JP2014216775A - Imaging apparatus, detection method, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an imaging apparatus, a detection method, and a program capable of reliably detecting a flickering defective pixel in an imaging device.SOLUTION: An imaging apparatus 1 comprises: an abnormal pixel determination unit 15 which determines whether an image is normal or not on the basis of the intensities of electric signals outputted respectively from plural pixels of an imaging device 6; and a flickering pixel detection unit 16 which refers to intensity distribution information recorded by an intensity distribution information recording unit 232 and detects a pixel which has been determined to be abnormal by the abnormal pixel determination unit 15 more frequently than a predetermined number of times, as the flickering defective pixel where the intensity of the electric signal varies irregularly.

Description

  The present invention relates to an imaging apparatus including an imaging device that captures an image of a subject and generates image data of the subject, a detection method for detecting a blinking defective pixel of the imaging device, and a program.

  2. Description of the Related Art Conventionally, solid-state imaging devices such as CCD (Charge Coupled Device) and CMOS (Complementary Metal Oxide Semiconductor) provided in an imaging apparatus such as a digital camera receive a plurality of light signals and perform photoelectric conversion to output an electrical signal. It consists of pixels. In such an image sensor, it is known that there is a defective pixel that outputs an abnormal electrical signal that has no correlation with the amount of received light. There are two types of defect images: steady defective pixels that always output abnormal electrical signals due to dust adhering to the light-receiving surface, crystal defects in the element, etc., and blinking that outputs abnormal electrical signals irregularly. There are defective pixels.

  The blinking defective pixel appears in the captured image as irregular image noise at the time of shooting by long exposure. This noise appears as a white spot in a dark part of the live view image, for example, a part of the night sky, particularly when the imaging apparatus displays a live view image while imaging a night view or the like as a subject. As a technique for removing the noise, a technique is known in which the imaging element is imaged as many times as the imaging condition in a light-shielded state, and a blinking defective pixel is detected from the plurality of captured images (Patent Literature). 1).

JP 2007-199907 A

  However, since the blinking defective pixel irregularly outputs an abnormal electric signal, even the above-described Patent Document 1 sometimes cannot detect the blinking defective pixel. For this reason, the technique which can detect the blink defect pixel in an image sensor reliably was desired.

  The present invention has been made in view of the above, and an object thereof is to provide an imaging apparatus, a detection method, and a program capable of reliably detecting a blinking defective pixel in an imaging element.

  In order to solve the above-described problems and achieve the object, an imaging apparatus according to the present invention includes a plurality of pixels that output an electric signal by receiving light imaged on a predetermined subject and performing photoelectric conversion. Based on the electrical signals respectively output from the plurality of pixels during a light shielding period in which the imaging elements arranged in a two-dimensional shape and the light receiving surface of the imaging element are shielded, intensity distribution information for each pixel is obtained. An intensity distribution information recording unit that accumulates and records during imaging, an abnormal pixel determination unit that determines whether a pixel is abnormal based on the intensity of the electrical signal output from each of the plurality of pixels, and Referring to the intensity distribution information recorded by the intensity distribution information recording unit, a blinking defect in which the intensity of the electrical signal changes irregularly for pixels in which the number of times determined as abnormal by the abnormal pixel determination unit is a predetermined number or more Picture Characterized in that and a flashing pixel detector for detecting a.

  Moreover, the imaging device according to the present invention is the above-described invention, wherein the flashing pixel information recording unit that records position information in the imaging element corresponding to the flashing defective pixel detected by the flashing pixel detection unit, and the flashing pixel information A pixel correction unit that corrects the electrical signal output from the blinking defective pixel using the electrical signal output from another pixel based on the position information recorded by the recording unit. To do.

  In the image pickup apparatus according to the present invention, in the above invention, a display unit that displays an image configured by the electrical signals output from the plurality of pixels, and a position in the image that the display unit displays are displayed. An input unit that receives an input of an instruction signal to be specified, and the abnormal pixel determination unit is output from each pixel of the imaging element corresponding to a region including at least a part of a position corresponding to the instruction signal It is characterized by determining whether the intensity | strength of an electrical signal is abnormal.

  The imaging apparatus according to the present invention may further include a display control unit that causes the display unit to display a menu screen for setting shooting conditions of the imaging apparatus, and the display control unit includes the display control unit in the light shielding period. This is a period during which the menu screen is displayed on the display unit.

  In the imaging device according to the present invention, in the above invention, the light shielding period is a period in which the display unit displays a still image for a predetermined time immediately after the imaging device performs still image shooting. It is characterized by that.

  In the imaging device according to the present invention, in the above invention, the light shielding period is a period during which an initial operation is performed after the imaging device is turned on, or an end operation when the imaging device is stopped. It is characterized by the period.

  The image pickup apparatus according to the present invention is the image pickup apparatus according to the above invention, wherein a shutter that adjusts exposure and light shielding by opening and closing a curtain that covers the light receiving surface of the image sensor, a shutter drive unit that drives the shutter, and the light shielding. And an imaging control unit that switches the light receiving surface of the imaging device to a light-shielding state by driving the shutter driving unit during the period.

  In addition, a detection method according to the present invention includes an imaging device in which a plurality of pixels that output an electrical signal are two-dimensionally arranged by receiving light imaged from a predetermined subject and performing photoelectric conversion. An abnormal pixel determination step for determining whether or not a pixel is abnormal based on the intensity of the electrical signal output from each of the plurality of pixels, the detection method executed by the imaging device, and the imaging element An intensity distribution information recording unit that accumulates and records intensity distribution information for each pixel during each imaging based on the electrical signals output from the plurality of pixels during a light shielding period in which the light receiving surface is shielded. Referring to intensity distribution information, a blinking image for detecting a pixel whose number of times determined to be abnormal by the abnormal pixel determination step is a predetermined number or more as a blinking defective pixel whose intensity of the electrical signal changes irregularly Characterized in that it comprises a detection step.

  In addition, a program according to the present invention includes an imaging device in which a plurality of pixels are arranged in a two-dimensional array, which receives light imaged from a predetermined subject and outputs an electrical signal by performing photoelectric conversion. An abnormal pixel determination step for determining whether or not a pixel is abnormal based on the intensity of the electrical signal output from each of the plurality of pixels, the program to be executed by the imaging device; The intensity distribution information recording unit that accumulates and records intensity distribution information for each pixel during each imaging based on the electrical signals output from the plurality of pixels during a light shielding period in which the light receiving surface is shielded. With reference to the distribution information, a pixel that is determined to be abnormal by the abnormal pixel determination step is detected as a blinking defective pixel whose intensity of the electrical signal changes irregularly. Characterized in that to execute a blink pixel detection step.

  According to the present invention, it is possible to reliably detect a blinking defective pixel in an image sensor.

FIG. 1 is a perspective view illustrating a configuration of a side facing the user of the imaging apparatus according to the first embodiment of the present invention. FIG. 2 is a block diagram illustrating a functional configuration of the imaging apparatus according to the first embodiment of the present invention. FIG. 3 is a flowchart illustrating an outline of processing executed by the imaging apparatus according to the first embodiment of the present invention. FIG. 4 is a flowchart showing an outline of the blinking defective pixel detection process of FIG. FIG. 5 is a diagram schematically illustrating each pixel on the imaging surface of the imaging element included in the imaging apparatus according to the first embodiment of the present invention. FIG. 6 is a diagram showing luminance distribution information of the pixels in FIG. FIG. 7 is a diagram showing luminance distribution information of the blinking defective pixel in FIG. FIG. 8 is a flowchart illustrating an outline of processing executed by the imaging apparatus according to the second embodiment of the present invention. FIG. 9 is a flowchart showing an outline of the blinking defective pixel detection process of FIG. FIG. 10 is a diagram schematically illustrating setting of a detection area for detecting a blinking defective pixel with respect to a live view image displayed by the display unit of the imaging apparatus according to the second embodiment of the present invention. FIG. 11 is a diagram schematically illustrating pixels in the detection area.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention (hereinafter referred to as “embodiments”) will be described with reference to the drawings. The present invention is not limited to the embodiments described below. Further, in the description of the drawings, the same portions will be described with the same reference numerals.

(Embodiment 1)
FIG. 1 is a perspective view illustrating a configuration of a side (back side) facing the user of the imaging apparatus according to the first embodiment of the present invention. FIG. 2 is a block diagram illustrating a functional configuration of the imaging apparatus according to the first embodiment of the present invention. An imaging apparatus 1 shown in FIGS. 1 and 2 includes a main body unit 2 and a lens unit 3 that is detachably attached to the main body unit 2 and receives light from a predetermined visual field region.

  The main body 2 includes a shutter 4, a shutter driving unit 5, an image sensor 6, an image sensor driving unit 7, a signal processing unit 8, an A / D conversion unit 9, an image processing unit 10, and an AE processing unit. 11, AF processing unit 12, image compression / decompression unit 13, luminance conversion unit 14, abnormal pixel determination unit 15, flashing pixel detection unit 16, flashing pixel registration unit 17, input unit 18, and display unit 19, display drive unit 20, memory I / F 21, recording medium 22, SDRAM (Synchronous Dynamic Random Access Memory) 23, Flash memory 24, main body communication unit 25, bus 26, control unit 27 .

  The shutter 4 sets an optical image on the image sensor 6 to an exposure state or a light shielding state. The shutter 4 is configured using a mechanical shutter such as a focal plane shutter.

  The shutter drive unit 5 drives the shutter 4 under the control of the control unit 27. The shutter drive unit 5 is configured using a voice coil motor, a stepping motor, or the like.

  The imaging device 6 uses a CCD or CMOS or the like in which a plurality of pixels that output an electric signal (image signal) by receiving light imaged by the lens unit 3 and performing photoelectric conversion are two-dimensionally arranged. Composed. In the imaging device 6, a plurality of pixels each having a photodiode that accumulates charges according to the amount of light and an amplifier that amplifies the charges accumulated by the photodiodes are two-dimensionally arranged. Although not shown, the image pickup device 6 controls the switching of whether or not to store the photoelectrically converted charge to the photodiode in each pixel, and transmits the stored charge to the amplifier. The pixel circuit by the readout selection circuit is connected, receives the light collected by the lens unit 3 and performs photoelectric conversion to generate image data (electric signal), and this image data is signaled Output to the processing unit 8.

  Under the control of the control unit 27, the image sensor driving unit 7 controls the start and end of accumulation of photoelectrically converted charges to the image sensor 6 at a predetermined timing, and transmits the accumulated charges to the amplifier. To control. Then, the image processing unit 8 outputs image data (analog electric signal) from the output of the amplifier. In this sense, the image sensor driving unit 7 functions as an electronic shutter. Further, under the control of the control unit 27, the image sensor driving unit 7 causes the image sensor 6 to output image data at a predetermined frame rate (for example, 30 fps or 60 fps) corresponding to the exposure time. Further, at the time of moving image shooting or live view operation, the image sensor driving unit 7 thins out a predetermined line of the image sensor 6, for example, even lines or odd lines under the control of the control unit 27. 6 causes the signal processing unit 8 to continuously output image data at a high frame rate (for example, 120 fps).

  Under the control of the control unit 27, the signal processing unit 8 performs analog processing on the image data input from the image sensor 6 and outputs the analog data to the A / D conversion unit 9. Specifically, the signal processing unit 8 performs noise reduction processing, gain increase processing, and the like on the image data.

  The A / D conversion unit 9 performs A / D conversion on the analog signal image data input from the signal processing unit 8 to convert the image data into digital image data (RAW data). The data is output to the SDRAM 23.

  The image processing unit 10 acquires image data for each frame from the SDRAM 23 via the bus 26, and performs various types of image processing on the acquired image data (RAW data) to generate processed image data ( Development processing). The processed image data is output to the SDRAM 23 via the bus 26. Specifically, the image processing unit 10 corrects at least black output for the image data, an optical black (OB) subtraction process, a white balance (WB) adjustment process for adjusting the color of the image data, a color Basic image processing is performed to generate a captured image including matrix calculation processing, gamma correction processing, color reproduction processing, edge enhancement processing, and the like. Note that the image processing unit 10 performs image data synchronization processing when the image sensor 6 is a Bayer array. In addition, the image processing unit 10 includes a pixel correction unit 101.

  The pixel correction unit 101 converts an electrical signal of a defective flashing pixel into an electrical signal of another pixel based on position information of the defective flashing pixel in the image sensor 6 recorded by a flashing pixel information recording unit 243 of the flash memory 24 described later. Correct using the signal. For example, the pixel correction unit 101 corrects an electrical signal of a blinking defective pixel using electrical signals of four pixels around or adjacent to the blinking defective pixel (for details of the correction method, see, for example, JP-A-6-303531). No. publication or Japanese Patent No. 3805421).

  The AE processing unit 11 acquires image data recorded in the SDRAM 23 via the bus 26, and sets an exposure condition for performing still image shooting or moving image shooting based on the acquired image data. Specifically, the AE processing unit 11 extracts a luminance component from the image data, calculates subject luminance, and sets, for example, a set value of an aperture value (F value), a shutter speed, and the like based on the calculated subject luminance. The automatic exposure of the imaging device 1 is performed by determining.

  The AF processing unit 12 acquires image data recorded in the SDRAM 23 via the bus 26, and adjusts the automatic focus of the imaging device 1 based on the acquired image data. For example, the AF processing unit 12 extracts a high-frequency component signal at a spatial frequency from the image data, and performs AF (Auto Focus) calculation processing on the high-frequency component signal (that is, the degree of contrast of the image). ) Is determined and the focus evaluation of the imaging apparatus 1 is determined, and the automatic focus of the imaging apparatus 1 is adjusted.

  The image compression / decompression unit 13 acquires image data from the SDRAM 23 via the bus 26, compresses the acquired image data according to a predetermined format, and outputs the compressed image data to the SDRAM 23. Here, the predetermined format includes a JPEG (Joint Photographic Experts Group) system, a Motion JPEG system, and an MP4 (H.264) system. The image compression / decompression unit 13 acquires image data (compressed image data) recorded on the recording medium 22 via the bus 26 and the memory I / F 21, expands (decompresses) the acquired image data, and stores it in the SDRAM 23. Output.

  The luminance conversion unit 14 converts the intensity of the electrical signal output for each pixel of the image sensor 6 into luminance information. Specifically, the luminance conversion unit 14 acquires one frame of image data generated by the image sensor 6 from the SDRAM 23 via the bus 26, and converts an electrical signal for each pixel constituting the acquired image data into luminance information. And output to the SDRAM 23 and the abnormal pixel determination unit 15, respectively.

  The abnormal pixel determination unit 15 determines whether or not the pixel is abnormal based on the intensity of the electric signal output from each of the plurality of pixels of the image sensor 6. Specifically, the abnormal pixel determination unit 15 determines whether or not the intensity of the electric signal output from each pixel of the image sensor 6 is equal to or greater than a threshold value indicating an abnormal value of the image. Specifically, the abnormal pixel determination unit 15 determines whether or not the luminance information for each pixel input from the luminance conversion unit 14 is greater than or equal to a preset threshold value indicating pixel abnormality.

  The blinking pixel detection unit 16 refers to the intensity distribution information for each pixel of the electrical signal output from each of the plurality of pixels of the image sensor 6 recorded by the SDRAM 23, and the number of times that the abnormal pixel determination unit 15 determines that the abnormality is present. A pixel more than a predetermined number of times is determined as a blinking defective pixel whose electric signal intensity changes irregularly.

  The blinking pixel registration unit 17 records and registers the position information (address information) of the corresponding pixel in the image sensor 6 detected by the blinking pixel detection unit 16 in the flash memory 24.

  The input unit 18 records the power switch 181 that switches the power state of the imaging apparatus 1 to an on state or an off state, a release switch 182 that receives an input of a still image release signal that gives a still image shooting instruction, and the recording medium 22 records. A deletion switch 183 that accepts an input of a deletion signal for deleting image data, an operation switch 184 that switches various settings of the imaging apparatus 1, a menu switch 185 that displays various settings of the imaging apparatus 1 on the display unit 19, and a recording medium 22 A reproduction switch 186 for displaying an image corresponding to the image data recorded on the display unit 19, a moving image switch 187 for receiving an input of a moving image release signal for giving an instruction to shoot a moving image, and detecting an external contact and detecting this A touch panel 188 for receiving position signal input according to the position .

  The release switch 182 can be moved back and forth by an external press, and receives an input of a first release signal (hereinafter referred to as a “1st release signal”) instructing a shooting preparation operation when half-pressed, while being fully pressed. In this case, a second release signal (hereinafter referred to as “2nd release signal”) for instructing still image shooting is received. The operation switch 184 includes up / down / left / right direction switches 184a to 184d for performing selection setting on the menu screen and the like, and a determination switch 184e (OK switch) for determining an operation by the direction switches 184a to 184d on the menu screen or the like ( (See FIG. 1). The operation switch 184 may be configured using a dial switch or the like.

  The touch panel 188 is provided so as to overlap the display area of the display unit 19, detects a touch of an object from the outside, and outputs a position signal (a signal indicating a coordinate position) corresponding to the detected touch position to the control unit 27. To do. Further, the touch panel 188 detects a position (coordinate position) touched based on information displayed on the display unit 19 by the user, for example, an icon image or a thumbnail image, and is performed by the imaging apparatus 1 according to the detected touch position. An input of an instruction signal for instructing an operation or a selection signal for selecting an image may be received. In general, the touch panel 188 includes a resistance film method, a capacitance method, an optical method, and the like. In the present embodiment, any type of touch panel is applicable.

  The display unit 19 is configured using a display panel made of liquid crystal, organic EL (Electro Luminescence), or the like, and displays live view images corresponding to the image data generated by the image sensor 6 and / or image data recorded by the recording medium 22. Display the corresponding captured image.

  The display drive unit 20 acquires image data recorded in the SDRAM 23 or image data recorded in the recording medium 22 via the bus 26 and causes the display unit 19 to display a captured image corresponding to the acquired image data. Here, for image display, a rec view display that displays image data immediately after shooting for a predetermined time (for example, 3 seconds), a reproduction display that reproduces image data recorded on the recording medium 22, and an image sensor 6 are continuously displayed. Live view display that sequentially displays live view images corresponding to image data to be generated in time series. Further, the display unit 19 displays a menu screen for setting operation information of the imaging apparatus 1 and shooting conditions relating to shooting.

  The recording medium 22 is configured using a memory card or the like mounted from the outside of the imaging device 1. The recording medium 22 is detachably attached to the imaging device 1 via the memory I / F 21. The recording medium 22 records the image data processed by the image processing unit 10 or the image compression / decompression unit 13 or outputs the image data recorded on the recording medium 22. The recording medium 22 may output the imaging program and various types of information to the flash memory 24 via the memory I / F 21 and the bus 26 under the control of the control unit 27.

  The SDRAM 23 temporarily records image data (RAW data) input from the A / D conversion unit 9 via the bus 26, image data input from the image processing unit 10, and information being processed by the imaging device 1. . For example, the SDRAM 23 temporarily records image data that the image sensor 6 sequentially outputs for each frame via the signal processing unit 8, the A / D conversion unit 9, and the bus 26. The SDRAM 23 is configured using a volatile memory. The SDRAM 23 also has an image data recording unit 231 that records image data and an intensity distribution for each pixel (for each position information) of an electrical signal output from each of the plurality of pixels of the image sensor 6 when the image sensor 6 is shielded from light. An intensity distribution information recording unit 232 that accumulates and records information for each imaging of the imaging apparatus 1. The intensity distribution information recording unit 232 records the intensity of the electric signal as luminance information converted by the luminance conversion unit 14.

  The flash memory 24 includes a program recording unit 241, a defective pixel information recording unit 242, and a blinking pixel information recording unit 243. The program recording unit 241 includes various programs for operating the imaging apparatus 1, the program according to the first embodiment, various data used during execution of the program, and each of the image processing operations performed by the image processing unit 10. Records image processing parameters and the like. The defective pixel information recording unit 242 records position information of defective pixels in the image sensor 6. The blinking pixel information recording unit 243 records position information of blinking defective pixels in the image sensor 6.

  The main body communication unit 25 is a communication interface for communicating control signals and the like to the lens unit 3 attached to the main body unit 2.

  The bus 26 is configured using a transmission path or the like that connects each component of the imaging device 1. The bus 26 is a main communication path for transferring various data generated inside the imaging apparatus 1 to each component of the imaging apparatus 1.

  The control unit 27 is configured using a CPU (Central Processing Unit) or the like, and receives instructions and data corresponding to each unit constituting the imaging apparatus 1 in response to an instruction signal or a release signal from the input unit 18 via the bus 26. The operation of the imaging apparatus 1 is comprehensively controlled by performing transfer or the like.

  Here, a detailed configuration of the control unit 27 will be described. The control unit 27 includes an imaging control unit 271 and a display control unit 272.

  When the 2nd release signal is input from the release switch 182, the imaging control unit 271 performs control for starting the imaging operation in the imaging device 1. Here, the imaging operation in the imaging apparatus 1 is the signal processing unit 8, the A / D conversion unit 9, and the image processing for the image data output from the imaging device 6 by driving the shutter driving unit 5 and the imaging device driving unit 7. An operation in which the unit 10 performs a predetermined process. The image data thus processed is compressed by the image compression / decompression unit 13 under the control of the control unit 27 and recorded on the recording medium 22 via the bus 26 and the memory I / F 21.

  The display control unit 272 controls the display mode of the display unit 19. Specifically, the display control unit 272 drives the display driving unit 20 and causes the display unit 19 to display a live view image corresponding to the image data on which the image processing unit 10 has performed image processing.

  The main body 2 having the above configuration may be provided with a voice input / output function, a flash function, an electronic viewfinder (EVF), and the like.

  The lens unit 3 includes an optical system 31, a lens driving unit 32, a diaphragm 33, a diaphragm driving unit 34, a lens operation unit 35, a lens flash memory 36, a lens communication unit 37, a lens control unit 38, Is provided.

  The optical system 31 is configured using one or a plurality of lenses, and collects light from a predetermined visual field region. The optical system 31 has an optical zoom function for changing the angle of view and a focus function for changing the focus. The lens driving unit 32 is configured using a DC motor, a stepping motor, or the like, and changes the focus position, the angle of view, and the like of the optical system 31 by moving the lens of the optical system 31 on the optical axis O.

  The diaphragm 33 adjusts the exposure by limiting the amount of incident light collected by the optical system 31. The aperture drive unit 34 is configured using a stepping motor or the like, and drives the aperture 33.

  As shown in FIG. 1, the lens operation unit 35 is a ring provided around the lens barrel of the lens unit 3, and receives an operation signal for starting an optical zoom operation in the lens unit 3 or in the lens unit 3. An instruction signal for instructing adjustment of the focus position is received. The lens operation unit 35 may be a push switch or the like.

  The lens flash memory 36 records lens information including a control program for determining the position and movement of the optical system 31, lens characteristics of the optical system 31, and various parameters.

  The lens communication unit 37 is a communication interface for communicating with the main body communication unit 25 of the main body unit 2 when the lens unit 3 is attached to the main body unit 2.

  The lens control unit 38 is configured using a CPU or the like. The lens control unit 38 controls the operation of the lens unit 3 in accordance with an operation signal from the lens operation unit 35 or an instruction signal from the main body unit 2. Specifically, the lens control unit 38 drives the lens driving unit 32 in accordance with an operation signal from the lens operation unit 35 to focus the lens unit 3 and change the zoom, and also drives the aperture driving unit 34. To change the aperture value. When the lens unit 3 is attached to the main body unit 2, the lens control unit 38 transmits the focus position information of the lens unit 3, the focal length, unique information for identifying the lens unit 3, and the like to the main body unit 2. It may be.

  Processing executed by the imaging apparatus 1 configured as described above will be described. FIG. 3 is a flowchart illustrating an outline of processing executed by the imaging apparatus 1.

  As shown in FIG. 3, when the power switch 181 is operated and the power of the imaging device 1 is turned on (step S101: Yes), the imaging mode is set in the imaging device 1 (step S102: Yes). The imaging apparatus 1 executes a blinking pixel detection process for detecting a blinking defective pixel in the image sensor 6 (step S103). Note that the imaging device 1 performs the blinking pixel detection process during a period in which various initial operations are performed in the shooting operation of the imaging device 1.

  FIG. 4 is a flowchart showing an outline of the blinking pixel detection process in step S103. As shown in FIG. 4, the imaging control unit 271 drives the shutter driving unit 5 to close the shutter 4 to set the light receiving surface of the imaging device 6 in a light-shielded state, and generates dark image data on the imaging device 6. The data is output to the image data recording unit 231 of the SDRAM 23 via the signal processing unit 8, the A / D conversion unit 9, and the bus 26 (step S201).

  Subsequently, the luminance conversion unit 14 acquires image data (RAW data) at the time of light shielding from the image data recording unit 231 of the SDRAM 23 via the bus 26, and the electrical signal (pixel signal) of each pixel of the image corresponding to the acquired image data. The intensity at the dark current level is converted into luminance information (step S202).

  Thereafter, the luminance conversion unit 14 outputs the luminance information for each pixel to the intensity distribution information recording unit 232 via the bus 26 to update the luminance distribution information (histogram information) for each pixel of the image sensor 6 (step S203). . In the first embodiment, the luminance distribution information functions as intensity distribution information.

  Subsequently, the abnormal pixel determination unit 15 determines whether or not the luminance information of each pixel converted by the luminance conversion unit 14 is greater than or equal to a threshold value indicating an abnormal value of the pixel (step S204).

  FIG. 5 is a diagram schematically illustrating each pixel on the imaging surface of the imaging device 6. FIG. 6 is a diagram showing luminance distribution information of the pixel P1 in FIG. FIG. 7 is a diagram showing luminance distribution information of the blinking defective pixel P2 in FIG. In FIG. 5, the blinking defective pixel P2 is represented by hatching, and other pixels including the normal pixel P1 are represented by white. 6 and 7, the horizontal axis indicates the luminance intensity I (level), and the vertical axis indicates the number of appearances recorded in the intensity distribution information recording unit 232.

As shown in FIGS. 5 and 6, the luminance of the normal pixel P1 immediately, is less than the threshold L _1, the luminance distribution is substantially uniform. In contrast, as shown in FIG. 7, the luminance of the flashing defective pixel P2 immediately, becomes the threshold L ₁ or more, the luminance distribution is uneven. Therefore, abnormal pixel determination unit 15 determines the luminance information determines whether the threshold value L ₁ or more for each pixel luminance conversion unit 14 converts the threshold L ₁ or more pixels as a candidate of the blinking defective pixel. Here, the threshold value L ₁ is, for example, 2000 LSB in terms of 12 bits.

After step S204, if it is determined that there is a threshold value L ₁ or more pixels by the abnormal pixel determining unit 15 (step S205: Yes), flashing pixel detector 16 of each pixel intensity distribution information recording unit 232 records Based on the luminance distribution information, it is determined whether or not the number of appearances of pixels determined to be greater than or equal to the threshold L ₁ by the abnormal pixel determination unit 15 is greater than or equal to a predetermined number (step S206). Specifically, as illustrated in FIG. 7, the blinking pixel detection unit 16 includes the threshold L ₁ determined by the abnormal pixel determination unit 15 based on the luminance distribution information of each pixel recorded by the intensity distribution information recording unit 232. occurrences of more pixels it is determined whether a predetermined number of times L ₂ or more, detecting a predetermined number of times L ₂ or more pixels as a blinking defective pixel. Here, the predetermined number of times is 10% of the number of updates of the luminance distribution information recorded by the intensity distribution information recording unit 232. That is, when the luminance distribution information is updated 10 times, it is one time. If the number of occurrences of pixels flashing pixel detection unit 16 is determined to be the threshold value L ₁ or by the abnormal pixel determining section 15 is equal to or more than the predetermined number of times (step S206: Yes), the imaging apparatus 1 proceeds to step S207 To do. On the other hand, when the blinking pixel detection unit 16 determines that the number of appearances of the pixel determined by the abnormal pixel determination unit 15 is not equal to or greater than the predetermined number (step S206: No), the imaging device 1 performs the main routine of FIG. Return to.

  In step S <b> 207, the blinking pixel registration unit 17 records the position information (pixel address) of the blinking defective pixel in the image sensor 6 detected by the blinking pixel detection unit 16 in the blinking pixel information recording unit 243. After step S207, the imaging apparatus 1 returns to the main routine in FIG.

After step S204, if there is no threshold L ₁ or more pixels by the abnormal pixel determining unit 15 (step S205: No), the imaging apparatus returns to the main routine of FIG.

  Returning to FIG. 3, the description of step S104 and subsequent steps will be continued. In step S <b> 104, the display control unit 272 causes the display unit 19 to display a live view image corresponding to the image data generated by the image sensor 6.

  Subsequently, when a release signal is input from the release switch 182 (step S105: Yes), the imaging control unit 271 causes the imaging device 1 to perform still image shooting (step S106). At this time, the pixel correction unit 101 detects the position information of the defective pixel in the image sensor 6 recorded by the defective pixel information recording unit 242 and the position information of the blinking defective pixel in the image sensor 6 recorded by the flashing pixel information recording unit 243. Referring to the image signals of defective pixels and blinking defective pixels, interpolation or correction is performed using image signals of peripheral pixels or image signals of adjacent pixels.

  Thereafter, the display control unit 272 causes the display unit 19 to display the still image obtained by performing the image processing on the image data (RAW data) generated during the still image shooting on the display unit 19 for a predetermined time, for example, 3 seconds. (Step S107).

  Subsequently, the imaging apparatus 1 executes the blinking pixel detection process described above in step S103 (step S108).

  Thereafter, when the power switch 181 is operated and the power of the imaging device 1 is turned off (step S109: Yes), the imaging device 1 performs the end operation for returning the various operation states to the initial values. The blinking pixel detection process described above is executed in step S103 (step S110), and the imaging apparatus 1 ends this process.

  In step S109, when the power of the imaging device 1 is not turned off (step S109: No), the imaging device 1 returns to step S102.

  In step S105, when the release signal is not input from the release switch 182 (step S105: No), the imaging apparatus 1 proceeds to step S111.

  Subsequently, when an instruction signal for instructing display of the menu screen of the imaging apparatus 1 is input from the menu switch 185 (step S111: Yes), the display control unit 272 displays the menu image of the imaging apparatus 1 on the display unit 19. (Step S112).

  Thereafter, the imaging device 1 executes the blinking pixel detection process described above in step S103 (step S113). In this case, the imaging device 1 may perform the blinking pixel detection process a plurality of times during the period in which the display unit 19 continues to display the menu screen or the parameter setting period of the imaging device 1 by the user. Further, the imaging device 1 may execute the menu screen display by the display unit 19 and the blinking pixel detection process in parallel. After step S113, the imaging apparatus 1 proceeds to step S109.

  In step S111, when the instruction signal instructing display of the menu screen of the imaging device 1 is not input from the menu switch 185 (step S111: No), the imaging device 1 proceeds to step S109.

  In step S101, when the power switch 181 is not operated and the power of the imaging device 1 is not turned on (step S101: No), the imaging device 1 stands by until the power is turned on.

  In step S102, when the shooting mode is not set in the imaging device 1 (step S102: No), when the playback mode is set in the imaging device 1 (step S114: Yes), the display control unit 272 displays the recording medium. A reproduction display process is executed to display a reproduction image corresponding to the image data recorded in 22 on the display unit 19 (step S115). After step S115, the imaging apparatus 1 proceeds to step S109.

  In step S102, when the imaging mode is not set in the imaging apparatus 1 (step S102: No), when the playback mode is not set in the imaging apparatus 1 (step S114: No), the imaging apparatus 1 performs step S109. Migrate to

According to the first embodiment of the present invention described above, the blinking pixel detection unit 16 refers to the intensity of the electrical signal of each pixel recorded by the intensity distribution information recording unit 232 and the number of appearances of this intensity, thereby detecting an abnormal pixel. A pixel having a predetermined number of times L ₂ or more that is determined by the determination unit 15 to have an electric signal intensity determined to be greater than or equal to the threshold value L ₁ is determined as a blinking pixel, so that a blinking defective pixel in the image sensor 6 can be reliably detected. it can.

  Further, according to the first embodiment of the present invention, even if the cycle of occurrence of blinking defective pixels is irregular, it can be reliably detected.

  In addition, according to the first embodiment of the present invention, the blinking defective pixel and the steady defective pixel are corrected simultaneously with the normal FPN (fixed pattern noise) correction process, so that the correction process is performed in a short time. Therefore, for example, continuous shooting (continuous shooting) can be easily performed.

  Further, according to the first embodiment of the present invention, a blinking defective pixel can be reliably detected, so that overcorrection of a normal pixel can be prevented. Furthermore, it is possible to prevent erroneous correction of normal pixels by a noise estimation method based on occurrence probability, which corrects generally known random noise, and can perform appropriate correction processing.

  Further, according to the first embodiment of the present invention, when the power switch 181 of the imaging apparatus 1 is operated and the power supply of the imaging apparatus 1 is turned on, or when the power supply of the imaging apparatus 1 is turned off At this time (when stopped), the image pickup control unit 271 drives the shutter drive unit 5 and the image pickup device drive unit 7 to cause the image pickup device 6 to generate dark image data. Thereby, since the defective blinking pixel is detected during the period that affects the normal imaging operation, it is possible to prevent the subject from missing a photo opportunity.

  Further, according to the first embodiment of the present invention, when the display unit 19 displays the menu screen, the image pickup control unit 271 drives the shutter drive unit 5 and the image pickup device drive unit 7, whereby the image pickup device. 6 causes dark image data to be generated. Thereby, the blinking defective pixel can be detected in a period in which the normal imaging operation is not affected.

  Further, according to Embodiment 1 of the present invention, when the imaging device 1 displays a still image captured by the display unit 19 for a predetermined time immediately after the imaging device 1 performs still image capturing, the imaging control unit 271 performs the shutter operation. By driving the drive unit 5 and the image sensor drive unit 7, the image sensor 6 is caused to generate dark image data. Thereby, the blinking defective pixel can be detected in a period in which the normal imaging operation is not affected.

(Embodiment 2)
Next, a second embodiment of the present invention will be described. The imaging apparatus according to the second embodiment has the same configuration as that of the first embodiment described above, and the processing to be executed is different. Therefore, in the following, processing executed by the imaging apparatus according to the second embodiment will be described. In addition, the same code | symbol is attached | subjected to the structure same as the imaging device 1 concerning Embodiment 1 mentioned above, and description is abbreviate | omitted.

  FIG. 8 is a flowchart illustrating an outline of processing executed by the imaging apparatus 1 according to the second embodiment. Steps S301 to S302 correspond to the contents of Steps S101 to S102 in FIG.

  Subsequently, the imaging device 1 executes a blinking pixel detection process for detecting a blinking defective pixel in the image sensor 6 (step S303).

  FIG. 9 is a flowchart showing an outline of the blinking pixel detection process in step S303. As shown in FIG. 9, the imaging control unit 271 drives the shutter driving unit 5 to close the shutter 4 to set the imaging device 6 in the light shielding state, and the image data in the dark (light shielding state) is stored in the imaging device 6. The data is generated and output to the image data recording unit 231 of the SDRAM 23 via the signal processing unit 8, the A / D conversion unit 9, and the bus 26 (step S401).

Subsequently, the control unit 27 determines whether or not a detection region for detecting a blinking defective pixel is designated in the image sensor 6 (step S402). Specifically, as shown in FIG. 10, the control unit 27, with respect to the live view image _{W 1} of the display unit 19 displays (FIG. 10 (a)), the desired area the user via the touch panel 188, for example, By touching the region where the blinking defective pixel P2 is generated (FIG. 10B), it is determined whether or not the detection region R1 for detecting the blinking defective pixel is designated in the imaging device 6. When the control unit 27 determines that the detection area for detecting the blinking defective pixel is designated in the image sensor 6 (step S402: Yes), the imaging device 1 proceeds to step S403 to be described later. On the other hand, when the control unit 27 determines that the detection region for detecting the blinking defective pixel is not designated in the image sensor 6 (step S402: No), the imaging device 1 proceeds to step S409 described later. .

  In step S403, the luminance conversion unit 14 acquires image data (RAW data) at the time of light shielding from the image data recording unit 231 of the SDRAM 23 via the bus 26, and the electrical signal of each pixel of the image corresponding to the acquired image data. Is converted into luminance information.

  Thereafter, the luminance conversion unit 14 outputs the luminance information for each pixel to the intensity distribution information recording unit 232 via the bus 26, and updates the luminance distribution information for each pixel (step S404).

Subsequently, the abnormal pixel determination unit 15 sets the luminance information to the threshold value L _{1 for} each pixel in the detection region R1 of the image sensor 6 specified by the touch panel 188 based on the luminance information of each pixel detected by the luminance conversion unit 14. It is determined whether or not this is the case (step S405). Specifically, as illustrated in FIG. 11, the abnormal pixel determination unit 15 determines whether or not the luminance information is greater than or equal to a threshold L _{1 for} each pixel in the detection region R1 of the image sensor 6 specified by the touch panel 188. .

When the abnormal pixel determination unit 15 determines that there is a pixel that is equal to or greater than the threshold L ₁ in the detection region R1 (step S406: Yes), the blinking pixel detection unit 16 sets each pixel that the intensity distribution information recording unit 232 records. based on the luminance distribution information, and determines the number of occurrences of the detection area pixels determined as the threshold value L ₁ or by the abnormal pixel determining unit 15 in the R1 of the image sensor 6 to or greater than the predetermined number of times (step S407) . Specifically, the blinking pixel detection unit 16 determines that the number of appearances of the pixel equal to or higher than the threshold L ₁ determined by the abnormal pixel determination unit 15 based on the luminance distribution information of each pixel recorded by the intensity distribution information recording unit 232. it is judged whether or not a predetermined number of times L ₂ or more, detecting a predetermined number of times L ₂ or more pixels as a blinking defective pixel. When the blinking pixel detection unit 16 determines that the number of pixels determined by the abnormal pixel determination unit 15 is equal to or greater than the predetermined number (step S407: Yes), the imaging device 1 proceeds to step S408. On the other hand, when the blinking pixel detection unit 16 determines that the number of pixels determined by the abnormal pixel determination unit 15 is not equal to or greater than the predetermined number (step S407: No), the imaging device 1 goes to the main routine of FIG. Return.

  In step S <b> 408, the blinking pixel registration unit 17 records pixel position information (pixel address) in the image sensor 6 detected by the blinking pixel detection unit 16 in the blinking pixel information recording unit 243. After step S408, the imaging apparatus 1 returns to the main routine in FIG.

  Steps S409 to S414 correspond to the contents of steps S202 to S207 in FIG. 4, respectively. After step S414, the imaging apparatus 1 returns to the main routine of FIG.

  Returning to FIG. 8, the description of step S304 and subsequent steps will be continued. Step S304 corresponds to the content of step S104 of FIG.

Subsequently, when the display unit 19 to live view image W ₁ to be displayed, the user via the touch panel 188 is touched to the desired area, e.g., area blinking defective pixel P2 has occurred (step S305: Yes ) The imaging apparatus 1 executes the above-described blinking pixel detection process (step S306). After step S306, the imaging device 1 proceeds to step S307. If this respect, with respect to the live view image W ₁ of the display unit 19 displays the user via the touch panel 188 is not touched to the region desired region, for example flashing defective pixel P2 has occurred (step (S305: No), the imaging apparatus 1 proceeds to step S307.

  Steps S307 to S316 correspond to the contents of steps S105 to S114 in FIG. In steps S310, S312 and S315, the blinking pixel detection process shown in FIG. 9 is executed.

  In step S317, the display control unit 272 causes the display unit 19 to display a reproduced image corresponding to the image data recorded by the recording medium 22.

  Subsequently, when the reproduced image displayed on the display unit 19 is touched (step S318: Yes), the control unit 27 adds an area including the touch position to the SDRAM 23 based on the position signal input from the touch panel 188. Recording is performed (step S319). After step S319, the imaging device 1 proceeds to step S320. On the other hand, when the reproduced image displayed on the display unit 19 is not touched (step S318: No), the imaging device 1 proceeds to step S320.

  Subsequently, when an instruction signal for instructing image switching is input from the menu switch 185 (step S320: Yes), the display control unit 272 switches the reproduced image to be displayed on the display unit 19 (step S321). After step S321, the imaging apparatus 1 returns to step S318. On the other hand, when an instruction signal for instructing image switching is not input from the menu switch 185 (step S320: No), the imaging apparatus 1 proceeds to step S311.

  According to the second embodiment of the present invention described above, since the same effect as that of the first embodiment described above is obtained, a blinking defective pixel in the image sensor 6 can be reliably detected.

  Further, according to the second embodiment of the present invention, a detection area in which a blinking defective pixel is detected by the user touching the live view image via the touch panel 188 is set, and the area including the touch position is set. Since the blinking pixel detection unit 16 determines the blinking defective pixel, it is possible to reduce the load caused by the calculation of the imaging device 1 and to prevent an increase in the capacity of the SDRAM 23.

  Further, according to the second embodiment of the present invention, an area including a point due to a blinking defective pixel generated in a live view image displayed on the display unit 19 can be designated by an intuitive operation.

(Other embodiments)
In addition to a digital single-lens reflex camera, the imaging device according to the present invention is also applicable to, for example, a digital camera that can be equipped with accessories, a digital video camera, and an electronic device such as a mobile phone or a tablet-type mobile device having an imaging function. can do.

  In the present invention, the main body portion and the lens portion may be integrally formed.

  Further, in the present invention, the image pickup apparatus according to the above-described embodiment has been described using a consumer digital camera as an example. However, the present invention is not limited thereto, and examples of an observation apparatus using an image pickup device include a digital microscope apparatus, a video scope, and the like. The present invention can be applied to an endoscope apparatus or an endoscope system such as an endoscope scope, or an imaging apparatus such as a remote sensing camera such as a surveillance camera.

  The program executed by the imaging apparatus according to the present invention is file data in an installable format or executable format, and is a CD-ROM, flexible disk (FD), CD-R, DVD (Digital Versatile Disk), USB medium. And recorded on a computer-readable recording medium such as a flash memory.

  The program executed by the imaging apparatus according to the present invention may be downloaded via a network and recorded in a flash memory, a recording medium, or the like. Furthermore, the program to be executed by the imaging apparatus according to the present invention may be provided or distributed via a network such as the Internet.

  In the description of the flowchart in the present specification, the context of the processing between steps is clearly indicated using expressions such as “first”, “after”, “follow”, etc., in order to implement the present invention. The order of processing required is not uniquely determined by their representation. That is, the order of processing in the flowcharts described in this specification can be changed within a consistent range.

  As described above, the present invention can include various embodiments not described herein, and various design changes and the like can be made within the scope of the technical idea specified by the claims. Is possible.

DESCRIPTION OF SYMBOLS 1 Imaging device 2 Main body part 3 Lens part 4 Shutter 5 Shutter drive part 6 Imaging element 7 Imaging element drive part 8 Signal processing part 9 A / D conversion part 10 Image processing part 11 AE processing part 12 AF processing part 13 Image compression / expansion part DESCRIPTION OF SYMBOLS 14 Brightness conversion part 15 Abnormal pixel determination part 16 Flashing pixel detection part 17 Flashing pixel registration part 18 Input part 19 Display part 20 Display drive part 21 Memory I / F
22 Recording medium 23 SDRAM
24 Flash Memory 25 Main Unit Communication Unit 26 Bus 27 Control Unit 31 Optical System 32 Lens Drive Unit 33 Aperture 34 Aperture Drive Unit 35 Lens Operation Unit 36 Lens Flash Memory 37 Lens Communication Unit 38 Lens Control Unit 101 Pixel Correction Unit 181 Power Switch 182 Release Switch 183 Delete switch 184 Operation switch 185 Menu switch 186 Playback switch 187 Movie switch 188 Touch panel 231 Image data recording unit 232 Intensity distribution information recording unit 241 Program recording unit 242 Defective pixel information recording unit 243 Flashing pixel information recording unit

Claims (9)

An image sensor in which a plurality of pixels that receive light formed on a predetermined subject and output photoelectric signals by performing photoelectric conversion;
Intensity distribution information recording that accumulates and records intensity distribution information for each pixel during each imaging based on the electrical signals output from the plurality of pixels during a light shielding period in which the light receiving surface of the imaging element is shielded. And
An abnormal pixel determination unit that determines whether the pixel is abnormal based on the intensity of the electrical signal output from each of the plurality of pixels;
Referring to the intensity distribution information recorded by the intensity distribution information recording unit, blinking in which the intensity of the electric signal changes irregularly for pixels in which the number of times determined to be abnormal by the abnormal pixel determination unit is a predetermined number or more A blinking pixel detection unit for detecting as a defective pixel;
An imaging apparatus comprising: A blinking pixel information recording unit that records position information in the image sensor corresponding to the blinking defective pixel detected by the blinking pixel detection unit;
Based on the position information recorded by the blinking pixel information recording unit, a pixel correction unit that corrects the electric signal output by the blinking defective pixel using the electric signal output by another pixel;
The imaging apparatus according to claim 1, further comprising: A display unit configured to display an image formed by the electrical signals output from the plurality of pixels,
An input unit that receives an input of an instruction signal that designates a position in the image displayed by the display unit;
With
The abnormal pixel determination unit determines whether or not the intensity of the electric signal output from each pixel of the image sensor corresponding to a region including at least a part of a position corresponding to the instruction signal is abnormal. The imaging device according to claim 1, wherein: A display control unit for displaying a menu screen for setting shooting conditions of the imaging apparatus on the display unit;
The imaging apparatus according to claim 3, wherein the light shielding period is a period in which the display control unit displays the menu screen on the display unit.   The imaging apparatus according to claim 3, wherein the light shielding period is a period in which the display unit displays a still image for a predetermined time immediately after the imaging apparatus performs still image shooting.   The light shielding period is a period during which an initial operation is performed after the imaging apparatus is turned on, or a period during which an end operation is performed when the imaging apparatus is stopped. 4. The imaging device according to any one of 3. A shutter for adjusting exposure and shading by opening and closing a curtain covering the light receiving surface of the image sensor;
A shutter drive unit for driving the shutter;
An imaging control unit that switches the light receiving surface of the imaging element to a light shielding state by driving the shutter driving unit during the light shielding period;
The imaging apparatus according to claim 1, further comprising: This is a detection method executed by an imaging device having an imaging device in which a plurality of pixels that output electrical signals are two-dimensionally arranged by receiving light imaged from a predetermined subject and performing photoelectric conversion. And
An abnormal pixel determination step for determining whether or not the pixel is abnormal based on the intensity of the electrical signal output from each of the plurality of pixels;
Intensity distribution information recording that accumulates and records intensity distribution information for each pixel during each imaging based on the electrical signals output from the plurality of pixels during a light shielding period in which the light receiving surface of the imaging element is shielded. Referring to the intensity distribution information of the unit, blinking pixel detection for detecting a pixel whose number of times determined to be abnormal by the abnormal pixel determination step is a predetermined number or more as a flashing defective pixel whose intensity of the electrical signal changes irregularly Steps,
A detection method comprising: A program to be executed by an imaging device including an imaging device in which a plurality of pixels are arranged in a two-dimensional array, which receives light imaged from a predetermined subject and outputs an electrical signal by performing photoelectric conversion. And
An abnormal pixel determination step for determining whether or not the pixel is abnormal based on the intensity of the electrical signal output from each of the plurality of pixels;
Intensity distribution information recording that accumulates and records intensity distribution information for each pixel during each imaging based on the electrical signals output from the plurality of pixels during a light shielding period in which the light receiving surface of the imaging element is shielded. Referring to the intensity distribution information of the unit, blinking pixel detection for detecting a pixel whose number of times determined to be abnormal by the abnormal pixel determination step is a predetermined number or more as a flashing defective pixel whose intensity of the electrical signal changes irregularly Steps,
A program characterized by having executed.

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