Multi-mode single photon avalanche diode reconfigurable receiving system and reconfiguration method

Abstract

The application relates to the technical field of perception imaging, and discloses a single-photon avalanche diode reconfigurable receiving system and a reconfiguration method of multiple working modes, which comprise at least one reconfigurable pixel module, at least one multiplexer, at least one signal processing circuit, a working mode / reconfiguration control circuit and a data processing module; the working mode / reconfiguration control circuit is used for selecting a near-distance working mode and a long-distance working mode; the multiplexer has the near-distance and long-distance working modes; and the data processing module is used for rearranging and combining input distance information quantization results based on the working mode to obtain complete imaging information. The application solves the problem that the data processing module in the prior art is used for rearranging and combining input distance information quantization results based on the working mode to obtain complete imaging information, and has the characteristics of improving a photosensitive area and quickly and accurately outputting a detection result.

Description

Technical Field

[0001] The present invention relates to the field of perception imaging technology, and more specifically, to a single-photon avalanche diode reconfigurable receiving system with multiple working modes and a reconstruction method. Background Art

[0002] LiDAR sensing and imaging technology using single photon avalanche diodes (SPADs) plays an important role in industrial robots, medical treatment, self-driving cars and other application fields. Figure 1 As shown in FIG, the SPAD-based lidar perception imaging receiving system detects the distance between objects by actively emitting a laser beam to the target object and detecting the flight time of the reflected beam.

[0003] SPADs operating in Geiger mode, where the reverse bias voltage is higher than the avalanche breakdown voltage, can theoretically induce an avalanche effect under a strong electric field with only a small number of incident photons, thus having a very high photoelectric conversion gain. Figure 2 As shown, in the SPAD-based lidar perception imaging receiving system, in order to increase the photosensitivity area, detection probability and reduce the loss of effective signals caused by the SPAD being falsely triggered by noise and entering the dead zone, multiple SPADs are usually combined as a group of macro pixels and connected to subsequent signal processing circuits.

[0004] In existing SPAD-based LiDAR sensing and imaging systems, the SPADs are organized into fixed macropixel units, meaning each macropixel is composed of a fixed number of SPADs. To meet the demands of large-array, high-resolution depth-sensing imaging, simply increasing the number of pixels proportionally is not only expensive but also faces issues such as poor pixel consistency due to the large-area distribution of SPADs.

[0005] like Figure 2 As shown, the prior art has a pixel reconfiguration technology that uses the principle of time-sharing multiplexing to change the physical position of the SPAD that constitutes the macro pixel, thereby improving the imaging resolution without increasing the circuit area.

[0006] However, the existing technology has the problem of being unable to quickly switch the receiving mode based on the detection target. Therefore, how to invent a reconfigurable receiving system that can switch the receiving mode based on demand is a technical problem that urgently needs to be solved in this technical field. Summary of the Invention

[0007] The application provides a single-photon avalanche diode reconfigurable receiving system and a reconfiguration method of multiple working modes to solve the problem that the prior art cannot quickly switch the receiving mode based on a detection target.

[0008] To achieve the above-mentioned application purposes, the technical solutions are as follows:

[0009] A single-photon avalanche diode reconfigurable receiving system of multiple working modes comprises at least one reconfigurable pixel module, at least one multiplexer, at least one signal processing circuit, a working mode / reconfiguration control circuit and a data processing module.

[0010] The reconfigurable pixel module, the multiplexer, the signal processing circuit and the data processing module are electrically connected in sequence; the output end of the working mode / reconfiguration control circuit is electrically connected with the gate control ends of the multiplexer, the signal processing circuit and the data processing module.

[0011] The reconfigurable pixel module is composed of a plurality of single-photon avalanche diodes (SPADs) and corresponding front-end circuits, and is used for receiving reflected light beams.

[0012] The multiplexer is used for selecting the SPADs and corresponding front-end circuits of the corresponding reconfigurable pixel module to combine or switch to form corresponding macro-pixel units, and inputting the output of each macro-pixel unit into the signal processing circuit.

[0013] The signal processing circuit is used for processing and quantizing the output of each macro-pixel unit to obtain corresponding distance information quantization results.

[0014] The working mode / reconfiguration control circuit is used for selecting a working mode and outputting corresponding reconfiguration and working mode pulse signals.

[0015] The data processing module is used for rearranging and combining the input distance information quantization results based on the working mode to obtain complete imaging information.

[0016] Preferably, the multiplexer has a near-distance working mode and a far-distance working mode; in the near-distance working mode, the multiplexer uses a time division multiplexing method to reconfigure the SPADs and corresponding front-end circuits of the corresponding reconfigurable pixel module to obtain a macro-pixel unit; in the far-distance working mode, the multiplexer combines all the SPADs and corresponding front-end circuits in the corresponding reconfigurable pixel module into a macro-pixel unit; and the working mode / reconfiguration control circuit is used for selecting either the near-distance working mode or the far-distance working mode.

[0017] Furthermore, specifically, each reconfigurable pixel module corresponds to a signal processing circuit; and each reconfigurable pixel module is correspondingly connected to at least one multiplexer.

[0018] Furthermore, the reconfigurable pixel module is composed of K SPADs (m1×m2) and a front-end circuit corresponding to each SPAD.

[0019] Furthermore, in the close-range working mode, the macro pixel unit of the multiplexer combination consists of n1 x n2 SPADs and their corresponding front-end circuits, where n1 <m1、n2<m2:远距离工作模式中,多路选择器组合的宏像素单元由m1×m2个SPAD及相应的前端电路组成。其中K、m1、m2、n1、n2均为大于0的正整数。

[0020] Furthermore, the signal processing circuit includes a cascaded noise filtering circuit and a time-to-digital converter circuit, which are used to process and quantize the output of the SPAD and its corresponding front-end circuit to obtain the final distance information quantization result; the noise filtering circuit adjusts the noise filtering threshold based on the pulse signal input by the working mode / reconstruction control circuit.

[0021] Furthermore, in the close-range working mode, the SPAD of the corresponding reconfigurable pixel module and its corresponding front-end circuit are reconfigured using a time-division multiplexing method. The specific steps are as follows:

[0022] Define the time range and divide it into several fixed-length time slots, each of which allows different configurations and working modes to run;

[0023] In each time slot, a multiplexer is used to select and combine different SPADs and corresponding front-end circuits;

[0024] During the selection and combination process, hardware resources are reused in different time slots to reduce complexity and power consumption;

[0025] All SPADs are combined according to the time slot to obtain a reconstructed macro pixel unit consisting of n1 x n2 SPADs and their corresponding front-end circuits.

[0026] Furthermore, based on the selection of the working mode, the input distance information quantization results are rearranged and combined, specifically:

[0027] In the close-range working mode, due to the use of time-division multiplexing reconfigurable mode, based on the predefined mapping relationship, the distance information quantization result data of all macro-pixel units are rearranged according to the order of the complete image, and the data block corresponding to each time slot is placed at the corresponding position in the final image to obtain a complete frame of imaging information;

[0028] In the long-distance working mode, the detection efficiency of the receiving end is tested. If the detection efficiency of the receiving end is not less than the set condition, all the distance information quantization results are directly arranged in sequence to obtain a complete frame of imaging information; when the detection efficiency of the receiving end is less than the set condition, the distance information quantization results corresponding to each number of adjacent macro-pixel units are merged and then all the distance information quantization results are arranged in sequence to obtain a complete frame of imaging information.

[0029] Furthermore, the distance information quantization results corresponding to each number of adjacent macro-pixel units are merged and then arranged in sequence to obtain a complete frame of imaging information. Specifically, the distance information quantization results corresponding to a single macro-pixel unit and its N adjacent macro-pixel units are processed by weighted filtering to obtain a merged distance information quantization result, where N is an arbitrary positive integer.

[0030] A method for reconfiguring a single-photon avalanche diode reconfigurable receiving system with multiple working modes includes the following specific steps:

[0031] Based on the distance of the target object to be detected, the operating mode / reconfiguration control circuit is set to a close distance operating mode or a long distance operating mode;

[0032] The working mode / reconfiguration control circuit outputs reconstruction and working mode pulse signals to the multiplexer, signal processing circuit, and data processing module, setting the multiplexer, signal processing circuit, and data processing module to corresponding working modes;

[0033] The multiplexer selects the SPAD of the corresponding reconfigurable pixel module and its corresponding front-end circuit based on its working mode to combine or switch to form the corresponding macro pixel unit;

[0034] After all macro-pixel units receive light signals, they are output to the signal processing circuit through the multiplexer;

[0035] The distance information quantization results output by the signal processing circuit are input to the data processing module; the data processing module rearranges and combines the input distance information quantization results based on its working mode to obtain complete imaging information.

[0036] The beneficial effects of the present invention are as follows:

[0037] The present invention proposes a single-photon avalanche diode reconfigurable receiving system and reconstruction method with multiple working modes, including at least one reconfigurable pixel module, at least one multiplexer, at least one signal processing circuit, a working mode / reconstruction control circuit, and a data processing module, wherein the working mode / reconstruction control circuit is used to select the working mode, and the multiplexer and the data processing module adjust their working mode based on the working mode selected by the working mode / reconstruction control circuit. They can quickly select a suitable receiving mode based on the detection environment, solving the problem in the prior art that the receiving mode cannot be quickly switched based on the detection target. The system has the characteristics of increasing the photosensitive area and quickly and accurately outputting the detection results. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is a working diagram of the existing SPAD-based lidar perception imaging system.

[0039] Figure 2 This is the block diagram of the receiving end system of the existing SPAD-based lidar perception imaging system.

[0040] Figure 3 This is a principle block diagram of a single-photon avalanche diode reconfigurable receiving system with multiple working modes.

[0041] Figure 4 It is a logic block diagram of the working mode selection of the working mode / reconstruction control circuit.

[0042] Figure 5 This is a schematic diagram of the reconstruction of the close-range working mode of a multi-working mode single-photon avalanche diode reconfigurable receiving system proposed by the present invention.

[0043] Figure 6 This is a schematic diagram of long-distance working mode reconstruction of a multi-working mode single-photon avalanche diode reconfigurable receiving system proposed by the present invention.

[0044] Figure 7 This is a schematic diagram of a specific reconstruction of a close-range working mode of a multi-working mode single-photon avalanche diode reconfigurable receiving system proposed by the present invention in Example 2.

[0045] Figure 8 This is a schematic diagram of a specific reconstruction of a long-distance working mode of a multi-working mode single-photon avalanche diode reconfigurable receiving system proposed by the present invention in Example 2.

[0046] Figure 9 It is a flow chart of a reconstruction method of a single-photon avalanche diode reconfigurable receiving system with multiple working modes according to the present invention. DETAILED DESCRIPTION

[0047] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0048] Example 1

[0049] like Figure 3 As shown, a multi-working mode single-photon avalanche diode reconfigurable receiving system includes multiple reconfigurable pixel modules, multiple multiplexers, multiple signal processing circuits, working mode / reconfiguration control circuits, and a data processing module;

[0050] The reconfigurable pixel module, the multiplexer, the signal processing circuit, and the data processing module are electrically connected in sequence; the output end of the working mode / reconfiguration control circuit is electrically connected to the strobe control end of the multiplexer, the signal processing circuit, and the data processing module;

[0051] The reconfigurable pixel module is composed of several single-photon avalanche diodes (SPADs) and their corresponding front-end circuits, which are used to receive echo photon signals, convert them into digital pulse signals, and quench and reset the SPADs to ensure their stable operation.

[0052] like Figure 4 、 Figure 5 、 Figure 6 As shown, the multiplexer is used to select the SPADs of the corresponding reconfigurable pixel module and their corresponding front-end circuits to combine or switch to form a corresponding macro-pixel unit, and input the output signal of each macro-pixel unit into a signal processing circuit; the multiplexer has short-range and long-range working modes; in the short-range working mode, the multiplexer uses a time-division multiplexing method to reconstruct the SPADs of the corresponding reconfigurable pixel module and their corresponding front-end circuits to obtain a macro-pixel unit; in the long-range working mode, the multiplexer combines all the SPADs in the corresponding reconfigurable pixel module and their corresponding front-end circuits into a macro-pixel unit;

[0053] The signal processing circuit is used to process and quantize the output of each macro pixel unit to obtain the corresponding distance information quantization result;

[0054] The working mode / reconstruction control circuit is used to select either the short-distance working mode or the long-distance working mode, and output corresponding reconstruction and working mode pulse signals;

[0055] The data processing module is used to rearrange and combine the input distance information quantization results based on the working mode to obtain complete imaging information.

[0056] In a specific embodiment, each reconfigurable pixel module corresponds to a signal processing circuit; and each reconfigurable pixel module is connected to at least one multiplexer.

[0057] Example 2

[0058] More specifically, in a specific embodiment, the reconfigurable pixel module is composed of 3 x 3 = 9 SPADs and their corresponding front-end circuits.

[0059] In a specific embodiment, Figure 7 、 Figure 8 As shown in the figure, in the close-range working mode, the macro pixel unit of the multiplexer combination consists of 2 x 2 = 4 SPADs and their corresponding front-end circuits; in the long-range working mode, the macro pixel unit of the multiplexer combination consists of 3 x 3 = 9 SPADs and their corresponding front-end circuits.

[0060] In this embodiment, in the close-range working mode, any four adjacent SPADs and their corresponding front-end circuits can be selected for reconstruction to obtain four different reconstruction modes;

[0061] In one specific embodiment, the signal processing circuit includes a cascaded noise filtering circuit and a time-to-digital converter circuit, which is used to process and quantize the output of the SPAD and its corresponding front-end circuit to obtain the final quantized distance information. The noise filtering circuit adjusts the noise filtering threshold based on the pulse signal input by the operating mode / reconstruction control circuit. The noise filtering threshold in the long-distance operating mode is adjusted to be lower than the noise filtering threshold in the short-distance operating mode.

[0062] In a specific embodiment, in the close-range working mode, the SPAD of the corresponding reconfigurable pixel module and its corresponding front-end circuit are reconfigured using a time division multiplexing method. The specific steps are as follows:

[0063] Define the time range and divide it into several fixed-length time slots, each of which allows different configurations and working modes to run;

[0064] In each time slot, a multiplexer is used to select and combine different SPADs and corresponding front-end circuits;

[0065] During the selection and combination process, hardware resources are reused in different time slots to reduce complexity and power consumption;

[0066] All SPADs are combined according to the time slot to obtain a reconstructed macro-pixel unit consisting of 2 x 2 = 4 SPADs and their corresponding front-end circuits.

[0067] In a specific embodiment, based on the selection of the working mode, the input distance information quantization results are rearranged and combined, specifically:

[0068] In the close-range working mode, due to the use of time-division multiplexing reconfigurable mode, based on the predefined mapping relationship, the distance information quantization result data of all macro-pixel units are rearranged according to the order of the complete image, and the data block corresponding to each time slot is placed at the corresponding position in the final image to obtain a complete frame of imaging information;

[0069] In the long-distance working mode, the detection efficiency of the receiving end is tested. If the detection efficiency of the receiving end is not less than the set condition, all the distance information quantization results are directly arranged in sequence to obtain a complete frame of imaging information; when the detection efficiency of the receiving end is less than the set condition, the distance information quantization results corresponding to each number of adjacent macro-pixel units are merged and then all the distance information quantization results are arranged in sequence to obtain a complete frame of imaging information.

[0070] In a specific embodiment, the distance information quantization results corresponding to each number of adjacent macro-pixel units are merged and then all the merged distance information quantization results are arranged in sequence to obtain a complete frame of imaging information. Specifically, the distance information quantization results corresponding to a single macro-pixel unit and its N adjacent macro-pixel units are processed by weighted filtering to obtain a merged distance information quantization result, where N is an arbitrary positive integer.

[0071] Building on existing technologies, this invention further proposes a multi-mode single-photon avalanche diode (SPAD) reconfigurable receiving system and reconstruction method. This invention introduces new reconstruction methods, including close-range and long-range detection modes. This allows for flexible increases or decreases in the number of SPADs within a single macropixel, increasing the photosensitive area and detection probability while minimizing the loss of effective signals caused by the SPAD entering dead zones due to false triggering by noise. The combination of close-range and long-range detection modes effectively addresses the needs of diverse applications.

[0072] Example 3

[0073] like Figure 9 As shown, a reconstruction method of a single-photon avalanche diode reconfigurable receiving system with multiple working modes includes the following specific steps:

[0074] Based on the distance of the target object to be detected, the operating mode / reconfiguration control circuit is set to a close distance operating mode or a long distance operating mode;

[0075] The working mode / reconfiguration control circuit outputs reconstruction and working mode pulse signals to the multiplexer, signal processing circuit, and data processing module, setting the multiplexer, signal processing circuit, and data processing module to corresponding working modes;

[0076] The multiplexer selects the SPAD of the corresponding reconfigurable pixel module and its corresponding front-end circuit based on its working mode to combine or switch to form the corresponding macro pixel unit;

[0077] After all macro-pixel units receive light signals, they are output to the signal processing circuit through the multiplexer;

[0078] The distance information quantization results output by the signal processing circuit are input to the data processing module; the data processing module rearranges and combines the input distance information quantization results based on its working mode to obtain complete imaging information.

[0079] Obviously, the above embodiments of the present invention are merely examples for the purpose of illustrating the present invention, and are not intended to limit the embodiments of the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. A multi-mode single-photon avalanche diode reconfigurable receiving system, characterized by: Comprising at least one reconfigurable pixel module, at least one multiplexer, at least one signal processing circuit, a working mode / reconstruction control circuit, and a data processing module; The reconfigurable pixel module, the multiplexer, the signal processing circuit, and the data processing module are electrically connected in sequence; the output end of the working mode / reconstruction control circuit is electrically connected to the gating control ends of the multiplexer, the signal processing circuit, and the data processing module; The reconfigurable pixel module is composed of a plurality of single photon avalanche diodes (SPADs) and their corresponding front-end circuits, and is used to receive reflected light beams; The multiplexer is used to select the SPADs of the corresponding reconfigurable pixel module and their corresponding front-end circuits for combination or switching to form corresponding macro pixel units, and input the output of each macro pixel unit into the signal processing circuit; the multiplexer has a close-range and a long-range working mode; in the close-range working mode, the multiplexer uses the time division multiplexing method to reconstruct the SPADs of the corresponding reconfigurable pixel module and their corresponding front-end circuits to obtain a macro pixel unit; in the long-range working mode, the multiplexer combines all the SPADs in the corresponding reconfigurable pixel module and their corresponding front-end circuits into a macro pixel unit; the working mode / reconstruction control circuit is used to select either the close-range working mode or the long-range working mode; The signal processing circuit is used to process and quantify the output of each macro pixel unit to obtain a corresponding distance information quantization result; The working mode / reconstruction control circuit is used to select a working mode and output corresponding reconstruction and working mode pulse signals; The data processing module is used to rearrange and combine the input distance information quantization result based on the working mode to obtain complete imaging information.

2. The multi-mode single-photon avalanche diode reconfigurable receiving system according to claim 1, characterized in that: Specifically, each reconfigurable pixel module corresponds to a signal processing circuit; each reconfigurable pixel module is correspondingly connected to at least one multiplexer.

3. The multi-mode single-photon avalanche diode reconfigurable receiving system according to claim 2, characterized in that: The reconfigurable pixel module is composed of K units each consisting of m1×m2 SPADs and the front-end circuit corresponding to each SPAD; 4. The multi-mode single-photon avalanche diode reconfigurable receiving system according to claim 3, characterized in that: In the close-range working mode, the macro pixel unit combined by the multiplexer consists of n1 x n2 SPADs and their corresponding front-end circuits, where n1 < m1 and n2 < m2; in the long-range working mode, the macro pixel unit combined by the multiplexer consists of m1×m2 SPADs and the corresponding front-end circuits; where K, m1, m2, n1, and n2 are all positive integers greater than 0.

5. The multi-mode single-photon avalanche diode reconfigurable receiving system according to claim 4, characterized in that: The signal processing circuit includes a cascaded noise filtering circuit and a time-to-digital converter circuit, and is used to process and quantify the output of the SPAD and its corresponding front-end circuit to obtain a final distance information quantization result; the noise filtering circuit adjusts the noise filtering threshold based on the pulse signal input by the working mode / reconstruction control circuit.

6. The multi-mode single-photon avalanche diode reconfigurable receiving system according to claim 5, characterized in that: In the close-range working mode, the time division multiplexing method is used to reconstruct the SPADs of the corresponding reconfigurable pixel module and their corresponding front-end circuits. The specific steps are as follows: Define a time range, divide the time range into a number of time slots with a fixed length, and each time slot allows different configurations and working modes to run; In each time slot, a multiplexer is used to select and combine different SPADs and corresponding front-end circuits; During the selection and combination process, hardware resources are reused in different time slots to reduce complexity and power consumption; All SPADs are combined according to the time slot to obtain a reconstructed macro pixel unit consisting of n1 x n2 SPADs and their corresponding front-end circuits.

7. The multi-mode single-photon avalanche diode reconfigurable receiving system according to claim 6, characterized in that: Based on the selection of the working mode, the input distance information quantization results are rearranged and combined, specifically: In the close-range working mode, due to the use of time-division multiplexing reconfigurable mode, based on the predefined mapping relationship, the distance information quantization result data of all macro-pixel units are rearranged according to the order of the complete image, and the data block corresponding to each time slot is placed at the corresponding position in the final image to obtain a complete frame of imaging information; In the long-distance working mode, the detection efficiency of the receiving end is tested. If the detection efficiency of the receiving end is not less than the set condition, all the distance information quantization results are directly arranged in order to obtain a complete frame of imaging information; When the detection efficiency of the receiving end is less than the set condition, the distance information quantization results corresponding to each number of adjacent macro-pixel units are merged and then all the distance information quantization results are arranged in sequence to obtain a complete frame of imaging information.

8. The multi-mode single-photon avalanche diode reconfigurable receiving system according to claim 7, characterized in that: The distance information quantization results corresponding to each number of adjacent macro-pixel units are merged and then arranged in sequence to obtain a complete frame of imaging information. Specifically, the distance information quantization results corresponding to a single macro-pixel unit and its N adjacent macro-pixel units are processed by weighted filtering to obtain a merged distance information quantization result, where N is an arbitrary positive integer.

9. A method for reconfiguring a single-photon avalanche diode reconfigurable receiving system with multiple working modes according to any one of claims 1 to 8, characterized in that: The specific steps include: Based on the distance of the target object to be detected, the operating mode / reconfiguration control circuit is set to a close distance operating mode or a long distance operating mode; The working mode / reconfiguration control circuit outputs reconstruction and working mode pulse signals to the multiplexer, signal processing circuit, and data processing module, setting the multiplexer, signal processing circuit, and data processing module to corresponding working modes; The multiplexer selects the SPAD of the corresponding reconfigurable pixel module and its corresponding front-end circuit based on its working mode to combine or switch to form the corresponding macro pixel unit; After all macro-pixel units receive light signals, they are output to the signal processing circuit through the multiplexer; The distance information quantization result output by the signal processing circuit is input into the data processing module; The data processing module rearranges and combines the input distance information quantization results based on its working mode to obtain complete imaging information.

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