JP3680334B2 - Pixel unevenness correction apparatus and method - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a pixel unevenness correction apparatus and method for correcting pixel unevenness such as so-called white scratches that occur in a CCD (solid-state imaging device).
[0002]
[Prior art]
For example, a conventional pixel unevenness correction device that corrects pixel unevenness (a so-called white defect or the like having an offset in the element output level) of a CCD (solid-state imaging device) mounted on a video camera or the like is a pixel unevenness of the CCD. A ROM (Read Only Memory) that stores correction data consisting of data on the position of the scratch (hereinafter simply referred to as a scratch) and the level of the scratch, and processing according to the data read from the ROM And a dedicated IC (integrated circuit) for performing the above. Here, the position of the scratch on the CCD and the level of the scratch are measured, for example, at the time of manufacturing a video camera on which the CCD is mounted, and the position (relative address) of the measured scratch and the level of the scratch (for example, Relative value) data is stored in the ROM. The relative address of the flaw position is information indicating how far the next flaw position is from one flaw position on the CCD. The relative value of the flaw level is the flaw level at a certain position. This is information indicating how much the level of the scratch at the next position has changed. In this way, the scratch position is stored as a relative address, and the scratch level is stored as a relative value in order to simplify processing when performing correction processing later using the scratch position and level data. is there.
[0003]
The video camera is equipped with the pixel non-uniformity correction device. Therefore, the video camera reads data on the position and level of scratches stored in advance in the ROM after the power is turned on, for example. Scratch correction is performed based on the data.
[0004]
[Problems to be solved by the invention]
Incidentally, as described above, in the conventional video camera, the data on the position and level of the scratch on the CCD is written in the ROM of the pixel unevenness correction device when the video camera is manufactured. If the CCD is newly damaged after the camera is shipped (for example, after the camera is passed to the user), the correction cannot be made.
[0005]
Therefore, when a new scratch is generated in the CCD after shipment of the video camera in this way, the video camera must be sent to a service station, for example, and the data in the ROM must be rewritten. In this case, the service station measures the position and level of the CCD scratch on the video camera, and the scratch position and level data is updated together with the scratch position and level data previously stored in the ROM. The data is written in a ROM (another ROM not storing data), and this new ROM is replaced with an old ROM that has been previously mounted.
[0006]
For this reason, the service station includes a dedicated jig for performing work such as measurement of the position and level of the scratch and replacement of the ROM, a personal computer, a new ROM not storing data, and access to this ROM. Many devices such as a ROM writer for writing data are required.
[0007]
If the video camera is expensive and indispensable for the station, for example, for a broadcasting station, prepare an alternative camera for the period during which the video camera is being repaired. It has to be expensive and time consuming.
[0008]
In addition, when replacing the ROM, an operation of writing new correction data in the new ROM, removing the old ROM mounted on the substrate of the pixel unevenness correction device, for example, via a socket, and inserting the new ROM Is required. In this operation, troubles such as a mistake in insertion into the socket, damage to the substrate due to insertion or removal from the socket, damage to the pattern, and destruction due to static electricity may occur.
[0009]
Therefore, in view of the above situation, the present invention can easily and inexpensively correct the pixel unevenness even if a new scratch is generated in the CCD, and further, it is possible to correct the pixel unevenness without replacing the ROM. A correction apparatus and method are provided.
[0010]
[Means for Solving the Problems]
The pixel unevenness correction apparatus of the present invention has been proposed in order to achieve the above-described object, and the pixel unevenness correction apparatus that corrects the pixel unevenness generated in the solid-state image sensor has already existed in the solid-state image sensor. Non-volatile first memory means for storing relative position data and relative level data of pixel unevenness, generation means for generating absolute position data and absolute level data of pixel unevenness newly generated in the solid-state imaging device, and the new A rewritable non-volatile second memory means for storing absolute position data and absolute level data of pixel irregularities generated in the memory, relative position data and relative level data of the first memory means, and second memory means Control means for processing absolute position data and absolute level data and developing them in a rewritable third memory means, and developing them in the third memory means And the correction means for correcting the pixel unevenness by reading out the pixel unevenness position data and level data, and the control means uses the absolute position data and absolute level data of the second memory means as relative position data. In addition, the data is developed in the third memory means after correcting the relative level data.
[0011]
The pixel unevenness correction apparatus of the present invention also has cursor generating means for generating cross cursor data to be displayed on the screen, and the position of the newly generated pixel unevenness is displayed on the screen. Measure with Furthermore, the pixel unevenness correction apparatus of the present invention also has level determining means for determining the level of pixel unevenness that has been measured at the position. In addition to the above-described configuration, the pixel unevenness correction device of the present invention has at least an optical system that forms a subject image on a solid-state image sensor and a conversion system that converts an image signal from the solid-state image sensor into a video signal. It also has a part.
[0012]
Next, the pixel unevenness correction method of the present invention is a pixel unevenness correction method for correcting pixel unevenness that occurs in a solid-state image sensor, and generates absolute position data and absolute level data of pixel unevenness that has newly occurred in the solid-state image sensor. The newly generated absolute position data and absolute level data of pixel unevenness are stored in a rewritable nonvolatile memory, and the relative position data and relative level data of the pixel unevenness already existing in the solid-state imaging device, Newly generated absolute position data and absolute level data of pixel unevenness are processed into relative position data and data corrected to the relative level data, and developed into a rewritable memory, and the developed relative position data of pixel unevenness and Relative level data is read from the memory, and pixel unevenness is corrected.
[0013]
Further, in the pixel unevenness correction method of the present invention, a cross cursor is displayed on the screen, the position of the newly generated pixel unevenness is measured with the cross cursor displayed on the screen, and the measurement of the position is further performed. A correction level is set by judging from the level of pixel unevenness performed, and correction is performed at the correction level to determine the appropriateness of the measured position and the correction level. Furthermore, after determining that the measured position and correction level are appropriate, the measured position data and correction level data can be rewritten as the newly generated pixel unevenness position data and level data. Store in non-volatile memory.
[0014]
[Action]
According to the pixel unevenness correction apparatus and method of the present invention, since the pixel unevenness position data and level data that have already existed in the solid-state imaging device are originally stored, it is possible to correct these already existing pixel unevenness. It is. Here, when new pixel unevenness occurs, the position data and level data of the newly generated pixel unevenness are generated, and the newly generated pixel unevenness position data and level data can be rewritten. To store. Therefore, if the newly generated pixel unevenness position data and level data stored in the rewritable nonvolatile memory are used, the pixel unevenness can be corrected. Further, since the pixel unevenness position data and level data that already existed in the solid-state imaging device are also stored originally, the newly generated pixel unevenness position data and level stored in the rewritable nonvolatile memory are stored. By deploying the data and the existing pixel unevenness position data and level data together in a rewritable memory, it becomes possible to correct not only old pixel unevenness but also new pixel unevenness.
[0015]
【Example】
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
[0016]
FIG. 1 shows the configuration of an embodiment of a pixel unevenness correction apparatus to which the pixel unevenness correction method of the present invention is applied. The pixel unevenness correction apparatus of the present embodiment is applied to a device having a CCD such as a video camera, for example, and in the following description, a case where it is mounted on a video camera is described. The pixel unevenness referred to in this embodiment has an offset in the element output level of the CCD, and includes not only so-called white scratches but also black scratches. In the following description, the pixel unevenness is simply referred to as a scratch.
[0017]
In FIG. 1, the pixel unevenness correction apparatus mounted on the video camera of the embodiment of the present invention uses the position data (relative address data) and level data (relative level data) of the scratches already present in the CCD at the time of shipment from the factory. A ROM (Read Only Memory) 4 which is a nonvolatile first memory means for storing, an operation panel 20 and a CPU 1 as a generating means for generating absolute address data and absolute level data of a scratch newly generated in the CCD. Process the EEPROM (electrically erasable programmable ROM) 2 as a rewritable non-volatile second memory means for storing the absolute address data and absolute level data of the newly generated scratch, and the data of the ROM 4 and the EEPROM 7 The CPU 3 which expands in the RAM 7 which is the third rewritable memory means, And a defect correction IC 10 that reads out the position data and level data of the defect developed in the RAM 7 and outputs a gate pulse at a position to be corrected as a part of the correction means for correcting the defect. To do.
[0018]
First, the function of each component in FIG. 1 will be described in order.
[0019]
The remote control panel 20 has a total of three, a horizontal address adjustment volume for adjusting the horizontal address of the CCD, a vertical address adjustment volume for adjusting the vertical address of the CCD, and a level adjustment volume for adjusting the level. A volume at least, and a correction on / off switch for instructing whether or not to correct flaws; a store on / off switch for instructing whether or not to store flaw data; and a cursor A total of three switches, a cursor on / off switch for instructing on / off of the cursor, are arranged. The address actually corresponds to the position on the screen specified by the cross cursor displayed on the screen as will be described later. Further, each volume and switch of the remote operation panel 20 can be arranged on a main panel section for controlling the camera, or can be arranged on a rear panel at the rear part of the camera body. Further, the operation panel 20 is also provided with a mode switch for switching the CCD reading mode between the field mode and the frame mode.
[0020]
A CPU (central processing unit) 1 is a CPU on the camera body side, and communicates with the CPU 3 on the CCD block side. As described later, the position and level of a CCD scratch addressed by the operation panel 20 are described. And has a function of transmitting information on the flaw position and level to the CCD 3. From the CPU 1, absolute address data corresponding to the address designated by the operation panel 20 and level data represented by the absolute value adjusted by the operation panel 20 are output and sent to the CPU 3.
[0021]
The EEPROM 2 which is a rewritable non-volatile memory stores data on the position (absolute address value) of the scratch newly generated in the CCD obtained as described later and data on the level (absolute value).
[0022]
The CPU 3 is a CPU mounted on the CCD block, communicates with the camera body, and has a function of controlling and operating each component (corresponding component in the CCD block) of the pixel unevenness correction apparatus of the present invention. . Further, the CPU 3 converts the absolute address data sent from the CPU 1 into relative address data similar to that stored in the ROM 4 described below, and also converts the level represented by the absolute value into a relative value. Process.
[0023]
The ROM 4 stores flaw position data (relative address data) and level data (relative value) at a level to be corrected, which is detected when the video camera is manufactured, for example, when the CCD is fixed. As described above, the relative value of the scratch position and the relative value of the level are information indicating how far the next scratch position is from a certain scratch position on the CCD and the next position with respect to the scratch level at a certain position. It is information indicating how much the level of scratches has changed. In addition, the scratch position is stored as a relative address in the ROM 4 and the scratch level is stored as a relative value, so that the processing when the correction process is performed later using the scratch position and level data can be simplified. Because. In this embodiment, even if there is no scratch, for example, the CPU 3 inserts a dummy scratch into the H blanking period every 3H (H is a horizontal scanning period).
[0024]
The cursor generation circuit 5 has a function of generating cross cursor data by being controlled by a serial data group including data (S.DATA), load data (S.LD), and clock (S.CLK) from the CPU 1. The crosshair cursor data is sent to the subsequent configuration via the output terminal 21. Specifically, the cross cursor data is sent to the image signal processing system, and is displayed as a cross cursor on a viewfinder, a liquid crystal display, or a connected television monitor screen, for example. The cursor generation circuit 5 is supplied with a vertical drive pulse VD, a horizontal drive pulse HD, and a clock CLK in order to generate cross cursor data for performing the display.
[0025]
The selector 6 has two input terminals connected to an address bus (16 bits) from the CPU 3 and an address bus (16 bits) from a defect correction IC 10 to be described later, and inputs (address data) of these two input terminals to the CPU 3. Are switched and output based on a switching control signal from. That is, the relative address data read from the ROM 4 by the read control signal of the CPU 3 is input to one input terminal of the selector 6, and the relative address data from the defect correction IC 10 is input to the other input terminal. Based on the switching control signal of the CPU 3, one of these relative address data is output and sent to a RAM (Random Access Memory) 7.
[0026]
The RAM 7 is composed of, for example, 1M (megabyte) SRAM (static RAM), and the data represented by the absolute value read from the EEPROM 2 is changed to the level represented by the relative value by the CPU 3, and Data of a level represented by a relative value read from the ROM 4 by the read control signal is developed according to the control signal from the CPU 3. The developed data is read by address data (relative address) from the scratch correction IC 10 switched by the selector 6.
[0027]
The buffer 8 is controlled by the scratch correction IC 10, outputs the level (relative value) data read from the RAM 7, and sends it to the scratch correction IC 10.
[0028]
The buffer 9 is controlled to be written and read by the CPU 3, and the level data represented by the relative value read from the ROM 4 and the level data read from the EEPROM 2 and converted to the relative value by the CPU 3 are stored in the RAM 7. It has a bidirectional input / output function for sending and sending the level (relative value) data read from the RAM 7 to the CPU 3.
[0029]
The flaw correction IC 10 is a flaw correction-dedicated IC comprising a gate array. The scratch correction IC 10 is supplied with the same serial data group as that sent to the cursor generation circuit 5 from the CPU 1, outputs the relative address data to the RAM 7 via the selector 6, and reads the level read from the RAM 7. In order to send (relative value) data to the D / A converter 11 and to output correction signals for the three primary colors R (red), G (green), and B (blue) based on the level data from the RAM 7. Has a function of outputting the gate pulse. The defect correction IC 10 is also supplied with the vertical drive pulse VD, the horizontal drive pulse HD, and the clock CLK.
[0030]
The D / A converter 11 has a function of converting 8-bit level data corresponding to the scratch supplied from the scratch correction IC 10 into an analog amount in accordance with the clock from the scratch correction IC 10. Send to switch 12.
[0031]
The switch 12 turns on / off the analog amount obtained from the D / A converter 11 by using the gate pulse for each of R, G, B from the defect correction IC 10 as a switching control signal, so that each of R, G, B It has a function of outputting a correction signal for the channel.
[0032]
Next, a basic operation for correcting a newly generated scratch (that is, the scratch correction method of the present invention) in a video camera equipped with the scratch correction apparatus of the present invention will be described with reference to FIG.
[0033]
In FIG. 2, in step S1, the CCD readout is frame readout.
[0034]
In the next step S2, the position of a newly generated scratch is measured with a cross cursor. In other words, the position of the flaw is measured by aligning the position of the cross cursor on the flaw on the screen (adjusting the horizontal address and the vertical address). In step S3, the level of the scratch at the measured position is measured, and the correction level is determined by judging from the level.
[0035]
In step S4, the above-described scratch correction is tried with the determined correction level (this correction is referred to as pre-correction). This pre-correction is performed in order to confirm whether the position of the scratch is correct and whether the determined correction level is a correct correction level. That is, in the next step S5, it is determined whether or not the correction has been made correctly by the pre-correction. If the correction has not been made correctly, the process returns to step S2 and the processes from step S2 to step S4 are repeated again. If it is determined in step S5 that the correction is correct, the process proceeds to step S6.
[0036]
In this step S6, flaw position data (absolute address data) and level (absolute value) data in the correct pre-correction are stored.
[0037]
In the next step S7, the power is once turned off and then turned on again in order to determine whether or not the store has been performed. In the next step S8, it is determined whether or not the newly generated scratch is corrected normally on the screen after the power is turned off and on. If it is determined in step S8 that the correction has not been made normally, the process returns to step S1 and the processes from step S1 to step S8 are performed again. If it is determined in step S8 that the correction is normal, the process ends.
[0038]
In the pixel unevenness correction method of the present invention, pixel unevenness, that is, a defect is corrected by the above-described procedure. The above-described flowchart of FIG. 2 is an operation for correcting one newly generated scratch. However, when there are a plurality of newly generated scratches, the processing of FIG. All scratches can be corrected.
[0039]
Next, the specific operation when the pixel unevenness correction method of the present invention shown in the flowchart of FIG. 2 is applied to the pixel unevenness correction apparatus (video camera) of the present embodiment described with reference to FIG. It becomes like this.
[0040]
First, in step S1, the CCD read mode is set to the frame mode by operating a mode changeover switch on the operation panel 20 for controlling the video camera.
[0041]
In the next step S2, the cursor on / off switch of the operation panel 20 is turned on, and the horizontal address adjustment volume and the vertical address adjustment volume on the operation panel 20 are further operated. The cursor-on signal and the horizontal address data and the vertical address data of the crosshair cursor are output. These data are sent to the CPU 1, made into a serial data group by the CPU 1, and sent to the cursor generation circuit 5. The cursor generation circuit 5 generates cross-cursor data to be displayed on the screen based on the supplied data, and the cross-cursor data is sent to the subsequent configuration via the terminal 21. Thus, in the state where the cross cursor is displayed on the screen, the position of the scratch is measured by aligning the position of the cross cursor with the newly generated scratch on the screen. The position of the scratch is obtained as absolute address data in the horizontal direction and the vertical direction.
[0042]
Next, in step S3, the level of the scratch at the measured position is measured, and based on the level, the level adjustment volume on the operation panel 20 is operated to adjust the correction level (absolute for absolute correction). Level).
[0043]
In the next step S4, the correction on / off switch on the operation panel 20 is operated to turn on the pre-correction. When the pre-correction is turned on, the address data and the correction level data obtained in steps S2 and S3 are converted from the CPU 1 into serial data and sent to the CPU 3. Upon receiving this data, the CPU 3 reads the relative address data and relative level data already stored at the time of manufacture from the ROM 4 and processes the absolute address and absolute level data sent from the CPU 1 and stores them in the ROM 4. The data of the relative address and the relative level which are the same as those described above are converted into the RAM 7. After development in the RAM 7, the address setting in the RAM 7 is switched to the address data from the defect correction IC 10, thereby pre-correction is performed at the determined correction level. Thereafter, the pre-correction is turned off by operating the correction on / off switch on the operation panel 20. After the pre-correction is turned off, the CPU 3 further expands only the data in the ROM 4 in the RAM 7 and performs an operation of ignoring the address and level data for the original scratch. That is, the CPU 3 distinguishes newly generated scratches from existing scratches.
[0044]
In the next step S5, it is determined whether or not the pre-correction has been correctly corrected. If the correction has not been correctly performed, the process returns to step S2 and the processes from step S2 to step S4 are repeated again. If it is determined in step S5 that the correction is correct, the process proceeds to step S6.
[0045]
In step S6, the store on / off switch on the operation panel 20 is operated to correct the correct correction data and address data, that is, the horizontal and vertical absolute address data corresponding to the newly generated scratch. The absolute level data of the correction data is stored in the EEPROM 2. In this case, when the store on / off switch is turned on, data (absolute address data and absolute level data) corresponding to the new flaw is sent from the CPU 1 to the CPU 3, and the CPU 3 writes the supplied data into the EEPROM 2. This makes it possible to correct newly generated scratches.
[0046]
In the next step S7, the power is turned off and turned on again in order to recheck whether the data is actually written in the EEPROM 2. When the power is turned on, the CPU 3 reads out the data stored in the EEPROM 2 and the data in the ROM 4 and develops them on the RAM 7. Thereafter, the data developed in the RAM 7 is read by address setting from the defect correction IC 10 and defect correction using this data is performed. By this scratch correction, in step S8, it is determined whether or not the newly generated scratch along with the previously existing scratch is corrected normally on the screen after the power is turned off and on. If it is determined that it has been done, the process is terminated.
[0047]
As described above, according to the pixel unevenness correcting apparatus and method of the embodiment of the present invention, by installing a circuit for correcting newly generated scratches in the CCD block, scratches generated after the time of factory shipment, It can be easily erased without the need for a dedicated jig or device. Further, since the data for the newly generated scratch is stored in the EEPROM 2, it is not necessary to replace the ROM 4 containing the scratch data from the beginning as it is, so that no trouble occurs when the ROM is replaced. Furthermore, although it depends on the capacity of the EEPROM 2, the data for newly generated scratches can correspond to, for example, about 70 scratches at the maximum, and therefore the CCD block itself is used for correcting new scratches after shipment from the factory. There is no need for replacement.
[0048]
Note that a conventional defect correction device mounted on a video camera corresponds to a portion surrounded by a dotted line in FIG. Further, the portion other than the portion surrounded by the dotted line in the CCD block in FIG. 1 is constituted by a conventional personal computer such as a service station and a dedicated jig.
[0049]
【The invention's effect】
As is clear from the above description, in the pixel unevenness correcting apparatus and method of the present invention, when new pixel unevenness occurs, the newly generated pixel unevenness position data and level data are generated, and these new data are generated. Since the pixel unevenness position data and level data generated in the memory are stored in a rewritable nonvolatile memory, newly generated pixel unevenness position data stored in the rewritable nonvolatile memory. And by using the level data, it is possible to correct these pixel unevenness. Further, since the pixel unevenness position data and level data that already existed in the solid-state imaging device are also stored originally, the newly generated pixel unevenness position data and level stored in the rewritable nonvolatile memory are stored. By developing the data and the pixel unevenness position data and level data that have already existed in a rewritable memory, it is possible to correct not only old pixel unevenness but also new pixel unevenness. Therefore, in the pixel unevenness correction apparatus and method according to the present invention, even if a new scratch is generated in the CCD, it is possible to correct at a service station without any work at the service station, and further, it is not necessary to replace the ROM. Become.
[Brief description of the drawings]
FIG. 1 is a block circuit diagram showing a configuration of a main part of a video camera equipped with a pixel unevenness correction apparatus according to an embodiment of the present invention.
FIG. 2 is a flowchart showing a procedure of a pixel unevenness correction method of the present invention.
[Explanation of symbols]
1,3 CPU
2 EEPROM
4 ROM
5 Cursor generation circuit
6 Selector
7 RAM
8,9 buffer
10 Scratch correction IC
11 D / A converter
12 switch
20 Operation panel

Claims (6)

In a pixel unevenness correction apparatus that corrects pixel unevenness that occurs in a solid-state imaging device,
Non-volatile first memory means for storing relative position data and relative level data of pixel unevenness that already existed in the solid-state imaging device;
Generating means for generating absolute position data and absolute level data of pixel unevenness newly generated in the solid-state imaging device;
A rewritable nonvolatile second memory means for storing the absolute position data and absolute level data of the newly generated pixel unevenness;
Control means for processing the relative position data and relative level data of the first memory means and the absolute position data and absolute level data of the second memory means to develop them into a rewritable third memory means;
Reads the position data and the level data of the pixel unevenness developed in the third memory means, have a correcting means for correcting the pixel irregularities,
The pixel unevenness is characterized in that the control means converts the absolute position data and absolute level data of the second memory means into relative position data and relative level data and develops them in the third memory means. Correction device. A cursor generating means for generating cross cursor data to be displayed on the screen;
2. The pixel unevenness correction apparatus according to claim 1, wherein the position of the newly generated pixel unevenness is measured by a cross cursor displayed on the screen.   3. The pixel unevenness correcting device according to claim 2, further comprising level determining means for determining a level of pixel unevenness at which the position is measured.   The pixel according to claim 1, further comprising: a camera unit including at least an optical system that forms a subject image on the solid-state image sensor and a conversion system that converts an image signal from the solid-state image sensor into a video signal. Unevenness correction device. In a pixel unevenness correction method for correcting pixel unevenness that occurs in a solid-state imaging device,
Generate absolute position data and absolute level data of pixel unevenness newly generated in the solid-state image sensor,
Store the absolute position data and absolute level data of the newly generated pixel unevenness in a rewritable nonvolatile memory,
Relative position data and relative level data of pixel unevenness already existing in the solid-state imaging device, and data obtained by converting the newly generated absolute position data and absolute level data of pixel unevenness into relative position data and relative level data. Process and expand to rewritable memory,
A pixel unevenness correction method comprising: reading out the developed relative position data and relative level data of pixel unevenness from a memory, and correcting pixel unevenness.   6. The pixel unevenness correction method according to claim 5, wherein a cross cursor is displayed on the screen, and the position of the newly generated pixel unevenness is measured with the cross cursor displayed on the screen.

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