JP2006108878A - Imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging apparatus capable of carrying out proper dark shading correction not susceptible to the effect of a peculiar pattern. <P>SOLUTION: When generating horizontal shading correction data, a system control circuit 50 captures a data image in a first image region comprising a plurality of predetermined lines, and generates horizontal shading correction data on the basis of the dark image. Thereafter whether or not the correction data are data not proper to be used for the horizontal shading correction is verified, and when a result of the verification judges that the horizontal shading correction data are proper, the production of the horizontal shading correction data is completed without any modification, however when the result of the verification judges that the horizontal shading correction data are improper, the horizontal shading correction data are corrected or second correction data are produced newly from another image region and the production of the correction data is finished. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an imaging apparatus, an imaging method, a program, and a storage medium for imaging, recording, and reproducing still images and moving images, 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 imaging device such as a CCD or CMOS like this electronic camera, the dark image data read out after the charge accumulation is performed in the same manner as in the main photographing without exposing the imaging device, and the imaging device. Dark noise correction processing can be performed by performing arithmetic processing using the actual captured image data read after charge accumulation in the exposed state. This correction processing means is referred to herein as first correction means.

  As a result, it is possible to obtain a high-quality image by correcting the captured image data against image quality degradation such as pixel current loss due to dark current noise generated in the image sensor and minute scratches inherent to the image sensor.

  In particular, since dark current noise 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. For this, the dark noise correction processing is a useful function.

  However, in the imaging apparatus using the above correction means, when performing the main shooting after shooting the dark image data, the shooting frame interval can be made constant during the continuous shooting, but the dark image shooting time during the single shooting As a result, the shutter release time lag increases by the amount, and there is a risk of missing a valuable photo opportunity.

  On the other hand, when dark image data is taken after the actual shooting, the shutter release time lag can be reduced during single shooting, but the shooting interval between the first frame and the second frame is increased by the dark image shooting time during continuous shooting. Therefore, there is a problem that the interval between the photographing frames cannot be made constant.

  In addition, photographing conditions and environmental conditions when exposure was not performed at long seconds or exposure at high temperatures were not considered at all. That is, there is circuit system noise other than image quality deterioration such as pixel current loss due to dark current noise generated in the image sensor and minute scratches specific to the image sensor, but this has not been considered. Here, the circuit system noise is fixed pattern noise as dark offset generated due to voltage non-uniformity or element variation due to the resistance component of the power supply line in the sensor.

  Furthermore, although the above-described imaging apparatus is effective for correcting fixed pattern noise that does not change for each shooting, the random noise component generated in a different pattern for each shooting is rather increased by correction. There was also a problem. As a result, under conditions where random noise is more dominant than fixed pattern noise components, it is a cause of degradation of image quality.

  Further, as means for correcting the photographed image data, there is a correcting means for preparing correction data such as a horizontal mapping of a dark image in advance and correcting the image data photographed using the correction data. This correction means is referred to herein as second correction means.

  The second correction means will be described with reference to FIG.

  In image shooting, first, the entire dark image or a part (FIG. 15A) is acquired by shooting without exposing the image sensor, and the dark image is mapped in the vertical direction so that one dark horizontal line is obtained. Data (FIG. 15-b) is created and stored on the memory. Subsequently, a main image (FIG. 15C) is acquired by photographing in a state where the image sensor is exposed. Then, the difference between the correction image (FIG. 15-d) obtained by developing the horizontal one-line dark data (FIG. 15-b) stored in the memory and the main image (FIG. 15-c). By generating an image, an image (FIG. 15-e) in which the horizontal dark shading component is corrected can be obtained.

  As a method for generating correction data used in the second correction means, a method of creating in advance in the production process of the factory and storing it in the memory unit, and acquiring a part of the dark image immediately before shooting, from the image There is a method for generating correction data.

  In the former case, it is not necessary to pick up and read out a black image again at the time of shooting one image, so that the time required for one shooting can be shortened. Further, there is an advantage that the random noise component is not increased as in the case of using the first correction means.

  The latter is less susceptible to changes due to the surrounding environment such as the temperature of dark noise to be corrected, and uses only a part of the black image as compared to the first correction means that performs correction using the entire black image range. The advantage is that the time required for one imaging is short.

  However, the second correction method for correcting a dark image using the dark image correction data has the following problems.

  In other words, if there is a unique pattern or the like due to dark current at a high temperature in the dark image that is the basis of the correction data generation, there is a fear that the generated correction data may have an abnormal portion. However, there is a possibility that the image is deteriorated by performing image correction using.

  A correction example for deteriorating the image will be described with reference to FIGS. 16 and 17.

  The correction example in FIG. 16 is for a case where the output level floats due to the influence of dark current at the four corners of the screen due to heat generation in the peripheral circuits of the image sensor at high temperatures or during long-time shooting. The dark image in this case is as shown in FIG.

  When horizontal dark correction data is generated using the first region of the image, the correction data is as shown in FIG. When the original image FIG. 16-a) is corrected using the correction data, an image in which the left and right sides of the screen are sunk like the image of FIG. 16-c) is generated.

  The correction example in FIG. 17 is a case where there are point flaws or a group of point flaws that grow greatly at high temperatures or during long-time shooting. The dark image in this case is as shown in FIG.

When horizontal dark correction data is generated using the first region of the image, the correction data is as shown in FIG. Then, when the original image FIG. 17A is corrected using this correction data, an image having lines (bands) sinking above and below the scratch is generated as in the image of FIG. 17C.
JP-A-8-307775

  SUMMARY An advantage of some aspects of the invention is that it provides an imaging apparatus that can perform appropriate dark shading correction that is not easily affected by a unique pattern.

In order to achieve the above object, the imaging apparatus of the present invention provides:
In an imaging device that records a captured image on a recording medium, a first imaging mode that captures an image in a non-exposure state to obtain first image data, and a second image data that captures an image in an exposure state. First correction for generating first shading correction data from an imaging means capable of imaging in the second imaging mode and a first area which is the whole or a part of the first image data obtained in the first imaging mode When the data generation means, the correction data determination means for determining whether the first shading correction data is appropriate, and the correction data determination means determine that the first correction data is inappropriate Correction data correction means for correcting the first shading correction data and dark shading correction for the second image data using the first shading correction data. Characterized in that a be dark shading correction means.

  According to the present invention, when correction is performed by selecting correction data stored in advance, since it is not necessary to shoot dark image data, the shutter release time lag can be reduced, and the photographer can take a photo opportunity with the release time lag. Never miss it.

  Further, when it is predicted that the amount to be corrected differs greatly from the correction data stored in advance due to the shooting conditions such as ISO sensitivity and shutter speed and the environmental conditions such as the ambient temperature, it is obtained in the first imaging mode. By performing correction using horizontal dark shading correction data newly generated from the obtained dark image data, it is possible to prevent the image quality from deteriorating.

  Furthermore, by making the correction data stored in advance one-dimensional correction data, the processing becomes simple and at the same time, the memory for storing the correction data can be reduced.

  In this way, it is possible to prevent deterioration of image quality while reducing the dark image capturing that causes the shutter release time lag as much as possible.

  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 modes, and one-dimensional correction data used when performing horizontal dark shading correction. This one-dimensional correction data is created and written at the time of adjustment in the production process, or is created and written when the power is turned on or immediately before actual photographing. As a method for creating this one-dimensional correction data, as described above with reference to FIG. 15, for example, by performing projection calculation on the whole image or a plurality of lines of an image obtained by performing dark photographing, a horizontal line is obtained. A method of using data can be considered.

  As the correction data, a dark image captured immediately before the production process or actual shooting may be stored as it is as two-dimensional data. However, some image pickup devices have a small fixed pattern noise in the vertical direction and need only be corrected in the horizontal direction.

  Here, as a generation factor of the fixed pattern noise, there is a large difference (variation) in the readout path where the signal of the pixel portion reaches the final output stage when the signal is read out from the circuit system of the image sensor. FIG. 2 is a diagram showing mixing of fixed pattern noise in the horizontal and vertical directions. The fixed pattern noise in the horizontal direction depends on the difference between the readout path of the vertical line a and the readout path of the vertical line b in the figure. Also, the fixed pattern noise in the vertical direction depends on the difference between the readout path of the horizontal line c and the readout path of the horizontal line d in the figure. For example, as shown in FIG. 2, in the case of an image sensor in which each horizontal line shares a readout circuit and noise that is mixed when transferring the signal of each horizontal line to the common readout circuit due to circuit layout or the like, Fixed pattern noise in the vertical direction is small and does not need to be corrected. In an imaging apparatus using such an imaging element, fixed pattern noise can be removed by correcting the main image using one-dimensional correction data in the horizontal direction.

  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 line-of-sight 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 14, 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. Further, as interfaces and connectors of different standards, those conforming to standards such as PCMCIA cards and CF (Compact Flash (registered trademark)) cards may be used.

  Further, when the interfaces 90 and 94 and the connectors 92 and 96 are configured using a standard conforming to a PCMCIA card or a CF (Compact Flash (registered trademark)) card, a LAN card, a modem card, a USB card, and an IEEE 1394 card are used. By connecting various communication cards such as communication cards such as P1284 card, SCSI card, PHS, etc., image data and management information attached to the image data are mutually transferred between peripheral devices such as other computers and printers. Is possible.

  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. 3 and 4 are flowcharts showing the shooting operation processing procedure 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.

  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.

  The system control circuit 50 determines whether or not the shutter switch SW1 has been pressed (step S121). If the shutter switch SW1 has not been 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 S122). In the photometric process, the flash is set if necessary. Details of the distance measurement / photometry processing will be described later.

  Thereafter, in steps S123 to S128, correction data to be used for horizontal dark shading correction is selected. First, the camera setting sensitivity is determined. That is, it is determined whether or not the sensitivity set by the ISO sensitivity setting switch 69 is less than ISO 800 (step S123). The reason for this determination is that, under ISO 800, the exposure amount is small, so that dark current noise generated in the image sensor or image quality deterioration due to pixel defects due to a small flaw unique to the image sensor is conspicuous. In the present embodiment, ISO 800 is used, but other set sensitivity such as ISO 1600 may be used. If it is ISO 800 or higher, the process proceeds to step S127. On the other hand, if it is lower than ISO 800, it is further determined whether or not the set sensitivity is lower than ISO 400 (step S124).

  When the temperature is lower than ISO 400, the process proceeds to step S128. On the other hand, when the temperature is higher than ISO 400, it is determined whether the ambient temperature Temp measured by the thermometer 44 is lower than 28 ° C. (step S125). If it is less than 28 ° C., the process proceeds to step S128. If it is 28 ° C. or more, it is determined whether or not the shutter time Tv is less than 1 second (step S126). If it is less than 1 second, the process proceeds to step S128. If it is 1 second or more, the process proceeds to step S127.

  In the condition determination in steps S124 to S126, values of ISO 400, 28 ° C., and 1 second are set as threshold values. However, depending on the characteristics of the image sensor 14, appropriate values may be used. Of course.

  Here, dark current noise increases with the charge accumulation time and the temperature rise of the image sensor, so when performing exposure at long seconds or exposure at high temperatures, correction data stored in advance cannot be corrected. There is. Therefore, correction data must be generated again using a dark image taken under the same environment as that at the time of actual photographing.

  Therefore, if none of the conditions in steps S124 to S126 is satisfied, correction data is created anew (step S127). Details of the generation of the correction data will be described later.

  In addition, in the processes of steps S116 to S118, if any of the conditions is satisfied, it can be determined that there is no problem using the correction data generated in advance in the production process. The data is repeatedly developed in the predetermined area of the memory 30 by the same number of lines as the actual image in the vertical direction (step S128).

  In step S128, the system control circuit 50 reads the one-dimensional correction data used for horizontal dark shading correction from the nonvolatile memory 56, and stores the one-dimensional data in the predetermined area of the memory 30 in the vertical direction in the same number as the actual image. Repeat as many times as the number of lines. After the expansion of the correction data, the process proceeds to step S129. The method of correcting the main image using the horizontal dark shading correction data is as shown in FIG.

  Then, it is determined whether or not the shutter switch SW2 is pressed (step S129). If the shutter switch SW2 is not pressed, it is determined whether or not the shutter switch SW1 is released (step S130), and the shutter switch SW1. Steps S129 and S130 are repeated until is released or the shutter switch SW2 is pressed. If the shutter switch SW1 is released in step S130, the process proceeds to step S102.

  On the other hand, when the shutter switch SW2 is pressed in step S129, 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 S131). 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 S132). 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 step S131.

  On the other hand, if it is determined in step S131 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 S133). Details of this photographing process will be described later.

  When the photographing process in step S133 is completed, the system control circuit 50 performs subtraction processing using the horizontal dark shading correction data developed in step S123 or the horizontal dark shading correction data newly generated in step S127, thereby capturing an image. Dark correction calculation processing is performed to cancel dark current noise and the like of the element 14 (step S134).

  As described above, when the correction calculation process is performed using the horizontal dark shading correction data, it is possible to correct the image quality deterioration due to the horizontal dark current noise and the fixed pattern noise generated in the image sensor 14.

  When the horizontal dark shading correction in step S134 is completed, the system control circuit 50 reads a part of the image data written in a predetermined area of the memory 30 via the memory control circuit 22 and WB necessary for performing development processing. (White balance) integration calculation processing and OB (optical black) integration calculation processing are performed, and the calculation result is stored in the internal memory or the memory 52 of the system control circuit 50.

  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 S135).

  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 photographed and completed a series of processing is written in the portion (step S136).

  Then, the system control circuit 50 reads the image data stored in the image storage buffer area of the memory 30 and records it on a memory card, a compact flash (registered trademark) card or the like via the interfaces 90 and 94 and the connectors 92 and 96. Recording processing for writing the read image data on the media 200 and 210 is started (step S137). This recording start process is performed on the image data every time new image data is shot and 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.

  As described above, a series of processing relating to photographing is completed.

  FIG. 5 is a flowchart showing the distance measurement / photometry processing procedure in step S122. 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 photometry control unit 46 via the aperture 312, the lens mounts 306 and 106, the mirrors 130 and 132, and the photometry 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).

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

  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.

  6 and 7 are flowcharts showing the photographing processing procedure in step S133. 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.

  FIG. 8 is a flowchart for explaining one embodiment of the horizontal shading correction data generation procedure in step S127.

  The system control circuit 50 sets a predetermined correction data generation image area consisting of a plurality of lines (step S501), captures a dark image in the area (step S502), and performs horizontal shading based on the dark image. Correction data is created (step S503). Details regarding dark image capturing will be described later.

  Thereafter, it is verified whether the correction data created in step S503 is not suitable for use in horizontal shading correction due to the influence of the abnormal output section existing in the image area set in step S501. (Step S504). Details regarding the verification of the correction data will be described later.

  As a result of the verification in step S504, when it is determined that the horizontal shading correction data generated in step S503 is appropriate (step S505), the generation of correction data is completed as it is, and it is determined that it is inappropriate. In this case, correction data correction is performed by interpolating an abnormal portion of the correction data extracted at the time of verification of the correction data in step S504 using correction data values before and after the correction data (step S506). Complete the generation.

  FIG. 9 is a flowchart for explaining another embodiment of the horizontal shading correction data generation procedure in step S127.

  The system control circuit 50 sets a first image area composed of a plurality of predetermined lines (step S601), captures a dark image in the area (step S602), and based on the dark image, sets the first image area. Horizontal shading correction data is generated (step S603). Details regarding dark image capturing will be described later.

  After that, the first correction data created in step S603 becomes correction data that is not suitable for use in horizontal shading correction due to the influence of the abnormal output unit existing in the first image area set in step S601. It is verified whether it is not present (step S604). Details regarding the verification of the correction data will be described later.

  As a result of the verification in step S604, if it is determined that the first correction data generated in step S603 is appropriate (step S605), the generation of correction data is completed as it is.

  On the other hand, if it is determined that the first correction data generated in step S603 is inappropriate, step S606 for determining from which image region the correction data currently generated is generated. In this step, in response to the determination that the current correction data is generated from the first image area (step S606), the correction data generation image area is changed to the second image area. (Step S607).

  Thereafter, for the second image region, the same procedure as that for generating the first correction data is performed in steps S602 to S604, and the generation and verification of the second correction data are performed.

  If it is determined that the second correction data is appropriate (step S605), the generation of the correction data is completed as it is, and if it is determined that the correction data is inappropriate, the current correction data is determined in step 606. In response to the determination that the image data is generated from the second image area (step S606), the generation of correction data is completed as it is.

  As described above, in the horizontal shading correction data generation procedure described with reference to the flowchart of FIG. 9, only two image regions are used for correction data generation. Of course, in the present invention, the most appropriate from three or more regions is used. A procedure for selecting correction data may be used.

  FIG. 10 is a flowchart showing the dark capture processing procedure in steps S502 and S602. After performing the charge clear operation of the image sensor 14 (step S401), the system control circuit 50 starts charge accumulation of the image sensor 14 with the shutter 12 closed (step S402).

  It is determined whether or not a predetermined charge accumulation time that has been set has elapsed (step S403). When the charge accumulation time has elapsed, the system control circuit 50 finishes the charge accumulation of the image sensor 14 (step S404), and then reads a predetermined number of rows of charge signals from the image sensor 14 to perform A / D conversion. The image data (dark image data) is written in a predetermined area of the memory 30 via the device 16, the image processing circuit 20, and the memory control circuit 22 (step S405). Thereafter, the present process is terminated and the process returns to the correction data generation process.

  FIG. 11 is a flowchart for explaining one embodiment of the horizontal shading correction data verification procedure in steps S504 and S604.

  The system control circuit 50 calculates the average value of the correction data (step S701), and subsequently calculates the maximum value and the minimum value (steps S702 and S703).

  The difference between the maximum value of the correction data calculated in step S702 and the average value of the correction data calculated in step S701 is calculated, and it is verified whether the value is equal to or greater than a predetermined value (for example, 1000LSB) (step S1). S704). If it is equal to or smaller than the predetermined value, the difference between the average value of the correction data calculated in step S701 and the minimum value of the correction data calculated in step S703 is calculated, and the value is set to a predetermined value (for example, 100LSB) or more is verified (step S705). If the determination result in step 705 is equal to or smaller than the predetermined value, the process proceeds to step S706, and the correction data is determined to be appropriate for correction (OK). If either of the determination results in steps S704 and 705 is equal to or greater than a predetermined value, the process proceeds to step S707, and the correction data is determined to be inappropriate (NG) for correction. When the suitability of the correction data is determined as a result of step S706 and step S707, this process is terminated and the process returns to the correction data generation process.

  FIG. 12 is a flowchart for explaining another embodiment of the horizontal shading correction data verification procedure in steps S504 and S604.

  First, the system control circuit 50 creates differential correction data by calculating the difference between adjacent data and arranging the values for the correction data (step S801).

  Next, the average value of the differential correction data is calculated (step S802), and the maximum value and the minimum value are also calculated (steps S803 and S804).

  The difference between the maximum value of the differential correction data calculated in step S803 and the average value of the differential correction data calculated in step S802 is calculated, and it is verified whether the value is equal to or greater than a predetermined value (for example, 100LSB). (Step S804). If it is equal to or smaller than the predetermined value, the difference between the average value of the differential correction data calculated in step S802 and the minimum value of the differential correction data calculated in step S803 is calculated, and the value is a predetermined value that is set in advance. It is verified whether or not (for example, 100LSB) or more (step S805). If the determination result in step 805 is equal to or smaller than the predetermined value, the process proceeds to step S806, and the correction data is determined to be appropriate for correction (OK). If either of the determination results in steps S804 and 805 is equal to or greater than a predetermined value, the process proceeds to step S807, and the correction data is determined to be inappropriate (NG) for correction. When the suitability of the correction data is determined as a result of step S806 and step S807, this process is terminated and the process returns to the correction data generation process.

  The verification of the correction data using the differential correction data requires a large amount of calculation because the correction data must be differentiated compared to the verification using the correction data itself described with reference to FIG. However, since the influence of monotonous horizontal shading that can be corrected by the horizontal shading correction can be removed, it is possible to detect abnormal points with higher accuracy.

  As described above, in the horizontal shading correction data verification procedure described with reference to the flowcharts of FIGS. 11 and 12, the average value is used as the representative value of the correction data. However, the present invention is not limited to this, and for example, the median value (median) Etc. may be used. Further, in both correction data verification procedures, it has been described that the correction data is verified based on the difference between the maximum value and the average value, and the minimum value and the average value, but the present invention is not limited to this, for example, the maximum value A verification procedure that determines that the correction data is inappropriate when the difference between the minimum value and the minimum value is greater than or equal to a predetermined value may be used. Further, even if there is a correction data or differential correction data that is not a difference value but whose absolute value is outside a predetermined range, a verification procedure for determining that the correction data is inappropriate is also possible. Good.

  A correction example by the imaging apparatus of the present embodiment will be described with reference to FIGS. 13 and 14.

  The correction example in FIG. 13 is for correcting the image used when the conventional correction is described with reference to FIG. The dark image in this case is as shown in FIG.

  When horizontal dark correction data is generated using the first region of the image, the correction data is as shown in FIG. 13-b1. When a derivative of the correction data is created in order to determine whether the first correction data is appropriate, the result is as shown in FIG. 13-b2. When this differential correction data is verified, since the difference between the minimum value and the average value is equal to or greater than a predetermined value, it is determined that there is an abnormal point in the correction data generation region, and the first data created using this first region is determined. One correction data is determined to be inappropriate for correction. Therefore, second correction data (FIG. 13-c1) and differential correction data (FIG. 13-C2) are generated anew using the second region. Since the differential correction data has a difference between the maximum value and the minimum value within a predetermined range, it is determined that the second correction data is suitable for correction.

  Then, by correcting the original image FIG. 13-a using the second correction data, an image that is normally corrected except for the abnormal points as in the image of FIG. 13-d is obtained.

  The correction example in FIG. 14 is for correcting the image used when the conventional correction is described with reference to FIG. 17, and this is also the second example in which no abnormal point exists, as in the correction example in FIG. 13. By generating the second correction data from this area, an image that has been normally corrected except for abnormal points as in the image of FIG. 14D can be obtained.

  As described above, in the imaging apparatus according to the present embodiment, even when an abnormal output portion occurs in the screen under severe shooting environments such as high temperature, long time shooting, and high ISO sensitivity shooting, By performing a processing procedure for verifying whether correction data for shading correction is appropriate for correction, it is possible to avoid performing shading correction using erroneous correction data affected by an abnormal part, that is, It is possible to generate the best image with appropriate dark shading correction under various conditions.

  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, in the above embodiment, when horizontal dark shading correction is performed, correction data is expanded in the memory 30. However, without performing this expansion processing, correction is performed sequentially from the main image while capturing image data from the image sensor 14. It is also possible to correct so that the data is subtracted.

  In this embodiment, the horizontal dark shading correction data expansion process (S128) is performed after the shutter switch SW1 is pressed. However, the correction data may be expanded when the camera is turned on. .

  Similarly, the horizontal dark shading correction data generation process (S127) is performed after the shutter switch SW1 is pressed. For example, when the camera is turned on in order to reduce the release time lag at the time of shooting. A sequence in which correction data is generated and correction data is re-generated when various settings such as ISO sensitivity and shooting mode are switched may be used. For example, in order to perform correction under the same conditions as the moment of shooting, The sequence may be such that correction data is generated immediately before actual imaging after the shutter switch SW2 is pressed.

  In the present embodiment, when the shooting environment is normal, horizontal shading correction is performed using correction data acquired in advance at the factory and recorded in the memory 30, and at high temperatures, long seconds, and high ISO sensitivity. The correction sequence is created by creating correction data from a dark image. However, in a shooting environment where a good image cannot be obtained by only one-dimensional shading correction, such as at high temperatures, long seconds, and high ISO sensitivity. May perform a so-called black-drawing sequence in which one black image is directly subtracted from the captured main image.

  Furthermore, although the correction data is one-dimensional data in the horizontal direction, it may be one-dimensional data or two-dimensional data in the vertical direction. Further, as shown in FIG. 9, both the horizontal and vertical one-dimensional data are stored in the correction data development process (S123), even if it is not the entire two-dimensional image data. When developing the dimension data, the dark shading in both the horizontal and vertical directions can be corrected by adjusting the correction amount for each line using the one-dimensional data in the vertical direction. FIG. 9 is a diagram showing correction of the main image using one-dimensional data in both the vertical and horizontal directions. In this case, the vertical direction is further stored as a mathematical formula without being stored as one-dimensional correction data. When developing the one-dimensional data in the horizontal direction, this formula is applied to darkness in the vertical direction. You may make it correct | amend shading.

  In the above-described embodiment, the case where the charge accumulation time of the main photographing process and the charge accumulation time of the dark capturing process are made equal is shown. However, as long as sufficient data for correcting the dark current noise and the like is obtained. The charge accumulation time may be different.

  Furthermore, since the photographing operation cannot be performed during the execution of the dark capture processing operations in steps S502 and S602, an image indicating that the image processing apparatus 100 is busy is displayed by the display unit 54 and / or the image display unit 28. You may make it alert | report an audio | voice.

  Further, in the present embodiment, the case where the photographing operation is performed by moving the mirror 130 between the mirror up position and the mirror down position has been described. However, the mirror 130 is configured as a half mirror so that the photographing operation is performed without moving. May be.

  Further, the recording media 200 and 210 are not only memory cards such as PCMCIA cards and compact flash (registered trademark), hard disks, but also micro DAT, magneto-optical disks, optical disks such as CD-R and CD-RW, DVDs and the like. It may be composed of a phase change optical disk or the like. Furthermore, the recording media 200 and 210 may be composite media in which a memory card and a hard disk are integrated. In this case, a part of the composite medium may be detachable.

  In the above embodiment, the recording media 200 and 210 are separated from the image processing apparatus 100 and can be arbitrarily connected. However, any or all of the recording media remain fixed to the image processing apparatus 100. There may be. Further, the image processing apparatus 100 may be configured such that a single or a plurality of recording media 200 and 210 can be connected.

  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. 3 to 5 and FIGS. 6 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 this embodiment. It is a figure which shows mixing of the fixed pattern noise in a horizontal and vertical direction. It is a flowchart which shows the imaging | photography operation processing procedure of this embodiment. It is a flowchart which shows the imaging | photography operation | movement process procedure following FIG. 3 of this embodiment. It is a flowchart which shows the distance measurement and photometry processing procedure of this embodiment. It is a flowchart which shows the imaging | photography process procedure of this embodiment. It is a flowchart which shows the imaging | photography process procedure following FIG. 6 of this embodiment. It is a flowchart which shows the one horizontal shading data generation processing procedure of this embodiment. It is a flowchart which shows another horizontal shading data generation processing procedure of this embodiment. It is a flowchart which shows the dark acquisition process procedure of this embodiment. It is a flowchart which shows one horizontal shading data verification process procedure of this embodiment. It is a flowchart which shows another horizontal shading data verification processing procedure of this embodiment. It is a figure explaining the example of amendment of one picture of this embodiment. It is a figure explaining the example of amendment of another picture of this embodiment. It is a figure which shows correction | amendment of this image by horizontal dark shading correction data. It is a figure explaining the example of correction of one picture of a conventional example. It is a figure explaining the example of a correction of another image of a prior art example.

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
100 Image processing apparatus

Claims (18)

  In an imaging apparatus that records a captured image on a recording medium, a first imaging mode that captures images in a non-exposure state to obtain first image data, and a second imaging data that captures images in an exposure state. First correction for generating first shading correction data from an imaging means capable of imaging in the second imaging mode and a first area which is the whole or a part of the first image data obtained in the first imaging mode When the data generation means, the correction data determination means for determining whether the first shading correction data is appropriate, and the correction data determination means determine that the first correction data is inappropriate Correction data correction means for correcting the first shading correction data, and dark shading correction for the second image data using the first shading correction data. Imaging apparatus being characterized in that a be dark shading correction means.   The imaging apparatus according to claim 1, wherein the correction data determination unit determines that the correction data is inappropriate when the difference between the maximum value and the minimum value of the correction data is equal to or greater than a predetermined value.   The correction data determination means determines that the correction data is inappropriate when a difference between a maximum value and a minimum value of the correction data and an average value is a predetermined value or more. Imaging device.   The correction data determination means determines that the correction data is inappropriate when a difference between a maximum value and a minimum value of the correction data and a median value is a predetermined value or more. Imaging device.   The correction data determination means determines that the correction data is inappropriate when a difference between a maximum value and a minimum value of difference values between adjacent output values of the correction data is equal to or greater than a predetermined value. The imaging device according to claim 1.   The correction data determination means determines that the correction data is inappropriate when the difference between the maximum value and the minimum value of the difference values between adjacent output values of the correction data is equal to or greater than a predetermined value. The imaging apparatus according to claim 1, wherein:   The correction data determination means determines that the correction data is inappropriate when the difference between the maximum value and the minimum value of the difference values between adjacent output values of the correction data is greater than or equal to a predetermined value. The imaging apparatus according to claim 1, wherein:   The correction data correcting means has correction data abnormal part detecting means for detecting an inappropriate part in the first correction data, and the part of the abnormal part detected by the correction data abnormal part searching means The imaging apparatus according to claim 1, wherein the correction data is corrected by interpolating from the data with an approximate expression.   9. The imaging apparatus according to claim 8, wherein the correction data abnormality portion detecting means detects a portion where the output value is outside a predetermined numerical range as an inappropriate portion.   9. The imaging apparatus according to claim 8, wherein the correction data abnormal portion detecting means detects a portion where the difference from the average value of the entire correction data is a predetermined value or more as an inappropriate portion.   9. The imaging apparatus according to claim 8, wherein the correction data abnormal portion detecting means detects a portion where a difference from a median value of the entire correction data is a predetermined value or more as an inappropriate portion.   9. The correction data abnormal portion detecting means detects a portion where a difference value between two adjacent output values of correction data is equal to or greater than a predetermined value and its peripheral portion as an inappropriate portion. Imaging device.   The correction data correction means generates second shading correction data from a second area different from the first area in the first image data obtained in the first imaging mode. The imaging apparatus according to claim 1, wherein the second correction data is replaced with the first correction data.   The correction data correction means re-takes the first image data again in the first imaging mode when the correction data determination means determines that the first correction data is inappropriate. The imaging apparatus according to claim 1, wherein the correction data generation unit regenerates the first correction data from the first image data.   The imaging apparatus according to claim 1, wherein the correction data generation unit generates correction data in advance in the imaging apparatus production process.   The imaging apparatus according to claim 1, wherein the correction data generation unit generates correction data when the imaging apparatus is powered on.   The imaging apparatus according to claim 1, wherein the correction data generation unit generates correction data when various imaging conditions of the imaging apparatus are set or changed.   The imaging apparatus according to claim 1, wherein the correction data generation unit generates correction data immediately before imaging by the imaging apparatus.