JP2008271034A - Imaging apparatus, and control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging apparatus capable of making beat noise and linear scratches inconspicuous, and to provide a control method. <P>SOLUTION: The imaging apparatus is provided with a solid-state imaging element 102 and a digital signal processing part 107. The digital signal processing part 107 is provided with a vertical line/horizontal line detection circuit 204 and a contour emphasis circuit 205. The vertical line/horizontal line detection circuit 204 detects beat noise components or linear scratches in the light shielding part of the solid-state imaging element 102. The contour emphasis circuit 205 controls a contour emphasis amount in contour emphasis processing when generating images on the basis of the signals of the light receiving part of the solid-state imaging element 102 corresponding to the detected result of the beat noise components or the linear scratches by the vertical line/horizontal line detection circuit 204. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an imaging device including a solid-state imaging device and a control method.

  2. Description of the Related Art Conventionally, there is an imaging device that images a subject using a solid-state imaging device. Based on the image of the subject imaged by this type of imaging device, the presence / absence of vertical lines / horizontal lines generated in the vertical direction in the image array of the solid-state imaging device is determined, and the determination result is reflected in the luminance signal processing. A technique has been proposed (see, for example, Patent Document 1).

In addition, a technique has been proposed in which smear correction (a phenomenon in which light streaks occur when an image of a brightly shining subject is imaged) is corrected in the imaging device, and the information of the light shielding part of the solid-state imaging device is reflected in the light receiving part (For example, refer to Patent Document 2).
JP 63-028190 A JP 2006-024985 A

  In recent years, the driving frequency has been increased due to the increase in the number of pixels of the solid-state imaging device, and the density of components mounted on the substrate has been increased due to the downsizing of the imaging device. Along with this, there is a problem that beat noise tends to be applied to the video signal processed by the imaging apparatus. In addition, there is a problem that linear scratches are likely to occur in the pixel array due to narrowing the pixel pitch in the pixel array of the solid-state imaging device. Regarding beat noise, it is a major premise to suppress the occurrence of beat noise in the imaging device circuit that is the generation source, but there is a limit to suppressing the occurrence of beat noise. The same applies to the generation of beat noise in the solid-state imaging device.

  An object of the present invention is to provide an imaging device and a control method that can make beat noise and linear scratches inconspicuous.

  In order to achieve the above-described object, an imaging apparatus according to the present invention is an imaging apparatus that performs imaging by photoelectrically converting an optical image of a subject using a solid-state imaging element having a light-receiving unit and a light-shielding unit. The detection means for detecting the presence or absence of beat noise components or linear flaws in the light shielding portion, and the contour enhancement amount in the contour enhancement processing when generating an image from the signal of the light receiving portion of the solid-state imaging device, And a control means for controlling according to the detection result.

  According to the present invention, the amount of contour enhancement in the contour enhancement processing is controlled based on the detection result of beat noise components or linear flaws in the light shielding portion of the solid-state imaging device. Thereby, it becomes possible to make the beat noise or the linear flaw caused by the increase in the number of pixels of the solid-state image pickup device mounted on the image pickup device and the increase in the density of parts inconspicuous.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram showing a configuration of an imaging apparatus according to an embodiment of the present invention.

  In FIG. 1, the imaging apparatus includes an optical system 101, an optical system control unit 102, a solid-state imaging device 103, an imaging system control unit 104, an analog signal processing unit 105, and an A / D conversion unit 106. Further, the imaging apparatus includes a digital signal processing unit 107 (detection unit, control unit), an internal storage unit 108, an interface (hereinafter referred to as I / F) unit 109, an image display unit 110, a clock generation circuit 110, and a control unit (not shown). Control means). The imaging apparatus performs imaging by photoelectrically converting an optical image of a subject using a solid-state imaging device 103 having a light receiving unit and a light shielding unit.

  The optical system 101 forms an image of incident light on the solid-state image sensor 103 as the subject is imaged by the imaging apparatus. The optical system control unit 102 controls the exposure operation, zoom operation, focus operation, and the like in the optical system 101. The solid-state imaging device 103 includes a light receiving unit and a light shielding unit including an image generation region, and performs photoelectric conversion that converts an optical image of a subject formed through the optical system 101 into an electric signal. The imaging system control unit 104 drives the solid-state imaging device 103. The analog signal processing unit 105 performs a process of clamping a signal output from the solid-state image sensor 103, a process of applying a gain, and the like.

  The A / D conversion unit 106 performs analog / digital (A / D) conversion of the analog signal output from the analog signal processing unit 105 into a digital signal. The digital signal processing unit 107 generates image data to be output from the digital signal A / D converted by the A / D conversion unit 106. The internal storage unit 108 temporarily stores image data when the digital signal processing unit 107 generates image data to be output.

  The I / F unit 109 manages an interface with an external storage device for finally storing the image data generated by the digital signal processing unit 107. The image display unit 110 is a display unit as an electronic viewfinder that displays the image data generated by the digital signal processing unit 107. The clock generation circuit 110 supplies drive clocks to analog components and digital components, respectively. A control unit (not shown) controls the entire imaging apparatus and executes the processing shown in the flowchart of FIG. 3 based on the control program.

  In addition, in FIG. 1, the difference between 33.75 MHz (analog) and 27 MHz (digital) differs between the analog component and the digital component because the drive clock of the analog component is different from that of the analog component. It shows riding as a component. The beat noise component is generated due to the arrangement of the constituent elements, the problem of the wiring of the signal line, the fluctuation of the power supply (voltage fluctuation), and the level varies greatly depending on the configuration.

  FIG. 2 is a block diagram illustrating a configuration of the digital signal processing unit 107 of the imaging apparatus.

  FIG. 2 shows the configuration of the digital signal processing unit 107 that generates image data and detects the vertical and horizontal lines of the light shielding unit of the solid-state imaging device. The digital signal processing unit 107 includes a color conversion circuit 201, a color processing circuit 202, a luminance processing circuit 203, a vertical / horizontal line detection circuit 204 (detection means), an outline enhancement circuit 205 (control means), and a synthesis circuit 206. .

  The color conversion circuit 201 generates and separates a luminance signal Y and color difference signals Cr and Cb from the image signal (RGB signal) input after A / D conversion by the A / D conversion unit 106. The color processing circuit 202 performs white balance processing, achromatic processing for reducing the intensity of high / low luminance colors, gamma processing, and the like on the color difference signals Cr and Cb. The luminance processing circuit 203 performs filter processing, luminance correction processing, gamma processing, and the like on the luminance signal Y.

  The vertical line / horizontal line detection circuit 204 detects the presence or absence of a vertical beat noise component or a linear flaw (vertical line) in the light-shielding portion of the solid-state image sensor 103, and detects a horizontal beat noise component or a linear flaw ( Detection of the presence or absence of horizontal lines). In the present embodiment, vertical lines and horizontal lines before exposure in the pixel array of the solid-state image sensor 103 are detected. The contour emphasis circuit 205 performs filter processing on the luminance signal Y, and performs contour emphasis in consideration of the vertical line / horizontal line determination of the vertical line / horizontal line detection circuit 204. In this embodiment, vertical lines and horizontal lines are determined, and contour enhancement is performed for each vertical line and horizontal line. The synthesizing circuit 206 synthesizes the luminance signal Y and the color difference signals Cr and Cb and outputs them as YCrCb signals.

  This embodiment has the following features.

  The vertical / horizontal line detection circuit 204 detects the presence or absence of beat noise components or linear flaws in the light-shielding portion of the solid-state imaging device. The contour emphasis circuit 205 controls the amount of contour emphasis in the contour emphasis process when generating an image from the signal of the light receiving unit of the solid-state imaging device according to the detection result of the vertical line / horizontal line detection circuit 204.

  In the case of FIG. 4 to be described later, the light receiving portion and the light shielding portion of the solid-state imaging device are each set as a single region. The vertical / horizontal line detection circuit 204 detects the presence or absence of beat noise components or linear flaws in a single region of the light-shielding portion of the solid-state imaging device. The contour emphasis circuit 205 performs the following control when a beat noise component or a linear flaw is detected in a single region of the light shielding portion by the vertical line / horizontal line detection circuit 204. Control is performed to weaken the contour enhancement amount in the contour enhancement processing for a single region of the light receiving unit of the solid-state imaging device.

  In the case of FIG. 5 to be described later, the light receiving portion and the light shielding portion of the solid-state imaging device are each divided into a plurality of regions. The vertical / horizontal line detection circuit 204 detects the presence or absence of beat noise components or linear flaws in each region of the light-shielding portion of the solid-state imaging device. The contour emphasis circuit 205 performs the following control when a beat noise component or a linear flaw is detected in the corresponding area among the areas of the light shielding portion by the vertical line / horizontal line detection circuit 204. Control is performed to weaken the contour enhancement amount in the contour enhancement processing for the region corresponding to the corresponding region of the light shielding portion among the regions of the light receiving unit of the solid-state imaging device.

  The vertical line / horizontal line detection circuit 204 detects the presence or absence of beat noise components or linear flaws for each of a plurality of pixels constituting the light-shielding portion of the solid-state imaging device. The contour emphasis circuit 205 performs the following control when the vertical line / horizontal line detection circuit 204 detects a beat noise component or a linear flaw in a corresponding pixel among the pixels of the light shielding portion. Control is performed to weaken the edge enhancement amount in the edge enhancement processing for the pixels corresponding to the corresponding pixels of the light shielding portion among the plurality of pixels constituting the light receiving portion of the solid-state imaging device.

  In addition, the vertical line / horizontal line detection circuit 204 detects whether or not there is a line (vertical line) in one direction in the solid-state image sensor as a beat noise component or a linear flaw in the light-shielding portion of the solid-state image sensor, and crosses the one direction. The presence or absence of a direction line (horizontal line) is detected. The outline emphasis circuit 205 performs the following control when the vertical line / horizontal line detection circuit 204 detects a line in one direction or a line in the other direction. Control is performed to individually weaken the contour enhancement amount in one direction or the contour enhancement amount in the other direction.

  Next, the operation of the imaging apparatus according to the present embodiment having the above-described configuration will be described in detail with reference to FIGS.

  FIG. 3 is a flowchart regarding horizontal / vertical line detection of the solid-state imaging device. (A) is a flowchart which shows a horizontal line detection process, (b) is a flowchart which shows a vertical line detection process. The processing shown in this flowchart is executed based on a control program by the control unit of the imaging apparatus using the vertical / horizontal line detection circuit 204 and the contour enhancement circuit 205 of the digital signal processing unit 107.

  3A, the control unit of the imaging apparatus obtains an average value of pixels in the horizontal direction with respect to the horizontal OB portion of the solid-state image sensor 103 (step S301), and calculates the average value of pixels and a preset threshold value. Compare (step S302). If there is a pixel larger than the threshold value from the comparison, the control unit performs determination (control) to weaken the vertical contour enhancement amount (vertical contour enhancement parameter) by a certain amount (step S303).

  In FIG. 3B, the control unit of the imaging apparatus obtains the average value of the pixels in the vertical direction with respect to the vertical OB part of the solid-state image sensor 103 (step S304), and calculates the average value of the pixels and a preset threshold value. Compare (step S305). If there is a pixel larger than the threshold value from the comparison, the control unit performs determination (control) to weaken the horizontal contour enhancement amount (horizontal contour enhancement parameter) by a certain amount (step S306).

  In the processes shown in FIGS. 3A and 3B, one threshold is set and the amount of contour enhancement that can be changed is also binary. However, the present invention is not limited to this. It may be set.

  FIG. 4 is a diagram for explaining an operation in a case where the uniform outline enhancement amount of the screen of the solid-state imaging device can be changed. 4A is a diagram showing a pixel arrangement of a solid-state imaging device, FIG. 4B is a diagram showing horizontal and vertical OB calculation areas, and FIG. 4C is a diagram showing vertical contour enhancement amounts. 4 (d) is a diagram showing the amount of horizontal contour emphasis.

  As shown in FIG. 4A, the solid-state imaging device includes an image generation region 401 for generating an output image, a light receiving unit 402, and a light shielding unit 403. In the illustrated example, there is shown a case where there are three beat noise components of a horizontal line A, a horizontal line B, and a vertical line C or a linear scratch in the pixel array of the solid-state imaging device.

  As shown in FIG. 4B, the solid-state imaging device has a horizontal OB (Optical Black: light-shielding portion) calculation area 404 (HOB) corresponding to the horizontal side and the vertical side of the image generation area 401, respectively. ) And a vertical OB calculation area 405 (VOB). In the horizontal OB calculation area 404, horizontal lines are detected, and in the vertical OB calculation area 405, vertical lines are detected. Here, it is assumed that the horizontal line A and the vertical line C are low-level linear scratches, and the horizontal line B is a high-level linear scratch.

  At this time, since there is a high level horizontal line B in the horizontal OB calculation area 404, as shown in FIG. 4C, the vertical outline enhancement amount is controlled to be considerably weakened (expressed as -2). Further, since there is a low level vertical line C in the vertical OB calculation area 405, the horizontal outline emphasis amount is controlled to be slightly weakened (expressed as -1) as shown in FIG. As described above, when a high-level horizontal line and a low-level vertical line are detected in the pixel array of the solid-state imaging device, the contour enhancement circuit 205 sets the vertical contour enhancement amount to −2 and the horizontal contour enhancement amount to −1. Set each.

  FIG. 5 is a diagram for explaining the operation when the contour enhancement amount can be changed for each region of the solid-state imaging device. 5A is a diagram showing a pixel arrangement of a solid-state imaging device, FIG. 5B is a diagram showing horizontal and vertical OB calculation regions, and FIG. 5C is a diagram showing vertical contour enhancement amounts. FIG. 5D is a diagram illustrating the amount of horizontal contour enhancement.

  As illustrated in FIG. 5A, the solid-state imaging device includes an image generation region 501, a light receiving unit 502, and a light shielding unit 503 while the screen is divided into a plurality of regions. In the illustrated example, there is shown a case where there are three beat noise components of a horizontal line A, a horizontal line B, and a vertical line C or a linear scratch in the pixel array of the solid-state imaging device.

  As shown in FIG. 5B, the solid-state imaging device includes a horizontal OB calculation area 504 (HOB1 to 4) and a vertical OB corresponding to each of the divided parts obtained by dividing the image generation area 501 into four in each direction. Calculation areas 505 (VOB1 to VOB4) are provided. In the horizontal OB calculation area 504, horizontal lines are detected, and in the vertical OB calculation area 505, vertical lines are detected. Here, it is assumed that the horizontal line A and the vertical line C are low-level linear scratches, and the horizontal line B is a high-level linear scratch.

  At this time, since the horizontal OB calculation area HOB2 has a low level horizontal line A and the horizontal OB calculation area HOB3 has a high level horizontal line B, as shown in FIG. Set. That is, the contour emphasis circuit 205 sets the vertical contour emphasis amount to −1 for the region with the horizontal line A, −2 to the vertical contour emphasis amount for the region with the horizontal line B, and sets the vertical contour emphasis amount to 0 for the region where the horizontal line is not detected. Set to each.

  Further, since there is a low level vertical line C in the vertical OB calculation area VOB3, as shown in FIG. 5D, the horizontal outline emphasis amount is set for each block. That is, the contour emphasizing circuit 205 sets the horizontal contour emphasis amount to −1 for the region with the vertical line C, and 0 to the horizontal contour emphasis amount for the region where the vertical line is not detected.

  In FIG. 5, the image generation area 501 of the solid-state image sensor is divided into a plurality of areas. However, the present invention is not limited to this, and vertical and horizontal lines are detected for each pixel of the solid-state image sensor, and the amount of contour enhancement is determined. It may be reflected in (contour emphasis parameter).

  As described above, according to the present embodiment, the beat noise component or linear scratch (vertical line) in the vertical direction and the beat noise component or linear scratch (in the horizontal direction) in the light-shielding portion of the solid-state imaging device ( (Horizontal line) is detected. Then, according to the detection result of the beat noise component or the linear flaw, the amount of contour enhancement in the contour enhancement processing when generating an image from the signal of the light receiving unit of the solid-state imaging device is controlled. Thereby, it becomes possible to make the beat noise or the linear flaw caused by the increase in the number of pixels of the solid-state image pickup device mounted on the image pickup device and the increase in the density of parts inconspicuous.

It is a block diagram which shows the structure of the imaging device which concerns on embodiment of this invention. It is a block diagram which shows the structure of the digital signal processing part of an imaging device. It is a flowchart regarding horizontal line and vertical line detection of a solid-state image sensor. (A) is a flowchart which shows a horizontal line detection process, (b) is a flowchart which shows a vertical line detection process. It is a figure explaining operation | movement in the case of enabling change of the screen uniform outline emphasis amount of a solid-state image sensor. (A) is a figure which shows the pixel arrangement | sequence of a solid-state image sensor, (b) is a figure which shows a horizontal and vertical OB calculation area | region, (c) is a figure which shows the amount of vertical outline emphasis, (d) is a horizontal outline. It is a figure which shows the emphasis amount. It is a figure explaining operation | movement in the case of enabling change of an outline emphasis amount for every area | region of a solid-state image sensor. (A) is a figure which shows the pixel arrangement | sequence of a solid-state image sensor, (b) is a figure which shows a horizontal and vertical OB calculation area | region, (c) is a figure which shows the amount of vertical outline emphasis, (d) is a horizontal outline. It is a figure which shows the emphasis amount.

Explanation of symbols

DESCRIPTION OF SYMBOLS 103 Solid-state image sensor 104 Imaging system control part 107 Digital signal processing part 111 Clock generation circuit 201 Color conversion circuit 202 Color processing circuit 203 Luminance processing circuit 204 Vertical line / horizontal line detection circuit 205 Outline enhancement circuit 401 Image generation area 402 Light receiving part 403 Light shielding Section 404 Horizontal OB calculation area 405 Vertical OB calculation area

Claims (10)

In an imaging device that performs imaging by photoelectrically converting an optical image of a subject by a solid-state imaging device having a light receiving unit and a light shielding unit,
Detecting means for detecting the presence or absence of beat noise components or linear flaws in the light-shielding portion of the solid-state imaging device;
Control means for controlling the amount of contour enhancement in contour enhancement processing when generating an image from the signal of the light receiving unit of the solid-state imaging device according to the detection result of the detection means;
An imaging apparatus comprising: Each of the light receiving portion and the light shielding portion of the solid-state image sensor is a single region,
The detection means detects the presence or absence of beat noise components or linear flaws for the single region of the light-shielding portion of the solid-state imaging device,
When the detection means detects a beat noise component or a linear flaw in the single region of the light shielding unit, the contour of the single region of the light receiving unit of the solid-state imaging device is the contour. The imaging apparatus according to claim 1, wherein control for weakening an edge enhancement amount in the enhancement processing is performed. Dividing the light-receiving portion and the light-shielding portion of the solid-state image sensor into a plurality of regions,
The detection means detects the presence or absence of beat noise components or linear flaws for each region of the light-shielding portion of the solid-state imaging device,
When the beat noise component or the linear flaw is detected in the corresponding region among the regions of the light shielding unit by the detecting unit, the control unit includes the region of the light receiving unit of the solid-state imaging device. The imaging apparatus according to claim 1, wherein control is performed to weaken a contour emphasis amount in the contour emphasis processing for a region corresponding to the corresponding region of the light shielding unit. The detecting means detects the presence or absence of beat noise components or linear flaws for each of a plurality of pixels constituting the light shielding portion of the solid-state imaging device,
When the detection means detects a beat noise component or a linear flaw in the corresponding pixel among the pixels of the light shielding unit, the control unit detects a plurality of pixels constituting the light receiving unit of the solid-state imaging device. The image pickup apparatus according to claim 1, wherein control is performed to weaken a contour enhancement amount in the contour enhancement processing for a pixel corresponding to the corresponding pixel of the light shielding unit. The detection means detects the presence or absence of a line in one direction and the presence or absence of a line in the other direction intersecting the one direction as a beat noise component or a linear flaw in the light shielding portion of the solid-state image sensor. And
The control means performs control to individually weaken the contour enhancement amount in the one direction or the contour enhancement amount in the other direction when the line in the one direction or the line in the other direction is detected by the detection means. The imaging apparatus according to claim 2, wherein the imaging apparatus is characterized. In a control method of an imaging device that performs imaging by photoelectrically converting an optical image of a subject by a solid-state imaging device having a light receiving unit and a light shielding unit,
A detection step of detecting the presence or absence of beat noise components or linear flaws in the light-shielding portion of the solid-state imaging device;
A control step of controlling the amount of contour enhancement in the contour enhancement processing when generating an image from the signal of the light receiving unit of the solid-state imaging device according to the detection result of the detection step;
A control method characterized by comprising: Each of the light receiving portion and the light shielding portion of the solid-state image sensor is a single region,
In the detection step, the presence or absence of a beat noise component or a linear scratch is detected for the single region of the light-shielding portion of the solid-state imaging device,
In the control step, when a beat noise component or a linear flaw is detected in the single region of the light shielding unit by the detection step, the contour of the single region of the light receiving unit of the solid-state imaging device is detected. The control method according to claim 6, wherein control for weakening a contour enhancement amount in the enhancement processing is performed. Dividing the light-receiving portion and the light-shielding portion of the solid-state image sensor into a plurality of regions,
In the detection step, the presence or absence of a beat noise component or a linear scratch is detected for each region of the light-shielding portion of the solid-state imaging device,
In the control step, when a beat noise component or a linear flaw is detected in the corresponding region among the regions of the light shielding unit in the detection step, the region of the light receiving unit of the solid-state imaging device The control method according to claim 6, wherein control is performed to weaken a contour emphasis amount in the contour emphasis processing for a region corresponding to the corresponding region of the light shielding unit. In the detection step, the presence or absence of a beat noise component or a linear flaw is detected for each of a plurality of pixels constituting the light-shielding portion of the solid-state image sensor,
In the control step, when a beat noise component or a linear flaw is detected in the corresponding pixel among the pixels of the light shielding unit in the detection step, a plurality of pixels constituting the light receiving unit of the solid-state imaging device are detected. The control method according to claim 6, wherein control is performed to weaken a contour emphasis amount in the contour emphasis processing for a pixel corresponding to the corresponding pixel of the light shielding portion. In the detection step, the presence or absence of a line in one direction in the solid-state image sensor and the presence or absence of a line in another direction intersecting the one direction are detected as beat noise components or linear flaws in the light-shielding portion of the solid-state image sensor. And
In the control step, when the line in the one direction or the line in the other direction is detected in the detection step, control for individually weakening the contour enhancement amount in the one direction or the contour enhancement amount in the other direction is performed. The control method according to claim 7, wherein the control method is characterized in that:

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