JP6148568B2 - Solid-state imaging device and video signal correction program - Google Patents

Description

  The present invention relates to a solid-state imaging device and a video signal blur correction program for correcting a color shift (blurring) of a video signal due to chromatic aberration (magnification chromatic aberration) of a lens.

In general, a lens of an imaging device (camera) that captures a color video signal has a refractive index that varies depending on the frequency of light, and a position where an image is formed between light having a long wavelength and light having a short wavelength is shifted. Blur occurs in the video shot. In a color image composed of the three primary colors of red (R), green (G), and blue (B), red having a longer wavelength and blue having a shorter wavelength than green are shifted in different directions. Red or blue blur occurs at the boundary between white and white. The amount of blur is proportional to the N (N is an integer) power of the distance from the center on the screen, and varies depending on lens parameters such as zoom, focus, and iris. Generally, the allowable chromatic aberration of a lens is about one pixel (one scanning line), and therefore the allowable ratio of chromatic aberration of the lens is the ratio of one pixel (one scanning line) to the image height, that is, the reciprocal of the number of effective scanning lines. It becomes.
As shown in FIG. 3 which is a schematic diagram of a change in the example of the chromatic aberration of magnification due to zooming of the zoom lens, the lateral chromatic aberration due to zoom changes individually in a nonlinear manner. An image height circle is a circle centered on the center of the screen and having a diameter of the screen height (image height). In SDTV (Standard Definition TeleVision), the allowable chromatic aberration of the lens with an effective scanning line of about 486 to 576 is about 0.2% of pixels with respect to the image height, and HDTV (High Definition TeleVision) is effective scanning line. The allowable chromatic aberration of a lens with about 720 to 1080 is about 0.1%. In UHDTV (Ultra High Definition TeleVision), the allowable chromatic aberration of a lens with an effective scanning line of about 2160 is 0. If it is about 05% and about 4320, the allowable chromatic aberration of the lens is about 0.025%. In addition, expensive fluorite or a combination of low-dispersion glass and high-refractive index glass may be used in order to suppress chromatic aberration, and the zoom lens is generally larger and more expensive than the photographing apparatus main body.

  Therefore, the amount of deviation of the image formation position of red and blue light with respect to green due to this lateral chromatic aberration is obtained in advance for each pixel, and the deviation is corrected for the red and blue primary color signals of the photographed color video signal. Thus, a technique for correcting blurring of a video signal due to lateral chromatic aberration is disclosed (see Patent Document 1). Also disclosed is a technique for converting luminance signals and color difference signals into primary color signals of red, green, and blue, and correcting distortion due to lens distortion and blur due to lateral chromatic aberration (see Patent Document 2).

  The inventions described in Patent Document 1 and Patent Document 2 can be realized when lens parameters such as zoom, focus, and iris are constant. On the other hand, when shooting a video signal (moving image) of a television program or the like with a camera, generally, it is often performed by changing lens parameters in various ways. In this case, in the inventions described in Patent Document 1 and Patent Document 2, if data indicating the amount of deviation of the imaging position corresponding to the change of the lens parameter is prepared in advance, it is difficult to acquire this data. In addition, a huge amount of data needs to be stored, which is not realistic.

  In order to solve this problem, for example, the invention described in Patent Document 3 has been proposed. The invention described in Patent Document 3 eliminates blurring of a color image due to chromatic aberration of magnification based on the lens parameter even when the lens parameter is changed to various values.

  However, the invention described in Patent Document 3 does not indicate an appropriate standard for the number of correction data stored in the storage unit. For this reason, the invention described in Patent Document 3 requires a large-capacity storage unit when the number of correction data is too large. On the other hand, the invention described in Patent Document 3 makes it difficult to select appropriate correction data if the number of correction data is too small, and the correction amount calculated using the correction data is significantly different from the actual shift amount of the video. Therefore, the correction cannot be performed accurately.

  In order to solve this problem, in order to provide a magnification chromatic aberration / image distortion correction device capable of accurate correction with a simpler configuration, the magnification chromatic aberration / image distortion correction device includes a correction data generation unit, correction data Correction data storage means for storing the correction data, a plurality of correction data are input, the number of correction data stored is calculated based on the storage capacity of the correction data storage means or a predetermined evaluation value, and the input correction data is stored Correction data thinning means to be written into the correction data storage means after thinning below, signal input means, lens parameter input means, correction data storage means, correction data selection means, correction amount calculation means, aberration correction means, A technique including a signal storage unit and a signal output unit is disclosed (see Patent Document 4).

  Specifically, Patent Document 4 describes the value of a lens parameter of a camera that captures a video signal, the amount of image formation position shift due to chromatic aberration of magnification for each pixel of the image, and the amount of distortion of the image. A magnification chromatic aberration / image distortion correction apparatus that corrects at least one of color shift caused by the chromatic aberration of magnification and distortion of the video image using correction data that correlates at least one of the aberration amounts, and is a primary color. Correction data storage means for storing the correction data of the first primary color, the second primary color, and the third primary color, and a plurality of the correction data are input, and based on the storage capacity of the correction data storage means or a predetermined evaluation value Correction data to be written in the correction data storage means after calculating the stored number of the correction data and thinning the input correction data below the stored number Subtracting means, signal input means for inputting the first primary color signal, the second primary color signal and the third primary color signal indicating the brightness of the first primary color, the second primary color and the third primary color for each pixel, and this signal Lens parameter input means for inputting photographing lens parameters corresponding to the pixels of the first primary color signal, the second primary color signal, and the third primary color signal inputted from the input means, which are lens parameters when photographing the video. And correction data selection means for selecting correction data of two lens parameters sandwiching the value of the photographing lens parameter stored in the correction data storage means on the basis of the photographing lens parameter input from the lens parameter input means And the magnification in the photographing lens parameter based on the correction data selected by the correction data selection means Based on a correction amount calculation means for calculating a correction amount for correcting at least one of color shift due to chromatic aberration and distortion of the image by interpolation, and the correction amount calculated by the correction amount calculation means, the first amount Correction means for correcting the pixel values indicating the brightness of each pixel of the primary color signal, the second primary color signal, and the third primary color signal, and the first primary color signal, the second primary color signal, and the pixel values corrected by the correction means, And a chromatic aberration magnification / image distortion correction apparatus comprising: a signal output unit configured to output a third primary color signal.

  That is, the invention described in Patent Document 4 that generates correction data, thins it below the stored number, stores it, inputs lens parameters, selects correction data, calculates a correction amount, and corrects the aberration of the signal. The structure and operation are still complicated and not suitable for miniaturization.

  Further, in the imaging apparatus and method, the amount of chromatic aberration according to the distance from the reference position in the color image based on the color image signal output from the photoelectric conversion means is detected, and the amount according to the detected distance from the reference position is detected. A technique is disclosed in which predetermined signal processing for correcting chromatic aberration is performed on a color video signal based on the amount of aberration (see Patent Document 5).

  However, the invention described in Patent Document 5 corrects chromatic aberration approximated by a cubic curve of distance for each focus position for each individual. That is, since the lens parameters such as zoom, extender, and iris are not taken into account, the accuracy of correcting the chromatic aberration of the zoom lens as shown in FIG. 3 in the schematic diagram of the change in the chromatic aberration of magnification due to the zoom of the zoom lens is still high enough. It is not possible to use a zoom lens with low cost and large chromatic aberration.

  Therefore, in the prior art, the configuration, operation and setting are still complicated and not suitable for downsizing, or are still proportional to the Nth power of the distance from the center on the screen, and the focus, zoom, extender, iris, etc. The accuracy of correcting the chromatic aberration of the zoom lens that changes depending on the lens parameters such as is not sufficiently high, and a zoom lens that has low chromatic aberration and large change in chromatic aberration cannot be used at low cost.

JP-A-6-292207 JP 2000-3437 A JP 2006-135805 A JP 2011-182071 A JP 2000-299874 A

  Therefore, the present invention eliminates the need for complicated settings, and with a simple configuration, a color video signal capable of correcting the magnification chromatic aberration of the zoom lens, which changes according to the extender, zoom, focus, and iris lens parameters, with sufficiently high accuracy. It is an object of the present invention to provide a solid-state imaging device and a program that perform correction.

In order to solve the above-described problems, the present invention provides a plurality of lens magnification chromatic aberrations acquired from the lens in a solid-state imaging device that has a lens that outputs a plurality of magnification chromatic aberration characteristic information and a solid-state imaging device and outputs a color video signal. Based on the characteristics, a correction formula for the chromatic aberration of magnification at each position of the current lens extender, zoom, focus and iris is obtained, and the correction amount of the chromatic aberration of magnification in each of the horizontal component and the vertical component of the screen where the video signal is divided into regions is calculated. The calculation means and the horizontal correction amount and the vertical correction amount of each area are switched by the horizontal address and the vertical address that are currently processing the video signal, and the shift amount of the vertical image shift unit and the shift of the horizontal image shift unit are changed. Means for correcting magnification chromatic aberration of a color video signal by performing image shift as a quantity. .
Further, in the solid-state imaging device, for the zoom, focus and iris positions of the previous lens, linear interpolation from the correction formula at the division points in the vicinity of the current zoom, focus and iris positions, A solid-state imaging device having means for calculating a correction equation for chromatic aberration of magnification at each of zoom, focus, and iris positions.

Further, in a solid-state imaging device that has a lens that outputs a plurality of magnification chromatic aberration characteristic information and a solid-state imaging device and outputs a color video signal, the current lens (extender, zoom) is obtained from the plurality of lens magnification chromatic aberration characteristics acquired from the lens. A function for calculating a correction formula for chromatic aberration of magnification at each position (for focus, iris), calculating a horizontal correction component for a horizontal component and a vertical component of a screen obtained by dividing a video signal, and a horizontal correction for each region The amount of vertical and vertical correction is switched between the horizontal address and the vertical address that are currently processing the video signal, and the image shift is performed as the shift amount of the vertical image shift unit and the shift amount of the horizontal image shift unit. A video signal correction program characterized by realizing a function of correcting lateral chromatic aberration.
Furthermore, in the magnification chromatic aberration correction program, for each position (zoom, focus, and iris) of the lens, the correction at a division point in the vicinity of the current zoom and each position (zoom, focus, and iris) of the lens. A video signal correction program that realizes a function of calculating a correction equation for correcting chromatic aberration of magnification at each position (zoom, focus, and iris) of the lens by linear interpolation from the equation.

  According to the present invention, the correction of the color chromatic aberration of the zoom lens, which changes according to the lens parameters of the extender, zoom, focus, and iris, can be easily corrected with sufficient accuracy without the need for complicated settings. Makes it possible to

1 is a block diagram showing the configuration of a television camera (solid-state imaging device) that corrects lateral chromatic aberration according to an embodiment of the present invention. FIG. 4 is a schematic diagram for explaining a method of dividing an area having a chromatic aberration of magnification according to an embodiment of the present invention. Schematic diagram of chromatic aberration characteristics example of the image height circle by zooming with the zoom lens

  An embodiment of the present invention will be described with reference to FIG. 1 which is a block diagram showing the configuration of a television camera (solid-state imaging device) that corrects lateral chromatic aberration.

  The television camera (solid-state imaging device) 100 acquires lens data from the lens 101 by the lens data acquisition unit 102. The lens data is classified into two types: lens magnification chromatic aberration characteristic data and lens extender, zoom, focus, and iris positions. Lens magnification chromatic aberration characteristic expression data is acquired by the lens magnification chromatic aberration characteristic expression acquisition unit 103 when the camera is started or when the lens is connected, and the correction chromatic aberration characteristic expression is a correction expression storage unit that is an object moved with respect to the axis of the distance from the lens center. It stores in 104.

  The correction formula is a correction formula of the first or higher correction amount using the distance from the center of the lens as a parameter, and the RG color difference and the BG color difference respectively have correction formulas. It is associated with the iris position, focus position, zoom position, and extender state at the division point. The number of division points and the number of extender states differ depending on the lens. Therefore, the lens data acquisition unit 102 calculates correction formulas of the first order or more by the number obtained by multiplying all of RG and BG of two color differences, the number of iris position division points, the number of focus position division points, the number of zoom position division points, the number of extender states. Is acquired and stored in the correction formula storage unit 104.

  The lens position data acquisition unit 105 acquires the current iris position, focus position, zoom position, and extender lens position by real-time processing because the lens position during camera operation changes according to the scene in the program.

  The current lens position of the lens position data acquisition unit 105 is a continuous value position, but the correction formula stored in the correction formula storage unit is a correction formula at each division point of the discrete lens positions, so the correction formula is used as it is. It cannot be applied. The extender state of the correction formula storage unit selected from the extender state of the current lens position is determined. For the iris position, the focus position, and the zoom position, the RG correction formula and the BG correction formula for the current lens position are calculated by linear interpolation from the correction formulas at the division points near the current lens position. Since the correction formula is of the first order or higher, linear interpolation is performed for each coefficient.

The lens position data acquisition unit 105 acquires the current iris position, focus position, zoom position, and extender lens position by real-time processing because the lens position during camera operation changes according to the scene in the program.
Although the current lens position of the lens position data acquisition unit 105 is a continuous value position, the correction formula stored in each region correction amount storage unit 109 is a correction formula at each division point of the discrete lens positions, so correction is performed. Expressions cannot be applied as they are. The extender state of each area correction amount storage unit 109 selected from the extender state of the current lens position is determined. For the iris position, the focus position, and the zoom position, each region correction amount calculation unit 106 performs linear interpolation from a correction formula at a division point in the vicinity of the current lens position to obtain an RG correction formula for the current lens position, BG A correction formula is calculated. Since the correction formula is of the first order or higher, linear interpolation is performed for each coefficient.

  FIG. 2 shows an embodiment of the present invention of a region dividing method for obtaining the RG aberration correction amount and the RG aberration correction amount at the center address of each region of the video signal from the determined correction formula. In FIG. 2, the screen is divided into 128-pixel widths in the horizontal and vertical directions from the center of the screen, and each region has a correction amount. From the aberration correction amount at the center address of each region and the center address of each region, the correction amount is separated into a vertical direction correction amount, a horizontal direction correction amount, and respective components. This is performed for each region.

  The calculated vertical direction correction amount and horizontal direction correction amount of each region are output from the correction amount output unit 107 and stored in each region correction amount storage unit 109 of the video signal processing unit. A signal obtained by converting incident light that has passed through the lens into an imaging electric signal by the imaging unit 108 is input to the video signal processing unit 120. Since the current region is determined from the vertical address 110 and the horizontal address 116 currently being processed, the vertical correction amount switching unit 111 selects the vertical correction amount to be applied from each region correction amount storage unit 109 and inputs it in the vertical image shift unit. The corrected video signal is output by shifting the correction amount selected by the vertical image shift unit 113 by the horizontal image. Similarly in the horizontal direction, since the current area is determined from the vertical address 110 and the horizontal address 116 currently being processed, the horizontal correction amount switching unit 112 selects a horizontal correction amount to be applied from each region correction amount storage unit 109, and The video signal input to the horizontal image shift unit 114 is output by shifting the horizontal correction amount selected by the horizontal image shift unit 114 by a horizontal image.

  Here, in the television camera, even the extender state changes during operation, so each position of the lens is acquired by real-time processing, and high accuracy is obtained using the correction formula of the magnification chromatic aberration characteristic formula that matches each lens position. It is important to correct the video signal for correcting the lateral chromatic aberration. Especially when using a zoom lens with an extender with low cost and large chromatic aberration for surveillance applications, each lens position is acquired in real-time processing, and a correction formula for the magnification chromatic aberration characteristic formula for each lens position is used. It is very important to perform video signal correction with high-accuracy magnification chromatic aberration correction suitable for miniaturization.

  The video signal processing result obtained by the video signal correction processing is subjected to video signal processing such as other gamma correction and detail processing, and is output from the video signal output unit 115.

  According to the above-described embodiment of the present invention, the chromatic aberration of the zoom lens that changes depending on the lens parameters of the extender, zoom, focus, and iris can be changed with the zoom lens zoom without using complicated settings. Even if the chromatic aberration of magnification due to zooming of the zoom lens as shown in FIG. 3 of the schematic diagram of the change changes nonlinearly individually, the video signal can be easily corrected with sufficiently high accuracy by the correction value interpolated from the correction formula by linear interpolation. Can do.

The present invention is applied to correction of chromatic aberration of magnification in a photographing apparatus that shoots a color video signal, and in particular, correction of video signal of high-precision magnification chromatic aberration correction suitable for miniaturization when using a zoom lens with an extender that is low in price and has large chromatic aberration. it can.
Here, the chromatic aberration of the lens allowed for SDTV is about 0.2% from 486 to 576 effective scan lines, and the chromatic aberration of the lens allowed for HDTV about 720 to 1080 effective scan lines is about 0.2%. Is about 0.1%. In UHDTV, if the number of effective scanning lines is about 2160, the allowable chromatic aberration of the lens is about 0.05%, and if about 4320, the allowable chromatic aberration of the lens is 0.025%. Degree. In addition, the zoom lens is generally larger and more expensive than the photographing apparatus main body.
Therefore, in the present invention, when an SDTV zoom lens is used in an HDTV photographing apparatus, a chromatic aberration zoom lens for HDTV is used in a UHDTV photographing apparatus, or a zoom lens having about 2160 effective scanning lines is provided. The present invention can be applied to video signal correction of high-accuracy chromatic aberration correction suitable for downsizing in a wide range of applications such as when used in a photographing apparatus of a degree.

Also, the color shift at the upper and lower ends of the screen is usually not as noticeable as the center of the screen. However, if information such as earthquake bulletins, election bulletins, heavy rain flood warnings, etc. is inserted into the L-shape of the screen during monitoring or broadcasting, the upper and lower sides of the captured image moved inside the receiver with the L-shaped information The color shift at the edge becomes noticeable. Furthermore, for monitoring and broadcasting, the chromatic aberration of the lens becomes the largest. In addition to using the telephoto end frequently, an extender in which the chromatic aberration of the lens changes greatly during operation is turned on and off.
Therefore, the present invention can be applied to high-accuracy chromatic aberration correction video signal correction suitable for miniaturization in a wide range of applications such as when an HDTV or UHDTV photographing apparatus is used for monitoring or broadcasting.

  DESCRIPTION OF SYMBOLS 100: Television camera (solid-state imaging device), 101: Lens, 102: Lens data acquisition part, 103: Lens magnification chromatic aberration characteristic formula acquisition part, 104: Correction formula storage part, 105: Lens position data acquisition part, 106: Each Area correction amount calculation unit, 107: correction amount output unit, 108: imaging unit, 109: each region correction amount storage unit, 110: vertical address, 111: vertical correction amount switching unit, 112: horizontal correction amount switching unit, 113: Vertical image shift unit, 114: horizontal image shift unit, 115: video signal output unit, 116: horizontal address, 120: video signal processing unit,

Claims (4)

In a solid-state imaging device that has a lens that outputs a plurality of magnification chromatic aberration characteristic information and a solid-state imaging device and outputs a color video signal,
From the plurality of lens magnification chromatic aberration characteristics acquired from the lens, a correction formula for magnification chromatic aberration at each position of the current lens extender, zoom, focus, and iris , and position data of the current lens are obtained,
Means for calculating a correction amount of lateral chromatic aberration in each of the horizontal component and the vertical component of the screen obtained by dividing the video signal into regions based on the obtained correction formula and position data ;
The horizontal direction correction amount and the vertical direction correction amount of each area are switched by the horizontal address and the vertical address that are currently processing the video signal, and the image shift is performed as the shift amount of the vertical image shift unit and the shift amount of the horizontal image shift unit. Means for correcting magnification chromatic aberration of a color video signal by performing. 2. The solid-state imaging device according to claim 1, wherein the zoom, focus and iris positions of the lens are obtained by linear interpolation from the correction formulas at the division points in the vicinity of the current zoom, focus and iris positions. A solid-state imaging device comprising means for calculating a correction amount of lateral chromatic aberration at each of the current zoom, focus and iris positions by calculating RG correction and BG correction of positions. In a solid-state imaging device that has a lens that outputs a plurality of magnification chromatic aberration characteristic information and a solid-state imaging device and outputs a color video signal,
Obtains the current lens iris position, focus position, zoom position, and extender lens position from multiple lens magnification chromatic aberration characteristics obtained from the lens in real-time processing, and obtains a correction formula for magnification chromatic aberration at each of the obtained positions. A function for calculating a correction amount for each of the horizontal component and the vertical component of the screen obtained by dividing the video signal into regions;
The horizontal correction amount and the vertical correction amount of each of these areas are switched by the horizontal address and the vertical address that are currently processing the video signal, and the image shift is performed as the shift amount of the vertical image shift unit and the shift amount of the horizontal image shift unit. A video signal correction program for realizing a function of correcting magnification chromatic aberration of a color video signal by performing 4. The magnification chromatic aberration correction program according to claim 3, wherein for each position of the lens, a correction formula for correcting the chromatic aberration of magnification at each position of the lens by linear interpolation from the correction expression at a dividing point in the vicinity of the current position of the lens. A video signal correction program characterized by realizing a function for calculating the image.

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