A cluster search method and circuit integrated on a CMOS pixel detector chip

Abstract

The application discloses a cluster searching method and circuit integrated on a CMOS pixel detector, and relates to the technical field of cluster searching.The method comprises the following steps: obtaining a plurality of initial pixels on the CMOS pixel detector; judging each initial pixel as a blank pixel, a fire pixel or a potential seed pixel; if the pixel is a potential seed pixel, judging whether the potential seed pixel is a seed pixel under a 3*3 window; if a plurality of pixels adjacent to the seed pixel under the 3*3 window are all virtual seed pixels in the 3*3 window, the 3*3 seed pixel is a seed pixel of a 5*5 window; marking all adjacent fire pixels of the seed pixels of the 5*5 window, and completing the search of the cluster in the detector chip.The application can realize on-chip integration and real-time search, and can realize the positioning of the gap between the blank pixels under the cluster searching window.

Description

Technical Field

[0001] This invention relates to the field of cluster search technology, and in particular to a cluster search method and circuit integrated on a CMOS pixel detector. Background Technology

[0002] Reference Figure 1-3 A cluster is information about a single particle hitting a detector in high-energy physics experiments. In applications of CMOS pixel detector chips, such as those used in the International Linear Accelerator (ILC), high-energy charged particles are incident on the CMOS pixel detector. The particle energy deposition generates 70–80 hole-hole pairs per micrometer. The movement of these charges causes several adjacent pixels to form "fired pixels," which together constitute a cluster. This cluster information can be used to reconstruct particle motion tracks and perform subsequent tasks such as particle identification.

[0003] Reference 1, "Performance of the reconstruction algorithms of the FIRST experiment pixel sensors vertex detector," discloses a cluster finding algorithm based on the "first neighbor" approach. The algorithm locates the initial pixel by sequentially traversing all its neighboring pixels to achieve cluster finding. Its drawback is that the sequential traversal of all neighboring pixels and the complex iterative process limit this method to offline implementation, making on-chip integration on a CMOS pixel detector chip impossible.

[0004] Reference 2, "A 2-D clustering algorithm for data reconstruction in vertex detector of ILC," proposes an on-chip clustering algorithm based on a column-level ADC architecture. The paper utilizes an on-chip register structure and compares pixels row by row to determine the initial pixel and find the cluster within a 5×5 window. This method enables on-chip integration and cluster finding of a CMOS pixel detector chip. Its drawback is that it cannot guarantee the detection of gaps between the initial pixel and the lit pixel within the 5×5 window. Summary of the Invention

[0005] This invention provides a cluster search method for on-chip integration of a CMOS pixel detector, which solves the problems of existing cluster search methods that cannot achieve on-chip integration and cannot identify the gaps between blank pixels belonging to the same cluster.

[0006] This invention provides a cluster search method integrated on-chip in a CMOS pixel detector, comprising the following steps:

[0007] Acquire multiple initial pixels on the CMOS pixel detector;

[0008] The pixel value of each initial pixel is compared with the noise pixel threshold and the seed pixel threshold. Based on the comparison result, the initial pixel is determined to be a blank pixel, a burning pixel, or a potential seed pixel.

[0009] If the initial pixel is a potential seed pixel and its pixel value is greater than the pixel values ​​of its 8 neighboring pixels, then the potential seed pixel is determined to be a seed pixel in a 3×3 window.

[0010] The pixel value of the seed pixel under the 3×3 window is passed to multiple adjacent burning pixels to replace the pixel values ​​of multiple adjacent burning pixels. It is then determined whether the adjacent burning pixels are virtual seed pixels of the 3×3 window.

[0011] If multiple adjacent burning pixels of a seed pixel under a 3×3 window are virtual seed pixels of the 3×3 window, then the seed pixel under the 3×3 window is the seed pixel of the 5×5 window.

[0012] Mark the adjacent burning pixels of the seed pixels in all 5×5 windows to complete the search for clusters in the detector chip.

[0013] Preferably, the pixel value of each initial pixel is compared with a noise pixel threshold and a seed pixel threshold, and the initial pixel is determined to be a blank pixel, a burning pixel, or a potential seed pixel based on the comparison result, including the following steps:

[0014] The pixel value of each initial pixel is compared with the noise pixel threshold. If the initial pixel value is greater than the noise pixel threshold, the initial pixel is a burning pixel; otherwise, the initial pixel is a blank pixel.

[0015] Each ignited pixel is compared with a seed pixel threshold. If the pixel value of the ignited pixel is greater than the seed pixel threshold, then the ignited pixel is a potential seed pixel.

[0016] Preferably, if the initial pixel is a potential seed pixel and the pixel value of the potential seed pixel is not greater than the pixel values ​​of 8 adjacent pixels, then the potential seed pixel is determined to be a fire pixel.

[0017] Preferably, determining whether the burning pixel is a virtual seed pixel of a 3×3 window includes the following steps:

[0018] If there is exactly one seed pixel in the 3×3 window among the 8 neighboring pixels of the burning pixel, then the pixel value of the burning pixel is replaced by the pixel value of the seed pixel in the 3×3 window.

[0019] If the pixel value of the replaced burning pixel is not less than the pixel values ​​of 8 adjacent pixels, then the replaced burning pixel is the virtual seed pixel of the 3×3 window, and the result is fed back to the 8 adjacent pixels.

[0020] Preferably, if there are multiple or no seed pixels under the 3×3 window among the eight adjacent pixels of the burning pixel, the pixel is judged as a blank pixel.

[0021] Preferably, if the pixel value of the replaced burning pixel is less than the pixel values ​​of the 8 adjacent pixels, then the replaced burning pixel is not the virtual seed pixel of the 3×3 window, and this result is fed back to the 8 adjacent pixels.

[0022] A cluster search circuit integrated on-chip in a CMOS pixel detector includes multiple pixel modules integrated on a silicon wafer, wherein the multiple pixel modules form an array, and each pixel module includes:

[0023] The pixel acquisition module is used to acquire multiple initial pixels on the CMOS pixel detector.

[0024] The first judgment module is used to compare the pixel value of each initial pixel with the noise pixel threshold and the seed pixel threshold, and determine whether the initial pixel is a blank pixel, a burning pixel or a potential seed pixel based on the comparison result.

[0025] The second judgment module is used to receive the judgment result of the first judgment module. If the initial pixel is a potential seed pixel and the pixel value is greater than the pixel value of 8 adjacent pixels, then the potential seed pixel is judged to be a seed pixel under the 3×3 window.

[0026] The third judgment module is used to pass the pixel value of the seed pixel under the 3×3 window to multiple adjacent burning pixels, replace the pixel value of multiple adjacent burning pixels, and determine whether the adjacent burning pixels are virtual seed pixels of the 3×3 window.

[0027] The fourth judgment module is used to receive the judgment result of the third judgment module. If multiple adjacent fire pixels of the seed pixel under the 3×3 window are virtual seed pixels in the 3×3 window, then the 3×3 seed pixel is the seed pixel of the 5×5 window.

[0028] The marking module is used to mark the adjacent burning pixels of all seed pixels in the 5×5 window, thus completing the search for clusters in the detector chip.

[0029] Preferably, the first determination module includes:

[0030] The first comparator is used to compare the pixel value of the initial pixel with the noise pixel threshold to determine whether the initial pixel is a blank pixel or a burning pixel.

[0031] The second comparator is used to compare the pixel value of the burning pixel with the seed pixel threshold to determine whether the burning pixel is a potential seed pixel.

[0032] The second judgment module includes:

[0033] A multiplexer is used to receive the pixel values ​​of eight adjacent initial pixels and the pixel values ​​of potential seed pixels, and output the pixel value of the potential seed pixel.

[0034] Four third comparators are used to receive the pixel values ​​of the four adjacent pixels in the four directions and compare the pixel value of the potential seed pixel with the pixel values ​​of the four surrounding initial pixels.

[0035] The first AND operator is used to receive the comparison results of the four third comparators and the third comparators in the surrounding neighboring pixels, and to determine whether the potential seed pixel is a seed pixel in the 3×3 window.

[0036] Preferably, it also includes an OR operator, used to receive the result of the first AND operator of the eight surrounding adjacent pixels, and determine whether there is a seed pixel under a 3×3 window among the adjacent pixels around the burning pixel;

[0037] The third judgment module is the same as the second judgment module;

[0038] The multiplexer is also used to receive the judgment result of the OR operator and the pixel values ​​of the eight surrounding neighboring pixels and the pixel value of the pixel in which it is located, and output the pixel value of the seed pixel in the 3×3 window of the surrounding neighboring pixels to replace the value of the current pixel.

[0039] The four third comparators are also used to receive the pixel values ​​of four adjacent pixels in four directions, and compare the replaced pixel value with the pixel values ​​of the four surrounding pixels.

[0040] The first AND operator is also used to receive multiple comparison results from four third comparators and the third comparators in the surrounding adjacent pixels, and to determine whether the replaced pixel value is a virtual seed pixel of a 3×3 window.

[0041] Preferably, the fourth judgment module includes:

[0042] The second AND operator is used to receive the result of the first AND operator from the eight surrounding neighboring pixels and determine whether the current pixel is a seed pixel in the 5×5 window.

[0043] Compared with the prior art, the beneficial effects of the present invention are:

[0044] This invention simultaneously identifies blank pixels, burning pixels, or potential seed pixels from multiple initial pixels on a CMOS pixel detector. For potential seed pixels, a 3×3 window is used for seed pixel identification. The pixel values ​​of these seed pixels are then passed to multiple adjacent burning pixels. For each adjacent burning pixel, a 3×3 window is used for virtual seed pixel identification. This virtual seed pixel design enables seed pixel identification within a 5×5 window and the determination of the gaps between blank pixels in burning pixels. This invention allows for on-chip integration and real-time searching, and can locate the gaps between blank pixels in burning pixels within a cluster search window. Attached Figure Description

[0045] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0046] Figure 1 This is a schematic diagram of a commonly used array structure for CMOS pixel detectors;

[0047] Figure 2 This is a cross-sectional view of the track of charged particles in a CMOS pixel detector and the formation process of ignited pixels.

[0048] Figure 3 A top view showing the shape of a cluster;

[0049] Figure 4 This is a flowchart of a cluster search method integrated on-chip for a CMOS pixel detector according to the present invention.

[0050] Figure 5 This is a schematic diagram of the structure of an on-chip cluster search circuit for a CMOS pixel detector according to the present invention.

[0051] Figure 6 This is a schematic diagram of the pixel type determination process in this embodiment;

[0052] Where: (a): blank pixel, on fire pixel or potential seed pixel; (b): seed pixel under 3×3 window; (c): virtual seed pixel of 3×3 window; (d): seed pixel of 5×5 window. Detailed Implementation

[0053] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0054] Reference Figure 4 This invention provides an on-chip integrated cluster search method for CMOS pixel detectors, enabling real-time on-chip integrated cluster search for high-energy physics CMOS pixel detector chips. Specifically, it includes the following steps:

[0055] Step 1: Acquire multiple initial pixels on the CMOS pixel detector.

[0056] Step 2: Compare the pixel value of each initial pixel with the noise pixel threshold. If the pixel value is greater than the noise pixel threshold, the initial pixel is a burning pixel; otherwise, the initial pixel is a blank pixel. Compare the burning pixel with the seed pixel threshold. If the pixel value is greater than the seed pixel threshold, the pixel is a potential seed pixel.

[0057] Step 3: The potential seed pixel is compared with its eight neighboring pixel values. If the pixel is greater than its eight neighboring pixels, it becomes the seed pixel for the 3×3 window. This pixel value is then passed to neighboring burning pixels, replacing their values. The replaced pixel values ​​are compared with their neighboring burning pixels. If these replaced pixels are not less than their neighboring pixels, they become virtual seed pixels for the 3×3 window. If all neighboring burning pixels of the seed pixel in the 3×3 window are virtual seed pixels in the 3×3 window, then this 3×3 seed pixel becomes the seed pixel for the 5×5 window, and its neighboring burning pixels in the 5×5 window form a cluster.

[0058] Step 4: All burning pixels receive the calculation results from 8 neighboring pixels. If there is a seed pixel under a 3×3 window among the neighboring pixels, the pixel value of that pixel is replaced by the seed pixel value under the 3×3 window, and the pixel value is compared with the neighboring pixel values. If it is not less than the neighboring burning pixel, the burning pixel becomes the virtual seed pixel in the 3×3 window, and the result is fed back to the 8 neighboring pixels.

[0059] Example

[0060] Reference Figure 6 (a) All pixels are compared with the noise pixel threshold and the seed pixel threshold. P0 and P1 are greater than the seed pixel threshold and are marked as potential seed pixels. P2, P3 and P4 are greater than the noise pixel threshold but less than the seed pixel threshold and are marked as on fire pixels.

[0061] Reference Figure 6 (b) The potential seed pixel is compared with its 8 neighboring pixels. If it is greater than the 8 neighboring pixels, then the pixel is the seed pixel in the 3×3 window. If P0 is greater than the 8 neighboring pixels, then P0 is the seed pixel in the 3×3 window. If P1 is less than the neighboring pixel P0, then P1 is not the seed pixel in the 3×3 window.

[0062] Reference Figure 6 (c) The value of the seed pixel P0 in the 3×3 window is passed to the burning pixel in the neighboring pixels and its pixel value is replaced. The value of P0 is passed to the pixel positions P1, P3, and P4 and their pixel values ​​are replaced. The replacement values ​​are compared with their neighboring pixels. If the replacement value P0 of the pixel positions P1, P3, and P4 is not less than its neighboring pixel, then the pixels P1, P3, and P4 are the virtual seed pixels of the 3×3 window.

[0063] Reference Figure 6 (d) The seed pixel in a 3×3 window receives the operation results of its neighboring pixels. If its neighboring pixels are all virtual seed pixels of the 3×3 window, then the pixel is the seed pixel of the 5×5 window. The pixels adjacent to P0 (P1, P3, P4) are all virtual seed pixels of the 3×3 window, so P0 is the seed pixel of the 5×5 window.

[0064] Reference Figure 5 This invention also provides an on-chip cluster search circuit for a CMOS pixel detector. It includes multiple pixel modules integrated on a silicon wafer, forming an array. Each pixel module includes a pixel acquisition module, a first judgment module, a second judgment module, a third judgment module, a fourth judgment module, and a marking module.

[0065] The pixel acquisition module is used to acquire multiple initial pixels on the CMOS pixel detector.

[0066] The first judgment module is used to compare the pixel value of each initial pixel with the noise pixel threshold and the seed pixel threshold, and determine whether the initial pixel is a blank pixel, a burning pixel or a potential seed pixel based on the comparison result.

[0067] The second judgment module is used to receive the judgment result of the first judgment module. If the initial pixel is a potential seed pixel and the pixel value is greater than the pixel value of 8 adjacent pixels, then the potential seed pixel is judged to be a seed pixel under the 3×3 window.

[0068] The third judgment module is used to pass the pixel value of the seed pixel under the 3×3 window to multiple adjacent burning pixels, replace the pixel values ​​of multiple adjacent burning pixels, and determine whether the adjacent burning pixels are virtual seed pixels of the 3×3 window.

[0069] The fourth judgment module is used to receive the judgment result of the third judgment module. If multiple adjacent fire pixels of the seed pixel under the 3×3 window are virtual seed pixels in the 3×3 window, then the 3×3 seed pixel is the seed pixel of the 5×5 window.

[0070] The marking module marks adjacent burning pixels in all 5×5 windows, completing the search for clusters in the detector chip.

[0071] The first judgment module includes a first comparator (i.e., comparator 1) and a second comparator (i.e., comparator 2).

[0072] The first comparator is used to compare the pixel value of the initial pixel with the noise pixel threshold to determine whether the initial pixel is a blank pixel or a burning pixel.

[0073] The second comparator is used to compare the pixel value of the burning pixel with the seed pixel threshold to determine whether the burning pixel is a potential seed pixel.

[0074] The second decision module includes a multiplexer (multiplexing module), four third comparators (i.e., comparators 3-6), and a first AND operator (i.e., AND operation module 2).

[0075] The multiplexer is used to receive the pixel values ​​of the eight surrounding initial pixels and the pixel values ​​of the potential seed pixel, and output the pixel value of the potential seed pixel.

[0076] Four third comparators are used to receive the pixel values ​​of the four adjacent pixels in the four directions and compare the pixel value of the potential seed pixel with the pixel values ​​of the four surrounding initial pixels. The comparison is made with the upper adjacent pixel, the upper right adjacent pixel, the right adjacent pixel, and the lower right adjacent pixel, while the corresponding comparisons are performed based on the comparators integrated within the lower adjacent pixel, the lower left adjacent pixel, the left adjacent pixel, and the upper left adjacent pixel.

[0077] The first AND operator is used to receive the comparison results of the four third comparators and the third comparators in the surrounding neighboring pixels, and to determine whether the potential seed pixel is a seed pixel in the 3×3 window.

[0078] The OR operator is used to receive the result of the AND operation module of the eight surrounding adjacent pixels and determine whether there is a seed pixel under a 3×3 window among the adjacent pixels around the burning pixel.

[0079] The third judgment module is the same as the second judgment module, except that the timing is different.

[0080] The multiplexer is also used to receive the judgment result of the OR operator, as well as the pixel values ​​of the eight surrounding neighboring pixels and the pixel value of the current pixel, and outputs the pixel value of the seed pixel in the 3×3 window of the surrounding neighboring pixels to replace the current pixel value.

[0081] The four third comparators are also used to receive the pixel values ​​of the four adjacent pixels in the four directions, and compare the replaced pixel value with the pixel values ​​of the four surrounding pixels.

[0082] The first AND operator is also used to receive multiple comparison results from the four third comparators and the third comparators in the surrounding adjacent pixels, and to determine whether the replacement pixel value is a virtual seed pixel of the 3×3 window.

[0083] The fourth judgment module includes a second AND operator (AND operator module 1), which is used to receive the first AND operator result of the eight surrounding adjacent pixels and determine whether the current pixel is a seed pixel under the 5×5 window.

[0084] In this embodiment, the first comparator, the second comparator, the OR operator, the multiplexer, the four third comparators, the first AND operator, and the second AND operator can all be implemented using MOS transistors.

[0085] If the pixel is on fire, it receives the result of the AND operation module 2 of the adjacent 8 pixels and operates in the OR operation module. If the result is true, it indicates that there is a seed pixel under a 3×3 window among the adjacent pixels. The pixel selects the seed pixel value under the adjacent 3×3 window through the multiplexer and replaces the pixel value. The replaced pixel value is compared with the adjacent pixels, and the comparison result is operated in the AND operation module 2. If the result is true, the on fire pixel is a virtual seed pixel under a 3×3 window, and the result is fed back to the adjacent pixels.

[0086] The seed pixel under the 3×3 window performs an AND operation on the result of the AND operation module 2 of the 8 adjacent pixels in the AND operation module 1. If the result is true, it indicates that the 8 adjacent pixels are all virtual seed pixels under the 3×3 window. Then the seed pixel under the 3×3 window is the seed pixel of the 5×5 window, and the adjacent burning pixels in the window fill the 5×5 cluster.

[0087] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0088] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A cluster search method integrated on-chip in a CMOS pixel detector, characterized in that, Includes the following steps: Acquire multiple initial pixels on the CMOS pixel detector; The pixel value of each initial pixel is compared with the noise pixel threshold and the seed pixel threshold. Based on the comparison result, the initial pixel is determined to be a blank pixel, a burning pixel, or a potential seed pixel. If the initial pixel is a potential seed pixel and its pixel value is greater than the pixel values ​​of its 8 neighboring pixels, then the potential seed pixel is determined to be a seed pixel in a 3×3 window. The pixel value of the seed pixel under the 3×3 window is passed to multiple adjacent burning pixels to replace the pixel values ​​of multiple adjacent burning pixels. It is then determined whether the adjacent burning pixels are virtual seed pixels of the 3×3 window. If multiple adjacent burning pixels of a seed pixel under a 3×3 window are virtual seed pixels of the 3×3 window, then the seed pixel under the 3×3 window is the seed pixel of the 5×5 window. Mark the adjacent burning pixels of the seed pixels in all 5×5 windows to complete the search for clusters in the detector chip.

2. The cluster search method for on-chip integration of a CMOS pixel detector as described in claim 1, characterized in that, The pixel value of each initial pixel is compared with the noise pixel threshold and the seed pixel threshold. Based on the comparison result, the initial pixel is determined to be a blank pixel, a burning pixel, or a potential seed pixel. This includes the following steps: The pixel value of each initial pixel is compared with the noise pixel threshold. If the pixel value of the initial pixel is greater than the noise pixel threshold, the initial pixel is a burning pixel; otherwise, the initial pixel is a blank pixel. Each ignited pixel is compared with a seed pixel threshold. If the pixel value of the ignited pixel is greater than the seed pixel threshold, then the ignited pixel is a potential seed pixel.

3. The cluster search method for on-chip integration of a CMOS pixel detector as described in claim 1, characterized in that, If the initial pixel is a potential seed pixel, and the pixel value of the potential seed pixel is not greater than the pixel values ​​of its 8 neighboring pixels, then the potential seed pixel is determined to be a burning pixel.

4. The cluster search method for on-chip integration of a CMOS pixel detector as described in claim 3, characterized in that, Determining whether the burning pixel is a virtual seed pixel of a 3x3 window includes the following steps: If there is exactly one seed pixel in the 3×3 window among the 8 neighboring pixels of the burning pixel, then the pixel value of the burning pixel is replaced by the pixel value of the seed pixel in the 3×3 window. If the pixel value of the replaced burning pixel is not less than the pixel values ​​of 8 adjacent pixels, then the replaced burning pixel is the virtual seed pixel of the 3×3 window, and the result is fed back to the 8 adjacent pixels.

5. The cluster search method for on-chip integration of a CMOS pixel detector as described in claim 4, characterized in that, If there are multiple or no seed pixels within the 3×3 window among the 8 neighboring pixels of the burning pixel, then the pixel is judged as a blank pixel.

6. The cluster search method for on-chip integration of a CMOS pixel detector as described in claim 4, characterized in that, If the pixel value of the replaced burning pixel is less than the pixel values ​​of its 8 neighboring pixels, then the replaced burning pixel is not the virtual seed pixel of the 3×3 window, and the result is fed back to the 8 neighboring pixels.

7. A cluster search circuit integrated on-chip in a CMOS pixel detector, characterized in that, Includes multiple pixel modules integrated on a silicon wafer, wherein the multiple pixel modules form an array, and each pixel module includes: The pixel acquisition module is used to acquire multiple initial pixels on the CMOS pixel detector. The first judgment module is used to compare the pixel value of each initial pixel with the noise pixel threshold and the seed pixel threshold, and determine whether the initial pixel is a blank pixel, a burning pixel or a potential seed pixel based on the comparison result. The second judgment module is used to receive the judgment result of the first judgment module. If the initial pixel is a potential seed pixel and the pixel value is greater than the pixel value of 8 adjacent pixels, then the potential seed pixel is judged to be a seed pixel under the 3×3 window. The third judgment module is used to pass the pixel value of the seed pixel under the 3×3 window to multiple adjacent burning pixels, replace the pixel value of multiple adjacent burning pixels, and determine whether the adjacent burning pixels are virtual seed pixels of the 3×3 window. The fourth judgment module is used to receive the judgment result of the third judgment module. If multiple adjacent fire pixels of the seed pixel under the 3×3 window are virtual seed pixels in the 3×3 window, then the 3×3 seed pixel is the seed pixel of the 5×5 window. The marking module is used to mark the adjacent burning pixels of all seed pixels in the 5×5 window, thus completing the search for clusters in the detector chip.

8. The cluster search circuit integrated on-chip in a CMOS pixel detector as described in claim 7, characterized in that, The first judgment module includes: The first comparator is used to compare the pixel value of the initial pixel with the noise pixel threshold to determine whether the initial pixel is a blank pixel or a burning pixel. The second comparator is used to compare the pixel value of the burning pixel with the seed pixel threshold to determine whether the burning pixel is a potential seed pixel. The second judgment module includes: A multiplexer is used to receive the pixel values ​​of eight adjacent initial pixels and the pixel values ​​of potential seed pixels, and output the pixel value of the potential seed pixel. Four third comparators are used to receive the pixel values ​​of the four adjacent pixels in the four directions and compare the pixel value of the potential seed pixel with the pixel values ​​of the four surrounding initial pixels. The first AND operator is used to receive the comparison results of the four third comparators and the third comparators in the surrounding neighboring pixels, and to determine whether the potential seed pixel is a seed pixel in the 3×3 window.

9. The cluster search circuit integrated on-chip in a CMOS pixel detector as described in claim 8, characterized in that, It also includes an OR operator, which receives the result of the first AND operator of the eight surrounding adjacent pixels and determines whether there is a seed pixel under a 3×3 window among the adjacent pixels around the burning pixel. The third judgment module is the same as the second judgment module; The multiplexer is also used to receive the judgment result of the OR operator and the pixel values ​​of the eight surrounding neighboring pixels and the pixel value of the pixel in which it is located, and outputs the pixel value of the seed pixel in the 3×3 window of the surrounding neighboring pixels to replace the value of the current pixel. The four third comparators are also used to receive the pixel values ​​of four adjacent pixels in four directions, and compare the replaced pixel value with the pixel values ​​of the four surrounding pixels. The first AND operator is also used to receive multiple comparison results from four third comparators and the third comparators in the surrounding adjacent pixels, and to determine whether the replaced pixel value is a virtual seed pixel of a 3×3 window.

10. The cluster search circuit integrated on-chip in a CMOS pixel detector as described in claim 9, characterized in that, The fourth judgment module includes: The second AND operator is used to receive the result of the first AND operator from the eight surrounding neighboring pixels and determine whether the current pixel is a seed pixel in the 5×5 window.

Images