KR100740625B1 - Method for sharing line memory in image processing system - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a line memory sharing method of an image processing system, and to share line memory used for bad pixel processing for 6x6 data and color interpolation processing for 5x5 data. According to the invention, the volume of the system can be reduced.

Line memory, shared, bad pixels, correction, color interpolation

Description

Method for sharing line memory in image processing system

1 is a schematic diagram for explaining a layout of a bad pixel correcting unit and a color interpolation unit in a conventional image processing system;

2 is a configuration diagram of a first embodiment of an image processing system according to the present invention;

3 is a detailed structural diagram of an embodiment of a bad pixel correction unit of FIG. 2;

FIG. 4B is an exemplary view illustrating the separation of the Bayer pattern of FIG. 4A into components having a 3 × 3 structure; FIG.

5 is a detailed structural diagram of an embodiment of the pattern comparison unit of FIG. 3;

6 is a configuration diagram of a second embodiment of an image processing system according to the present invention;

7 is a detailed structural diagram of an embodiment of a bad pixel correction unit of FIG. 6;

8 is a detailed structural diagram of an embodiment of a bad pixel detection unit of FIG. 7;

9 is a detailed structural diagram of an embodiment of the hot pixel detection unit of FIG. 7;

<Explanation of symbols for the main parts of the drawings>

210: bad pixel correction unit 220: color interpolation unit

The present invention relates to a line memory sharing method of an image processing system, and more particularly, to a line memory sharing method of an image processing system for sharing a line memory used in a bad pixel correction and color interpolation apparatus.

The image processing system includes a bad pixel correction unit and a color interpolation unit, and these two devices generally perform the processing sequentially.

1 is a schematic diagram for explaining a layout of a bad pixel corrector and a color interpolator in a conventional image processing system.

As shown in the figure, it includes a bad pixel correcting unit 110 and a color interpolation unit 120 of a conventional image processing system, usually 5x5 data are both input.

Therefore, the bad pixel corrector 110 and the color interpolator 120 require four line memories 130 and 140, respectively.

However, such a conventional image processing system has a problem in that the volume of the system becomes large because a line memory is required for each device.

SUMMARY OF THE INVENTION The present invention has been proposed to solve the above-described problems, and is intended to share a line memory used for bad pixel processing for 6x6 data and color interpolation processing for 5x5 data. Its purpose is to provide a line memory sharing method.

In order to achieve the above object, according to a preferred embodiment of the present invention, a bad pixel correction unit for outputting 1 pixel of data by correcting the bad pixels of the data as 6 × 6 data input, 5 A color interpolation unit for performing color interpolation by inputting x5 data, five line memories used for inputting image data having a 6x6 structure into the bad pixel correction unit, and 5x by the color interpolation unit. A line memory sharing method of an image processing system including four line memories used for inputting image data having five structures, the method comprising: four lines for storing an output of the bad pixel correcting unit and inputting the color interpolation unit Four lines of memory for inputting the bad pixel correcting unit and the color interpolator using the output of the memory as the input of the bad pixel correcting unit. The lines shared memory characterized in that sharing a four line memory for input is provided.

In addition, according to another embodiment of the present invention, a bad pixel correction unit for outputting the 6 × 6 data data by correcting the bad pixels of the data by inputting 6 × 6 data, and 5 × 5 data as input A color interpolation unit for performing color interpolation, five line memories used for inputting 6 × 6 image data into the bad pixel correction unit, and 5 × 5 image data input to the color interpolation unit. A line memory sharing method of an image processing system including four line memories used for performing the above operation, wherein the input of the color interpolation unit is performed by using 5 lines of data among the outputs of the bad pixel correction unit as the input of the color interpolation unit. A line memory sharing method is provided which reduces four line memories for the present invention.

The above objects, features and advantages will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. First of all, in adding reference numerals to the components of each drawing, it should be noted that the same components have the same number as much as possible even if displayed on different drawings. Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is a configuration diagram of a first embodiment of an image processing system according to the present invention.

As shown in the figure, the image processing system of the present invention includes a bad pixel correction unit 210 and a color interpolation unit 220, and includes four line memories 230 and two line memories 240 and 250. It is configured to include). The traveling direction of the line is as shown in FIG. 2.

The defective pixel correcting unit 210 of the present invention outputs a pixel of 1 pixel to a 6x6 mask, which will be described first.

3 is a detailed structural diagram of an embodiment of a bad pixel correction unit of FIG. 2.

As illustrated in the drawing, the bad pixel processing apparatus of the present invention includes a component separator 310, a pattern comparator 320, and a corrector 330.

The component separator 310 separates the input 6 × 6 bayer pattern into four components having a 3 × 3 structure as shown in FIG. 4. FIG. 4A is an exemplary view illustrating a 6 × 6 Bayer pattern image input to FIG. 3, and FIG. 4B is an exemplary view illustrating the separation of the Bayer pattern of FIG. 4A into components having a 3 × 3 structure.

As shown in the figure, the component separator 410 of the present invention uses the same component, i.e., R (red), Gr (G in green line; green), Gb (G in line GB) and the same component. The data is separated into a 3 × 3 data structure composed only of B (blue) components.

In the description of the present invention, assuming that 'B5' of FIG. 4B is assumed to be the center pixel of FIG. 2A will be described, and then generalized.

The pattern comparison unit 420 obtains a pattern of each component data (the distribution of pixel values based on a median. The same applies below), and then compares the pattern of the component including the center pixel with the pattern of other components. The measured value based on the component including the center pixel is obtained, and the measured value based on the center pixel is obtained by comparing the center pixel and the surrounding pixel values in the component including the center pixel. Hereinafter, with reference to the drawings will be described in detail.

5 is a detailed structural diagram of an example of the pattern comparison unit of FIG. 3.

As shown in the drawing, the pattern comparison unit 320 of the present invention includes a median detector 321, an absolute value detector 1 322, a difference value detector 323, a comparison value detector 324, and an external flag generation. The unit 325 includes an absolute value detector 2 326 and an internal flag generator 327. In the drawing, except for the input (Gr, Gb, R, B) signal, the flow of the signal is processed as a single line, but it is obvious to those skilled in the art that various data are included therein. Do.

The median detector 321 detects median values of Gr, R, B, and Gb data, each having an input 3x3 structure. Let the medians corresponding to the above data be M1, M2, M3 and M4, respectively.

The absolute value detection unit 1 322 detects the absolute value Abs_Gri of the value obtained by subtracting the median value M1 from the respective constituent elements (Gri, i = 1 to 9) by explaining the case of Gr data. Similarly for the R, B and Gb data, the absolute values Abs_Ri, Abs_Bi and Abs_Gbi of the respective components (Ri, Bi and Gbi, i = 1 to 9) minus the median values M2, M3 and M4 are detected.

The difference detection unit 323 is a value obtained by subtracting Abs_Gri, Abs_Ri and Abs_Gbi, which are outputs of the absolute value detection unit 1 322 of the remaining data, from Abs_Bi, which is the output of the absolute value detection unit 1 322 of the B data having the center pixel B5, respectively. The absolute values Diff1_i, Diff2_i and Diff3_i are detected.

The comparison value detector 324 generates a value COMP_i obtained by adding the Diff1_i, Diff2_i, and Diff3_i to generate an external flag.

The external flag generator 325 compares the comparison value detected above with the input bad pixel threshold (dead_threshold) and the hot pixel threshold (hot_threshold) to generate a flag for the presence of the bad pixel and the hot pixel. At this time, the bad pixel threshold (dead_threshold) and the hot pixel threshold (hot_threshold) are adjustable values.

That is, the external flag generator 325 compares the comparison value for each element and the bad pixel threshold value respectively and has a comparison value larger than the bad pixel threshold value. When i is 5 (that is, the comparison value for the center pixel) In the case of larger than the bad pixel threshold value, a flag (dead_flag) for the presence of a bad pixel is set to one. Otherwise, dead_flag is zero.

On the other hand, the external flag generator 325 compares the comparison value for each element and the hot pixel threshold value, respectively, and has a comparison value larger than the hot pixel threshold value, where i is 5 (that is, the comparison value for the center pixel is In case of being larger than the hot pixel threshold value, a flag (hot_flag) for whether there is a hot pixel is set to 1. Otherwise hot_flag is zero.

Thereafter, the external flag generator 325 sets the external flag external_flag to 1 when dead_flag or hot_flag is 1. In other cases (that is, when dead_flag and hot_flag are both zero), the external flag is set to 0 and output to the correction unit 330 of FIG.

On the other hand, the absolute value detector 2 326 detects Abs_Ci, which is the absolute value of the value obtained by subtracting the center pixel value from each element (except B5) of the B data including the center pixel B5.

The internal flag generator 327 sets a threshold value thr for the internal flag by using the threshold value Y_threshold for the applied illumination classification and M1 to M4 which are medians of 3 × 3 data, thereby generating an internal flag. do. Y_threshold is system adjustable.

When the arithmetic mean of the median value of each component is defined as Y_m, the internal flag generation unit 327 sets thr to 0 when Y_m is smaller than Y_threshold, and sets thr to 50 otherwise. However, the present invention is not limited thereto, and the value may vary depending on the system. The thr set in this way is compared with the absolute value for each element generated by the absolute value detection unit 2 (326), and when any one of the eight values is smaller than thr, the internal flag (internal_flag) is set to 0. If not (ie, the absolute value for all elements is larger than thr), the internal flag is set to 1 and transmitted to the correction unit 330.

The correction unit 330 outputs the output as the median value of the B data having a 3x3 structure when both the external flag and the internal flag are 1; otherwise, B5 is used as the output of the correction unit 330 as it is.

As described above, the bad pixel correction unit 210 of the present invention receives 6x6 data as an input, and its output is 1 pixel of data. When the line corresponding to this output is referred to as the E line of FIG. 2, the bad pixel correction unit 210 of the image processing system of the present invention has already output the A to D lines, and three of these lines are B to The D line is stored in four line memories.

Accordingly, the color interpolation unit 220 having 5 × 5 data as input receives the A through E lines, and the bad pixel correcting unit 210 of the present invention already calculates the data calculated by the bad pixel correcting unit 210. Lines B to D, an E line currently being operated, and F and G lines that have not yet been calculated are input. Therefore, according to the present invention, the inputs of the bad pixel correcting unit 210 and the color interpolator 220 are shared by four line memories 230, and are required for input of the bad pixel correcting unit 210. Two more lines of memory are needed, the F line and the A line required for color interpolation.

Therefore, according to the present invention, in a system requiring eight line memories, two line memories can be reduced by allowing four to be shared. In addition, according to the related art, the bad pixel compensator requires 5 line memories to input 6 × 6 data, and the color interpolator requires 4 line memories to input 5 × 5 data. Although line memory is required, according to the present invention, since four line memories can be shared, three line memories can be reduced.

On the other hand, the bad pixel correction unit 210 of the present invention has been described for the case of input 6 × 6 data, but according to the general bad pixel processing apparatus that inputs 5 × 5 data, a total of five line memory is required Thus, three line memories can be reduced.

6 is a configuration diagram of a second embodiment of an image processing system according to the present invention.

As shown in the figure, the image processing system of the present invention includes a bad pixel correction unit 610 and a color interpolation unit 620, and includes five line memories 630. The traveling direction of the line is as shown in FIG. 6.

The defective pixel correcting unit 610 of the present invention outputs 6x6 data to a 6x6 mask, which will be described first.

7 is a detailed structural diagram of an embodiment of a bad pixel correction unit of FIG. 6.

As shown in the drawing, the processing apparatus according to the present invention includes a component separator 710, a bad pixel detector 720, and a hot pixel detector 730.

The component separator 710 separates the input 6 × 6 bayer pattern into four components having a 3 × 3 structure as shown in FIG. 4. Hereinafter, the Gr, R, B, and Gb component data of the 3x3 structure will be referred to as C1, C2, C3, and C4, respectively, for convenience.

The bad pixel detection unit 720 obtains a pattern of each component data, compares patterns of other components, obtains a measurement value based on each component, and compares the measured values to determine whether the pixel is a bad pixel. Hereinafter, with reference to the drawings will be described in more detail.

8 is a detailed structural diagram of an exemplary bad pixel detection unit of FIG. 7.

As shown in the drawing, the bad pixel detection unit 720 of the present invention includes a median value detection unit 721, an absolute value detection unit 722, a comparison value detection unit 723, a threshold value setting unit 724, and an output determination unit ( 725). Except for the input signals (C1, C2, C3, C4) in the drawings, the signal flow is processed as one line, but it is obvious to those skilled in the art that various data are included therein. .

The median detector 721 detects median values of C1, C2, C3, and C4 data having an input 3x3 structure, respectively. Let the medians corresponding to the above data be M1, M2, M3 and M4, respectively.

For example, the absolute value detection unit 722 detects the absolute value Abs_1i of the value obtained by subtracting the median value M1 from each of the constituent elements Gri, i = 1 to 9 when explaining the case of C1 data. Similarly for the C2, C3 and C4 data, the absolute values Abs_2i, Abs_3i and Abs_4i of the values obtained by subtracting the median values M2, M3 and M4 from the respective constituent elements (Ri, Bi and Gbi, i = 1 to 9) are detected.

The comparison value detector 723 obtains a comparison value by obtaining an absolute value of a value obtained by subtracting the other output from one output with respect to the output of the absolute value detector 722 obtained above. That is, the absolute values of the values obtained by subtracting the remaining Abs_2i, Abs_3i and Abs_4i from Abs_1i are calculated, and the sums thereof are calculated to obtain COMP_1i. In this manner, COMP_2i, COMP_3i and COMP_4i are obtained.

The threshold setting unit 724 sets the threshold value thr for the internal flag by using the threshold Y_threshold for illuminance classification applied and M1 to M4 which are medians of 3x3 data. Y_threshold is system adjustable. When the arithmetic mean of the median value of each component data is defined as Y_m, the threshold value setting unit 724 sets thr to 0 when Y_m is smaller than Y_threshold, and sets thr to 50 otherwise. However, the present invention is not limited thereto, and the value may vary depending on the system.

The output determination unit 725 compares the four comparison values detected by the comparison value detection unit 723 and the applied dead pixel threshold value (dead_threshold), respectively. Outputs That is, a 3 × 3 Cj (j = 1 to 4) image is output as it is. Therefore, the data output by the output determination unit 125 becomes an original image of 6 × 6 size. In the following description, 'Size3 × 3_Cj1' refers to the first component of Cj data having a size of 3 × 3.

If there is a comparison value larger than the bad pixel threshold, the output determination unit 725 reconstructs the image, and takes a method of constructing pixels for each element.

In order to configure Size3 × 3_Cj1 (the first element of Size3 × 3_Cj, j = 1 to 4), the output determination unit 725 is configured to include the surrounding elements (i.e., Size3 × 3_Cj2, Size3 × 3_Cj5 and The absolute value of the value minus Size3 × 3_Cj4) is compared with the threshold value thr, and if any one is smaller than the threshold value, the original input value, Size3 × 3_Cj1, is output; The median of 3_Cj2, Size3x3_Cj4, and Size3x3_Cj5 is output.

In addition, in order to configure Size3 × 3_Cj2 (the second element of Size3 × 3_Cj, j = 1 to 4), the output determining unit 725 has a peripheral element (that is, Size3 × 3_Cj1, Size3 × 3_Cj3, Size3) in the second element. The absolute value of the value minus × 3_Cj4, Size3 × 3_Cj5 and Size3 × 3_Cj6) is compared with the threshold thr, respectively, and if any one is smaller than the threshold, the original input value, Size3 × 3_Cj2, is output. In this case, the median values of the surrounding elements Size3x3_Cj1, Size3x3_Cj3, Size3x3_Cj4, Size3x3_Cj5, and Size3x3_Cj6 are output. In this way, an output value is determined for all the elements of Size3 × 3_Cj (j = 1 to 4), and the Size3 × 3_Cj (j = 1 to 4) data is transmitted to the hot pixel determination unit 730 of FIG.

The hot pixel determiner 730 obtains a pattern of input component data, compares patterns of other components, obtains measurement values based on each component, and compares the measured values to determine whether the pixels are hot pixels. Hereinafter, with reference to the drawings will be described in more detail.

9 is a detailed structural diagram of an embodiment of the hot pixel detection unit of FIG. 7.

As shown in the figure, the hot pixel detector 730 of the present invention includes a median detector 731, an absolute detector 732, a comparison detector 733, and an output determiner 734. In the drawing, except for the input signals (Size3 × 3C1, Size3 × 3C2, Size3 × 3C3, Size3 × 3C4), the signal flow is treated as one line, but various data are included in the drawings. Self-explanatory to those who have knowledge.

The median value detector 731 detects median values of C1, C2, C3, and C4 data having an input 3x3 structure, respectively. Let the median values corresponding to the above data be M5, M6, M7 and M8, respectively.

For example, the absolute value detector 732 detects the absolute value Abs_5i of the value obtained by subtracting the median value M5 from each of the constituent elements (Size3 × 3C1i, i = 1 to 9). Similarly for Size3 × 3C2, Size3 × 3C3, and Size3 × 3C4 data, the absolute value of each component (Size3 × 3C2i, Size3 × 3C3i and Size3 × 3C4i, i = 1 to 9) minus the median values M6, M7, and M8, respectively The values Abs_6i, Abs_7i and Abs_8i are detected.

The comparison value detector 733 obtains an absolute value of the output obtained by subtracting the other output from the output of the absolute value detector 732 obtained above, and adds the absolute value to obtain the comparison value. That is, the absolute values of the values obtained by subtracting the remaining Abs_6i, Abs_7i, and Abs_8i from Abs_5i are calculated, and the sums are calculated to obtain COMP_5i. In this manner, COMP_6i, COMP_7i and COMP_8i are obtained.

The output determination unit 734 compares the four comparison values detected by the comparison value detection unit 733 and the applied hot pixel threshold value hot_threshold, respectively, and outputs the original image when there is no comparison value larger than the hot pixel threshold value. do. That is, a 3 × 3 Cj (j = 1 to 4) image is output as it is. Therefore, the data output from the output determination unit 734 becomes an original image of 6x6 size.

If there is a comparison value larger than the hot pixel threshold, the output determination unit 734 reconstructs the image, and takes a method of constructing pixels for each element.

In order to construct Size3 × 3_Cj1 (the first element of Size3 × 3_Cj, j = 1 to 4), the output determining unit 734 is configured to include the peripheral elements (i.e., Size3 × 3_Cj2, Size3 × 3_Cj5 and The absolute value of the value obtained by subtracting Size3 × 3_Cj4) is compared with the threshold value thr determined and transmitted by the threshold value determination unit 724 of the bad pixel detection unit 720, respectively. The value Size3x3_Cj1 is output. Otherwise, the median values of the surrounding elements Size3x3_Cj2, Size3x3_Cj4 and Size3x3_Cj5 are output.

Further, in order to configure Size3 × 3_Cj2 (the second element of Size3 × 3_Cj, j = 1 to 4), the output determining unit 734 includes the surrounding elements (that is, Size3 × 3_Cj1 and Size3 × in FIG. 5). Compare the absolute values of 3_Cj3, Size3 × 3_Cj4, Size3 × 3_Cj5, and Size3 × 3_Cj6) with the threshold thr, and if any one is smaller than the threshold, output the original input, Size3 × 3_Cj2. Otherwise, the median values of the surrounding elements Size3x3_Cj1, Size3x3_Cj3, Size3x3_Cj4, Size3x3_Cj5, and Size3x3_Cj6 are output. In this way, the output values are determined for all the members of Size3x3_Cj (j = 1-4), and the Size3x3_Cj (j = 1-4) data can be output. This outputs 6x6 data.

Accordingly, the color interpolator 620 of FIG. 6 may perform color interpolation by inputting five of the outputs of six lines of the bad pixel corrector.

According to the second embodiment of the present invention, since only five line memories are required for the bad pixel processing, three conventional eight individually used line memories can be reduced.

In addition, according to the related art, the bad pixel compensator requires 5 line memories to input 6 × 6 data, and the color interpolator requires 4 line memories to input 5 × 5 data. Although line memory is required, according to the present invention, since five line memories can be shared, four line memories can be reduced.

The present invention described above is not limited to the above-described embodiments and the accompanying drawings, and various substitutions, modifications, and changes can be made in the art without departing from the technical spirit of the present invention. It will be clear to those of ordinary knowledge.

The present invention as described above has the effect of reducing the volume of the system by sharing the line memory used for bad pixel processing and color interpolation processing.

Claims (2)

A bad pixel correction unit for correcting a bad pixel of the data by inputting 6 × 6 data and outputting 1 pixel of data, a color interpolation unit for performing color interpolation by inputting 5 × 5 data, and An image including five line memories used to input image data having a 6 × 6 structure into a bad pixel correction unit, and four line memories used to input image data having a 5 × 5 structure into a color interpolation unit. In the line memory sharing method of the processing system, Four line memories for input of the bad pixel correction unit and four line memories for storing the output of the bad pixel correction unit and inputting the color interpolation unit to the bad pixel correction unit. A line memory sharing method characterized by sharing four line memories for input of a color interpolator. A bad pixel correction unit for correcting bad pixels of the data by inputting 6 × 6 data and outputting 6 × 6 data data, a color interpolation unit for performing color interpolation by inputting 5 × 5 data; 5 line memories used to input 6 × 6 structure image data to the bad pixel correcting unit, and 4 line memories used to input 5 × 5 structure image data to the color interpolation unit. In the line memory sharing method of the image processing system, And reducing the four line memories for input of the color interpolator by using five lines of data among the outputs of the bad pixel corrector as the input of the color interpolator.

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