JP3805421B2 - Pixel defect correction device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pixel defect correction device, and more particularly, to a pixel defect correction device that corrects defective pixels of an image sensor and outputs them as normal image data.
[0002]
[Prior art]
A solid-state imaging device such as a CCD is an imaging device configured by arranging a large number of photoelectric conversion elements on a semiconductor substrate, and is much smaller, lighter, and cheaper than an imaging tube that has been used for a long time. Since it has advantages, it is used in various fields such as TV cameras and image sensors.
[0003]
In recent years, such an image sensor is required to be as small as possible with high sensitivity and high image quality, and a large number of ultrafine pixels have been built on a small chip. For this reason, for example, defective pixels that are susceptible to the effects of crystal defects on the semiconductor substrate, defective patterns, dust attached to the substrate surface, etc., and are not able to perform photoelectric conversion normally may occur, and yield in productivity. This is one of the factors that hinder the improvement.
[0004]
Therefore, in order to improve the yield, technical means for relieving pixel defects by replacing pixel data read from defective pixels with pixel data read from normal pixels is disclosed in, for example, Japanese Patent Laid-Open Nos. 5-68209 and 5-5-1. No. 48974, JP-A-5-236358, JP-A-6-6643, and the like.
[0005]
The overall configuration of such a conventional pixel defect correction apparatus will be described with reference to the block diagram of FIG. 1 showing an embodiment of the present invention.
[0006]
The pixel defect correction apparatus includes a lens system 1 that forms an optical image of an incident subject, an image pickup device 2 that photoelectrically converts the subject image formed by the lens system 1 and outputs it as an electrical signal, and amplification. And an analog processing circuit 3 that adjusts the output from the image sensor 2 to an input level of an A / D converter 4 to be described later by performing processing such as optical black clamping, and the analog signal output from the analog processing circuit 3 is digitally converted. An A / D converter 4 for converting into a signal, a frame memory 5 for temporarily storing captured image data, a display memory 6 for storing data to be displayed on a monitor, and the like from the display memory 6 Output processing that converts image data so that it conforms to a standard such as a monitor (generally an analog signal is added by D / A conversion and then a synchronization signal is added) and outputs Path 7, a system controller 9 that manages the operation mode of the pixel defect correction device and performs pixel defect correction processing, and the image sensor 2 is controlled at a timing according to the mode by a mode signal output from the system controller 9. The image sensor driving circuit 8 that drives and reads out a signal is connected to the system controller 9 and the frame memory 5 by a bus, and transfers an image corrected for pixel defects to a personal computer or the like via a standard device such as SCSI. And a personal computer interface (personal computer I / F) 10.
[0007]
Next, the overall operation of such a pixel defect correction apparatus will be described.
[0008]
The subject image formed on the imaging surface of the imaging device 2 by the lens system 1 is photoelectrically converted by the imaging device 2 and output as an electrical signal. The output signal is amplified by the analog processing circuit 3 and then subjected to analog processing such as an optical black clamp, and is converted into digital data by the A / D converter 4.
[0009]
This digital data is once stored in the frame memory 5 and then subjected to pixel defect correction processing as will be described later by the system controller 9. The defect corrected image data is output from the frame memory 5, and data used for display is stored in the display memory 6.
[0010]
The display memory 6 reads the image data in accordance with the display timing and sends it to the output processing circuit 7.
[0011]
The output processing circuit 7 converts the digital signal received from the display memory 6 into an analog signal, adds a synchronization signal, and outputs it as a video signal to display means such as a monitor.
[0012]
Also, the defect-corrected data stored in the frame memory 5 is transferred to an external device such as a personal computer through the personal computer I / F 10, and then, for example, by a printer connected to the personal computer. Output as a print image.
[0013]
Next, the internal operation of the system controller 9 in the conventional pixel defect correction apparatus will be described with reference to the flowchart of FIG.
[0014]
The pixel signal imaged by the image sensor 2 is transferred to the frame memory 5 via the analog processing circuit 3 and the A / D converter 4 (step S51).
[0015]
Subsequently, it is determined whether or not coordinate data to be referenced remains in a table (defective pixel coordinate data table) in which coordinate data of defective pixels as shown in FIG. 12 is stored (step S52). If the reference is finished for the coordinate data of the pixel, the process proceeds to step S56 described later.
[0016]
On the other hand, if the coordinate data to be referred to remains, the horizontal coordinate data and the vertical coordinate data of the defective pixel are acquired from the defective pixel coordinate data table as shown in FIG. 12 (step S53). .
[0017]
Then, centering on the acquired coordinate data of the defective pixel, data of a pixel that is a normal pixel is obtained from surrounding pixels (step S54). Normally, if the pixel immediately adjacent to the left of the defective pixel or the pixel immediately adjacent to the right is a normal pixel, the pixel data is acquired.
[0018]
At this time, whether or not the pixel from which the pixel data is acquired is a normal pixel is determined by referring to the defective pixel coordinate data table shown in FIG. 12 and related to the pixel data to be acquired in the data table. If there is no coordinate that coincides with the coordinate, the pixel is regarded as a normal pixel.
[0019]
Next, the pixel data at the coordinate position of the defective pixel in step S53 is replaced with the pixel data of the normal pixel acquired in step S54 (step S55).
[0020]
Thereafter, the process returns to step S52 again, and the processes from step S52 to step S55 are repeated until there is no more coordinate data to be referred to.
[0021]
In step S52, when the coordinate data of all the pixel defect positions has been acquired from the defective pixel coordinate data table, the image data for which the pixel defect correction processing has been completed by the processing in steps S52 to S55 is performed. The data is output from the frame memory 5 to an output device such as a monitor or a personal computer (step S56), and this process ends.
[0022]
[Problems to be solved by the invention]
As described above, such a conventional pixel defect correction apparatus, when replacing a defective pixel with a surrounding normal pixel, determines whether or not the pixel to be replaced is a normal pixel in the defective pixel coordinate data table. The coordinate data relating to the defective pixel is searched, and if there is no same coordinate data, it is determined that the pixel is a normal pixel. However, in such a discriminating means, in order to discriminate whether or not the pixel is a normal pixel, the coordinate data of the pixel to be replaced must be checked against all the coordinate data in the data table for all defective pixels. However, there is a problem in that the entire pixel defect correction process takes time.
[0023]
In addition, the conventional pixel defect correction apparatus described above also includes the coordinate data of the pixel to be replaced in the data table for all defective pixels including defective pixels that are not to be read even when performing thinning readout or block readout. Since all the coordinate data has been collated, the entire pixel defect correction process still takes time.
[0024]
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a pixel defect correction apparatus that can efficiently perform pixel defect correction in a short time.
[0025]
[Means for Solving the Problems]
In order to achieve the above object, a pixel defect correction apparatus according to the present invention according to claim 1 is a pixel data fetching unit for fetching a pixel signal from an image sensor as image data into a frame memory, and a defective pixel according to the image sensor. Horizontal pixel data and vertical pixel coordinate data and normal pixel position data for replacing the defective pixel are provided as a defective pixel coordinate data table based on the defective pixel coordinate data and the normal pixel position data in the defective pixel coordinate data table. Pixel defect correction means for performing pixel defect correction processing for replacing pixel data of defective pixels with pixel data of normal pixels for the image data captured in the frame memory, and pixel defect correction processing is performed by the pixel defect correction means. Image data output means for outputting the obtained image data as normal image data. .
[0028]
Therefore, in the pixel defect correcting device according to the first aspect of the present invention, the pixel data capturing unit captures the pixel signal from the image sensor as image data into the frame memory, and the pixel defect correcting unit detects the defective pixel associated with the image sensor. Horizontal and vertical coordinate data and normal pixel position data for replacing the defective pixel are provided as a defective pixel coordinate data table, based on the defective pixel coordinate data and the normal pixel position data in the defective pixel coordinate data table. Then, pixel defect correction processing is performed on the image data captured in the frame memory to replace pixel data of defective pixels with pixel data of normal pixels, and the image data output means performs pixel defect correction processing by the pixel defect correction means. The made image data is output as normal image data.
[0031]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
FIGS. 1 to 4 show a first embodiment of the present invention. FIG. 1 is a block diagram showing a configuration of a pixel defect correction apparatus. FIG. 2 is a flowchart showing an operation of pixel defect correction processing by a system controller. FIG. 3 is a diagram showing a defective pixel coordinate data table, and FIG. 4 is a diagram showing replacement positions allocated around the defective pixel.
[0032]
As shown in FIG. 1, the pixel defect correcting apparatus is a lens system 1 that forms an optical image of an incident subject, and photoelectrically converts the subject image formed by the lens system 1 and outputs it as an electrical signal. From the image pickup device 2 that performs processing such as amplification and optical black clamping, and adjusts the output from the image pickup device 2 to the input level of an A / D converter 4 to be described later. An A / D converter 4 that converts the output analog signal into a digital signal, a pixel data fetching unit that temporarily stores captured image data, a frame memory 5 that is an image data output unit, and a monitor Display memory 6 for storing data to be displayed, and image data from the display memory 6 are converted so as to conform to a standard such as a monitor (generally D / A conversion) An output processing circuit 7 for outputting an analog signal after adding an analog signal) and a table memory for managing the operation mode of the pixel defect correcting device and storing a defective pixel coordinate data table to be described later. A system controller 9 as pixel defect correction means for performing defect correction processing, and an image sensor driving circuit 8 for reading the signal by driving the image sensor 2 at a timing corresponding to the mode by a mode signal output from the system controller 9; A personal computer interface (personal computer I / F) 10 that is connected to the system controller 9 and the frame memory 5 by a bus and transfers an image corrected for pixel defects to a personal computer or the like via a standard device such as SCSI. Consists of There.
[0033]
Next, the overall operation of the pixel defect correction apparatus as shown in FIG. 1 will be described.
[0034]
That is, the subject image formed on the imaging surface of the imaging device 2 by the lens system 1 is photoelectrically converted by the imaging device 2 and output as an electrical signal. The output signal is amplified by the analog processing circuit 3 and then subjected to analog processing such as an optical black clamp, and is converted into digital data by the A / D converter 4.
[0035]
This digital data is once stored in the frame memory 5 and then subjected to pixel defect correction processing as will be described later by the system controller 9. The defect corrected image data is output from the frame memory 5, and data used for display is stored in the display memory 6.
[0036]
The display memory 6 reads the image data in accordance with the display timing and sends it to the output processing circuit 7.
[0037]
The output processing circuit 7 converts the digital signal received from the display memory 6 into an analog signal, adds a synchronization signal, and outputs it as a video signal to display means such as a monitor.
[0038]
Also, the defect-corrected data stored in the frame memory 5 is transferred to an external device such as a personal computer through the personal computer I / F 10, and then, for example, by a printer connected to the personal computer. Output as a print image.
[0039]
Next, the operation of the system controller 9 in the pixel defect correction apparatus of this embodiment will be described with reference to the flowchart of FIG.
[0040]
The image data picked up by the image pickup device 2 is taken into the frame memory 5 through the analog processing circuit 3 and the A / D converter 4 (step S1).
[0041]
Next, it is determined whether or not coordinate data to be referred to remains based on the defective pixel coordinate data table as shown in FIG. 3 (step S2), and when the reference is completed for the coordinate data of all defective pixels. Then, the process proceeds to step S7 described later.
[0042]
On the other hand, when the coordinate data to be referred to remains, the horizontal coordinate data and the vertical coordinate data of the defective pixel are fetched from the defective pixel coordinate data table shown in FIG. 3 (step S3).
[0043]
Then, the replacement position data stored in the replacement position item indicating the position of the normal pixel for replacing the pixel data of the defective pixel with the pixel data of the normal pixel is acquired from the defective pixel coordinate data table shown in FIG. Step S4).
[0044]
Subsequently, the pixel data of the normal pixel at the position indicated by the acquired replacement position data is acquired (step S5).
[0045]
Here, the replacement position data stored in the replacement position item in the defective pixel coordinate data table is assigned, for example, as shown in FIG. Pixel position is 1, right pixel position is 2, lower pixel position is 3, upper pixel position is 4, upper left pixel position is 5, upper right pixel position is 6, lower left pixel position is 7, lower right pixel position is The replacement position is designated by setting the pixel position to 8, and so on.
[0046]
After obtaining the pixel data of the normal pixel in this way, the pixel data at the coordinate position of the defective pixel on the frame memory 5 is replaced with the pixel data of the normal pixel obtained in step S5 (step S6).
[0047]
Thereafter, the process returns to step S2 again, and the processes from step S2 to step S6 are repeated until there is no coordinate data to be referred to.
[0048]
In step S2, when there is no coordinate data to be referred to from the defective pixel coordinate data table, the image data of the frame memory 5 subjected to the pixel defect correction process is output (step S7), and the process ends. .
[0049]
According to the first embodiment, when the pixel data of the defective pixel is replaced with the pixel data of the normal pixel, the coordinate data of the pixel to be replaced for all the defective pixels is stored in the defective pixel coordinate data table. Since it is not necessary to collate with all coordinate data and the position of the pixel to be replaced is clear, the time for performing the pixel defect correction process can be shortened.
[0050]
FIGS. 5 to 7 show a second embodiment of the present invention. FIG. 5 is a flowchart showing the operation of pixel defect correction processing by the system controller. FIG. FIG. 7 is a diagram showing a defective pixel coordinate data table as four options, and FIG. 7 is a diagram showing a defective pixel coordinate data table in the case of performing thinning-out reading by a power of 2.
[0051]
In the second embodiment, the description of the same parts as those in the first embodiment will be omitted, and only different points will be mainly described.
[0052]
The pixel defect correction apparatus in this embodiment can cope with a thinning mode in which thinning readout is performed, and the configuration is the same as that shown in FIG.
[0053]
Next, the operation of the system controller 9 in the pixel defect correction apparatus of this embodiment will be described with reference to the flowchart of FIG.
[0054]
The image data picked up by the image pickup device 2 is taken into the frame memory 5 through the analog processing circuit 3 and the A / D converter 4 (step S11).
[0055]
Subsequently, a defective pixel coordinate data table is selected when the image data captured in step S11 is displayed in the thinning mode (step S12).
[0056]
Normally, one defective pixel coordinate data table includes coordinate data of defective pixels for all the pixels of the image sensor 2, and the defective pixel coordinate data table at this time is, for example, horizontal image data in the frame memory 5. When the pixels in the direction and the vertical direction are output by ½ decimation, the result is as shown in FIG.
[0057]
That is, the coordinate data of the defective pixel is an even number of horizontal coordinate data and an even number of vertical coordinate data, and one table, the horizontal coordinate data is even, and the vertical coordinate data is One table with odd number, horizontal coordinate data is odd and vertical coordinate data is even one table, horizontal coordinate data is odd and vertical coordinate data is odd One table is selected from those having a total of four table configurations.
[0058]
Next, it is determined whether or not the coordinate data to be referred to remains based on the selected defective pixel coordinate data table (step S13). If the reference is completed for the coordinate data of all the defective pixels, a step to be described later is performed. Proceed to S17.
[0059]
On the other hand, when the coordinate data to be referred to remains, the horizontal coordinate data and the vertical coordinate data of the defective pixel are fetched from the selected defective pixel coordinate data table (step S14).
[0060]
Then, normal pixels around the defective pixel are searched to acquire the pixel data (step S15).
[0061]
The pixel data at the coordinate position of the defective pixel on the frame memory 5 is replaced with the pixel data of the normal pixel acquired in step S15 (step S16).
[0062]
Thereafter, the process returns to step S13 again, and the processes from step S13 to step S16 are repeated until there is no coordinate data to be referred to.
[0063]
In step S13, when there is no coordinate data to be referred to from the defective pixel coordinate data table, the image data of the frame memory 5 subjected to the pixel defect correction process is output (step S17), and the process ends. .
[0064]
When the thinning mode is other than 1/2 and the contents of the frame memory 5 are output in a plurality of thinning modes, for example, 1/2 thinning, 1/4 thinning,... In the case where there is a plurality of thinning modes such as (the same applies hereinafter) and one of these thinning modes is selected and output, the pixel defect in each thinning mode as shown in FIG. By storing the coordinate data to be corrected in each table and configuring the defective pixel coordinate data table with these tables, the pixel defect correction processing can be performed by referring to the table corresponding to each thinning mode. it can.
[0065]
Further, at this time, the same coordinate data exists in each table of the defective pixel coordinate data table. However, in order not to overlap the coordinate data of each table, the table having the horizontal and vertical pixels of 1/2 ^ n is used as the head. Next, a table of 1/2 ^ (n-1) is arranged, and this table does not overlap with 1/2 ^ n in the defective pixel coordinate data of 1/2 ^ (n-1). Stores only coordinate data. Similarly, the coordinate data is sequentially stored in each table so as not to overlap.
[0066]
Then, in the designated thinning mode, when pixel defect correction processing is performed using a defective pixel coordinate data table, reference to coordinate data is started from the top table of each table arranged as described above, and sequentially By referring to the coordinate data up to the table corresponding to the designated thinning mode, it is possible to refer to all the coordinate data of the defective pixel that is the target in the thinning mode without overlapping.
[0067]
In the above description, the normal pixel around the defective pixel is searched and its pixel data is acquired. However, the data in each table shown in FIG. 6 and FIG. If the data indicating the replacement position as shown in FIG. 3 is also stored in the form, the efficiency can be further improved.
[0068]
According to the second embodiment as described above, when the pixel defect correction process is performed in the thinning mode, the pixel defect correction process is not performed on the non-target pixels, so that the process can be efficiently performed.
[0069]
FIGS. 8 to 10 show a third embodiment of the present invention. FIG. 8 is a flowchart showing an operation of pixel defect correction processing by the system controller. FIG. 9 is configured for each row direction (vertical direction). FIG. 10 is a diagram showing a defective pixel coordinate data table, and FIG. 10 is a diagram showing a defective pixel coordinate data table configured for each column direction (horizontal direction).
[0070]
In the third embodiment, description of parts that are the same as those in the first and second embodiments described above will be omitted, and only differences will be mainly described.
[0071]
The pixel defect correction apparatus according to this embodiment has a defective pixel coordinate data table classified corresponding to each row or each column using a pointer, preferably corresponding to partial reading. The electrical configuration of the apparatus is the same as that shown in FIG.
[0072]
Next, the operation of the system controller 9 in the pixel defect correction apparatus of this embodiment will be described with reference to the flowchart of FIG.
[0073]
The image data picked up by the image pickup device 2 is taken into the frame memory 5 through the analog processing circuit 3 and the A / D converter 4 (step S21).
[0074]
Horizontal (row) / vertical (column) start coordinates and end coordinates for reading and displaying part of the image data in the frame memory 5 are set (step S22).
[0075]
A pointer to the defective pixel coordinate data table in the start row is acquired from the defective pixel coordinate data index table as shown in FIG. 9 (step S23).
[0076]
Subsequently, it is determined whether or not the currently acquired defective pixel coordinate data table pointer row is an end row (step S24), and if it is an end row, the process proceeds to step S30 described later.
[0077]
On the other hand, if it is not the end line, it is determined whether there is coordinate data of the defective pixel from the pointer to the currently acquired defective pixel coordinate data table (step S25). Goes to step S29 to be described later.
[0078]
If there is defective pixel coordinate data, coordinate data is acquired from the defective pixel coordinate data table of FIG. 9 indicated by the pointer (step S26).
[0079]
It is determined whether or not the acquired coordinate data of the defective pixel is within the range from the start line to the end line of partial reading (step S27), and if it is within the range, pixel defect correction processing is performed ( From step S28), if it is not within the range, the process returns to step S25 without performing the process of step S28.
[0080]
The pixel defect correction processing in step S28 is the same as the processing described in steps S54 to S55 in FIG. 11, and the data of pixels that are normal pixels from the surrounding pixels centering on the coordinate data of the acquired defective pixels. And the pixel data at the coordinate position of the defective pixel is replaced with the acquired pixel data of the normal pixel.
[0081]
If all the coordinate data is processed and there is no unprocessed coordinate data in step S25, the pointer of the defective pixel coordinate table for the next row is obtained from the defective pixel coordinate index table (step S29). Return to step S24.
[0082]
In step S24, when the pointer to the defective pixel coordinate data table obtained in step S29 is the end line, the contents of the frame memory 5 are output (step S30), and this process is ended.
[0083]
In the above description, the defective pixel coordinate data table configured for each row direction (vertical direction) as shown in FIG. 9 is used. However, as shown in FIG. 10, it is configured for each column direction (horizontal direction). It goes without saying that a defective pixel coordinate data table can also be used.
[0084]
In the above description, the normal pixel around the defective pixel is searched and its pixel data is acquired. However, the data in each table shown in FIG. 9 and FIG. If the data indicating the replacement position as shown in FIG. 3 is also stored in the form, the efficiency can be further improved.
[0085]
According to the third embodiment, in the pixel defect correction at the time of outputting the image data by partial reading, it is not necessary to perform the pixel defect correction on the row data or the column data outside the range for displaying the image data. Therefore, the processing speed can be increased.
[0086]
The above-described embodiments as described in detail above include the following inventions.
[0087]
(1) pixel data fetching means for fetching pixel signals from the image sensor as image data into a frame memory;
The defective pixel coordinate data table includes coordinate data in the horizontal and vertical directions of the defective pixel and position data of a normal pixel that replaces the defective pixel, as the defective pixel coordinate data table. Pixel defect correction means for performing pixel defect correction processing for replacing pixel data of defective pixels with pixel data of normal pixels for the image data captured in the frame memory based on the data and position data of normal pixels;
Image data output means for outputting image data subjected to pixel defect correction processing by the pixel defect correction means as normal image data;
A pixel defect correction apparatus comprising:
[0088]
(2) pixel data fetching means for fetching pixel signals from the image sensor as image data into the frame memory;
A defective pixel coordinate data table having a plurality of tables corresponding to the thinning readout mode of the coordinate data in the horizontal direction and the vertical direction of the defective pixel related to the imaging element is provided, and the defective pixel coordinate data table includes a plurality of tables. Pixel defect correction means for performing pixel defect correction processing with reference to only a table necessary for performing thinning readout of the designated mode of
Image data output means for outputting image data subjected to pixel defect correction processing by the pixel defect correction means as normal image data;
A pixel defect correction apparatus comprising:
[0089]
(3) pixel data capturing means for capturing a pixel signal from the image sensor as image data in a frame memory;
A defective pixel coordinate data table having horizontal and vertical coordinate data of defective pixels related to the image sensor as a plurality of tables arranged for each horizontal coordinate or as a plurality of tables arranged for each vertical coordinate is provided. A pixel defect correction unit that performs pixel defect correction processing with reference to only a table necessary for performing a specified partial reading out of a plurality of tables included in the defective pixel coordinate data table, and the pixel defect correction unit. Image data output means for outputting image data subjected to pixel defect correction processing as normal image data;
A pixel defect correction apparatus comprising:
[0090]
(4) The pixel defect correction means further includes normal pixel position data for replacing the defective pixel in the defective pixel coordinate data table, and the defective pixel coordinate data and the normal pixel position data in the defective pixel coordinate data table (2), wherein pixel defect correction processing is performed on the image data fetched into the frame memory to replace pixel data of defective pixels with pixel data of normal pixels. Pixel defect correction device.
[0091]
(5) The pixel defect correction means further includes normal pixel position data for replacing the defective pixel in the defective pixel coordinate data table. The defective pixel coordinate data and the normal pixel position data in the defective pixel coordinate data table (3), wherein pixel defect correction processing is performed on the image data captured in the frame memory to replace pixel data of defective pixels with pixel data of normal pixels. Pixel defect correction device.
[0092]
(6) The plurality of tables corresponding to the thinning readout mode included in the defective pixel coordinate data table are stored so that data in each table do not overlap each other (2) or (4) 2. A pixel defect correcting device according to 1.
[0093]
(7) The pixel defect correcting means includes a plurality of tables corresponding to the thinning readout mode of the defective pixel coordinate data table, a coordinate data table in which both the horizontal direction and the vertical direction are even, and an even number in the horizontal direction. And a coordinate data table in which the vertical direction is odd, a coordinate data table in which the horizontal direction is odd and the vertical direction is even, and a coordinate data table in which both the horizontal direction and the vertical direction are odd numbers. (6) characterized in that, when a table is provided and image data obtained by half-thinning readout is output, pixel defect correction processing is performed with reference to one of the four tables. The pixel defect correction apparatus described.
[0094]
(8) The pixel defect correcting means is configured so that the data stored in the 1/2 ^ k thinning table is not duplicated as a plurality of tables corresponding to the thinning readout mode of the defective pixel coordinate data table. N 1/2 ^ k (k = n, n-1,..., 1) sequentially configuring a 1/2 ^ (k-1) thinning table (n represents a natural number and the symbol ^ represents a power) When a table for thinning out and a table for thinning out are provided and image data is output by 1/2 ^ m (n ≧ m ≧ 1) thinning, the above 1 / k up to k = n,. The pixel defect correction apparatus according to (6), wherein pixel defect correction processing is performed with reference to a 2 ^ k thinning table.
[0095]
(9) Of the plurality of tables included in the defective pixel coordinate data table, selection of a table necessary for partial reading is performed by selecting an index table having the start address of coordinate data in each horizontal direction or the start of coordinate data in each vertical direction The pixel defect correction device according to (3) or (5), which is performed by referring to an index table having addresses.
[0096]
(10) The pixel defect correction device according to (1), (4), or (5), wherein the position data of the normal pixel is a number sequentially assigned to each pixel located in the vicinity of the defective pixel. .
[0097]
According to the invention described in (1), when the pixel data of the defective pixel is replaced with the pixel data of the normal pixel, since the position data of the normal pixel to be replaced in advance is known, the normal pixel is referred to with reference to the defective pixel coordinate data table. Therefore, the processing time can be shortened.
[0098]
According to the invention described in (2), when there are a plurality of thinning-out reading modes, the coordinate data of defective pixels corresponding to each mode is collected for each table, so only the necessary table is referred to. Since it is not necessary to refer to an unnecessary table, pixel defect correction processing can be performed efficiently.
[0099]
According to the invention described in (3), when partial reading is performed, it is necessary to perform partial reading of a plurality of tables in which coordinate data of defective pixels is collected for each horizontal coordinate or each vertical coordinate. Since it is only necessary to refer to the table, and it is not necessary to refer to an unnecessary table, the pixel defect correction process can be performed efficiently.
[0100]
According to the invention described in (4), the same effect as that of the invention described in (2) above can be obtained, and when replacing pixel data of defective pixels with pixel data of normal pixels, position data of normal pixels to be replaced in advance Therefore, it is not necessary to determine whether the pixel is a normal pixel while referring to the defective pixel coordinate data table, and the processing time can be further shortened.
[0101]
According to the invention described in (5), the same effect as that of the invention described in (3) above can be obtained, and the position data of the normal pixel to be replaced in advance when the pixel data of the defective pixel is replaced with the pixel data of the normal pixel. Therefore, it is not necessary to determine whether the pixel is a normal pixel while referring to the defective pixel coordinate data table, and the processing time can be further shortened.
[0102]
According to the invention described in (6), the same effects as those of the invention described in (2) or (4) above are obtained, and the same table is used for each thinning readout mode of the defective pixel coordinate data table. Therefore, the amount of data in the defective pixel coordinate data table can be reduced, and the pixel defect correction processing can be performed efficiently.
[0103]
According to the invention described in (7), the same effects as in the invention described in (6) above can be obtained, and the horizontal pixel and the vertical pixel which are frequently used thinning readout are halved and read out. In this case, since only one table to be processed needs to be referred to, pixel defect correction processing can be performed efficiently.
[0104]
According to the invention described in (8), the same effect as that of the invention described in (6) above can be obtained, and when 1/2 ^ m decimation is performed, 1/2 of k = n,. It suffices to refer to the table for ^ k thinning out, and since the data in each table does not overlap, pixel defect correction processing can be performed efficiently.
[0105]
According to the invention described in (9), in order to achieve the same effect as the invention described in (3) or (5) above and to select a table necessary for partial reading by referring to the index table Thus, unnecessary table data is not read, the amount of data to be processed is reduced, and the time required for pixel defect correction processing can be shortened.
[0106]
According to the invention described in (10), the same effect as the invention described in (1), (4), or (5) can be obtained, and the position of the normal pixel to be replaced can be specified with a small amount of data. .
[0107]
【The invention's effect】
As described above, according to the pixel defect correction device of the present invention described in claim 1, when the pixel data of the defective pixel is replaced with the pixel data of the normal pixel, the position data of the normal pixel to be replaced in advance is known. It is not necessary to determine whether the pixel is a normal pixel while referring to the defective pixel coordinate data table, and the processing time can be shortened.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a pixel defect correction apparatus according to a first embodiment of the present invention.
FIG. 2 is a flowchart showing an operation of pixel defect correction processing by a system controller in the first embodiment.
FIG. 3 is a view showing a defective pixel coordinate data table of the first embodiment.
FIG. 4 is a diagram showing replacement positions allocated around defective pixels in the first embodiment.
FIG. 5 is a flowchart showing an operation of pixel defect correction processing by a system controller in the second embodiment of the present invention.
FIG. 6 is a diagram showing a defective pixel coordinate data table as four choices in the case of performing half-thinning readout in the second embodiment.
FIG. 7 is a diagram showing a defective pixel coordinate data table in the case where thinning-out reading by a power of 2 is performed in the second embodiment.
FIG. 8 is a flowchart showing an operation of pixel defect correction processing by a system controller in the third embodiment of the present invention.
FIG. 9 is a diagram showing a defective pixel coordinate data table configured for each row direction (vertical direction) in the third embodiment.
FIG. 10 is a diagram showing a defective pixel coordinate data table configured for each column direction (horizontal direction) in the third embodiment.
FIG. 11 is a flowchart showing an operation of pixel defect correction processing by a system controller in a conventional pixel defect correction apparatus.
FIG. 12 shows a conventional defective pixel coordinate data table.
[Explanation of symbols]
1 ... Lens system
2 ... Image sensor
3. Analog processing circuit
4 ... A / D converter
5. Frame memory (pixel data fetching means, image data output means)
6. Display memory
7 ... Output processing circuit
8 ... Image sensor driving circuit
9. System controller (pixel defect correction means)
10 ... Personal computer interface

Claims (1)

Pixel data capturing means for capturing a pixel signal from the image sensor as image data in a frame memory;
The defective pixel coordinate data table includes coordinate data in the horizontal and vertical directions of the defective pixel and position data of a normal pixel that replaces the defective pixel, as the defective pixel coordinate data table. Pixel defect correction means for performing pixel defect correction processing for replacing pixel data of defective pixels with pixel data of normal pixels for the image data captured in the frame memory based on the data and position data of normal pixels;
Image data output means for outputting image data subjected to pixel defect correction processing by the pixel defect correction means as normal image data;
A pixel defect correction apparatus comprising:

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