chromatic aberration can be detected with high precision throughout the entire screen. In addition, according to the chromatic aberration amount detecting method and chromatic aberration amount detecting device in the imaging device of the present invention, since the first image pick-up pattern and the second image pick-up pattern are arranged in a matrix shape, the chromatic aberration amount is detected in correspondence with the edge position of the matrix shape. It becomes possible and becomes excellent in utility.

Further, according to the chromatic aberration amount detecting method and chromatic aberration amount detecting device in the imaging device of the present invention, the intersections of four imaging modes adjacent to the upper, lower, left, and right sides are detected, and each of the two directions is set based on a plurality of intersections. The chromatic aberration amount can be detected in correspondence with the coordinates of the pixel positions at which the intersections are detected by detecting the luminance signal for each predetermined pixel column, detecting the edge position, and detecting the chromatic aberration amount at each of the plurality of intersection positions.

In addition, according to the chromatic aberration detection method and the chromatic aberration detection device of the imaging device of the present invention, the chromatic aberration amount in the left and right directions is detected by averaging the chromatic aberration amount at the edge position extending in the vertical direction from the intersection point. By detecting the chromatic aberration amount in the up-down direction by averaging the chromatic aberration amount in the edge position extending in the left-right direction, the chromatic aberration amount in the up-down direction and the left-right direction at the intersection position can be detected with high accuracy.

In addition, according to the chromatic aberration amount detecting method and chromatic aberration amount detecting device in the imaging device of the present invention, even when the first and second image capturing patterns are inclined, the aberration amount can be detected with high accuracy, and the chart is obtained by the image pickup device (eg For example, it does not need to be provided in the horizontal and vertical direction with respect to the camera), has the advantage of being easy to measure, and improves the detection efficiency of the chromatic aberration amount. In addition, there is an advantage that the chromatic aberration amount can be measured using this algorithm also for a lens having a large distortion aberration.

Further, according to the chromatic aberration amount detecting method and the chromatic aberration amount detecting device in the imaging device of the present invention, for each of the plurality of intersections, the predetermined first pixel number in the left and right directions at the intersection positions and the predetermined number in the vertical direction By sampling every two pixels and acquiring pixel values for each of a plurality of colors, and detecting the sampling position at which the amount of change in the pixel value is the largest based on the pixel value obtained by sampling, the first imaging mode and the first 2 The edge of an image pick-up can be detected with high precision, and also the chromatic aberration amount can be detected with high precision.

1 is an explanatory diagram of a conventional method for detecting chromatic aberration.

2 is a flowchart showing the procedure of the chromatic aberration amount detecting method in the image capturing apparatus according to the embodiment of the present invention.

FIG. 3 is a flowchart showing details of chromatic aberration measurement in the flowchart of FIG. 2.

4 is a block diagram showing an image pickup device according to the embodiment.

FIG. 5 is an explanatory diagram of chromatic aberration measurement in the embodiment, (a) is a conceptual diagram of chromatic aberration measurement, (b) is a chart form, and (c) is a chart showing arrangement of a chart with respect to an image sensor. to be.

FIG. 6 is an explanatory diagram when setting the inclination angle to the imaging pattern in the embodiment. FIG.

FIG. 7 is an explanatory diagram of chromatic aberration measurement in the embodiment, (a, b) is an explanatory diagram at the intersection detection, (c) is an explanatory diagram at the detection of the edge for each intersection, and (d) It is explanatory drawing at the time of setting a sampling pixel column about an intersection.

Fig. 8 is a diagram showing an example of the results of edge detection and chromatic aberration amount detection in the same embodiment, (a) shows a change in luminance for each sampling, and (b) shows a chromatic aberration amount detected for each intersection. It is also.

9 is a modification of the chart of the present embodiment.

Next, an embodiment of the chromatic aberration detection method and the chromatic aberration detection device in the imaging device of the present invention will be described with reference to the drawings.

2 is a flowchart showing a procedure of a chromatic aberration detection method in the imaging device of the embodiment of the present invention, FIG. 3 is a flowchart showing the details of chromatic aberration measurement in the flowchart of FIG. 2, and FIG. 4 is an imaging device in the embodiment. Fig. 5 is an explanatory diagram of chromatic aberration amount detection in the embodiment, Fig. 5 (a) is a conceptual diagram of chromatic aberration measurement, Fig. 5 (b) is a chart form, and Fig. 5 (c) is imaging. The figure which shows the arrangement | positioning of the chart with respect to an element.

6 is an explanatory diagram when setting the inclination angle to the image capturing in the embodiment, FIG. 7 is an explanatory diagram of chromatic aberration amount detection in the embodiment, and FIG. 7 (a, b) is a description at the time of intersection detection. Fig. 7 (c) is an explanatory diagram when detecting an edge for each intersection, and Fig. 7 (d) is an explanatory diagram when setting the sampling pixel string for the intersection, and Fig. 8 is edge detection and chromatic aberration in the embodiment. 8A is a diagram showing an example of the result of quantity detection, FIG. 8A shows a change in luminance for each sampling, FIG. 8B shows a chromatic aberration amount detected at each intersection, and FIG. 9 is a chart of this embodiment. It is a variation of.

First, as shown in FIG. 4, the chromatic aberration amount detecting device 20 of the present embodiment uses the digital image signal C obtained by photographing the chart CH through the imaging device 1 to obtain the chromatic aberration amount of the imaging lens 3 ( ΔR and ΔB in Fig. 5A are detected.

The imaging device 1 includes all of the lenses 2, the imaging lens 3 which guides the imaging signal P to the imaging device 5, and filters for removing harmful infrared rays and unnecessary spatial frequencies (infrared removal filters or optical filters) ( 4) an imaging element (CCD: Charge Coupled Devices) 5, an analog front end (AFE) 6 for converting an analog image signal output from the imaging element 5 into a digital image signal C, and outputting the image pickup element ( 5) and the TG (Timing Generator) 13 for controlling the AFE 6 at predetermined cycles, the focus driver 12 for performing slide driving in the optical axis direction (Z direction in FIG. 4) of the imaging lens 3, and the sensor. A focus detector 10 or the like for detecting the amount of sliding of the imaging lens 3 through 11 is provided.

The AFE 6 uses a correlated double sampling circuit (CDS: Correlated Double Sampling) (CDS) 7 and a correlated double sampling circuit 7 to remove noise from an analog image signal output through the image pickup device 5, and correlated double sampling. A / D for converting an analog image signal from the image pickup device 5 input through the variable gain amplifier (AGC) 8 and the variable gain amplifier 8 to amplify the image signal. The image signal output from the imaging element 5 is comprised by the converter 9, etc., is converted into the digital image signal C by a predetermined sampling frequency, and it outputs to the chromatic aberration amount detection apparatus 20. FIG.

The imaging element 5 is constituted by a plurality of photoelectric conversion elements arranged together, and configured to output an analog image signal by photoelectric conversion of the imaging signal P for each photoelectric conversion element.

Moreover, the imaging element 5 is equipped with the color filter which consists of three-color Bayer array of R (red) G (green) B (blue) corresponding to a photoelectric conversion element, and transmits the light quantity which passed the filter part of each color. Convert it to a signal and output it.

In the chart CH, as shown in Fig. 5B, the first black imaging image P1 and the white second imaging pattern P2 having different luminance are alternately arranged in the horizontal direction and the vertical direction.

In addition, in the chart CH, as shown in Fig. 5 (b, c), the arrangement of the first imaging form P1 and the second imaging form P2 is inclined by the inclination angle α with respect to the pixel arrangement in the imaging element 5. have. In addition, in this embodiment, one imaging area corresponds to about 100 pixels (pixels) read by the imaging element 5.

Next, as shown in FIG. 4, the chromatic aberration amount detecting device 20 stores the digital image signal C (so-called pixel signal indicating luminance of the pixel) input by the imaging device 1 for each color of RGB. In the intersection detection processing unit 25 and the intersection detection processing unit 25 detecting a plurality of intersection points of the first imaging mode P1 and the second imaging mode P2 based on the pixel signals stored in the field memory 21 and the field memory 21. Green (G) with respect to the edge position detected by the RGB edge detection processing unit 26 and the RGB edge detection processing unit 26 detecting the edge positions of the first imaging shape P1 and the second imaging mode P2 for each RGB around the detected intersection point. The chromatic aberration amount calculating unit 27 and the chromatic aberration amount calculating unit 27 that calculate the difference between the red (R) and the blue (B) with respect to the Chromatic Aberration Memory 28, CPU (Central Processing Unit) 29, ROM (Read Only Memory) 30 It is composed of a in accordance with the control program stored in the CPU (29), ROM (30), and controls the respective processing of the chromatic aberration amount detecting device 20.

The field memory 21 corresponds to a Bayer array, and has an R field memory 22 for storing the red (R) pixel signal, a G field memory 23 for storing the green (G) pixel signal, and It consists of the B field memory 24 which stores the pixel signal of (B).

The intersection detection processing unit 25 calculates a luminance gradient using a pixel value in a predetermined range centered on the pixel of interest as shown in Fig. 7 (a, b), and the luminance gradient of the pixel of interest having the greatest luminance gradient is shown. The position is detected as the intersection Int. Here, as shown in Fig. 7B, five pixels in the xy direction centered on the pixel of interest are set, and the intersection position is detected by adding weighting according to the pixel position. That is, multiply the coefficients shown in Fig. 7 (b) with respect to the pixel values of the top, bottom, left and right centering around the pixel of interest, and aggregate the results, making the aggregated result the evaluation value of the pixel of interest, and the evaluation value being a predetermined threshold value. The position of the pixel of interest when exceeding is set as the intersection Int, and as shown in FIG.7 (a), several intersection Int is detected in matrix form. In addition, in this embodiment, as the intersection Int is shown by the matrix shape at equal intervals, the first imaging mode P1 and the second imaging mode P2 are arranged.

As shown in Fig. 7C, the RGB edge detection processing unit 26 scans a plurality of pixel strings Hs and Vs positioned up, down, left and right through the intersection Int for each color of RGB to a predetermined sampling line length. In addition, the pixel values are sequentially obtained, and the sampling positions with the greatest amount of change in the pixel values with respect to adjacent sampling positions are detected as edges.

Specifically, the luminance (pixel value) of each pixel is obtained for each sampling as shown by the curve ln of FIG. 8 (a), and the change amount of the pixel value (slope SL) based on the pixel value obtained by the sampling as shown by the curve SL. The position Ep in which the most change amount (tilt SL) is large is detected as an edge.

In order to obtain the edge Ep, as shown in Fig. 7C, sampling Hs is performed in a plurality of columns in the upper and lower pixel ranges through the intersection Int, and the edges are detected for each column. The average of the average value of the edge position detected in the upper part and the average value of the edge position detected in the lower part is computed, and it is set as the edge position of the left-right direction in intersection Int.

Also, in the left and right pixel ranges through the intersection point Int, a plurality of columns of sampling (Vs) are respectively performed to detect edges for each column, and then the average value of the edge position detected at the left side and the edge position detected at the right side are obtained. The average of an average value is computed and it is set as the edge position of the up-down direction in intersection Int.

In addition, sampling is performed for each pixel of the same color, and when sampling Hs is performed along the left-right direction, as shown in FIG.5 (c), the sampling length SL11 of the left-right direction and the number of columns of the up-down direction of sampling are shown. Sampling number SN (4) indicating is determined in advance according to the required detection accuracy. Moreover, even when sampling Vs is performed along an up-down direction, the sampling length and the number of samplings of an up-down direction are predetermined.

Further, as shown in Fig. 7D, when detecting the left and right edge positions of the edges extending upward through the intersection point lnt, if the position of the sampling Hs1 is too close to the intersection Int, the edge EH is inclined so that the intersection point Since edge detection becomes difficult under the influence of the imaging pattern P1-2 located to the left from Int, it is preferable to have an appropriate interval S between the sampling line Hs1 and the intersection point lnt.

The space | interval S can be calculated geometrically, for example as shown in FIG.7 (d). That is, the interval S from the intersection lnt is defined by the edges as the known dose E (symbol E in Fig. 7 (d)), the inclination angle α, and the sampling line length SL, and L-SL / 2 and S = (W + L). It can obtain | require by the formula of xtan (alpha). That is, the space | interval S may be calculated | required so that the start position of sampling Hs1 may not enter in the imaging mode P1-2 in FIG.7 (d), and only the edge loss amount E will be spaced apart from P1-2.

Next, the chromatic aberration calculation unit 27 calculates the difference between the edge position of G (green) and the edge position of R (red) based on the edge position for each color detected by the RGB edge detection processing unit 26. It calculates as (the red) chromatic aberration amount (DELTA) R, and calculates the difference of the edge position of G (green) and the edge position of B (blue) as B (blue).

In addition, the edge detection means in this invention expresses the function by the RGB edge detection processing part 26, and the chromatic aberration amount detection means in this invention expresses the function by the chromatic aberration amount calculating part 27, and this invention The function of the intersection detection means in is expressed by the intersection detection processing unit 25.

As shown in Fig. 8B, the chromatic aberration storage 28 stores the coordinates XY of the plurality of intersection Int detected by the intersection detection processing unit 25, and corresponds to the intersection Int and corresponds to the chromatic aberration calculation unit 27. The enemy's aberration amount ΔR and the blue aberration amount ΔB calculated in the above are stored. At this time, the aberration amount of the red (R) and the aberration (B) of the blue (B) are respectively corresponded in the left-right direction (x direction) and the up-down direction (y direction), and ΔRx and ΔRy, ΔBx and ΔBy, respectively. Remember to.

Next, the procedure at the time of obtaining the chromatic aberration amount of the imaging lens 3 using chart CH is demonstrated based on FIG. 2, FIG. This procedure is executed by the CPU 29 giving a command signal to each functional unit based on a program stored in the ROM 30. 2 and 3 represent steps.

First, this procedure starts when the start signal is input to the chromatic aberration amount detecting device 20 by the operator. At this time, the position of the imaging lens 3 and the position of the chart CH are set in advance so that the imaging device 1 can properly photograph the chart CH.

Next, as shown in Fig. 2, in S100, the acquired data before being stored in the field memory 21 or the chromatic aberration amount storage unit 28 is erased and initialized, and then the process moves to S200.

Next, in S200, parameters for detecting the intersection Int and parameters for detecting the edge around the intersection Int are set. Specifically, the weighting coefficient for intersection detection (coefficient of FIG. 7 (b)) and the threshold value, sampling line length SL (code SL in FIG. 5 (c)) and the number of sampling lines SN (code SN in FIG. 5 (c)) ), Parameters indicating the interval S (symbol S in Fig. 7 (d)) from the intersection Int to the sampling line are set.

Next, in S300, the chart CH is photographed through the imaging device 1, the digital image signal C is read into the field memory 21, and then transferred to the chromatic aberration measurement of S400.

Next, as shown in FIG. 3, the chromatic aberration measurement acquires the position of the intersection Int through the intersection detection processing unit 25 in S411, and then moves to S412.

Next, in S412, one pixel color among the three colors of RGB is selected, and then, the process shifts to S413. The order of pixel color selection is determined in advance and stored in the ROM 30.

Next, in S413, pixel values (luminance) are acquired for each sampling line length x number of sampling lines in the vertical, vertical, and horizontal directions at the intersection, and then transferred to S414.

Next, in S414, the slope SL of the amount of change is calculated based on the pixel value for each sampling detected in S413, and an inflection point (corresponding to code Ep in Fig. 8) in which the most inclination SL is large is obtained. After that, the process moves to S415. At this time, through the intersection point lnt, each of the upper part, the lower part, the left part, and the right part is averaged by the number of sampling lines to obtain an inflection point.

Next, in S415, the average value of the inflection point obtained from the upper part and the inflection point obtained from the lower part is calculated as the starting point of the intersection point lnt, and this average value is obtained as the left and right edge position in the intersection point Int, and through the intersection point Int. The average value of the inflection point acquired in the left part and the inflection point acquired in the right part is calculated, and is acquired as an edge position of the up-down direction in an intersection.

Then, the process shifts to S416, it is determined whether or not there is a next pixel color, and when it is determined that there is no next pixel color (No), the process shifts to S417, and on the other hand, there is a next pixel color (Yes). When it is determined, the process moves to S412 and the process repeats from S412 to S416 until it is determined in S416 that there is no next pixel color.

Next, in S417, the chromatic aberration amount at the intersection Int is calculated based on the edge position Ep at the intersection Int for each of the RGB detected at S415. That is, the difference between the edge position Ep in the left and right directions of G and the left and right edge positions Ep in the R direction at the intersection point Int is calculated to obtain the chromatic aberration amount ΔRx in the left and right directions of R with respect to G, and the edges in the up and down directions of G The difference of the position Ep and the edge position Ep of the up-down direction of R is computed, and the chromatic aberration amount (DELTA) Ry of the up-down direction of R with respect to G is calculated | required. In addition, the difference between the edge position Ep in the left and right directions of G at the intersection Int and the edge position Ep in the left and right directions of B is calculated, the chromatic aberration amount ΔBx in the left and right directions of B with respect to G is obtained, and the top and bottom of G at the intersection point are calculated. The difference between the edge position Ep of the direction and the edge position Ep of the up-down direction of B is calculated, and the chromatic aberration amount (DELTA) By of the up-down direction of B with respect to G is calculated | required.

Then, the process moves to S418, it is determined whether or not the next intersection lnt exists, and when it is determined that the intersection lnt is present (Yes), S418 is repeated from S411, and there is no next intersection Int in S418 (No). When it is determined, the process moves to S500 in the flowchart of FIG.

Next, in S500, the chromatic aberration amount for each intersection Int is stored in the chromatic aberration amount storage unit 28, and the processing of the chromatic aberration amount detection is finished.

Further, from S412 to S416 correspond to the edge detection step of the present invention, S417 corresponds to the chromatic aberration amount detection step of the present invention, and S411 corresponds to the intersection detection step of the present invention.

As described above, the chromatic aberration amount detecting method and chromatic aberration amount detecting device 20 in the imaging device 1 according to the present embodiment alternately arrange the first imaging form P1 and the second imaging form P2 having different luminance. The chart CH is provided, the edge position Ep of the 1st imaging form P1 and the 2nd imaging form P2 is detected for every some color RGB, the difference of several colors is calculated | required with respect to the detected edge position Ep, and this difference is chromatic aberration. By detecting as amounts DELTA R and DELTA, the chromatic aberration amount can be detected with high accuracy over the entire screen based on the plurality of edges formed by the first and second imaging modes P1 and P2. In addition, according to the chromatic aberration amount detecting method and chromatic aberration amount detecting device 20 of the imaging device 1 of the present embodiment, since the first imaging form P1 and the second imaging form P2 are arranged in a matrix, the chromatic aberration amount is matrixed. Corresponds to the position of the shape, it can be detected and is excellent in practicality.

In addition, the chromatic aberration amount detecting method and chromatic aberration amount detecting device 20 in the imaging device 1 of the present embodiment detect the intersection Int in the four imaging shapes adjacent to each other up, down, left and right, and adjust the coordinates of the pixel to be the intersection. Correspondingly, the chromatic aberration amount can be detected.

In addition, the chromatic aberration amount detecting method and chromatic aberration amount detecting device 20 in the imaging device 1 of the present embodiment average the chromatic aberration amount at the edge EV position extending in the vertical direction starting from the intersection Int and the left and right directions The chromatic aberration amounts ΔRx and ΔBx are detected, and the chromatic aberration amounts ΔRy and ΔBy in the vertical direction are detected by averaging the chromatic aberration amounts at the edge EH positions extending in the left and right directions, so as to detect the chromatic aberration amounts ΔRy and ΔBy. The chromatic aberration amount in the direction can be detected with high accuracy.

In addition, the chromatic aberration amount detection method and chromatic aberration amount detection device 20 in the imaging device 1 of the present embodiment do not need to align the chart CH with respect to the imaging device (camera) 1 strictly horizontally and vertically. The detection efficiency of chromatic aberration is improved with the advantage of being easy to do.

In addition, the chromatic aberration amount detecting method and chromatic aberration amount detecting device 20 in the imaging device 1 according to the present embodiment have a predetermined number of pixels in the left and right directions and a vertical direction from the position of the intersection Int for each of the plurality of intersection Int. By sampling for every predetermined number of pixels in to obtain a pixel value for each of a plurality of colors, and detecting the sampling position where the amount of change in the pixel value is the largest based on the pixel value obtained by sampling, as the edge position Ep, The edges of the imaging form P1 and the second imaging form P2 can be detected with high precision.

As mentioned above, although one Example of this invention was described, this invention is not limited to the said Example, A various form can be set.

For example, in the present embodiment, although the chart CH has the imaging shapes of white (P2) and black (P1), different colors (for example, red, green, blue) may be used instead of white and black. .

The image signal output from the imaging element 5 is preferably raw data output through a color filter of RGB primary colors without using a complementary color filter.

In addition, the imaging device 1 according to the present invention replaces the imaging device 5, the correlated double sampling circuit 7, the variable gain amplifier 8, the A / D converter 9, and the like. Semiconductor) sensor may be used.

In addition, in the present invention, the position of the intersection Int is obtained in a matrix form at equal intervals, but in an area where the amount of aberration is small (for example, the screen center area), an area where the amount of aberration is larger than (for example, the screen center area) You may form so that the space | interval of intersection lnt may widen rather than the outer area | region. If necessary, the arrangement of intersection Int may be radial or concentric.

In the present embodiment, the plurality of imaging shapes P1 and P2 in the chart CH are inclined uniformly with respect to the arrangement direction (xy direction) of the imaging device 5, but as shown in FIG. You may tilt the imaging pattern P3 using the intersection Int as a starting point, respectively. In addition, you may change the inclination-angle (beta) for every intersection as needed at that time. That is, the inclination angle β may be configured to be smaller than the screen area where the aberration amount is small in the screen area with a large amount of aberrations, so as to increase the resolution of the aberration amount detection.

The present invention is useful for detecting the chromatic aberration amount of a lens by using an image signal obtained through an imaging device such as a CCD included in the imaging device.

Claims (10)

A chart in which the first and second imaging patterns having different luminance are alternately arranged; An imaging lens for drawing a chart image of the chart to an imaging device, A plurality of photoelectric conversion elements are arranged in a matrix shape, using the imaging element for photoelectric conversion of the chart image drawn through the imaging lens and outputting pixel signals of a plurality of colors corresponding to each of the photoelectric conversion elements. , An edge detection step of detecting edge positions of the first imaging form and the second imaging form for each of the plurality of colors based on the output of the pixel signal; And a chromatic aberration amount detecting step of obtaining a difference between the plurality of colors with respect to the edge position detected in the edge detecting step, and detecting the difference as a chromatic aberration amount. The method according to claim 1, The first imaging form and the second imaging form are alternately arranged in a plurality of rows in two directions in the vertical direction and the left and right directions perpendicular to each other, Based on the output values of the plurality of pixel signals output from the imaging device, the first and second imaging shapes adjacent to each other in the vertical direction and the first and second imaging shapes adjacent to the first and second imaging shapes in the vertical direction thereof are adjacent to each other in the horizontal direction. The intersection detection step of detecting an intersection in four imaging forms which consist of a 1st imaging form is provided, The edge detecting step detects the edge position by detecting a luminance signal for each predetermined pixel column in each of the two directions starting from the plurality of intersections. And the chromatic aberration amount detecting step detects the chromatic aberration amount at each of the plurality of intersections. The method according to claim 2, The chromatic aberration detection step detects the chromatic aberration amount in the left and right directions by averaging the chromatic aberration amount in the edge position extending in the vertical direction, starting from the intersection, and at the edge position extending in the left and right directions. And detecting the chromatic aberration in the vertical direction by averaging the chromatic aberration of the chromatic aberration. The method according to any one of claims 1 to 3, An array of chromatic aberrations in the imaging device, characterized in that the arrangement of the first and second imaging shapes is inclined with respect to the arrangement of the photoelectric conversion elements in the imaging device. The method according to any one of claims 2 to 4, The edge detection step, For each of the plurality of intersections, a pixel value for each of the plurality of colors is obtained by sampling every predetermined number of first pixels in the left and right directions and a predetermined number of second pixels in the vertical direction from the positions of the intersections. And a sampling position at which the amount of change in the pixel value is greatest based on the pixel value obtained by the sampling as the edge position. A chart in which the first and second imaging patterns having different luminance are alternately arranged; An imaging lens for drawing a chart image of the chart to an imaging device, A plurality of photoelectric conversion elements are arranged in a matrix form, the image pickup element for photoelectric conversion of the chart image drawn through the imaging lens, and outputs a plurality of color pixel signals corresponding to each of the photoelectric conversion elements; and, Based on the output of the pixel signal, Edge detecting means for detecting edge positions of the first image and the second image, for each of the plurality of colors; And chromatic aberration amount detecting means for obtaining a difference between the plurality of colors with respect to an edge position detected by the edge detecting means, and detecting the difference as a chromatic aberration amount. The method according to claim 6, The first imaging form and the second imaging form are alternately arranged in a row in two directions in the vertical direction and the left and right directions perpendicular to each other, Based on the output values of the plurality of pixel signals output from the imaging device, the first and second imaging shapes adjacent to each other in the vertical direction and the first and second imaging shapes adjacent to the first and second imaging shapes in the vertical direction thereof are adjacent to each other in the horizontal direction. The intersection detection means which detects an intersection in the four imaging forms which consist of a 1st imaging form is provided, The edge detecting means detects the edge position by detecting a luminance signal for each predetermined pixel column from each of the two directions starting from the plurality of intersections. The chromatic aberration amount detecting device is configured to detect the chromatic aberration amount at each of the plurality of intersections. The method according to claim 7, The chromatic aberration detection means detects the chromatic aberration amount in the left and right directions by averaging the chromatic aberration amount in the edge position extending in the vertical direction, starting from the intersection, and at the edge position extending in the left and right directions. And a chromatic aberration amount detecting device for detecting the chromatic aberration amount in the vertical direction. The method according to any one of claims 6 to 8, The chromatic aberration amount detection device according to the arrangement of the photoelectric conversion elements in the imaging device, wherein the arrangement of the first and second imaging shapes is inclined. The method according to any one of claims 7 to 9, The edge detecting means samples for each of the plurality of colors by sampling each predetermined number of first pixels in the left and right directions and a predetermined number of second pixels in the vertical direction from each of the plurality of intersections. A chromatic aberration amount detection device, configured to acquire a value and detect, as an edge position, a sampling position at which the amount of change in the pixel value is greatest based on the pixel value obtained by the sampling.

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