JP2007166087A - Imaging apparatus, imaging method, program, and storage medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform accurate direct-current reproduction performance for an output signal from an imaging element, and obtain a good image without picture impairment such as false horizontal line, etc. <P>SOLUTION: The imaging apparatus is provided with a light receiving region which is formed of a plurality of pixels for carrying out photoelectric conversion, an imaging means with a light shading region which is formed of a plurality of pixels for carrying out photoelectric conversion of a shaded light in order to form a black reference signal, a first correction means which carries out direct-current reproduction for each line based on the black reference signal, a shading data memory means which calculates a representative value of each column unit of the light shading region beforehand, a second correction means which carries out direct-current reproduction for each line using data of the shading data memory means, and a shading variance detection means which detects local variance of shading in a column direction of the signal in the light shading region. Based on the result of the shading variance detection means, the first and the second correction means are selected. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an imaging apparatus, an imaging method, a program, and a storage medium that capture, record, and reproduce a still image and a moving image, for example.

  Conventionally, as this type of imaging device, there has already been an imaging device such as an electronic camera that records and reproduces still images and moving images captured by a solid-state imaging device such as a CCD or CMOS, using a memory card having a solid-state memory element as a recording medium. It is commercially available.

  When imaging using a solid-state image sensor such as a CCD or CMOS, the black reference voltage changes due to the dark current generated even when the image sensor is not exposed. It is possible to correct the black reference voltage by correcting the signal in the light receiving region.

  As a result, it is possible to obtain a high-quality image by removing the DC component due to the dark current generated in the image sensor and correcting the shading in the column direction.

  In particular, since the DC voltage due to dark current increases with the charge accumulation time and the temperature rise of the image sensor, a large image quality improvement effect can be obtained when performing exposure at long seconds or exposure at high temperatures. The black reference voltage correction processing using the signal in the light shielding area is a useful function for the user.

For example, Patent Document 1 and Patent Document 2 can be cited as conventional examples.
JP 2002-170944 A JP 2000-32356 A

  However, in the conventional imaging apparatus such as an electronic camera, when performing direct current reproduction of the black reference voltage using the signal of the light shielding region, leakage of infrared light from the light receiving region to the light shielding region or the vicinity of the photoelectric conversion region. There is a possibility that wrong DC regeneration processing may be performed due to a phenomenon that the signal in the light shielding region is locally increased due to heat generation of the circuit or infrared light emission of the peripheral circuit.

  FIG. 5 is a diagram showing a situation where infrared light is incident on the light shielding region, and FIG. 6 is a diagram showing vertical shading of the light shielding region signal in the situation of FIG. It shows the situation where the floating has occurred.

  As a method of solving this problem, correction data storage means storing correction data for correcting image data, and correction for correcting image data obtained in the imaging mode using the stored correction data However, there is a problem that correction data stored in advance cannot be corrected accurately because of the difference between the environment in which the correction data is calculated and the shooting environment.

  SUMMARY An advantage of some aspects of the invention is that it provides an imaging apparatus, an imaging method, a program, and a storage medium that can reduce erroneous correction due to local floating of a light-shielding region and obtain good image quality.

An imaging unit having a light receiving region formed by a plurality of pixels for photoelectric conversion and a light shielding region formed by a plurality of pixels for photoelectric conversion to form a black reference signal; First correction means for performing DC regeneration for each row based on a reference signal;
A shading data storage means for calculating a representative value for each row of the light shielding area in advance and storing it as data for one column;
Second correction means for performing direct current reproduction for each row using the data of the shading data storage means;
A shading change detecting means for detecting a local change in shading in the column direction of the signal of the light shielding region;
An imaging apparatus, wherein the first and second correction means are selected based on a result of the shading change detection means.

  According to the present invention, it is possible to prevent the influence of local floating of the light shielding area and to obtain a good image quality.

  Embodiments of an imaging apparatus, an imaging method, a program, and a storage medium of the present invention will be described with reference to the drawings. The imaging apparatus of this embodiment is applied to an electronic camera.

  FIG. 1 is a block diagram illustrating a configuration of an electronic camera according to an embodiment. In the figure, reference numeral 100 denotes an image processing apparatus. Reference numeral 12 denotes a shutter having a diaphragm function for controlling the exposure amount of the image sensor 14. An image sensor 14 converts an optical image into an electric signal.

  The light beam incident on the photographing lens 310 in the lens unit 300 forms an optical image on the image sensor 14 guided by the single-lens reflex system through the diaphragm 312, the lens mounts 306 and 106, the mirror 130, and the shutter 12.

  Reference numeral 16 denotes an A / D converter that converts an analog signal output from the image sensor 14 into a digital signal. A timing generation circuit 18 supplies a clock signal and a control signal to the image sensor 14, the A / D converter 16 and the D / A converter 26, and is controlled by the memory control circuit 22 and the system control circuit 50.

  An image processing circuit 20 performs predetermined pixel interpolation processing and color conversion processing on the data from the A / D converter 16 or the data from the memory control circuit 22. The image processing circuit 20 performs predetermined calculation processing using image data taken as necessary, and the system control circuit 50 controls the exposure (shutter) control unit 40 and the distance measurement control unit 42 based on the obtained calculation result. TTL (through-the-lens) AF (autofocus) processing, AE (automatic exposure) processing, and EF (flash dimming) processing for control are performed. The image processing circuit 20 performs predetermined arithmetic processing using the captured image data, and performs TTL AWB (auto white balance) processing based on the obtained arithmetic result.

  In the present embodiment, since the distance measurement control unit 42 and the photometry control unit 46 are provided exclusively, the system control circuit 50 uses the distance measurement control unit 42 and the photometry control unit 46 to perform AF (autofocus) processing. , AE (automatic exposure) processing and EF (flash dimming) processing are performed, and the image processing circuit 20 is used for AF (autofocus) processing, AE (automatic exposure) processing, and EF (flash dimming) processing. It is good also as a structure which does not perform each process.

  Further, the AF (auto focus) process, the AE (automatic exposure) process, and the EF (flash dimming) process are performed using the distance measurement control unit 42 and the photometry control unit 46, and the image processing circuit 20 is used. The AF (autofocus) process, the AE (automatic exposure) process, and the EF (flash dimming) process may be performed.

  A memory control circuit 22 controls the A / D converter 16, the timing generation circuit 18, the image processing circuit 20, the image display memory 24, the D / A converter 26, the memory 30, and the compression / decompression circuit 32.

  Data from the A / D converter 16 is written into the image display memory 24 or the memory 30 via the image processing circuit 20 and the memory control circuit 22 or directly via the memory control circuit 22.

  Reference numeral 24 is an image display memory, and 26 is a D / A converter. Reference numeral 28 denotes an image display unit comprising a TFT type LCD. The display image data written in the image display memory 24 is displayed on the image display unit 28 via the D / A converter 26. When the captured image data is sequentially displayed on the image display unit 28, an electronic viewfinder function can be realized. Further, the image display unit 28 can arbitrarily turn on / off the display in accordance with an instruction from the system control circuit 50. When the display is turned off, the power consumption of the image processing apparatus 100 can be greatly reduced. Can do.

  Reference numeral 30 denotes a memory for storing captured still images and moving images, and has a sufficient storage capacity to store a predetermined number of still images and a predetermined time of moving images. Therefore, even in continuous shooting or panoramic shooting in which a plurality of still images are continuously shot, it is possible to write a large amount of images to the memory 30 at high speed. The memory 30 can also be used as a work area for the system control circuit 50.

  A compression / decompression circuit 32 compresses and decompresses image data by adaptive discrete cosine transform (ADCT) or the like, reads an image stored in the memory 30, performs compression processing or decompression processing, and stores the processed data in the memory 30. Write to.

  Reference numeral 40 denotes a shutter control unit that controls the shutter 12 in cooperation with an aperture control unit 340 that controls the aperture 312 based on photometric information from the photometry control unit 46. Reference numeral 42 denotes a distance measurement control unit for performing AF (autofocus) processing. A light beam incident on the photographing lens 310 in the lens unit 300 is used to stop the aperture 312, lens mounts 306 and 106, the mirror 130, and a distance measurement sub-mirror (see FIG. The in-focus state of the image formed as an optical image is measured by entering with a single-lens reflex system via a not-shown).

  A thermometer 44 detects the ambient temperature in the photographing environment. When the thermometer is in the image sensor (sensor) 14, it is possible to predict the dark current of the sensor more accurately.

  Reference numeral 46 denotes a photometric control unit for performing AE (automatic exposure) processing. The light beam incident on the photographing lens 310 in the lens unit 300 is converted into an aperture 312, lens mounts 306 and 106, a mirror 130, and a photometric sub-mirror (not shown). The exposure state of the image formed as an optical image is measured. The photometry control unit 46 also has an EF (flash dimming) processing function in cooperation with the flash unit 48. A flash unit 48 has an AF auxiliary light projecting function and a flash light control function.

  As described above, based on the calculation result calculated by the image processing circuit 20 using the image data picked up by the image pickup device 14, the system control circuit 50 includes the exposure (shutter) control unit 40, the aperture control unit 340, It is possible to perform exposure control and AF (autofocus) control using the video TTL system for the distance measurement control unit 342.

  Further, AF (autofocus) control may be performed using a measurement result obtained by the distance measurement control unit 42 and a calculation result obtained by calculating the image data captured by the image sensor 14 by the image processing circuit 20. Further, exposure control may be performed using the measurement result obtained by the photometry control unit 46 and the calculation result obtained by calculating the image data captured by the image sensor 14 by the image processing circuit 20.

  Reference numeral 50 denotes a system control circuit that controls the entire image processing apparatus 100 and incorporates a known CPU and the like. Reference numeral 52 denotes a memory for storing constants, variables, programs, and the like for operating the system control circuit 50. Reference numeral 54 denotes a display unit having a liquid crystal display device, a speaker, and the like for displaying an operation state and a message with characters, images, voices, and the like in accordance with execution of a program in the system control circuit 50. An operation unit of the image processing device 100 It is installed at one or a plurality of places that are easily visible in the vicinity. The display unit 54 is configured by a combination of an LCD, an LED, a sound generating element, and the like. Some functions of the display unit 54 are provided in the optical viewfinder 104.

  Among the display contents of the display unit 54, what is displayed on the LCD or the like includes single shot / continuous shooting display, self-timer display, compression rate display, number of recorded pixels, number of recorded pixels, number of remaining images that can be captured, shutter Speed display, Aperture value display, Exposure compensation display, Flash display, Red-eye reduction display, Macro shooting display, Buzzer setting display, Clock battery level display, Battery level display, Error display, Multi-digit number information display and recording There are an attachment / detachment state display of the media 200 and 210, an attachment / detachment state display of the lens unit 300, a communication I / F operation display, a date / time display, and a display showing a connection state with an external computer.

  Among the display contents of the display unit 54, what is displayed in the optical finder 104 includes in-focus display, shooting preparation completion display, camera shake warning display, flash charge display, flash charge completion display, shutter speed display, aperture value. Display, exposure compensation display, recording medium writing operation display, and the like.

  Furthermore, among the display contents of the display unit 54, what is displayed on the LED or the like includes, for example, in-focus display, shooting preparation completion display, camera shake warning display, flash charge display, flash charge completion display, recording medium writing operation display, Macro shooting setting notification display, secondary battery charge display, etc.

  Among the display contents of the display unit 54, what is displayed on a lamp or the like includes, for example, a self-timer notification lamp. This self-timer notification lamp may be shared with AF auxiliary light.

  Reference numeral 56 denotes an electrically erasable / recordable nonvolatile memory storing a program and the like to be described later, and an EEPROM or the like is used as the nonvolatile memory. The nonvolatile memory 56 stores various parameters, setting values such as ISO sensitivity, setting mode, and one-dimensional shading correction data used when performing dark shading correction in the column direction. This one-dimensional shading correction data is created and written at the time of adjustment in the production process. As a method of creating the one-dimensional shading correction data, for example, a method of mainly generating data for one vertical column by projecting an image obtained by performing dark photographing can be considered.

  Reference numerals 60, 62, 64, 66, 68 and 70 are operation units for inputting various operation instructions of the system control circuit 50, and include one or a plurality of switches, dials, touch panels, pointing by gaze detection, voice recognition devices, and the like. Composed of a combination. Details of these operation units are shown below.

  Reference numeral 60 denotes a mode dial switch, which is an automatic shooting mode, program shooting mode, shutter speed priority shooting mode, aperture priority shooting mode, manual shooting mode, depth of focus priority (depth) shooting mode, portrait shooting mode, landscape shooting mode, and close-up shooting. Each function shooting mode such as a shooting mode, a sports shooting mode, a night view shooting mode, and a panoramic shooting mode can be switched and set.

  A shutter switch (SW1) 62 is turned on during the operation of a shutter button (not shown), and AF (auto focus) processing, AE (automatic exposure) processing, AWB (auto white balance) processing, EF (flash adjustment). Instructs the start of operation such as light processing.

  Reference numeral 64 denotes a shutter switch (SW2), which is turned on when the operation of a shutter button (not shown) is completed. The shutter switch (SW2) 64 is an exposure process for writing image data into the memory 30 via the A / D converter 16 and the memory control circuit 22 through the signal read from the image sensor 12, the image processing circuit 20 and the memory control circuit 22. The development processing using the calculation in the above, the image data is read from the memory 30, compressed by the compression / decompression circuit 32, and the start of a series of processing operations such as recording processing for writing the image data to the recording media 200 and 201 is instructed.

  Reference numeral 66 denotes a playback switch, which instructs to start a playback operation for reading an image shot in the shooting mode state from the memory 30 or the recording medium 200 or 210 and displaying it on the image display unit 28.

  Reference numeral 68 denotes a single / continuous shooting switch. When the shutter switch SW2 is pressed, a single shooting mode in which one frame is shot to be in a standby state, and shooting is continuously performed while the shutter switch SW2 is being pressed. The continuous shooting mode can be set.

  Reference numeral 69 denotes an ISO sensitivity setting switch, which can set the ISO sensitivity by changing the gain setting in the image sensor 14 or the image processing circuit 20.

  Reference numeral 70 denotes an operation unit composed of various buttons, a touch panel, etc., a menu button, a set button, a macro button, a multi-screen playback page break button, a flash setting button, a single shooting / continuous shooting / self-timer switching button, menu movement + (plus ) Button, menu shift-(minus) button, playback image shift + (plus) button, playback image-(minus) button, shooting image quality selection button, exposure compensation button, date / time setting button, panorama mode shooting and playback A selection / switch button for setting selection and switching of various functions at the time of execution, a determination / execution button for setting determination and execution of various functions at the time of shooting and playback in panoramic mode, etc. Image display ON / OFF switch to set ON / OFF, image taken immediately after shooting Quick review ON / OFF switch for setting the quick review function for automatically reproducing data, for selecting the compression rate of JPEG compression, or for selecting the CCD RAW mode for digitizing the image sensor signal and recording it on a recording medium Auto-focus operation starts when pressing the shutter switch SW1, a playback switch that can set each function mode, such as a compression mode switch, playback mode, multi-screen playback / erase mode, and PC connection mode. In this case, there is an AF mode setting switch that can set a one-shot AF mode that keeps the in-focus state and a servo AF mode that keeps the autofocus operation continuously while pressing the shutter switch SW1.

  Further, the functions of the plus button and the minus button can be selected more easily with numerical values and functions by providing a rotary dial switch.

  Reference numeral 72 denotes a power switch, which can be set to switch between power-on and power-off modes of the image processing apparatus 100. In addition, the power on and power off settings of various accessory devices such as the lens unit 300, the external strobe, and the recording media 200 and 210 connected to the image processing apparatus 100 can be switched.

  Reference numeral 80 denotes a power control unit, which includes a battery detection circuit, a DC-DC converter, a switch circuit that switches a block to be energized, and the like, detects whether or not a battery is installed, the type of battery, and the remaining battery level. The DC-DC converter is controlled based on the detection result and the instruction of the system control circuit 50, and a necessary voltage is supplied to each part including the recording medium for a necessary period.

  Reference numerals 82 and 84 denote connectors, 86 denotes a primary battery such as an alkaline battery or lithium battery, a secondary battery such as a NiCd battery, NiMH battery, or Li battery, an AC adapter, or the like.

  90 and 94 are interfaces with a recording medium such as a memory card or a hard disk, 92 and 96 are connectors for connecting to a recording medium such as a memory card or a hard disk, and 98 is a recording medium 200 or 210 attached to the connectors 92 or 96. It is a recording medium attachment / detachment detection unit that detects whether or not the recording medium is present.

  In this embodiment, two interfaces and connectors for attaching the recording medium are provided. However, a single or an arbitrary number of interfaces and connectors for attaching the recording medium may be provided. In addition, as interfaces and connectors of different standards, those compliant with a standard such as a PCMCIA card may be used.

  Further, when the interfaces 90 and 94 and the connectors 92 and 96 are configured using a PCMCIA car or other standard, communication such as LAN card, modem card, USB card, IEEE 1394 card, P1284 card, SCSI card, PHS, etc. By connecting various communication cards such as cards, it is possible to transfer image data and management information attached to the image data to and from peripheral devices such as other computers and printers.

  Reference numeral 104 denotes an optical viewfinder, which guides a light beam incident on the photographing lens 310 through an aperture 312, lens mounts 306 and 106, and mirrors 130 and 132 by a single-lens reflex system, and forms an optical image for display. Is possible. Accordingly, it is possible to perform shooting using only the optical viewfinder 104 without using the electronic viewfinder function of the image display unit 28. Further, in the optical viewfinder 104, some functions of the display unit 54, for example, a focus display, a camera shake warning display, a flash charge display, a shutter speed display, an aperture value display, an exposure correction display, and the like are provided.

  A communication unit 110 has various communication functions such as RS232C, USB, IEEE1394, P1284, SCSI, modem, LAN, and wireless communication. Reference numeral 112 denotes a connector for connecting the image processing apparatus 100 to another device by the communication unit 110 or an antenna for performing wireless communication.

  Reference numeral 120 denotes an interface for connecting the image processing apparatus 100 to the lens unit 300 in the lens mount 106. A connector 122 electrically connects the image processing apparatus 100 to the lens unit 300. A lens attachment / detachment detection unit 124 detects whether the lens unit 300 is attached to the lens mount 106 and / or the connector 122.

  The connector 122 transmits control signals, status signals, data signals, and the like between the image processing apparatus 100 and the lens unit 300, and also has a function of supplying currents of various voltages. Further, the connector 122 may be configured to transmit not only electrical communication but also optical communication, voice communication, and the like.

  Reference numerals 130 and 132 denote mirrors that guide light rays incident on the photographing lens 310 to the optical viewfinder 104 by a single-lens reflex system. The mirror 132 may be either a quick return mirror or a half mirror.

  Reference numeral 200 denotes a recording medium such as a memory card or a hard disk. The recording medium 200 includes a recording unit 202 composed of a semiconductor memory, a magnetic disk, and the like, an interface 204 with the image processing apparatus 100, and a connector 206 for connecting with the image processing apparatus 100. Reference numeral 210 denotes a recording medium such as a memory card or a hard disk, similar to the recording medium 200. The recording medium 210 includes a recording unit 212 composed of a semiconductor memory, a magnetic disk, or the like, an interface 214 with the image processing apparatus 100, and a connector 216 for connecting with the image processing apparatus 100.

  Reference numeral 300 denotes an interchangeable lens type lens unit. A lens mount 306 mechanically couples the lens unit 300 to the image processing apparatus 100. The lens mount 306 includes various functions for electrically connecting the lens unit 300 to the image processing apparatus 100.

  Reference numeral 310 denotes a photographing lens, and 312 denotes an aperture. Reference numeral 320 denotes an interface for connecting the lens unit 300 to the image processing apparatus 100 in the lens mount 306. A connector 322 electrically connects the lens unit 300 to the image processing apparatus 100.

  The connector 322 has a function of transmitting a control signal, a status signal, a data signal, and the like between the image processing apparatus 100 and the lens unit 300 and supplying various currents or supplying currents. The connector 322 may be configured to transmit not only an electrical signal but also an optical signal, an audio signal, and the like.

  Reference numeral 340 denotes an aperture control unit that controls the aperture 312 in cooperation with the shutter control unit 40 that controls the shutter 12 based on photometric information from the photometry control unit 46. A distance measurement control unit 342 controls focusing of the photographing lens 310. A zoom control unit 344 controls zooming of the photographing lens 310. A lens system control circuit 350 controls the entire lens unit 300. The lens system control circuit 350 includes identification information such as a memory and an identification number unique to the lens unit 300, management information, function information such as an open aperture value, a minimum aperture value, and a focal length. It also has a non-volatile memory function for holding current and past set values.

  The operation of the electronic camera having the above configuration will be described. 2, 3, 4, 7, 8, 9, and 10 are flowcharts illustrating the procedure of the photographing operation of the image processing apparatus 100. This processing program is stored in a storage medium such as the nonvolatile memory 56, loaded into the memory 52, and executed by the CPU in the system control circuit 50.

  Upon power-on such as battery replacement, the system control circuit 50 initializes flags, control variables, and the like, and performs necessary initial settings for each part of the image processing apparatus 100 (step S101). The system control unit 50 determines the setting position of the power switch 72 and determines whether or not the power switch 72 is set to power OFF (step S102).

  When the power switch 72 is set to power OFF, the display of each display unit is changed to the end state, and necessary parameters, setting values, and setting modes including flags and control variables are recorded in the nonvolatile memory 56. After the power control unit 80 performs a predetermined end process such as cutting off unnecessary power of each part of the image processing apparatus 100 including the image display unit 28 (step S103), the process returns to the process of step S102.

  On the other hand, when the power switch 72 is set to ON, the system control circuit 50 determines whether the remaining capacity of the power source 86 such as a battery and the operation status have a problem in the operation of the image processing apparatus 100 by the power control unit 80. Is determined (step S104). If it is determined that there is a problem, a predetermined warning is given by displaying an image or outputting sound on the display unit 54 (step S105), and then the process returns to step S102.

  On the other hand, if it is determined that there is no problem with the power supply 86, the system control circuit 50 determines the setting position of the mode dial switch 60 and determines whether or not the mode dial switch 60 is set to the shooting mode (step S106). ). When the mode dial switch 60 is set to another mode, the system control circuit 50 executes processing according to the selected mode (step S107), and returns to the processing of step S102 after execution.

  On the other hand, when the mode dial switch 60 is set to the shooting mode, it is determined whether or not the recording media 200 and 201 are attached, the management information of the image data recorded on the recording media 200 and 201 is acquired, and the recording is performed. It is determined whether or not the operation state of the mediums 200 and 201 has a problem in the operation of the image processing apparatus 100, particularly the recording / reproducing operation of the image data with respect to the recording medium (step S108). If it is determined that there is a problem, a predetermined warning is given by displaying an image or outputting sound on the display unit 54 (step S105), and then the process returns to step S102.

  On the other hand, when it is determined in step S108 that there is no problem, the system control circuit 50 checks the selection state of the single / continuous shooting switch 68 for selecting single shooting / continuous shooting (step S109). If single shooting is selected, the single shooting / continuous shooting flag is set to single shooting (step S110). If continuous shooting is selected, the single shooting / continuous shooting flag is set to continuous shooting (step S110). Step S111). In the single shooting / continuous shooting switch 68, when the shutter switch SW2 is pressed, a single shooting mode in which one frame is shot to be in a standby state, and continuous shooting is performed while the shutter switch SW2 is pressed. It is possible to switch the mode arbitrarily. The state of the single / continuous shooting flag is stored in the internal memory of the system control circuit 50 or the memory 52.

  The system control circuit 50 displays various setting states of the image processing apparatus 100 using images and sounds using the display unit 54 (step S112). Here, when the image display switch of the image display unit 28 is ON, various setting states of the image processing apparatus 100 may be displayed by an image or sound using the image display unit 28.

  It is determined whether or not the shutter switch SW1 is pressed (step S113). If the shutter switch SW1 is not pressed, the process returns to step S102. On the other hand, when the shutter switch SW1 is pressed, the system control circuit 50 performs a distance measurement process to focus the photographing lens 310 on the subject, and performs a light measurement process to determine an aperture value and a shutter speed. Photometric processing is performed (step S114). In the photometric process, the flash is set if necessary. Details of the distance measurement / photometry processing will be described later.

  Then, it is determined whether or not the shutter switch SW2 is pressed (step S115). If the shutter switch SW2 is not pressed, it is determined whether or not the shutter switch SW1 is released (step S116), and the shutter switch SW1. Steps S115 and S116 are repeated until is released or the shutter switch SW2 is pressed. If the shutter switch SW1 is released in step S116, the process proceeds to step S102.

  On the other hand, when the shutter switch SW2 is pressed in step S115, the system control circuit 50 determines whether or not the memory 30 has an image storage buffer area in which captured image data can be stored (step S126). If it is determined that there is no area where new image data can be stored in the image storage buffer area of the memory 30, a predetermined warning is given to the display unit 54 by displaying an image or outputting sound (step S127). The process returns to step S102.

  For example, immediately after performing the maximum number of continuous shots that can be stored in the image storage buffer area of the memory 30, the first image to be read from the memory 30 and written to the storage media 200, 210 is still the storage media 200, 210. This is a case where a single blank area cannot be secured in the image storage buffer area of the memory 30.

  Note that when the captured image data is compressed and stored in the image storage buffer area of the memory 30, the area that can be stored in consideration of the fact that the amount of compressed image data varies depending on the compression mode setting. Is in the image storage buffer area of the memory 30, it is determined in the process of step S126.

  On the other hand, if it is determined in step S126 that there is an image storage buffer area capable of storing the image data captured in the memory 30, the system control circuit 50 reads out the imaging signal that has been captured and accumulated for a predetermined time from the imaging element 14, and The photographed image data is written in a predetermined area of the memory 30 via the A / D converter 16, the image processing circuit 20 and the memory control circuit 22, or directly from the A / D converter 16 via the memory control circuit 22. An imaging process is executed (step S128). Details of this photographing process will be described later.

  When the shooting process in step S128 is completed, the system control circuit 50 reads out part of the image data written in the predetermined area of the memory 30 via the memory control circuit 22 and performs a shading correction process necessary for performing the development process. (Step S129), and the calculation result is stored in the internal memory of the system control circuit 50 or the memory 52.

  Then, the system control circuit 50 uses the memory control circuit 22 and, if necessary, the image processing circuit 20 to read the captured image data written in a predetermined area of the memory 30 and reads the internal memory or the memory 52 of the system control circuit 50. Are used to perform various development processes including an AWB (auto white balance) process, a gamma conversion process, and a color conversion process (step S130).

  FIG. 10 is a flowchart showing the shading correction procedure in step S129. Here, processing is performed to improve correction errors due to leakage of infrared light and dark current unevenness in the light shielding area, which are problems when correcting the subtraction of the DC component and the shading in the vertical direction of the screen with respect to the captured image.

  In step S401, the signal from the light shielding region of the captured image is divided into 16 in the column direction, and an average value is calculated for each block. In step S402, the difference calculation of the average value between adjacent blocks is performed, and it progresses to step 403 and it is judged whether the difference value max between each block is more than predetermined level Sd. If it is greater than or equal to Sd, it is determined that the light shielding region has a local float for some reason, and the process proceeds to step 404.

  If the difference value max between the blocks is equal to or lower than the predetermined level Sd in step S403, the process proceeds to step 409, where an average value in units of rows is calculated for the signal from the light-shielding region of the photographed image, and one column is used as a representative value for each row. Create shading data for minutes.

  In step 404, the shading data stored in the nonvolatile memory 56 is read. In step S405, the shading data is divided into 16 and an average value is calculated for each block. Next, the process proceeds to step 406, where the ratio of each block corresponding to the average value of each of the 16-divided blocks calculated from the shaded area of the captured image is obtained, and in step S407 where the mode value is K, the shading data is processed. Correction of K magnification is performed, and shading data for one column is obtained.

  The reason why the magnification of K is corrected in step S407 is that dark current noise increases with the charge accumulation time and the temperature rise of the image sensor, and is stored in advance when performing exposure at long seconds or exposure at high temperatures. This is because the correction data cannot be corrected and must be corrected using correction data in which the amount of change is corrected.

  Next, the shading data for one column obtained in step S407 or step S408 is uniformly subtracted for each row on the photographed image, and the shading correction routine is terminated.

  The system control circuit 50 reads out the image data written in a predetermined area of the memory 30, performs image compression processing according to the set mode by the compression / decompression circuit 32, and free images in the image storage buffer area of the memory 30. The image data that has been shot and finished a series of processing is written in the portion (step S131).

  Then, the system control circuit 50 reads the image data stored in the image storage buffer area of the memory 30 and reads the image data read to the recording media 200 and 210 such as a memory card via the interfaces 90 and 94 and the connectors 92 and 96. Recording processing for writing data is started (step S132). This recording start process is performed on the image data every time new image data that has been shot and finished a series of processes is newly written in the empty image portion of the image storage buffer area of the memory 30.

  Note that while the image data is being written to the recording media 200 and 201, a recording medium writing operation display such as blinking an LED is performed on the display unit 54 to indicate that the writing operation is being performed.

  Further, the system control circuit 50 determines whether or not the shutter switch SW1 has been pressed (step S133). If the shutter switch SW1 is released, the process returns to step S102. On the other hand, when the shutter switch SW1 is pressed, the process returns to step S115 to prepare for the next shooting in order to perform continuous shooting. As a result, a series of processing relating to photographing is completed.

  FIG. 7 is a flowchart showing the distance measurement / photometry processing procedure in step S114. In the distance measurement / photometry processing, the exchange of various signals between the system control circuit 50 and the aperture control unit 340 or the distance measurement control unit 342 includes an interface 120, a connector 122, a connector 322, an interface 320, and a lens system control circuit 350. Is done through.

  The system control circuit 50 starts an AF (autofocus) process using the image sensor 14, the distance measurement control unit 42, and the distance measurement control unit 342 (step S201).

  The system control circuit 50 causes the light beam incident on the photographing lens 310 to enter the distance measurement control unit 42 via the aperture 312, the lens mounts 306 and 106, the mirror 130, and the distance measurement sub-mirror (not shown). Then, the focusing state of the image formed as an optical image is determined, and ranging control is performed while driving the photographic lens 310 using the ranging control unit 342 until ranging (AF) is determined to be in focus. The AF control for detecting the in-focus state using the unit 42 is executed (steps S202 and S203).

  When ranging (AF) is determined to be in focus in step S203, the system control circuit 50 determines a focused distance point from a plurality of distance measurement points on the shooting screen, and the determined distance measurement point. Ranging data and / or setting parameters are stored in the internal memory of the system control circuit 50 or the memory 52 together with the data (step S204).

  Subsequently, the system control circuit 50 starts an AE (automatic exposure) process using the photometry control unit 46 (step S205). The system control circuit 50 causes the light beam incident on the photographing lens 310 to enter the photometric control unit 46 via the aperture 312, the lens mounts 306 and 106, the mirrors 130 and 132, and a photometric lens (not shown). Then, the exposure state of the image formed as an optical image is measured, and photometric processing is performed using the exposure (shutter) control unit 40 until it is determined that the exposure (AE) is appropriate (steps S206 and S207).

  If it is determined in step S207 that the exposure (AE) is appropriate, the system control circuit 50 stores the photometric data and / or setting parameters in the internal memory of the system control circuit 50 or the memory 52 (step S207A).

  The system control circuit 50 determines the aperture value (Av value) and the shutter speed (Tv value) according to the exposure (AE) result detected in the photometric process in step S206 and the shooting mode set by the mode dial switch 60. Is determined.

  Here, according to the determined shutter speed (Tv value), the system control circuit 50 determines the charge accumulation time of the image sensor 14, and performs the photographing process and the dark capturing process with the determined same charge accumulation time. Do.

  Based on the measurement data obtained by the photometric processing in step S206, the system control circuit 50 determines whether or not flashing is necessary (step S208). If flashing is necessary, the flash flag is set and charging is completed. The flash unit 48 is charged until this is done (steps S209 and S210). Then, when the charging of the flash unit 48 is completed, this process is terminated and the process returns to the main process.

8 and 9 are flowcharts showing the photographing processing procedure in step S128. In this photographing process, various signals are exchanged between the system control circuit 50 and the aperture control unit 340 or the distance measurement control unit 342 via the interface 120, the connector 122, the connector 322, the interface 320, and the lens system control circuit 350. Done.

  The system control circuit 50 moves the mirror 130 to the mirror up position by a mirror driving unit (not shown) (step S301), and according to the photometric data stored in the internal memory of the system control circuit 50 or the memory 52, the aperture control unit The diaphragm 312 is driven to a predetermined diaphragm value by 340 (step S302).

  After performing the charge clear operation of the image sensor 14 (step S303), the system control circuit 50 starts charge accumulation of the image sensor 14 (step S304), and opens the shutter 12 by the shutter control unit 40 (step S305). Exposure of the image sensor 14 is started (step S306).

  Then, it is determined whether or not the flash unit 48 is necessary based on the flash flag (step S307), and if necessary, the flash unit 48 is caused to emit light (step S308).

  The system control circuit 50 waits for the exposure of the image sensor 14 according to the photometric data (step S309), and when the exposure ends, the shutter control unit 40 closes the shutter 12 (step S310) and ends the exposure of the image sensor 14. .

  The system control circuit 50 drives the aperture 312 to the open aperture value by the aperture controller 340 (step S311), and moves the mirror 130 to the mirror down position by the mirror driver (not shown) (step S312).

  It is determined whether or not the set charge accumulation time has elapsed (step S313). If the set charge accumulation time has elapsed, the system control circuit 50 finishes the charge accumulation of the image sensor 14 (step S314), and then performs imaging. A charge signal is read out from the element 14, and a predetermined area of the memory 30 through the A / D converter 16, the image processing circuit 20, the memory control circuit 22, or directly from the A / D converter 16 through the memory control circuit 22. The photographed image data is written in (Step S315). When the series of processes is completed, the present process is terminated and the process returns to the main process.

  The above is the description of the embodiments of the present invention. However, the present invention is not limited to the configurations of these embodiments, and the functions shown in the claims or the functions of the configurations of the embodiments are included. Any configuration that can be achieved is applicable.

  For example, the block division of the shading data is 16 divisions, but other division numbers may be used. In this embodiment, the local change is a block division as a calculation method, but it may be an average value or a median value of a plurality of adjacent rows for each row.

  Further, although the magnification correction for the stored data is the mode value of the ratio for each corresponding block, it may be the minimum value or the median value.

  Further, although the correction data is one-dimensional data in the vertical direction, it may be one-dimensional data in the horizontal direction.

  It goes without saying that the present invention can also be applied to a case where the present invention is achieved by supplying software program codes for realizing the functions of the above-described embodiments to a system or apparatus. In this case, the program code itself realizes the novel function of the present invention, and the program itself and the storage medium storing the program constitute the present invention.

  In the above embodiment, the program codes shown in the flowcharts of FIGS. 2 to 4 and FIGS. 7 to 10 are stored in a ROM that is a storage medium. The storage medium for supplying the program code is not limited to the ROM, and for example, a flexible disk, a hard disk, a nonvolatile memory card, or the like can be used.

It is a block diagram which shows the structure of the electronic camera in embodiment. 3 is a flowchart illustrating a shooting operation processing procedure of the image processing apparatus 100. 3 is a flowchart illustrating a shooting operation processing procedure of the image processing apparatus 100. 3 is a flowchart illustrating a shooting operation processing procedure of the image processing apparatus 100. It is a figure which shows the condition of the infrared-light incidence of the image pick-up element in embodiment. It is a graph which shows the vertical shading of the light shielding area | region signal at the time of the infrared light incidence in FIG. 3 is a flowchart illustrating a shooting operation processing procedure of the image processing apparatus 100. 3 is a flowchart illustrating a shooting operation processing procedure of the image processing apparatus 100. 3 is a flowchart illustrating a shooting operation processing procedure of the image processing apparatus 100. 3 is a flowchart illustrating a shooting operation processing procedure of the image processing apparatus 100.

Explanation of symbols

14 Image sensor 44 Thermometer 50 System control circuit 56 Non-volatile memory 60 Mode dial 62 Shutter switch SW1
64 Shutter switch SW2
69 ISO sensitivity setting switch 100 Image processing apparatus

Claims (7)

An imaging unit having a light receiving region formed by a plurality of pixels for photoelectric conversion and a light shielding region formed by a plurality of pixels for photoelectric conversion to form a black reference signal; First correction means for performing DC regeneration for each row based on a reference signal;
A shading data storage means for calculating a representative value for each row of the light shielding area in advance and storing it as data for one column;
Second correction means for performing direct current reproduction for each row using the data of the shading data storage means;
A shading change detecting means for detecting a local change in shading in the column direction of the signal of the light shielding region;
An imaging apparatus, wherein the first and second correction means are selected based on a result of the shading change detection means.   2. The shading change detecting means calculates a representative value of each row unit of a signal of a light shielding region, and detects whether a differential value in a column direction of the representative value of each row unit is equal to or higher than a predetermined level. Imaging device.   The second correction means calculates the ratio of the data of the corresponding row between the representative value of each row of the signal of the light shielding area and the representative value of each row of the data stored in the shading data storage means, and calculates the mode value. The imaging apparatus according to claim 1, wherein correction is performed using correction data corrected with respect to data in the shading data storage means.   The second correction means calculates the ratio of the corresponding row data between the representative value of each row of the signal of the light shielding area and the representative value of each row of the data stored in the shading data storage means, and uses the minimum value. 2. The imaging apparatus according to claim 1, wherein correction is performed using correction data corrected with respect to the data stored in the shading data storage means.   The shading change detection means divides the light shielding area into blocks in the column direction, calculates a representative value in the block, and determines whether the difference between the representative values between adjacent blocks is a predetermined level or more. The imaging device according to claim 1, wherein the imaging device is selected.   The second correction unit calculates a representative value in the block obtained by dividing the light-shielding region into blocks in the column direction, calculates a representative value in the block divided in the column direction of the data in the shading data storage unit, and corresponds. 2. A ratio of representative values of blocks is obtained, a mode value is calculated, and correction is performed using correction data corrected for the data in the shading data storage means using the mode value. The imaging device described.   6. The imaging apparatus according to claim 1, wherein each representative value is an average value, a median value, or a mode value.

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