JP3990059B2 - Apparatus and method for correcting defective pixel of imaging device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a defective pixel correction apparatus for an imaging device and a method thereof. More specifically, the present invention relates to an apparatus and method for correcting a pixel signal caused by a defective imaging cell in an image signal obtained from a solid-state imaging device.
[0002]
[Prior art]
As is well known, a solid-state imaging device is provided with an array of imaging cells in which a large number of photosensitive elements are arranged. The photosensitive element included in the imaging cell array often includes cells that do not react to incident light and cells that generate an abnormally large dark current without incident light due to the manufacturing process. These defective cells are generally referred to as “black scratches” and “white scratches”, respectively, and are unavoidable in solid-state imaging devices.
[0003]
In view of this, there have been proposed a number of defective pixel correction methods for correcting pixel signals caused by these defective cells using pixel signals obtained from the surrounding imaging cells in the image signal output from the solid-state imaging device. ing. Japanese Laid-Open Patent Publication No. 7-59011 discloses a method of determining the defect level of a defective cell, that is, the defect level, when identifying the defective cell from the capacity limitation of the memory area for storing the position coordinates of the defective cell in the imaging cell array. Thus, an automatic detection apparatus for defective cells that stores the position coordinates of only cells having a high defect level is disclosed.
[0004]
By the way, from a solid-state imaging device, an image signal is generally raster-scanned in a time sequential manner in the horizontal and vertical scanning directions and output. When correcting a pixel signal of a defective cell, there is a method in which, for example, simple averaging is performed using pixel signals of a plurality of imaging cells adjacent to the cell, and the average value is replaced with the pixel signal of the defective cell. In addition, in the case of a burst-like defect in which a plurality of adjacent imaging cells are defective cells, when correcting the pixel signal of the burst-like target defective cell, the already corrected pixel signal of the defective cell adjacent to it is used. To do.
[0005]
[Problems to be solved by the invention]
Conventional defective pixel correction is performed by applying a correction algorithm only to defective cells of a predetermined level or higher, regardless of the defect level of the imaging cell. Therefore, for example, when defective cells exist in a burst state, a sufficiently good defective pixel correction cannot be performed because the corrected signal adversely affects the correction of other defective cells depending on the position of the defective cell. There was a thing.
[0006]
When the pixel signals of the defective cells are corrected in the output order, that is, the pixel signals of the defective cells in a time series with respect to the image signals output sequentially from the solid-state imaging device by raster scanning, the target defective cells in such a series of defective cells in a burst form The appropriateness of the correction of the pixel signal may greatly depend on the already corrected pixel signal of the defective cell adjacent thereto. In other words, if the correction of the pixel signal of the adjacent defective cell is not appropriate, the inappropriate correction value is used for correcting the pixel signal of the target defective cell. Therefore, the influence of the inappropriate correction value causes the correction of the pixel signal of the target cell. May appear strongly.
[0007]
An object of the present invention is to provide a defective pixel correction apparatus for an imaging device, and a method thereof, which can more appropriately correct a pixel signal of a defective imaging cell of a solid-state imaging device as compared with such a conventional technique. And
[0008]
[Means for Solving the Problems]
According to the present invention, defective pixel correction is performed with priority given to an imaging cell having a high defect level according to the degree of defect of the imaging cell in the imaging device, that is, the defect level. Used to correct defective pixels in other imaging cells.
[0009]
More specifically, the defective pixel correction apparatus for an imaging device according to the present invention includes an input unit that receives an image signal output from an imaging device having an imaging cell array in which a plurality of imaging cells are arranged, and a plurality of the image signals. When a pixel signal corresponding to a defective imaging cell among the imaging cells is included, correction means for correcting the pixel signal and defect degree data indicating the degree of the defect of the imaging cell having the defect are present. The storage means for storing corresponding to the imaging cell, and the control means for controlling the correction means according to the defect degree data, and for correcting the pixel signal corresponding to the imaging cell having a defect by the correction means, Referring to the defect degree data, the defective imaging cell and the degree of the defect are identified, and the correction means is an imaging cell having a high degree of defect according to the identified degree of defect. Corrects the pixel signal corresponding to the order of the lower imaging cell, if applicable, using the corrected result to the correction of the pixel signals of the lower imaging cells of the extent of the defect.
[0010]
According to the present invention, instead of the defect degree data, identification data for identifying the defective imaging cell according to the degree of the defect of the defective imaging cell is accumulated in the accumulation means, and the control means stores the identification data in the accumulation means. You may comprise so that the imaging cell with a defect and the grade of a defect may be identified with reference.
[0011]
Furthermore, the defect pixel correction method for an imaging device according to the present invention includes a step of preparing an image signal output from an imaging device having an imaging cell array in which a plurality of imaging cells are arranged, and the image signal includes a plurality of imaging cells. When a pixel signal corresponding to a defective imaging cell is included, a step of correcting the pixel signal, a step of preparing data related to the degree of the defect of the defective imaging cell, and referring to this data A pixel signal corresponding to the imaging cell having a defect degree in order from the imaging cell having a high degree of defect to the imaging cell having a low degree of defect. The obtained result is used to correct the pixel signal of the imaging cell with a low degree of defect.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Next, an embodiment of a defective pixel correction apparatus for an imaging device according to the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 shows an embodiment of a digital electronic still camera to which the present invention is applied. This camera 100 has a solid-state imaging device 102 such as a charge transfer device (CCD), for example, and corrects a pixel signal related to a defective imaging cell of an image signal 104 output from the solid-state imaging device 102 to output from a device output 106 An imaging device that outputs.
[0013]
The solid-state imaging device 102 has an imaging cell array 103 in which photosensitive elements are two-dimensionally arranged. Generally, these photosensitive elements include defective cells called black scratches or white scratches due to the manufacturing process. There are often. These defective cells can be obtained, for example, by providing defective cell data specifying their position, ie, coordinates on the array 103, from the supplier of the imaging device 102, or by capturing a two-dimensional image with uniform illumination. The position of the defective cell in the imaging cell array 103 can be known from the obtained image signal. These positions are preferably expressed in the form of coordinates (X, Y) in the X direction and Y direction (see FIG. 2) in the two-dimensional plane of the imaging cell array 103. The still camera 100 of the embodiment has a memory 108 for storing such defective cell data indicating the position of the defective cell. The structure of the defective cell data will be described later in detail.
[0014]
The imaging cell array 103 includes a large number of imaging cells 10 that store charges corresponding to incident light incident from the object field through an imaging optical system (not shown) of the camera 100, and the solid-state imaging device 102 has a timing described later. This is an imaging device that generates this accumulated charge at its output 104 in the form of an image signal in response to a drive signal 112 output from the generator 110. This output 104 is connected to the input of the sampling circuit 112. In the following description, a signal is designated by the reference numeral of the connecting line that appears. In this embodiment, a CCD is used as the solid-state imaging device. However, the present invention is not limited to this specific type of image pickup device, and can be effectively applied to an image pickup apparatus of another type such as a MOS type semiconductor image pickup device.
[0015]
The sampling circuit 112 amplifies the image signal input from the imaging device 102, samples the image signal 104 in response to the sampling pulse 116 supplied from the timing generator 110, and outputs this to the output 114 thereof. It is a sampling circuit. Output 114 is connected to an analog to digital (AD) converter 118.
[0016]
The analog / digital converter 118 is a conversion circuit that converts the sample value of the input 114 into corresponding digital data in response to a clock pulse supplied from the timing generator 110 through the connection line 120. The analog-to-digital converter 118 has an output 122 that outputs the converted digital data, which is connected to the input of the signal processing circuit 124.
[0017]
The signal processing circuit 124 also responds to a clock pulse or a synchronization signal supplied from the timing generator 110 through the connection line 120 to the image data 122 input to the input 122, for example, gradation correction or white balance adjustment. It is a signal processing function unit that performs signal processing and outputs it as an image signal to the apparatus output 106. In connection with this signal processing, the apparatus has a frame memory 126, which is connected to the signal processing circuit 124 by control and data lines 128 as shown. The frame memory 126 is a temporary storage device having a storage capacity for storing image signals for at least one frame, and the signal processing circuit 124 performs image data signal processing using the storage area of the frame memory 126.
[0018]
The signal processing circuit 124 cooperates with a system control unit 130 described later as a function particularly related to the present invention, and outputs a pixel signal due to a defective cell in the image signal 104 output from the solid-state imaging device 102 in the surroundings. It also has a defective pixel correction or interpolation function for correcting using the pixel signal of the imaging cell. This will be described in detail later. The frame memory 126 is not necessarily required depending on the defective pixel correction method in an apparatus configured to output an image signal in real time. When the scanning method is an interlace method, a field memory may be used instead of the frame memory depending on the application example.
[0019]
The system control unit 130 is connected to the timing generator 110 and the signal processing circuit 124 via connection lines 132 and 134, respectively, and in response to the operation of a shutter release button (not shown), the imaging operation and signals of the entire apparatus. This is an overall control unit that controls and controls processing operations. The system control unit 130 is also connected to the defective cell memory 108 by a connection line 136. In particular, as a function relevant to the present invention, the system control unit 130 controls the signal processing circuit 124 to store the defective cell location stored in the defective cell memory 108. A part of the defective pixel correction function for correcting the pixel signal of the defective cell according to the data is shared.
[0020]
In the present embodiment, in the defective cell memory 108, when there are defective cells in the imaging cell array 103 of the solid-state imaging device 102 included in the apparatus 100, 2 of the imaging cell array 103 for each of the defective cells. Coordinate data representing the position in the dimension array and defect level data representing the defect level are stored correspondingly.
[0021]
Referring to FIG. 2, a part of a state in which a large number of imaging cells 10 are arranged in the two-dimensional X and Y directions in the imaging cell array 103 of the solid-state imaging device 102 is schematically shown. For example, the X direction corresponds to the horizontal direction of the shooting screen, and the Y direction corresponds to the vertical direction. Each square represents one imaging cell 10. The numbers written inside the square 10 conceptually indicate the relative level of the luminance signal output from the cell 10. The upper edge is indicated by an X coordinate, and the left edge is indicated by a Y coordinate. In order to avoid complicated explanation, only a small number of imaging cells 10 in the imaging cell array 103 are shown in the figure, but in reality, a much larger number of cells are arranged two-dimensionally. Needless to say. Further, although simply referred to as “brightness signal level” or “brightness level”, these are not limited to the level of the so-called luminance signal Y, and for example, a signal level of a specific color component, for example, a G signal, that is, a large level. It shall be interpreted in a broad sense that also includes
[0022]
For example, if the luminance signal level output from the cell 12 positioned at the X, Y coordinates (1, 1) is “1”, in this example, the luminance signal output from the cell 14 positioned at the coordinates (2, 3) is set. The level 16 is “2”, and the cell 16 at the coordinates (3, 3) outputs the luminance signal level “10”. The other cells 10 generally output a pixel signal of level “1” in this example. Of these, if the two imaging cells 14 and 16 are defective cells, this embodiment simply averages the pixel signals of four cells adjacent to the individual defective cells in the vertical and horizontal directions. Thus, the pixel signal of the defective cell is corrected, that is, “backfill” is performed in which the defective pixel signal is replaced with a correction value.
[0023]
In the present embodiment, information indicating whether or not these imaging cells 14 and 16 are defective cells is held in the defective cell memory 108 as defective cell position data. FIG. 3 illustrates the state of the defective cell position data. The present invention is not limited to such a specific defective pixel interpolation method. For example, it may be configured such that defective pixel interpolation is performed using pixel signals of eight adjacent cells by adding image signals of four imaging cells adjacent in the diagonal direction of the target pixel. Alternatively, only pixel signals of two imaging cells adjacent in the horizontal X direction may be used. Furthermore, instead of the above-described simple addition averaging, a weighted average method weighted according to pixel positions may be used.
[0024]
FIG. 3 exemplifies defective cell position data of the defective cells 14 and 16 and surrounding cells for the part of the imaging cell array 103 shown in FIG. The storage location address of the memory 108 is shown in decimal notation on the left edge of the figure. Further, the coordinates (X, Y) of the imaging cell 10 are shown on the right edge for reference. For example, the address # 1003 corresponds to the imaging cell 14, the next address # 1004 corresponds to the imaging cell 16, and whether each imaging location is normal and whether it is a defective cell. For example, data indicating the degree of the defect, that is, the defect level is accumulated. In this embodiment, for example, a normal cell 10 located at coordinates (1, 3) or the like is indicated as a normal cell by recording a defect level “0”. A numerical value indicating is recorded. For example, the level “2” is recorded for the defect cell 14 located at the coordinates (2, 3), and the level “10” is recorded for the defect cell 16 located at the coordinates (3, 3). These defective cells 14 and 16 both correspond to so-called “white scratches”. All numerical values in the figure are expressed in decimal notation for convenience of explanation.
[0025]
As the defect level data, for example, data provided from the supplier of the solid-state imaging device 102 can be used. Alternatively, for example, a luminance level of a cell that generates a pixel signal having a luminance level that is abnormally higher or lower than that of the surrounding imaging cell from an image signal obtained by imaging a two-dimensional image with uniform illuminance with the imaging device 102. Or a value corresponding thereto may be adopted as the defect level value. In this embodiment, the latter example is used for the sake of simplicity.
[0026]
Referring to FIG. 4, the imaging cells 30 and 32 located at coordinates (62, 22) and (63, 22), respectively, are so-called “black scratches”. The other normal cells 10 output pixel signals with luminance level “10”, whereas the imaging cells 30 and 32 output pixel signals with luminance levels “0” and “1”, respectively. . FIG. 5 shows an example of defective cell position data of the defective cells 30 and 32 and the surrounding cells in the imaging cell array 103 shown in FIG. This figure uses the same notation as FIG. For example, the address # 2001 corresponds to the defect imaging cell 30, and the defect level is recorded as the value “10”. The next address # 2002 corresponds to the imaging cell 32 and the defect level is recorded as the value “9”. In other storage positions, a value “0” indicating that these cells are normal is recorded. In this example, the defect level value of the black flaw imaging cell is represented by the difference from the normal cell output level when a uniform subject is imaged at the maximum illuminance. The display method of the defect level is for explanation of the embodiment, and the present invention is not limited only to this specific display method.
[0027]
For example, as shown in FIG. 6, after the storage area # 4000 of the defective cell memory 108, the coordinates (X, Y) of the imaging cell are set in order from the cell having the highest defect level to the cell having the lowest defect level toward the oldest storage position. You may comprise so that it may record. In the example shown in the figure, the coordinates (X, Y) are shown in decimal numbers, and the address (# 4000) has coordinates (3, 3) indicating the imaging cell 16 (FIG. 2) having the highest defect level value in the imaging cell array 103. It is recorded. At the next address # 4001, the coordinates (62, 22) of the defect cell 30 (FIG. 4) indicating the second defect level value are recorded. In this example, the defect cells 16 and 30 have the same defect level value “10”, so that any of them may be treated as the first. Further, at the next address # 4002, the coordinates (2, 3) of the defect cell 14 indicating the third defect level value are recorded. Thus, hereinafter, in this example, the position coordinates (X, Y) are recorded in the memory 108 in ascending order from the highest defect level regardless of white scratches and black scratches. In the normal cell 10, position coordinates are recorded in the order of raster scanning on the screen as shown in the figure.
[0028]
The present invention is not limited to the configuration example of the specific defect level data as described herein. For example, defect level data may be configured by dividing white flaw cells from black flaw cells. In the application example having the configuration of the memory 108 described with reference to FIG. 6, such coordinate data may not be recorded in the memory 108 for the normal cell 10. In this embodiment, the coordinates (X, Y) are used to specify the position of the imaging cell 10. However, irrespective of such coordinates, for example, an identification display such as a number or a sign may be given to each imaging cell 10 so that a specific imaging cell 10 is represented by this.
[0029]
When the signal processing circuit 124 corrects the defective pixel signal to the image signal stored in the frame memory 126, the system control unit 130 refers to the defect level data in the defective cell memory 108 and selects an imaging cell with a high defect level. The imaging cell with a low defect level and the normal imaging cell are preferentially handled. In this way, in this embodiment, even if defective cells exist in a burst shape, the pixel signals of adjacent defective cells are corrected appropriately. Therefore, as in the prior art, the inappropriate correction value of the adjacent defective cell is used for correcting the pixel signal of the target defective cell, that is, by backfilling, the influence of the inappropriate correction value is corrected for the pixel signal of the target cell. It does not appear strongly in
[0030]
When a shutter release button (not shown) is operated in the operating state, the solid-state imaging device 102 samples the image signal 104 representing the object scene from the imaging cell array 103 in response to the drive pulse 116 from the timing generator 110. Output to circuit 112. The sampling circuit 112 amplifies the image signal 104, samples it in response to the sampling pulse 116, and provides it to the analog / digital converter 118 from its output 114.
[0031]
The analog / digital converter 118 converts the image signal sample value of the input 114 into digital data in response to the clock pulse 120. The converted digital data 122 is input to the signal processing circuit 124 and is temporarily stored in the frame memory 126 by the signal processing circuit 124 in this embodiment.
[0032]
Therefore, the signal processing circuit 124 corrects the pixel signal corresponding to the defective cell in the image signal stored in the frame memory 126, for example, prior to signal processing such as gradation correction. First, the system control unit 130 refers to defect level data in the defective cell memory 108, identifies defective cells in order from an imaging cell with a high defect level to an imaging cell with a low defect level, and corrects the pixel signal for these defective cells. The image signal subjected to the defective pixel correction is temporarily stored in the frame memory 126 and / or output from the signal processing circuit 124 to the device output 106. For example, an image storage device such as a memory card or a utilization device such as a communication line (not shown) is detachably connected to the device output 106, corrected for defective pixels, and subjected to signal processing such as gradation correction. An image signal is used in these utilization devices.
[0033]
More specifically, according to the present embodiment, the pixel signal of the defective imaging cell is first corrected for the pixel signal of the cell having a high defect level according to the degree of the defect, that is, the defect level, and the result of the correction The pixel signal of the cell having a low defect level is corrected using the value. In order to simplify the description, in the example of the pixel signal shown in FIG. 2, if the defective cells included in the imaging cell array 103 are only white scratch cells 14 and 16, the system control unit 130 stores the defective cell memory 108. With reference to the defect level data, first, it is identified that the cell having the highest defect level is the cell 16 located at the coordinates (3, 3) in this example.
[0034]
In an application example in which defective cell data is stored in the defective cell memory 108 in the format shown in FIG. 3, the system control unit 130 searches the entire memory area with reference to the memory 108 and finds the most defective level. The storage location of the accumulated content with a high value, in this example, # 1004 is identified. From this, the system control unit 130 can identify the defective cell at the position of the coordinates (3, 3). Further, in the application example in which the defective cell data is stored in the format shown in FIG. 6, the system control unit 130 refers to the memory 108 and first stores the accumulated contents of the beginning # 4000 of the storage position of the defective cell data. From this, the system control unit 130 identifies that the cell at the position of the coordinates (3, 3) is the highest level defective cell. Thereafter, in order to search for an imaging cell having the second or lower defect level, the same reading operation is sequentially performed for the storage position having a larger address value.
[0035]
The position of the identified defective cell 16 is notified from the system control unit 130 to the signal processing circuit 124. As a result, the signal processing unit 124 corrects the pixel signal of the luminance signal level “10” output from the defective cell 16 with priority over others. In this example, the pixel signal from the cell 16 at the coordinates (3, 3) is stored in the frame memory 126 with the luminance signal level value “10”.
[0036]
In the present embodiment, the signal processing circuit 124 according to a simple averaging method that corrects the pixel signal of the defective cell 16 by averaging the pixel signals of the cells 24, 26, 14, and 16 adjacent to the defective cell 16 in the vertical and horizontal directions. For the image signal of the frame memory 126, the luminance levels “1”, “1” and “2” “1” of the adjacent cells 24, 26 and 14, 28 of the defective cell 16 are simply averaged. As a result, the corrected pixel signal value “1.25” of the defective cell 16 is calculated. This correction value is accumulated in the storage position corresponding to the imaging cell 16 of the frame memory 126.
[0037]
Next, the system control unit 130 similarly identifies the cell having the second highest defect level, in this example, the defective cell 14 located at the coordinates (2, 3), from the defective cell data in the memory 108. Therefore, the signal processing circuit 124 uses the correction result value “1.25” as the luminance level for the adjacent cell 16 that has been subjected to correction first among the cells adjacent to the target defective cell 14 for the time being. Thus, the pixel signal of the defective cell 14 of interest is corrected. Therefore, for the new attention cell 14, the luminance levels “1”, “1” and “1” “1.25” of the adjacent cells 18, 20 and 22, 24 in the vertical and horizontal directions are simply averaged. The value “1.06” as a result is accumulated in the storage position corresponding to the imaging cell 14 in the frame memory 126, preferably with the value before correction.
[0038]
The correction result values for the defective cells 16 and 14 thus obtained are “1.25” and “1.06”. It can be seen that these values are very close to the luminance level “1” of the surrounding normal cells 10, 12, 18, 20, 22 and the like.
[0039]
For comparison, the image signal output from the image pickup device 102 is assumed to be in the raster scan order, that is, from the upper left pixel of the object scene screen to the right in the horizontal direction and in the vertical direction as in the prior art. If the defective pixel correction is performed on the pixel signal in time series, the corrected luminance levels of the defective cells 14 and 16 are the luminance levels “1” of the surrounding normal cells 10, 12, 18, 20, 22 and the like. Will be considerably different from each other, ie “3.25” and “1.56”, respectively.
[0040]
More specifically, in the example shown in FIG. 2, first, defective pixel correction is performed on the defective cell 14 located at the coordinates (2, 3). When the luminance levels “1”, “1” and “1” “10” of the adjacent cells 18, 20, 22 and 24 in the vertical and horizontal directions are simply averaged, the result value is “3.25”. Since the pixel sequential raster scanning method is in the X direction, the pixel signal of the next defective cell 16 in the X direction is then corrected. In that case, the correction value “3.25” is used for the defective cell 14 adjacent to the target pixel cell 16. Therefore, the luminance levels “1”, “1”, “3.25”, and “1” of the cells 24, 26, 14, and 28 adjacent to the new defective cell 16 in the vertical and horizontal directions are simply averaged. Therefore, the corrected pixel signal value of the defective cell 16 will be “1.56”. That is, the corrected luminance levels of the defective cells 14 and 16 are “3.25” and “1.56”, respectively. These values are considerably different from the brightness level “1” of the surrounding normal cells 10, 12, 18, 20, 22 and the like.
[0041]
【The invention's effect】
As described above, according to the present invention, the defective pixel signal caused by the defect of the imaging cell of the imaging device can be corrected more appropriately as compared with the related art.
[Brief description of the drawings]
FIG. 1 is a schematic block diagram showing the configuration of an embodiment of a digital electronic still camera to which the present invention is applied.
2 is an explanatory diagram conceptually illustrating an example of a level of a pixel signal output from an imaging cell array in the embodiment illustrated in FIG.
3 is an explanatory diagram showing an example of defective cell data stored in a defective cell memory in the embodiment in relation to the imaging cell shown in FIG. 2;
4 is an explanatory view similar to FIG. 2, conceptually showing another example of the level of the pixel signal output from the imaging cell array in the same embodiment. FIG.
5 is an explanatory view similar to FIG. 3, showing another example of defective cell data stored in the defective cell memory in the embodiment in relation to the imaging cell shown in FIG. 4; FIG.
6 is an explanatory view similar to FIG. 3, showing another example of defective cell data stored in the defective cell memory in the same embodiment. FIG.
[Explanation of symbols]
10 Imaging cell
14, 16 Defect imaging cell
102 Solid-state imaging device
103 Imaging cell array
108 defective cell memory
124 Signal processing circuit
126 frame memory
130 System controller

Claims (7)

Input means for receiving an image signal output from an imaging device having an imaging cell array in which a plurality of imaging cells are arranged;
First storage means for storing image signals to be input to the input means;
The When defective pixel signal corresponding to the imaging cell with one of the plurality of imaging cells in the image signal stored is included in the first storage means, to said first storage means corrects the pixel signal Correction means to accumulate ;
Second accumulation means for accumulating defect degree data representing the degree of defect of the defective imaging cell corresponding to the defective imaging cell;
Control means for controlling the correction means according to the defect degree data, and correcting the pixel signal corresponding to the defective imaging cell by the correction means ;
Signal processing means for correcting the pixel signal by the correction means and processing the image signal stored in the first storage means ;
The control means refers to the defect degree data to identify the imaging cell having the defect and the degree of the defect,
Prior to the processing by the signal processing means , the correction means corrects the pixel signal corresponding to the order of the imaging cell with the highest degree of defect from the imaging cell with the lowest degree according to the degree of the identified defect, and corresponds to the imaging cell to be corrected In this case, the corrected pixel correction apparatus of the imaging device, wherein the corrected result is used for correcting the pixel signal of the imaging cell having a low degree of defect. 2. The defective pixel correction apparatus according to claim 1, wherein the correction unit uses a pixel signal of an imaging cell adjacent to the defective imaging cell for correction. A digital electronic still camera comprising the defective pixel correction apparatus according to claim 1, wherein the imaging device is connected to the input means. Input means for receiving an image signal output from an imaging device having an imaging cell array in which a plurality of imaging cells are arranged;
First storage means for storing image signals to be input to the input means;
The When defective pixel signal corresponding to the imaging cell with one of the plurality of imaging cells in the image signal stored is included in the first storage means, to said first storage means corrects the pixel signal Correction means to accumulate ;
Second accumulating means for accumulating identification data for identifying the defective imaging cell according to the degree of defect of the defective imaging cell;
Control means for controlling the correction means, and correcting the pixel signal corresponding to the defective imaging cell by the correction means ;
Signal processing means for correcting the pixel signal by the correction means and processing the image signal stored in the first storage means ;
The control means identifies the defective imaging cell and the degree of the defect with reference to the identification data,
Prior to the processing by the signal processing means , the correction means corrects the pixel signal corresponding to the order of the imaging cell with the highest degree of defect from the imaging cell with the lowest degree according to the degree of the identified defect, and corresponds to the imaging cell to be corrected In this case, the corrected pixel correction apparatus of the imaging device, wherein the corrected result is used for correcting the pixel signal of the imaging cell having a low degree of defect. 5. The defective pixel correction apparatus according to claim 4, wherein the correction unit uses a pixel signal of an imaging cell adjacent to the defective imaging cell for correction. A digital electronic still camera comprising the defective pixel correction apparatus according to claim 4, wherein the imaging device is connected to the input unit. Preparing an image signal output from an imaging device having an imaging cell array in which a plurality of imaging cells are arranged;
A first step of correcting the pixel signal when the image signal includes a pixel signal corresponding to a defective imaging cell of the plurality of imaging cells;
Preparing data relating to the degree of defect of the defective imaging cell;
Referring to the data, for a defective imaging cell among the imaging cells, a second step of correcting pixel signals corresponding to an imaging cell having a high degree of defect to a low imaging cell ;
A signal processing step of processing the image signal in which the pixel signal is corrected by the second step ,
In the second step, if it corresponds to the imaging cell to be corrected, the corrected result is used for correcting the pixel signal of the imaging cell having a low degree of defect, and a defective pixel correction method for an imaging device, .

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