JP6096530B2 - Electronic camera - Google Patents

Description

  The present invention relates to an electronic camera, and more particularly to an electronic camera that performs pixel defect correction on an electronic image output from an imaging apparatus.

  An example of this type of camera is disclosed in Patent Document 1. According to this background art, each time the power switch is turned on, it is determined whether or not a predetermined period has elapsed since the reference date. When it is determined that the predetermined period has elapsed, a defective pixel is detected from the image sensor, and defective pixel information in the EEPROM is updated. The image signal of the subject imaged by the image sensor is subjected to pixel correction based on such defective pixel information. That is, defective pixel detection is executed when the power-on date has passed a predetermined period or more from the reference date. As a result, it is possible to appropriately correct a defective pixel that has been acquired later without impairing operability.

JP 2003-274288 A

  However, the background art does not assume that the amount of light leaking into the imaging surface varies depending on the design or setting of the optical system. For this reason, in the background art, there is a limit to the detection performance and thus the correction performance of defective pixels that are acquired later.

  Therefore, a main object of the present invention is to provide an electronic camera capable of enhancing the performance of correcting a defective pixel that is acquired later.

  An electronic camera according to the present invention (10: reference numeral corresponding to the embodiment; hereinafter the same) has an imaging surface in which a plurality of pixels are two-dimensionally arranged, and corresponds to an optical image captured on the imaging surface. Imaging means (20) for outputting, correction means (24) for performing pixel defect correction with reference to defective pixel information to the electronic image output from the imaging means, parameters defining the amount of incident light on the imaging surface from the power-off operation Detection means (S59, S75) to detect during the period until the power-on operation, and update to identify defective pixels that appear on the imaging surface and update the defective pixel information when the parameters detected by the detection means satisfy a predetermined condition Means (S61 to S63, S77, S81, S3, S31 to S35) are provided.

  Preferably, a support member (MT) that supports the zoom lens (12) in front of the imaging surface is further provided.

  More preferably, the detection means includes magnification detection means (S59) that measures the magnification of the zoom lens as a parameter, and the predetermined condition includes a magnification condition that the magnification detected by the magnification detection means belongs to a predetermined range.

  More preferably, the detection means further includes illuminance detection means (S75) for detecting the illuminance in front of the camera housing (CHS) as a parameter, and the predetermined condition is that the illuminance detected by the illuminance detection means is below a reference. In addition. Further, an intermittent activation means (S71) for intermittently starting the illuminance detection means during a period until the power-on operation when the magnification detected by the magnification detection means is out of the predetermined range is further provided.

  Preferably, registration means (S95 to S97) for registering a reference date in relation to the processing of the update means, and the detection means is activated when the number of days from the reference date registered by the registration means to the power-off operation exceeds a predetermined number The starting means (S55 to S57) is further provided.

  The parameter that defines the amount of light incident on the imaging surface is detected during the period from the power-off operation to the power-on operation. The defective pixel that appears on the imaging surface is specified when the detected parameter satisfies a predetermined condition, and the defective pixel information is updated based on the specified defective pixel. This improves the performance of correcting defective pixels that have been acquired.

  The above object, other objects, features and advantages of the present invention will become more apparent from the following detailed description of embodiments with reference to the drawings.

It is a block diagram which shows the basic composition of one Example of this invention. It is a block diagram which shows the structure of one Example of this invention. It is an illustration figure which shows an example of the allocation state of the evaluation area in an imaging surface. FIG. 3 is an illustrative view showing one example of a configuration of a register applied to the embodiment in FIG. 2; FIG. 10 is an illustrative view showing one example of a configuration of another register applied to the embodiment in FIG. 2; (A) is an illustrative view showing an example of a state where the camera casing is viewed from the front, and (B) is an illustrative view showing an example of a state where the camera casing and the manual zoom lens are viewed from the right side. ) Is an illustrative view showing one example of a state in which a manual zoom lens is mounted on a camera housing. FIG. 7 is a flowchart showing one portion of behavior of a main CPU applied to the embodiment in FIG. 2; FIG. 10 is a flowchart showing another portion of the behavior of the main CPU applied to the embodiment in FIG. 2. FIG. 10 is a flowchart showing still another portion of the behavior of the main CPU applied to the embodiment in FIG. 2; FIG. 7 is a flowchart showing one portion of behavior of a sub CPU applied to the embodiment in FIG. 2; FIG. 10 is a flowchart showing another portion of the behavior of the sub CPU applied to the embodiment in FIG. 2; FIG. 10 is a flowchart showing still another portion of the operation of the sub CPU applied to the embodiment in FIG. 2; FIG. 10 is a flowchart showing yet another portion of the behavior of the sub CPU applied to the embodiment in FIG. 2; It is a block diagram which shows the structure of the other Example of this invention.

Embodiments of the present invention will be described below with reference to the drawings.
[Basic configuration]

  Referring to FIG. 1, the electronic camera of this embodiment is basically configured as follows. The imaging unit 1 has an imaging surface in which a plurality of pixels are two-dimensionally arranged, and outputs an electronic image corresponding to an optical image captured on the imaging surface. The correction unit 2 performs pixel defect correction on the electronic image output from the imaging unit 1 with reference to defective pixel information. The detection unit 3 detects a parameter that defines the amount of light incident on the imaging surface during a period from the power-off operation to the power-on operation. The updating unit 4 updates the defective pixel information by specifying a defective pixel that appears on the imaging surface when the parameter detected by the detecting unit 3 satisfies a predetermined condition.

The parameter that defines the amount of light incident on the imaging surface is detected during the period from the power-off operation to the power-on operation. The defective pixel that appears on the imaging surface is specified when the detected parameter satisfies a predetermined condition, and the defective pixel information is updated based on the specified defective pixel. This improves the performance of correcting defective pixels that have been acquired.
[Example]

  Referring to FIG. 2, the digital camera 10 of this embodiment includes a power supply circuit 44. The power supply circuit 44 generates a plurality of DC voltages each indicating a different voltage value based on the battery 44bt. Some of the generated DC voltages are directly supplied to the sub CPU 48, and the other part of the generated DC voltages are supplied to the main system MS via the switch group 46. Therefore, the sub CPU 48 is always activated, while the main system MS is activated / stopped corresponding to the on / off of the switch group 46.

  When a power-on operation is performed by the power button 50, the sub CPU 48 turns on all the switch groups 46 in order to fully activate the main system MS, and thereafter gives a full activation notification to the main CPU 28.

  The main system MS includes a focus lens 14, a shutter mechanism 16, an aperture mechanism 18, and an imaging device 20 that are driven by a lens driver 22a, a shutter driver 22b, an aperture driver 22c, and a sensor driver 22d, respectively. A manual zoom lens 12 is detachably mounted in front of the focus lens 14.

  When the full activation notification is issued from the sub CPU 48, the main CPU 28 opens the shutter mechanism 16 through the driver 22b, instructs the sensor driver 22d and the camera processing circuit 24 to execute the moving image capturing process, and executes the moving image display process. Commands the LCD driver 36.

  The optical image representing the imaging scene is irradiated on the imaging surface of the imaging device 16 via the manual zoom lens 12, the focus lens 14, and the aperture unit 14. A plurality of pixels (= light receiving elements) are two-dimensionally arranged on the imaging surface. The imaging surface is covered with a color filter (not shown) in which R (Red), G (Green), and B (Blue) color elements are arranged in a Bayer manner. In each pixel, different amounts of charge are generated by photoelectric conversion according to the amount of light transmitted through the color filter.

  In response to a vertical synchronization signal Vsync periodically generated from an SG (Signal Generator) (not shown), the sensor driver 22d exposes the imaging surface of the imaging device 20 and charges generated on the imaging surface in a raster scanning manner. read out. From the imaging device 16, raw image data based on the read charges is periodically output.

  The camera processing circuit 24 performs a series of processes of digital clamp, pixel defect correction, gain control, color separation, white balance adjustment, and YUV conversion on the raw image data output from the imaging device 16. In particular, pixel defect correction is performed with reference to defective pixel information registered in the register RGST1 shown in FIG. The YUV format image data thus generated is written into the moving image area 34 a of the SDRAM 34 through the memory control circuit 32.

  The LCD driver 36 repeatedly reads out the image data thus written from the moving image area 34a through the memory control circuit 32, and drives the LCD monitor 38 based on the read image data. As a result, a moving image (through image) representing the imaging scene is displayed on the LCD monitor 38.

  With reference to FIG. 3, an evaluation area EVA is allocated to the imaging surface of the imaging device 16. The evaluation area EVA is divided into 16 in each of the horizontal direction and the vertical direction, and 256 divided areas form the evaluation area EVA. The camera processing circuit 24 shown in FIG. 2 also supplies Y data for forming image data in YUV format to the AE / AF evaluation circuit 26.

  The AE / AF evaluation circuit 26 integrates Y data belonging to the evaluation area EVA among the given Y data every time the vertical synchronization signal Vsync is generated. As a result, 256 integral values, that is, 256 AE evaluation values, are output from the AE / AF evaluation circuit 26 in response to the vertical synchronization signal Vsync.

  The AE / AF evaluation circuit 26 also integrates the high-frequency component of Y data belonging to the evaluation area EVA among the supplied Y data every time the vertical synchronization signal Vsync is generated. As a result, 256 integral values, that is, 256 AF evaluation values, are output from the AE / AF evaluation circuit 26 in response to the vertical synchronization signal Vsync.

  When the shutter button 30sh provided in the key input device 30 is in a non-operating state, the main CPU 28 executes the simple AE process based on the 256 AE evaluation values output from the AE / AF evaluation circuit 26, and sets the appropriate values. The EV value is calculated. The aperture amount and exposure time that define the calculated appropriate EV value are set in the aperture driver 22c and the sensor driver 22d, whereby the brightness of the through image is roughly adjusted.

  When the manual zoom lens 12 is operated, the zoom magnification changes, and the angle of view of the through image changes accordingly. With reference to FIGS. 6A to 6C, the manual zoom lens 12 is detachable and is supported by a lens mount MT provided on the front surface of the camera housing CHS when mounted. Further, due to the nature of the manual zoom lens 12, there is a zoom magnification range in which light leakage to the imaging surface cannot be completely blocked. This zoom magnification range is defined as “light leakage range”.

  When the shutter button 30sh is half-pressed, the main CPU 28 executes a strict AE process based on the 256 AE evaluation values output from the AE / AF evaluation circuit 26. Thus, the optimum EV value is calculated, and the aperture amount and the exposure time that define the calculated optimum EV value are also set in the aperture driver 22c and the sensor driver 22d. As a result, the brightness of the through image is adjusted to the optimum value.

  The main CPU 28 also executes AF processing based on the 256 AF evaluation values output from the AE / AF evaluation circuit 26. The focus lens 14 is moved in the optical axis direction by the lens driver 22a in order to search for a focal point, and is arranged at the focal point discovered by this. As a result, the sharpness of the through image is improved.

  When the shutter button 30sh is fully pressed, the main CPU 28 executes a still image capturing process. As a result, the shutter mechanism 16 is first closed, and the image data of the latest frame is taken into the recorded image area 34b. The shutter mechanism 16 is opened after the retracting is completed.

  Subsequently, the main CPU 28 commands the memory I / F 40 to execute the recording process. The memory I / F 40 reads one frame of image data stored in the recording image area 34 b through the memory control circuit 32 and records an image file containing the read image data on the recording medium 42.

  When a power-off operation is performed by the power button 50, the sub CPU 48 gives a full stop notification to the main CPU 28. The main CPU 28 controls the driver 22b to close the shutter mechanism 16, and the sub CPU 48 turns off all the switches 46 after the shutter mechanism 16 is closed. The main system MS is completely stopped when all the switch groups 46 are turned off.

  In the register RGST2 referred to by the sub CPU 48, the date when the previous pixel defect detection processing (= processing for detecting a defective pixel that occurs later) is executed is registered in the manner shown in FIG. If the number of days elapsed since the registration date is 10 days or more and the current zoom magnification of the manual zoom lens 12 is out of the light leakage range, pixel defect detection processing is executed.

  On the other hand, if the current zoom magnification of the manual zoom lens 12 belongs to the light leakage range even if the number of days elapsed from the date registered in the register RGST2 is 10 days or more, the illuminance in front of the imaging surface is It is detected by the illuminance sensor 52. If the detected illuminance falls below the reference value REF, the digital camera 10 is considered to be placed in a dark place, and the pixel defect detection process is also performed at this time. The illuminance in front of the imaging surface is detected every hour. If the detected illuminance is equal to or greater than the reference value REF for five consecutive times, the pixel defect detection process is stopped.

  In the pixel defect detection process, the sub CPU 28 first turns on a part of the switch group 46. As a result, the main system MS is partially activated (= except for the LCD driver 36 and the LCD monitor 38). Subsequently, the sub CPU 28 notifies the main CPU 28 of partial activation of the main system MS.

  When the partial activation notification is given, the main CPU 28 instructs the sensor driver 22d and the camera processing circuit 24 to acquire still image data for detecting defective pixels. The sensor driver 22d executes the exposure operation of the imaging surface and the readout operation of the electric charges generated thereby once. Since the shutter mechanism 16 is closed at this time, the raw image data output from the imaging device 16 represents a black image. The camera processing circuit 24 converts the raw image data output from the imaging device 20 into YUV format image data, and writes the converted image data into the work area 34 d of the SDRAM 34 through the memory control circuit 32.

  The main CPU 28 detects pixels whose luminance level exceeds the threshold value (= defective pixels that have been acquired) from the image data stored in the work area 34d, and updates the defective pixel information registered in the register RGST1. The position of the detected defective pixel is added to the register RGST1.

  When the defective pixel information registered in RGST1 is updated as described above, the sub CPU 48 updates the date registered in the register RGST2 to today's date. When the update is completed, the switch group 46 is turned off to stop the main system MS.

  The main CPU 28 executes a plurality of tasks including the imaging tasks shown in FIGS. 7 to 9 in parallel under the control of the multitask OS. Further, the sub CPU 48 executes processing according to the flowcharts shown in FIGS. The control program executed by the main CPU 28 is stored in the flash memory 28m, and the control program executed by the sub CPU 48 is stored in the flash memory 48m.

  Referring to FIG. 7, in step S <b> 1, it is determined whether or not a general activation notification is given from sub CPU 48. In step S <b> 3, it is determined whether or not a partial activation notification is given from sub CPU 48. If the decision result in the step S1 is YES, the process advances to a step S5 so as to control the shutter driver 22b and open the shutter mechanism 16. In step S7, the moving image capturing process is started, and in the subsequent step S9, the moving image display process is started.

  As a result of the processing in steps S5 to S9, an optical image representing the imaging scene is irradiated onto the imaging surface, and YUV format image data representing the imaging scene is repeatedly output from the camera processing circuit 24. A through image based on this image data is displayed on the LCD. The image is displayed on the LCD monitor 40 by the driver 36.

  In step S11, it is determined whether or not the shutter button 30sh has been half-pressed. If the determination result is NO, a simple AE process is executed in step S13. As a result, the brightness of the through image is roughly adjusted. In step S15, it is determined whether or not an overall stop notification is given from the sub CPU 48. If the determination result is NO, the process returns to step S11, whereas if the determination result is YES, the process proceeds to step S17. In step S17, the shutter driver 22b is controlled to close the shutter mechanism 16, and then the imaging task is terminated.

  If the decision result in the step S11 is YES, a strict AE process is executed in a step S19, and an AF process is executed in a step S21. As a result, the brightness and sharpness of the through image are adjusted to optimum values. In step S23, it is determined whether or not the shutter button 30sh has been fully pressed. In step S25, it is determined whether or not the operation of the shutter button 30sh has been released. If the determination result of step S25 is YES, it will return to step S11, and if the determination result of step S23 is YES, it will progress to step S27.

  In step S27, the still image capturing process is executed, and in step S29, the memory I / F 40 is instructed to execute the recording process. One frame of image data representing a scene at the time when the shutter button 30sh is fully pressed is saved from the moving image area 34a to the recorded image area 34b by the still image capturing process. The memory I / F 40 reads the image data stored in the recording image area 34 c through the memory control circuit 30 and records an image file containing the read image data on the recording medium 42. When the process of step S29 is completed, the process returns to step S11.

  If the decision result in the step S3 is YES, the process advances to a step S31 so as to instruct the sensor driver 22d and the camera processing circuit 24 to acquire still image data for detecting defective pixels.

  The sensor driver 22d executes the exposure operation of the imaging surface and the readout operation of the electric charges generated thereby once. Since the shutter mechanism 16 is closed at this time, the raw image data output from the imaging device 16 represents a black image. The camera processing circuit 24 converts the raw image data output from the imaging device 20 into YUV format image data, and writes the converted image data into the work area 34 d of the SDRAM 34 through the memory control circuit 32.

  In step S33, a pixel whose luminance level exceeds the threshold value (= defective pixel generated afterward) is detected from the image data stored in the work area 34d, and in step S35, the defective pixel information registered in the register RGST1 is updated. The position of the defective pixel detected in step S33 is added to the updated defective pixel information. When the process of step S35 is completed, the imaging task is terminated.

  Referring to FIG. 10, in step S41, it is repeatedly determined whether or not a power-on operation has been performed. If the determination result is updated from NO to YES, all of switch group 46 is turned on in step S43. As a result, the main system MS is fully activated. When the process of step S43 is completed, the process proceeds to step S45, and the main CPU 28 is notified of the full activation of the main system MS.

  In step S47, it is repeatedly determined whether or not a power-off operation has been performed. When the determination result is updated from NO to YES, the process proceeds to step S49 to notify the main CPU 28 of the entire stop of the main system MS. In step S51, it waits until the process of step S17 mentioned above is completed, and all the switch groups 46 are turned off in step S53. As a result, the main system MS is completely stopped.

  In step S55, the number of days elapsed from the date registered in the register RGST2 is measured. In step S57, it is determined whether or not the number of days elapsed is 10 days or more. If a determination result is NO, it will return to Step S41, and if a determination result is YES, it will progress to Step S59. In step S59, the current zoom magnification of the manual zoom lens 12 is detected, and in step S61, it is determined whether or not the detected zoom magnification belongs to the light leakage range. If the determination result is NO, pixel defect detection processing is executed in step S63, and then the process returns to step S41.

  On the other hand, if the determination result is YES, the variable K is set to “1” in a step S65, and the timer TM is reset and started in a step S67. In step S69, it is determined whether or not a power-on operation has been performed. In step S71, it is determined whether or not a time-out has occurred in the timer TM (= whether 1 hour has elapsed since reset and start). If the determination result of step S69 is YES, it will return to step S43, and if the determination result of step S71 is YES, it will progress to step S73.

  In step S73, the variable K is incremented, and in step S75, the output of the illuminance sensor 52 is acquired. In step S77, it is determined whether or not the acquired output, that is, the illuminance falls below the reference value REF. In step S79, it is determined whether or not the variable K exceeds the maximum value Kmax (= 5). If the determination result of step S79 is NO, it will return to step S67, and if the determination result of step S79 is YES, it will return to step S41. On the other hand, if the decision result in the step S77 is YES, a pixel defect detecting process is executed in a step S81, and thereafter, the process returns to the step S41.

  The pixel defect detection process in step S63 or S81 is executed according to a subroutine shown in FIG. First, in step S91, a part of the switch group 46 is turned on. As a result, the main system MS is partially activated (= except for the LCD driver 36 and the LCD monitor 38). In step S93, partial activation of the main system MS is notified to the main CPU 28, and in step S95, it is repeatedly determined whether or not the defective pixel information registered in RGST1 has been updated by the process in step S35 described above. When the determination result is updated from NO to YES, the process proceeds to step S97, and the date registered in the register RGST2 is updated to today's date. When the update is completed, the switch group 46 is turned off in step S99 to stop the main system MS, and then the process returns to the upper hierarchy routine.

  As can be understood from the above description, the imaging device 20 has an imaging surface in which a plurality of pixels are two-dimensionally arranged, and outputs raw image data corresponding to an optical image captured on the imaging surface. The camera processing circuit 24 performs pixel defect correction with reference to defective pixel information registered in the register RGST1 on the raw image data output from the imaging device 20. The sub CPU 48 detects a parameter (= zoom magnification or illuminance) that defines the amount of light incident on the imaging surface during a period from the power-off operation to the power-on operation (S59, S75), and the detected parameter satisfies the predetermined condition. In this case, defective pixel detection processing is executed (S61 to S63, S77, S81). The defective pixels appearing on the imaging surface are detected by the main CPU 28 (S31 to S33), and the defective pixel information registered in the register RGST1 is updated based on the detection result (S35).

  Thus, the parameter that defines the amount of light incident on the imaging surface is detected during the period from the power-off operation to the power-on operation. The defective pixel that appears on the imaging surface is specified when the detected parameter satisfies a predetermined condition, and the defective pixel information is updated based on the specified defective pixel. This improves the performance of correcting defective pixels that have been acquired.

  In this embodiment, the control program executed by the main CPU 28 is stored in advance in the flash memory 28m, and the control program executed by the sub CPU 48 is stored in advance in the flash memory 48m. However, as shown in FIG. 14, a communication I / F 54 is provided in the digital camera 10, and some control programs are prepared as internal control programs in the flash memories 28m and 48m from the beginning, while other control programs are externally provided. You may make it acquire from an external server as a control program. In this case, the above-described operation is realized by cooperation of the internal control program and the external control program.

  In this embodiment, the process executed by the main CPU 28 is divided into a plurality of tasks as described above. However, each task may be further divided into a plurality of small tasks, and a part of the divided plurality of small tasks may be integrated with other tasks. Further, when each task is divided into a plurality of small tasks, all or part of the tasks may be acquired from an external server.

DESCRIPTION OF SYMBOLS 10 ... Digital camera 12 ... Manual zoom lens 16 ... Shutter mechanism 24 ... Camera processing circuit 28 ... Main CPU
48 ... Sub CPU
52 ... Illuminance sensor

Claims (4)

An imaging unit having an imaging surface in which a plurality of pixels are two-dimensionally arranged and outputting an electronic image corresponding to an optical image captured on the imaging surface;
Correction means for performing pixel defect correction with reference to defective pixel information to the electronic image output from the imaging means;
Detection means for detecting a parameter that defines the amount of light incident on the imaging surface during a period from a power-off operation to a power-on operation, and the parameter detected by the detection device appeared on the imaging surface when a predetermined condition is satisfied Update means for identifying defective pixels and updating the defective pixel information ;
A support member that supports the zoom lens in front of the imaging surface;
The detection means includes magnification detection means for measuring the magnification of the zoom lens as the parameter,
The electronic camera , wherein the predetermined condition includes a magnification condition that a magnification detected by the magnification detection means belongs to a predetermined range . The detection means further includes illuminance detection means for detecting illuminance in front of the camera housing as the parameter,
It said predetermined conditions further comprise a condition that below the detected illuminance reference by said illuminance detection unit, according to claim 1 electronic camera according. The electronic camera according to claim 2 , further comprising an intermittent activation unit that intermittently activates the illuminance detection unit during a period until the power-on operation when a magnification detected by the magnification detection unit is out of the predetermined range. Registration means for registering a reference date in relation to the processing of the update means; and an activation means for activating the detection means when the number of days from the reference date registered by the registration means to the power-off operation exceeds a predetermined number. further comprising an electronic camera according to any one of claims 1 to 3.

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