Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N9/00—Details of colour television systems
  • H04N9/64—Circuits for processing colour signals
  • H04N9/646—Circuits for processing colour signals for image enhancement, e.g. vertical detail restoration, cross-colour elimination, contour correction, chrominance trapping filters
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N25/00—Circuitry of solid-state image sensors [SSIS]; Control thereof
  • H04N25/60—Noise processing, e.g. detecting, correcting, reducing or removing noise
  • H04N25/61—Noise processing, e.g. detecting, correcting, reducing or removing noise the noise originating only from the lens unit, e.g. flare, shading, vignetting or "cos4"
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N23/00—Cameras or camera modules comprising electronic image sensors; Control thereof
  • H04N23/10—Cameras or camera modules comprising electronic image sensors; Control thereof for generating image signals from different wavelengths
  • H04N23/12—Cameras or camera modules comprising electronic image sensors; Control thereof for generating image signals from different wavelengths with one sensor only
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N17/00—Diagnosis, testing or measuring for television systems or their details
  • H04N17/002—Diagnosis, testing or measuring for television systems or their details for television cameras
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N23/00—Cameras or camera modules comprising electronic image sensors; Control thereof
  • H04N23/80—Camera processing pipelines; Components thereof
  • H04N23/81—Camera processing pipelines; Components thereof for suppressing or minimising disturbance in the image signal generation
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N25/00—Circuitry of solid-state image sensors [SSIS]; Control thereof
  • H04N25/10—Circuitry of solid-state image sensors [SSIS]; Control thereof for transforming different wavelengths into image signals
  • H04N25/11—Arrangement of colour filter arrays [CFA]; Filter mosaics
  • H04N25/13—Arrangement of colour filter arrays [CFA]; Filter mosaics characterised by the spectral characteristics of the filter elements
  • H04N25/134—Arrangement of colour filter arrays [CFA]; Filter mosaics characterised by the spectral characteristics of the filter elements based on three different wavelength filter elements

Definitions

• the present invention relates to a chromatic aberration amount detection method and a chromatic aberration amount detection apparatus for detecting a chromatic aberration amount of a lens using an image signal obtained via an imaging element such as a C CD in an imaging apparatus.
• Fig. 1 (a) Conventionally, in a three-dimensional imaging device such as a digital camera, as shown in Fig. 1 (a), it is known that image deviation on the CCD occurs for each RGB color component due to the chromatic aberration of magnification of the lens. As the image is misaligned, the edge portion of the image appears as a color misalignment and the quality of the image deteriorates.
• the amount of chromatic aberration corresponding to the reference position force in the color video and the distance is detected, and based on the detected amount of chromatic aberration,
• an imaging device power s that corrects chromatic aberration.
• an imaging device that detects an effective edge in a color image and detects the amount of chromatic aberration according to the distance from the reference position based on the edge position o.
• a horizontal scanning area and a vertical scanning area are provided at the center of the screen, and in the horizontal scanning area at the center of the screen, the aberration in the straight direction can be ignored.
• the amount of aberration in the vertical direction is determined to be negligible in the vertical scanning area at the center of the screen, and the image area outside the central area is calculated.
• the horizontal direction and vertical of the center of the screen perpendicular to the video position There is a detection method in which the amount of aberration is calculated based on the amount of aberration in the straight direction (see, for example, Patent Document 1).
• Patent Document 1 Japanese Patent Application Laid-Open No. 2 0 0 2 — 3 2 0 2 3 7 Disclosure of Invention
• the amount of aberration in the vertical direction can be ignored in the horizontal scanning area at the center of the screen, and the horizontal direction in the vertical operation area at the center of the screen. Since the amount of aberration is negligible, there is still room for improvement in order to increase the detection accuracy of the amount of aberration.
• the image area is actually scanned to detect the amount of aberration ⁇ and is calculated using the horizontal and vertical aberration amounts in the central area. fear force s Me error occurs between the aberration amount and calculated yield Saryou the order canceling the error of this, there is room for improvement.
• the present invention is based on image data output via an image element.
• the invention described in the first aspect of the scope of the invention is the method for detecting the amount of chromatic aberration in the imaging apparatus, wherein the first and first imaging patterns having different luminances are alternately arranged in parallel.
• the chart image is guided to the image sensor ⁇ Imaging lens and a plurality of photoelectric conversion elements are arranged in a matrix, and the chart image is guided through the image sensor lens.
• a first image pattern based on the output of the pixel signal, using a HIJ image sensor that photoelectrically converts the image and outputs a pixel signal of a plurality of colors in association with each of the photoelectric conversion elements.
• the chromatic aberration amount detection method for an image pickup apparatus comprising: a chart in which first and second image pickup patterns having different luminances are alternately arranged; and The edge detection step for detecting the edge position with the second imaging pattern for each of the plurality of colors, and the edge position detected in the edge detection step, a difference between the plurality of colors is obtained, A chromatic aberration amount detecting step for detecting the difference as a chromatic aberration amount, so that the chromatic aberration amount can be detected based on a plurality of edges formed by the first and second imaging patterns.
• the amount of chromatic aberration can be detected accurately over the entire screen based on the image data output via
• the chromatic aberration amount detection method for an imaging device described in claim 1 since the first imaging pattern and the second imaging pattern are arranged in a matrix, the chromatic aberration amount is reduced. It can be detected by associating it with a tricky edge position, making it highly practical.
• the invention described in claim 2 is the chromatic aberration amount detection method in the imaging apparatus according to claim 1, wherein the first and second directions are perpendicular to each other in the vertical direction and the horizontal direction.
• the imaging pattern and the second imaging pattern are alternately arranged in a plurality of rows, and based on the output values of the plurality of pixel signals output from the imaging element, the first and second imaging patterns adjacent in the vertical direction
• An intersection detection step for detecting an intersection in the four imaging patterns including the second and first imaging patterns adjacent in the left-right direction with respect to the first and second imaging patterns in the vertical direction is provided, and the edge detection step
• the edge position is detected by detecting a luminance signal for each predetermined pixel column in each of the two directions with the plurality of intersections as base points, and the chromatic aberration amount detection step includes the plurality of chromatic aberration amount detection steps.
• the chromatic aberration amount detecting method in the imaging apparatus described in claim 2 the cross-inspection detecting step for detecting the intersections in the four imaging patterns adjacent vertically and horizontally is provided, and the edge detecting step is provided.
• the edge position is detected by detecting a luminance signal for each predetermined pixel row in each of two directions with a plurality of intersection points as base points, and a chromatic aberration amount detecting step is performed at each of the plurality of intersection positions.
• the invention described in claim 3 is the chromatic aberration amount detection method in the imaging apparatus according to claim 2, wherein the chromatic aberration amount detection step uses the intersection as a base point.
• the left and right chromatic aberration amounts are detected by averaging the chromatic aberration amounts at the edge positions extending in the vertical direction, and the upper and lower chromatic aberration amounts are averaged at the edge positions extending in the left and right direction. It is characterized in that the amount of chromatic aberration in the direction is detected.
• the chromatic aberration amount detection step averages the chromatic aberration amounts at the edge positions extending in the vertical direction with the intersection point as the base point. By detecting the amount of chromatic aberration in the left-right direction and averaging the amount of chromatic aberration at the edge position extending in the left-right direction to detect the amount of chromatic aberration in the up-down direction, the vertical direction and the left-right direction at the intersection position The amount of chromatic aberration can be accurately detected.
• the invention described in claim 4 is the chromatic aberration amount detection method in the imaging apparatus according to any one of claims 1 to 3, wherein the photoelectric conversion element in the imaging element The arrangement of the first and second imaging patterns is inclined with respect to the arrangement.
• the aberration amount detection method for an imaging device described in claim 4 the aberration amount can be detected with high accuracy even when the first and second imaging patterns are provided with an inclination.
• the imaging pattern P1 is For a chair tilted c with respect to the horizontal direction X, for example, an edge for each RGB is detected from the intersection I nt with respect to the vertical edge.
• Fig. 6 (b) in Fig.
• the chromatic aberration amount detection method for an image pickup apparatus since the chromatic aberration amount can be measured even on a tilted chart, the chart is taken as an image pickup apparatus.
• the camera does not need to be installed horizontally and vertically, and has the advantage of being easy to measure, and the detection efficiency of the amount of chromatic aberration is improved.
• the amount of chromatic aberration can be measured using this algorithm even for a lens having a large distortion.
• the chromatic aberration amount detection method in the imaging apparatus according to any one of claims 2 to 4 includes the edge detection step as in the invention according to claim 5.
• sampling is performed for each of the plurality of colors by sampling every predetermined first number of pixels in the left-right direction and each predetermined second number of pixels in the up-down direction from the position of the intersection point.
• the invention described in claim 6 is a chromatic aberration amount detecting device.
• An image sensor that photoelectrically converts a cheat image and outputs a pixel signal of a plurality of colors in association with each of the photoelectric conversion elements, and based on the output of the pixel signal, the first imaging
• An edge detection unit that detects an edge position between the pattern and the second imaging pattern for each of the plurality of colors, and an edge position detected by the edge detection unit to obtain a difference between the plurality of colors.
• a chromatic aberration amount detecting means for detecting the difference as a chromatic aberration amount is provided.
• the chromatic aberration amount detecting device described in claim 6 similarly to the invention described in claim 1, the chromatic aberration is based on a plurality of edges formed by the first and second imaging patterns. The amount of aberration can be detected over the entire screen based on the image data output through the image sensor.
• the chromatic aberration amount detecting device in the imaging device described in claim 6 since the first imaging pattern and the second imaging pattern are arranged in a matrix, the chromatic aberration amount is reduced. It can be detected in association with the tricked edge position, making it highly practical.
• the invention according to claim 7 is the chromatic aberration amount detecting device according to claim 6, wherein the first imaging pattern and the two in the vertical direction and the horizontal direction orthogonal to each other.
• the second imaging pattern is alternately arranged in a plurality of rows, and the first and second imaging patterns adjacent to each other in the vertical direction and the vertical direction are determined based on the output values of the plurality of pixel signals output from the imaging element.
• Intersection detection means for detecting an intersection in four imaging patterns consisting of the second and first imaging patterns adjacent in the left-right direction with respect to the first and second imaging patterns is provided, and the edge detection means includes The edge position is detected by detecting a luminance signal for each predetermined pixel column in each of the two directions using a plurality of intersection points as base points, and the chromatic aberration amount detecting means is configured to detect each of the plurality of intersection positions. At each time, the amount of chromatic aberration is detected It is configured to do so.
• the chromatic aberration amount detection device described in claim 7, as in the invention described in claim 2 a plurality of intersections in four imaging patterns adjacent in the vertical and horizontal directions are detected to detect a plurality of intersections.
• intersection point By using the intersection point as the base point, detecting the luminance signal for each predetermined pixel row in each of the two directions to detect the edge position, and detecting the amount of chromatic aberration at each of the plurality of intersection positions, The amount of chromatic aberration can be detected in association with the coordinates of the pixel position that is the intersection.
• the invention according to claim 8 is the chromatic aberration amount detecting device according to claim 7, wherein the chromatic aberration amount detecting means extends in the vertical direction with the intersection as a base point.
• the amount of chromatic aberration in the left and right direction is detected by averaging the amount of chromatic aberration at the edge position to be output, and the amount of chromatic aberration in the vertical direction is detected by averaging the amount of chromatic aberration at the edge position extending in the left and right direction. It is configured to do so.
• chromatic aberration amount detecting device similarly to the invention according to claim 3, chromatic aberration at the edge position extending in the vertical direction with the intersection as the base point
• the amount of chromatic aberration in the left-right direction is detected by averaging the amount, and the amount of chromatic aberration at the edge position extending in the left-right direction is averaged to detect the amount of chromatic aberration in the up-down direction.
• the amount of chromatic aberration in the vertical and horizontal directions can be accurately detected.
• the invention according to claim 9 is the chromatic aberration amount detection device according to any one of claims 6 to 8, wherein the photoelectric conversion element of the imaging element
• the arrangement is characterized in that the arrangement of the first and second imaging patterns is inclined with respect to the arrangement.
• the amount of aberration can be detected with high accuracy, and the chart can be detected with respect to the imaging device (for example, force mera). It is not necessary to install in the horizontal and vertical direction and it is easy to measure. It has advantages and improves the detection efficiency of chromatic aberration. In addition, even for lenses with large distortion, there is an advantage that the amount of chromatic aberration can be measured using this algorithm.
• the edge detection means includes: For each of a plurality of intersection points, the pixel for each of the plurality of colors is sampled for each of a predetermined first number of pixels in the left-right direction and a predetermined second number of pixels in the up-down direction from the position of the intersection point. The sampling position where the change amount of the pixel value is the largest is detected as the edge position based on the pixel value obtained by the sampling.
• the edges of the first imaging pattern and the second imaging pattern can be detected with high accuracy, and the chromatic aberration amount can be detected with high accuracy.
• the first imaging pattern and the first imaging pattern are provided with a chart in which the first and second imaging patterns having different luminances are arranged alternately. -Since the edge position with the imaging pattern is detected for each of multiple colors, the difference between multiple colors is determined for the detected edge position, and this difference is detected as the amount of chromatic aberration.
• the amount of chromatic aberration can be detected on the basis of the multiple edges formed by the, and as a result, the chromatic aberration can be accurately detected over the entire surface based on the image data output through the M image element. The amount of aberration can be detected.
• the chromatic aberration amount detection method and the chromatic aberration amount detection apparatus in the imaging apparatus of the present invention since the first imaging pattern and the second imaging pattern are arranged in a matrix shape, the chromatic aberration amount is matted. It can be detected in association with the risk edge position, making it highly practical.
• the intersections of four imaging patterns adjacent in the vertical and horizontal directions are detected, and each of the two directions is determined based on a plurality of intersection points.
• the chromatic aberration amount can be detected in correspondence with the coordinates of the pixel position at the intersection point.
• the chromatic aberration amounts in the left-right direction are averaged by averaging the chromatic aberration amounts at the edge positions extending in the vertical direction with the intersection point as the base point.
• the chromatic aberration amount detection method and the chromatic aberration amount detection apparatus in the imaging apparatus of the present invention even when the first and second imaging patterns are tilted, the aberration amount can be accurately detected, and the chart is imaged. It is not necessary to install the apparatus (for example, a camera) in the horizontal and vertical directions, and has the advantage of being easy to measure, and the detection efficiency of the amount of chromatic aberration is improved. In addition, even for lenses with large distortion, there is an advantage that the amount of chromatic aberration can be measured using this algorithm.
• FIG. 1 is an explanatory diagram of a conventional chromatic aberration detection method.
• FIG. 2 is a flowchart showing the procedure of the chromatic aberration detection method in the image pickup apparatus according to the embodiment of the present invention.
• Fig. 3 is a flowchart showing details of the measurement of chromatic aberration in the flowchart of Fig. 2.
• FIG. 4 is a block diagram showing the imaging device in the embodiment.
• FIG. 5 is an explanatory diagram of the measurement of the amount of chromatic aberration in the same example, and (a
• FIG. 6 is an explanatory diagram when setting the inclination angle to the imaging pattern in the same embodiment.
• FIG. 7 is an explanatory diagram of the measurement of the amount of chromatic aberration in the example, and (a)
• (b) is an explanatory diagram when detecting an intersection point
• (c) is an explanatory diagram when detecting an edge for each intersection point
• (d) is an explicit diagram when setting a sampling pixel row for the intersection point.
• FIG. 8 is a diagram showing an example of the results of edge detection and chromatic aberration amount detection in the same example, where (a) is a diagram showing the luminance change for each sampling.
• (B) is a figure showing the amount of chromatic aberration detected for every intersection.
• FIG. 9 shows a modification of the chart of this embodiment.
• Fig. 2 is a flowchart showing the procedure of the chromatic aberration detection method in the image pickup apparatus of the embodiment of the present invention
• Fig. 3 is a flowchart showing details of measurement of chromatic aberration in the flowchart of Fig. 2.
• Fig. 4 shows the imaging device in the same example.
• Fig. 5 is an explanatory diagram of chromatic aberration amount detection in the same embodiment
• Fig. 5 (a) is a conceptual diagram of chromatic aberration measurement
• Fig. 5 (b) is a diagram showing the form of a chart.
• Figure 5 (c) is a diagram showing the arrangement of the chart relative to the image sensor.
• FIG. 6 is an explanatory diagram when setting the inclination angle to the image pickup pattern in the same embodiment
• FIG. 7 is an explanatory diagram of chromatic aberration amount detection in the same embodiment
• FIGS. 7A and 7B are the intersection detection Fig. 7 (c) is an explanatory diagram when detecting an edge for each intersection
• Fig. 7 (d) is an explanatory diagram when setting a sampling pixel column for the intersection
• Fig. 8 is the same.
• FIGS. 8A and 8B are diagrams showing an example of the results of edge detection and chromatic aberration amount detection in the embodiment, in which FIG. 8A shows the luminance change for each sampling, and FIG. 8B is detected for each intersection.
• FIG. 9 shows the amount of chromatic aberration
• FIG. 9 shows a modification of the chart of this embodiment.
• the chromatic aberration amount detection device 20 of the present embodiment uses an image pickup lens using a digital image signal C obtained by photographing a chart CH via the image pickup device 1.
• the amount of chromatic aberration 3 (AR, ⁇ in Fig. 5 (a)) is detected.
• the imaging device 1 includes a front lens 2, an imaging lens 3 that guides the imaging signal P to the imaging device 5, a filter that removes harmful infrared rays and unnecessary spatial frequencies (an infrared ray removal filter, an optical filter, and the like). 4. Image sensor (CCD: Charge Coupled Devices) 5, Image sensor 5 forces, AFE (Analog Front) that converts analog image signal to digital image signal C and outputs it E nd) 6, Image sensor 5 and AFE 6 are controlled in a predetermined cycle TG (Timing Generator) 1 3, Focus drive that performs slide drive in the optical axis direction (Z direction in Fig.
• TG Charge Coupled Devices
• a focus detection unit 10 for detecting the slide amount of the imaging lens 3 through the slide drive unit 12 and the sensor 11 1 is provided.
• AFE 6 is a correlated double sampling circuit (CDS) that removes noise from the analog image signal output via image sensor 5, and a correlated double sampling circuit.
• the variable gain amplifier (AGC) that amplifies the image signal that has been correlated and double-sampled in Fig. 8 and the analog image signal from the image sensor 5 input through the variable gain amplifier 8
• the image signal output from the image sensor 5 is converted to a digital image signal C at a predetermined sampling frequency and output to the chromatic aberration detection device 20 To do.
• the imaging element 5 is configured by arranging a plurality of photoelectric conversion elements in parallel, and is configured to photoelectrically convert the imaging signal P for each photoelectric conversion element and output an analog image signal.
• the image sensor 5 includes a color filter composed of three colors of Bayer arrangement power R (red) G (green) B (blue) in association with the photoelectric conversion element, and the amount of light that has passed through the filter section of each color. Is converted into an electrical signal and output.
• the chart CH consists of a black first image pickup pattern P 1 and a white second image pickup pattern P 2 having different brightness alternately in the left-right direction and the up-down direction. It is installed side by side.
• the chart CH is inclined with respect to the pixel arrangement in the image sensor 5 in which the arrangement of the first imaging pattern P 1 and the second imaging pattern P 2 is inclined. It is inclined by the angle ⁇ .
• one imaging pattern area corresponds to about 100 pixels (pixels) read by the imaging device 5.
• the chromatic aberration amount detection device 20 converts the digital image signal C (a so-called pixel signal representing the luminance of the pixel) input from the imaging device 1 for each RGB color.
• Field memory 2 1 field memory Intersection detection processing unit 25 for detecting a plurality of intersections of the first imaging pattern PI and the second imaging pattern P 2 based on the pixel signal stored in the memory 2 1, intersection detection processing unit
• the chromatic aberration amount calculation unit 27 calculates the difference.
• the chromatic aberration amount storage unit 28 that stores the chromatic aberration amount associated with the intersection point 28, CPU (Centra 1 Processing Unit) 29, R OM (Red Only Memory) 30, etc. 2 9 is R OM
• Each process of the chromatic aberration amount detection device 20 is controlled according to the control program stored in 30.
• the field memory 2 1 is associated with the Bayer array, and the R field memory 2 2 that stores the red (R) pixel signal and the G field that stores the green (G) pixel signal. It consists of memory 2 3 and B field memory 2 4 that stores blue (B) pixel signals.
• the intersection detection processing unit 25 calculates a luminance gradient using a surface element value in a predetermined range centered on the target pixel, and the luminance gradient is the highest.
• the position of the pixel of interest that increases is detected as the intersection point Int.
• Fig. 7 (b) five pixels in the xy direction centered on the pixel of interest are set, and weighting according to the pixel position is added to detect this intersection point position.
• the vertical and horizontal pixel values centered on the target pixel are multiplied by the coefficients shown in Fig. 7 (b), and the results are totaled.The total result is used as the target pixel evaluation value.
• intersection point Int The position of the pixel of interest when the value exceeds a predetermined threshold is defined as an intersection point Int, and a plurality of intersection points Int are detected in a matrix form as shown in Fig. 7 (a).
• the intersection point Int is a matrix.
• the first imaging pattern P 1 and the second imaging pattern P so that they appear in a box shape at regular intervals.
• the RGB edge detection processing unit 26 has a plurality of pixel rows H s, V s positioned vertically and horizontally via the intersection I nt for each color of RGB. Are scanned with a predetermined sampling line length, and pixel values are sequentially obtained, and a sampling position having the largest pixel value change amount relative to the adjacent sampling position is detected as an edge.
• the luminance (pixel value) of each pixel is obtained for each sampling as represented by curve In in Fig. 8 (a), and the pixel obtained by sampling V is represented by curve SL.
• the amount of change (gradient S) of the pixel value is calculated based on the value, and the position EP where the largest amount of change (gradient SL) appears is detected as an edge.
• sampling of multiple columns (V s) is performed to detect the edge for each column, and then the edge detected in the left part Calculate the average of the average value of the position and the average value of the edge position detected at the right, and set it as the vertical edge position at the intersection Int.
• sampling is performed for each pixel of the same color, and when sampling H s is performed along the left-right direction, as shown in Fig. 5 (c), the sampling length SL ( 1 1) and the sampling number SN (4), which represents the number of vertical columns of sampling, are determined in advance according to the required detection accuracy. ing. Also, when performing sampling V s along the vertical direction, the vertical sampling length and the number of samplings are determined in advance.
• the distance S can be obtained geometrically as shown in Fig. 7 (d), for example. That is, the distance S from the intersection point Int is the blur amount E of the edge (Fig. 7
• the chromatic aberration amount 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 of each color detected by the RGB edge detection processing unit 26.
• the difference between the G (green) edge position and the blue (blue) edge position is calculated as the blue (blue) chromatic aberration amount ⁇ ⁇ .
• the function of the edge detection means in the present invention is expressed by the RG / edge detection processing unit 26, and the function of the chromatic aberration amount detection means in the present invention is expressed by the color difference amount calculation unit 27.
• the function of the intersection detection means is expressed by the intersection detection processing unit 25.
• the chromatic aberration amount storage unit 28 stores the coordinates XY of a plurality of intersections Int detected by the intersection detection processing unit 25, and also stores the intersections.
• the red aberration amount and the blue aberration amount ⁇ calculated by the chromatic aberration amount calculation unit 27 are stored in association with the point Int.
• the red (R) and blue (B) aberrations are correlated in the left-right direction (X direction) and the up-down direction (y direction), respectively, and AR x and AR y, ⁇ ⁇ Memorize as ⁇ and AB y.
• This procedure is executed by giving a command signal to each functional unit based on the program in which C P U 29 is stored in R O M 30.
• S represents a step.
• this procedure starts when an activation signal is input to the chromatic aberration amount detection device 20 by the operator.
• the position of the imaging lens 3 and the position of the chart CH are set in advance so that the chart CH can be appropriately photographed by the imaging apparatus 1.
• parameters for detecting the intersection point Int and parameters for detecting the edge around the intersection point Int are set. Specifically, the weighting factor for detecting the intersection (coefficient in Fig. 7 (b)), threshold, sampling line length SL (symbol SL in Fig. 5 (c)) and sampling line number SN (Fig. 5 (c )), The parameter representing the interval S from the intersection Itn to the sampling line (the symbol S in FIG. 7 (d)) etc. is set. Then, the chart CH is photographed, the digital image signal C is read into the field memory 21, and then the chromatic aberration measurement of S 400 is performed. Next, as shown in FIG. 3, in chromatic aberration measurement, the position of the intersection Int is acquired via the intersection detection processing unit 25 in S 4 11, and then the process proceeds to S 4 12.
• pixel values are acquired by the amount of the sampling line length X the number of sampling lines in the vertical and horizontal directions from the intersection point, and then the process proceeds to S 4 14.
• the change amount gradient SL is calculated, and the inflection point at which the gradient SL appears the most (the sign in FIG. 8). E), and then move to S 4 1 5.
• the inflection points are obtained by averaging the number of sampling lines for each of the upper, lower, left, and right portions via the intersection point Int.
• the average value of the inflection point obtained at the upper part and the inflection point obtained at the lower part is calculated with the intersection point Int as the base point, and this average value is calculated at the intersection point Int.
• S 4 1 6 determines whether or not there is a next pixel color. If it is determined that there is no next pixel color (N o), the process proceeds to S 4 1 7. If it is determined in 4 1 6 that the next pixel color is present (Y es), the process proceeds to S 4 1 2, and S 4 1 6 until it is determined that there is no next pixel color. Repeat S 4 1 6.
• the difference between the edge position E p in the left and right direction of G at the intersection point Int and the edge position E p in the left and right direction of B is calculated to obtain the amount of chromatic aberration ⁇ BX in the left and right direction of B with respect to G.
• the difference between the vertical edge position E p and the vertical edge position E p of B is calculated, and the vertical chromatic aberration amount ⁇ B y of B with respect to G is obtained.
• S 4 1 2 to S 4 16 correspond to the edge detection step of the present invention
• S 4 17 corresponds to the chromatic aberration amount detection step of the present invention
• S 4 1 1 represents the intersection of the present invention. This corresponds to the detection step.
• the chromatic aberration amount detection method and the chromatic aberration amount detection device 20 in the imaging apparatus 1 described in the present embodiment alternate the first imaging pattern P 1 and the second imaging pattern P 2 having different luminances.
• the edge position Ep of the first image pattern P1 and the second image pattern P2 is detected for each of multiple colors RGB, and there are multiple detected edge positions Ep.
• the amount of chromatic aberration can be accurately detected over the entire screen.
• the first imaging pattern P 1 and the second imaging pattern P 2 are arranged in a matrix shape, so that the chromatic aberration amount is reduced. It can be detected in association with a matrix-like position, and is highly practical.
• the chromatic aberration amount detection method and the chromatic aberration amount detection device 20 in the imaging apparatus 1 according to the present embodiment detect the intersection I nt in four imaging patterns adjacent vertically and horizontally, and associate them with the coordinates of the pixel that is the intersection.
• the chromatic aberration amount detection method and the chromatic aberration amount detection device 20 in the image pickup apparatus 1 according to the present embodiment can detect the chromatic aberration amount.
• the left and right chromatic aberration amounts ⁇ R x and ⁇ BX are detected by averaging the chromatic aberration amounts at the edge EH position extending in the left and right direction, and the vertical chromatic aberration amounts AR y, AB y By detecting this, the amount of chromatic aberration in the vertical and horizontal directions at the intersection Int can be detected with high accuracy.
• the chromatic aberration amount detection method and the chromatic aberration amount detection device 20 in the image pickup apparatus 1 of the present embodiment are easy to measure without the need to align the chart CH to the image pickup apparatus (camera) 1 strictly in the horizontal and vertical directions. It has advantages and improves the detection efficiency of chromatic aberration.
• the chromatic aberration amount detection method and the chromatic aberration amount detection device 20 in the imaging device 1 of the present embodiment are configured so that, for each of a plurality of intersection points I nt, a predetermined number of pixels in the left and right direction and a vertical direction from the position of the intersection point I nt. Sampling is performed for each predetermined number of pixels to obtain pixel values for multiple colors, and based on the pixel values obtained by sampling, the sampling position where the amount of change in pixel values is the largest is edged. By detecting the position E p, the edges of the first imaging pattern P 1 and the second imaging pattern P 2 can be detected with high accuracy.
• this invention is not limited to the said Example, It can take various aspects.
• chart C ⁇ ⁇ has white (P 2) and black ( ⁇ 1) imaging patterns, but other colors (for example, red, green, blue) are used instead of white and black. It may be used.
• the image signal output from the image sensor 5 is preferably Raw data output via a color filter of RGB primary color without using a complementary color filter.
• the imaging apparatus 1 includes a CMOS sensor instead of the imaging element 5, the correlated double sampling circuit 7, the variable gain amplifier 8, the A / D converter 9, and the like.
• the positions of the intersection points Int are obtained at regular intervals in a matrix V box shape.
• a region with a small amount of aberration for example, the center region of the screen
• a region with a large amount of aberration for example, the area outside the center area of the screen
• intersection points Int may be made radial or concentric as necessary.
• a pair of black imaging patterns P 3 may be inclined with the intersection point Int as the base point.
• the inclination angle ⁇ may be changed for each intersection as necessary.
• the tilt angle ⁇ may be configured so that the resolution of the detection of the aberration amount is improved by making the tilt angle ⁇ smaller than the screen area where the aberration amount is large and the aberration amount is small.
• the present invention is useful for detecting the amount of chromatic aberration of a lens using an image signal obtained via an image sensor such as CCD provided in the image pickup apparatus.

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• 2007
  • 2007-03-28 JP JP2007083303A patent/JP4469382B2/ja not_active Expired - Fee Related
• 2008
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