CN117031439A - Dynamic configuration depth detection method and depth sensing chip - Google Patents

Abstract

The invention provides a depth detection method and a depth sensing chip with dynamic configuration, wherein the method comprises the following steps: acquiring pixel configuration information, dividing the SPAD array into m x n pixels according to the pixel configuration information, and configuring an initial starting position, wherein each pixel comprises at least one SPAD unit, and one or more pixels are correspondingly connected with one TDC unit; setting a state machine, and starting from an initial starting position according to the frame number and pixel configuration information of the state machine, and sequentially controlling one pixel at a corresponding position to be sequentially opened in each frame according to a designated sequence; outputting the TDC data of each frame through a TDC unit connected to one pixel that is turned on; when the state machine completes one round of m x n frames, correspondingly generating m x n histograms according to the output m x n frames of TDC data; and calculating the depth values of the m x n pixels according to the m x n histograms. The depth detection of different pixel resolutions is realized by dynamically dividing pixel configuration and flexibly using the frame number of a state machine to dynamically open and close each pixel.

Description

Dynamic configuration depth detection method and depth sensing chip

Technical Field

The present invention relates to the field of depth sensing technologies, and in particular, to a dynamically configured depth detection method and a depth sensing chip.

Background

In the field of depth sensing, dtofs (direct time of flight ) technology is to transmit pulsed light to a target object, receive the pulsed light reflected from the target object with a high-performance photoelectric sensor, and measure the time of flight required for the transmitted light to return in a statistical histogram manner, thereby realizing depth detection, i.e., distance measurement, of the target object.

Single photon avalanche diodes (single photon avalanche diode, SPADs) are the most commonly used photosensors in current dtofdepth sensing systems, and SPAD arrays, which are typically composed of a plurality of SPADs arranged in a rectangular plane, respond to incident photons to achieve optical signal reception. When the current SPAD array works, the detection basic unit is fixedly configured, for example, if the SPAD array is a single-point system, the SPAD array is used as a single-point pixel, and the depth value of one pixel is output after the data of all SPADs are overlapped in one frame time. This approach makes depth detection less flexible and difficult to accommodate the number of pixels required in different depth detection environments.

Disclosure of Invention

In view of the above-mentioned shortcomings of the prior art, an object of the present invention is to provide a depth detection method and a depth sensor chip with dynamic configuration, so as to improve the flexibility of depth detection.

In order to achieve the above purpose, the invention adopts the following technical scheme:

the first aspect of the present invention provides a dynamically configured depth detection method, including the steps of:

acquiring pixel configuration information, dividing a SPAD array into m-n pixels according to the pixel configuration information, and configuring an initial starting position, wherein each pixel comprises at least one SPAD unit, one or more pixels are correspondingly connected with one TDC unit, and only one pixel is started at the same time;

setting a state machine, and controlling one pixel at a corresponding position to be sequentially opened in each frame according to a designated sequence from an initial opening position according to the frame number of the state machine and the pixel configuration information;

outputting the TDC data of each frame through a TDC unit connected to one pixel that is turned on;

when the state machine completes one round of m x n frames, correspondingly generating m x n histograms according to the output m x n frames of TDC data;

and calculating the depth values of the m x n pixels according to the m x n histograms.

In one embodiment, the obtaining the pixel configuration information, dividing the SPAD array into m×n pixels according to the pixel configuration information, and configuring the initial on position includes:

acquiring pixel configuration information, wherein the pixel configuration information comprises the number of pixels, the serial numbers of the pixels and the distribution of the pixels;

dividing the SPAD units with the same serial numbers in the SPAD array into the same pixel to obtain m x n pixels; the SPAD array comprises m×n SPAD units, M can be divided by M, and N can be divided by N.

In one embodiment, the enable signal of the SPAD unit corresponding to the pixel to be turned on is set to 1, and the enable signals of SPAD units corresponding to other pixels are set to 0.

In one embodiment, the controlling, in a specified order, one pixel at a corresponding position sequentially opened in each frame specifically includes:

in order of sequence numbers from small to large, one pixel at the position of sequence number 1 is turned on at the 1 st frame, one pixel at the position of sequence number 2 is turned on at the 2 nd frame, and so on, and one pixel at the position of sequence number m is turned on at the m x n frame.

In one embodiment, before the acquiring the pixel configuration information and dividing the SPAD array into m×n pixels according to the pixel configuration information and configuring the initial on position, the method further includes:

k TDC units and the priority of each TDC unit are configured, each TDC unit is connected to one or more pixels, k=m or n or other integer dividing m×n.

In one embodiment, the configuring the priority of each TDC unit specifically refers to:

the priority of the first TDC unit is highest at frame 1, the priority of the second TDC unit is highest at frame 2, …, the priority of the kth TDC unit is highest at the kth frame, the priority of the first TDC unit is highest at the k+1th frame, and so on until the detection output is stopped.

In one embodiment, the pixel configuration information includes a connection relationship between m×n pixels and k TDC units.

In one embodiment, the connection relationship is specifically:

the pixels sequentially connected to the first to kth TDC units are arranged in a cyclic manner with k as a period in the order of decreasing numbers.

In one embodiment, when the SPAD array is divided into 2×2 pixels and 4 TDC units are configured, the 1 pixel is connected to 1 TDC unit, and as the frame number increases, the pixel and the TDC unit are sequentially turned on in order of increasing numbers.

In one embodiment, when the SPAD array is divided into 4*4 pixels and 4 TDC units are configured, the 4 pixels are connected with 1 TDC unit, and the pixels and the TDC units are sequentially turned on in order of increasing number as the number of frames increases; wherein, the pixels with the serial numbers of 1, 5, 9 and 13 are connected with the first TDC unit; the pixels with the serial numbers of 2, 6, 10 and 14 are connected with a second TDC unit; the pixels with the serial numbers of 3, 7, 11 and 15 are connected with a third TDC unit; the pixels numbered 4, 8, 12 and 16 are connected to a fourth TDC unit.

In one embodiment, from the number 1 to the number m, every k number of pixels are distributed in the same partition, the pixels in the same partition are connected with the same TDC unit, and k is the number of TDC units; pixels of adjacent sequence numbers are distributed in different partitions.

In one embodiment, from sequence number 1 to sequence number m×n pixels, every k consecutive sequence number pixels are distributed in different k partitions clockwise in SPAD array;

m n/k pixels in the same partition are also distributed clockwise in the partition in the order of the sequence from small to large, and k is the number of TDC units.

A second aspect of the present invention provides a depth sensing chip comprising:

the SPAD array is divided into m x n pixels based on the acquired pixel configuration information and configures an initial starting position, wherein each pixel comprises at least one SPAD unit, and one or more pixels are correspondingly connected with one TDC unit;

a state machine configured to control one pixel at a corresponding position to be sequentially turned on at each frame in a specified order from an initial on position according to a frame number and the pixel configuration information;

the TDC array comprises a plurality of TDC units, wherein each TDC unit is used for receiving photon signals output by one pixel connected with the TDC unit in response to incident photons and outputting TDC data corresponding to the photon signals according to each frame;

the histogram module is used for correspondingly generating m x n histograms according to the output m x n frame TDC data when the state machine completes each round of m x n frames;

and the data processing module is used for calculating and obtaining depth values of m x n pixels according to the m x n histograms.

The beneficial effects of the invention are as follows: the depth detection method and the depth sensing chip with dynamic configuration are provided, and each pixel is dynamically opened and closed through the dynamic divided pixel configuration and the flexible use of the frame number of a state machine, so that the depth detection of different pixel resolutions is realized.

Drawings

The invention will be further described with reference to the accompanying drawings and examples, in which:

FIG. 1 is a flow chart of a dynamically configured depth detection method in an embodiment of the present invention;

FIG. 2 is a schematic diagram of a SPAD array configuration for single point detection in an embodiment of the present invention;

FIG. 3 is a schematic view of a SPAD array configuration for multi-point detection in an embodiment of the present invention;

FIG. 4 is a schematic diagram of another configuration of a SPAD array for multi-point detection according to an embodiment of the present invention;

FIG. 5 is a schematic diagram of another configuration of a SPAD array for multi-point detection in an embodiment of the present invention;

fig. 6 is a block diagram of a depth sensor chip according to an embodiment of the present invention.

Detailed Description

In order to make the technical problems, technical schemes and beneficial effects to be solved by the embodiments of the present invention more clear, the present invention is further described in detail below with reference to the accompanying drawings and the embodiments. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.

It will be understood that when an element is referred to as being "mounted" or "disposed" on another element, it can be directly on the other element or be indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or be indirectly connected to the other element. In addition, the connection may be for a fixing function or for a circuit communication function.

It is to be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like are merely for convenience in describing embodiments of the invention and to simplify the description by referring to the figures, rather than to indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus are not to be construed as limiting the invention.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the embodiments of the present invention, the meaning of "plurality" is two or more, unless explicitly defined otherwise.

The depth detection method of dynamic configuration provided by the embodiment of the invention is applied to a depth sensing chip based on a time of flight (TOF) method, the depth sensing chip at least comprises a SPAD array, the SPAD array is divided into m x n pixels based on acquired pixel configuration information and is configured with an initial starting position, wherein each pixel comprises at least one SPAD unit, and one or more pixels are correspondingly connected with one TDC unit; a state machine configured to control one pixel at a corresponding position to be sequentially turned on at each frame in a specified order from an initial on position according to the number of frames and the pixel configuration information; the TDC array comprises a plurality of TDC units, wherein each TDC unit is used for receiving photon signals output by one pixel connected with the TDC unit in response to incident photons and outputting TDC data corresponding to the photon signals according to each frame; the histogram module is used for correspondingly generating m x n histograms according to the output m x n frame TDC data when the state machine completes each round of m x n frames; and the data processing module is used for calculating and obtaining depth values of m x n pixels according to the m x n histograms.

Currently, a SPAD array, which is generally formed by arranging a plurality of SPAD units on a rectangular plane in a dtofdepth sensing system, responds to incident photons to realize optical signal reception. When the current SPAD array works, the detection basic unit and the TDC unit are fixedly configured, for example, if the SPAD array is a single-point system, the SPAD array is used as a single-point pixel, and the depth value of one pixel is output after all SPAD data are overlapped through the limited TDC unit in one frame time. This approach makes depth detection less flexible and difficult to accommodate the number of pixels required in different depth detection environments. Therefore, how to solve the problem is described below by a depth detection method applied to dynamic configuration of a depth sensing chip, so that the SPAD array is flexibly configured to be used for depth detection of different numbers of pixels, different pixel resolutions are realized, and the flexibility of depth detection is improved.

As shown in fig. 1, fig. 1 is a flowchart of a dynamically configured depth detection method according to an embodiment of the present invention, where the method specifically includes the following steps:

s101, acquiring pixel configuration information, dividing the SPAD array into m-n pixels according to the pixel configuration information, and configuring an initial starting position, wherein each pixel comprises at least one SPAD unit, one or more pixels are correspondingly connected with one TDC unit, and only one pixel is started at the same time.

In this embodiment, the dynamically configured SPAD array is divided into m×n pixels and an initial on position is configured by acquiring pixel configuration information, and only one pixel of the m×n pixels obtained by dividing is turned on at the same time, so as to obtain single pixel data with higher spatial resolution. Wherein m and n are positive integers greater than 1, each divided pixel includes at least one SPAD unit, and m and n may be equal or unequal, for example, an 8×8 SPAD array may be divided into 2×2, 4*4 pixels, and the like, which may be flexibly divided according to resolution requirements and the number of SPAD units in the SPAD array.

And because the number of the TDC units and the physical connection relation between each TDC unit and the SPAD unit are fixed, after the pixels are divided, one or more pixels are correspondingly connected with one TDC unit based on the difference of the number of the pixels, so that the recording and outputting of the flight time of photons received by all the pixels are ensured.

S102, setting a state machine, and controlling one pixel at a corresponding position to be sequentially opened in each frame according to a designated sequence from an initial opening position according to the frame number of the state machine and the pixel configuration information.

After dividing pixels, according to the frame number of the state machine and pixel configuration information such as the serial numbers and the distribution positions of the pixels, starting from an initial starting position, one pixel at a corresponding position is controlled to be sequentially opened in each frame according to a designated sequence. I.e. at frame 1 only one pixel at the initial on position is turned on, the pixels at the other positions are turned off; and opening one pixel at the next position according to a designated sequence in the 2 nd frame, closing the pixels at other positions, and so on, wherein only one pixel is opened in each frame, and the opening state of each pixel under different frames, namely different detection moments is controlled in sequence. The specified order may be flexibly set according to the detection requirement or the equipment condition, for example, based on the positions of the respective pixels in the order from top to bottom, the order from left to right, the "zigzag" order, the clockwise direction, the counterclockwise direction, and the like, which is not limited in this embodiment.

Specifically, when the on and off of each pixel of each frame are controlled, the enable signal of the SPAD unit corresponding to the pixel to be turned on is set to 1, and the enable signals of SPAD units corresponding to other pixels are set to 0. And setting enabling signals with different values for the SPAD units corresponding to the pixels under different frames, so as to realize accurate control of the working state of each pixel.

S103, outputting TDC data of each frame through a TDC unit connected with one pixel which is opened.

When one pixel is opened for detection in each frame, the TDC data of each frame is output through the TDC unit connected with the opened one pixel. Because only one pixel is opened in each frame, the TDC data obtained in each frame can be accurately corresponding to the data of the opened pixel no matter one pixel is connected with one TDC unit or a plurality of pixels share one TDC unit, and the detection accuracy is ensured.

S104, when the state machine completes each round of m x n frames, correspondingly generating m x n histograms according to the output m x n frames of TDC data;

and S105, calculating the depth values of the m x n pixels according to the m x n histograms.

As the detection continues, histogram construction and depth value output are performed with the number of divided pixels, i.e., m×n, as a period. When each pixel is opened once according to a specified sequence, a round of m x n frame detection is completed, and when each round of m x n frames is completed by a state machine, for example, from the 1 st frame to the m x n frame, m x n frame TDC data output by each TDC unit can be obtained, and the obtained m x n frame TDC data corresponds to the data of each pixel.

When m x n frames of one round are completed, corresponding m x n histograms are constructed and generated according to the m x n frame TDC data output under the current round, the m x n histograms are specifically histograms of each pixel under the current round, the m x n histograms are subjected to peak searching processing, the accurate flight time of each pixel is determined, and the depth value of the m x n pixels is calculated. According to the embodiment, the dynamic pixel configuration and the state machine are matched to control the opening and closing states of each pixel in different frames, so that the data of the pixels in different positions can be output by utilizing different frames on the basis of the SPAD array and the TDC array which are fixedly arranged, and the depth values of all the pixels are output when the frames with the same number as the pixels are completed in each round, thereby realizing dynamic depth detection with high pixel resolution and improving the flexibility of the depth detection.

In one embodiment, step S101 includes:

acquiring pixel configuration information, wherein the pixel configuration information comprises the number of pixels, the serial numbers of the pixels and the distribution of the pixels;

dividing the SPAD units with the same serial numbers in the SPAD array into the same pixel to obtain m x n pixels; the SPAD array comprises m×n SPAD units, M can be divided by M, and N can be divided by N.

In this embodiment, the pixel configuration information includes the number of pixels, the serial numbers of the pixels, and the distribution of the pixels, and specifically, the serial numbers of m×n SPAD units in the SPAD array may be configured to be used as the pixel configuration information, where SPAD units with the same serial numbers in the SPAD array are divided into the same pixels to obtain m×n pixels, so as to ensure the consistency of each pixel, M can be divided by M, and N can be divided by N.

As shown in fig. 2, the sequence number of each SPAD unit in the SPAD array is configured to be 1, and only one pixel performs single-point detection at this time; as shown in fig. 3, when SPAD units at different positions are respectively configured as 1-4, the SPAD array with the same size is divided into 2×2 pixels for multipoint detection; as shown in fig. 4, when SPAD units at different positions are respectively configured as 1-16, the SPAD array with the same size is divided into 4*4 pixels for multipoint detection; as shown in fig. 5, when SPAD cells at different positions are respectively configured to be 1-64, SPAD arrays with the same size are divided into 8×8 pixels for multipoint detection. The corresponding serial numbers are simply configured for the SPAD units at different positions, so that the dynamic pixel division of corresponding numbers and distributed positions can be realized.

In one embodiment, the method controls one pixel at a corresponding position to be sequentially opened in each frame according to a specified sequence, and specifically includes:

in order of sequence numbers from small to large, one pixel at the position of sequence number 1 is turned on at the 1 st frame, one pixel at the position of sequence number 2 is turned on at the 2 nd frame, and so on, and one pixel at the position of sequence number m is turned on at the m x n frame.

In this embodiment, on the basis of the number of pixels, the turn-on sequence of each pixel is controlled based on the number of pixels. And in the order from small to large, the sequence number corresponds to the frame number in each round of m x n frame detection, namely, one pixel at the position of 1 is opened in the 1 st frame, one pixel at the position of 2 is opened in the 2 nd frame, and the like, and one pixel at the position of m x n is opened in the m x n frame. The starting paths formed when each pixel is started according to the appointed sequence are from the position of the pixel with the sequence number of 1 to the position of the pixel with the sequence number of m, so that the starting of single pixel with the appointed sequence can be realized by controlling the precise sequence numbers only by configuring the sequence numbers of SPAD units corresponding to the pixels at different positions according to different starting paths in sequence.

In one embodiment, prior to step S101, the method further comprises:

k TDC units and the priority of each TDC unit are configured, each TDC unit is connected to one or more pixels, k=m or n or other integer dividing m×n.

In this embodiment, the depth sensing system is fixedly configured with k TDC units and priority of each TDC unit in advance, and each TDC unit is fixedly connected to a corresponding SPAD unit. After pixel division is performed based on the pixel configuration information, each TDC unit is connected to one or more pixels, that is, k=m or n or other numbers capable of dividing m by n, so that n or m/k pixels in the m×n pixels are connected to one TDC unit, and data output of all pixels can be achieved by sharing one TDC unit by multiple pixels under limited TDC units.

In one embodiment, the priority of each TDC unit is configured, specifically:

the priority of the first TDC unit is highest at frame 1, the priority of the second TDC unit is highest at frame 2, …, the priority of the kth TDC unit is highest at the kth frame, the priority of the first TDC unit is highest at the k+1th frame, and so on until the detection output is stopped.

In this embodiment, the priority of each TDC unit corresponds to the number of frames, and after the start of the detection, the priority of the first TDC unit is highest at the 1 st frame, the priority of the second TDC unit is highest at the 2 nd frame, …, the priority of the k-th TDC unit at the k-th frame, and as the detection continues, the priority of the first TDC unit at the k+1-th frame is reconfigured to be highest, and so on until the detection output is stopped. It is understood that if the total frame number at the time of stopping the detection output is less than or equal to k, the priority of the i-th TDC unit is highest at the i-th frame, i is the total frame number at the time of stopping the detection output, that is, there is no k+1 frame.

In one embodiment, the pixel configuration information further includes a connection relationship of m×n pixels and k TDC units.

Since the connection relationship between k TDC units and m×n SPAD units is fixed, when corresponding serial numbers are configured for SPAD units at different positions as pixel configuration information, the connection relationship between m×n pixels and k TDC units is included synchronously. Specifically, the sequence numbers of all the SPAD units can be configured based on the priority of all the TDC units under different frame numbers and in combination with the sequence requirement of pixel opening, so that the frame numbers correspond to the priority of the TDC units and the sequence of pixel opening, the TDC unit connected with one pixel opened in each frame has the highest priority in the current frame, and the detection efficiency is improved.

Specifically, for the connection of each pixel, each pixel sequentially connected to the first to kth TDC units is cyclically arranged in the order of decreasing numbers and with k as a period. For example, the SPAD array is divided into 4*4 pixels and configured with 4 TDC units, the pixels with numbers 1-4 are respectively and correspondingly connected with the first TDC unit to the fourth TDC unit, the pixels with numbers 5-8 are respectively and correspondingly connected with the first TDC unit to the fourth TDC unit, the pixels with numbers 9-12 are respectively and correspondingly connected with the first TDC unit to the fourth TDC unit, and the pixels with numbers 13-16 are respectively and correspondingly connected with the first TDC unit to the fourth TDC unit. When one pixel is opened in sequence from small to large in sequence, the sequence number corresponds to the frame number, the priority of the TDC unit connected with the opened pixel corresponds to the frame number, and each frame only opens one pixel connected with the TDC unit with the highest priority of the current frame, so that the data output efficiency is ensured.

In one embodiment, from the number 1 to the number m, every k number of pixels are distributed in the same partition, the pixels in the same partition are connected with the same TDC unit, and k is the number of TDC units; pixels of adjacent sequence numbers are distributed in different partitions.

In this embodiment, for the position distribution of each pixel, the SPAD array is partitioned based on the number k of TDC units, and the SPAD array is divided into k partitions, and after the pixels are partitioned, the pixels located in the same partition are connected to the same TDC unit. When the position distribution of each pixel is configured, the positions of each pixel are circularly configured in k partitions according to the sequence from small to large, as shown in fig. 4, when the SPAD array is divided into 4*4 pixels and 4 TDC units are configured, four regions with different gray scales are four partitions, and the positions of the pixels are circularly configured in the four partitions from the sequence number 1, so that the pixels with the sequence numbers 1, 5, 9 and 13 are in one partition, the pixels with the sequence numbers 2, 6, 10 and 14 are in the other partition, and the other sequence numbers are the same, so that the pixels with every 4 sequence numbers are distributed in the same partition, and the pixels with adjacent sequence numbers are distributed in different partitions.

Because each frame is opened only by one pixel, the pixel positions are partitioned and distributed according to the number of the TDC units, the switching and opening of each TDC unit under different frames can be correspondingly controlled based on the pixel positions required to be opened of each frame, all the TDC units are not required to be opened at the same time, and the detection power consumption is better saved. And because the pixels with adjacent serial numbers are distributed in different partitions, namely the pixels with adjacent serial numbers are necessarily connected with different TDC units, the condition that two continuous frames output data can not occur in the same TDC unit, and when a plurality of pixels share one TDC unit, the accuracy of the data can be effectively ensured, and the data confusion among different pixels is avoided.

In one embodiment, from sequence number 1 to sequence number m×n pixels, every k consecutive sequence number pixels are distributed in different k partitions clockwise in SPAD array; m n/k pixels in the same partition are also distributed clockwise in the partition in the order of the sequence from small to large, and k is the number of TDC units.

In this embodiment, on the basis that every k sequential pixels are distributed in the same partition, the position circulation configuration of each pixel in k partitions is further implemented in a clockwise direction, that is, the sequential pixels 1-sequential k are respectively distributed in the partition 1-partition k in the clockwise direction, and the sequential pixels k+1-sequential pixels 2k are also respectively distributed in the partition 1-partition k in the clockwise direction, so that the position distribution configuration of all the pixels is completed. As shown in fig. 4, when the SPAD array is divided into 4*4 pixels and 4 TDC units are configured, the pixels with numbers 1, 2, 3, and 4 are distributed in different 4 partitions in the SPAD array clockwise, and the pixels with numbers 5-8, 9-12, and 13-16 are the same.

The ordered pixel distribution can better correspond the opening positions of the pixels under different frames to the priorities of all the TDC units, for example, the priorities of the configured first TDC unit to the k-th TDC unit are periodically switched along with the frames, the partitions 1 to k corresponding to the first TDC unit to the k-th TDC unit are clockwise distributed, and all the pixels are also clockwise distributed in k partitions, so that the data output can be carried out by the TDC unit with the highest priority when one pixel is started in each frame, the frame rate can be improved as much as possible, and the increase of the detection duration caused by the number of the pixels converted by the frames is compensated.

For m×n/k pixels in the same partition, the pixels in the different partitions can be uniformly distributed in the partition from small to large in order of sequence numbers and also can be distributed clockwise so as to maintain and switch the consistency of the pixels in the different partitions. For example, in fig. 4, pixels with numbers 1, 5, 9, and 13 are also distributed clockwise in the same partition, and the pixel distribution in other partitions is the same. Of course, in other embodiments, m×n/k pixels in the same partition may also adopt other distribution rules, for example, the pixels are distributed in rows, columns, etc. in the partition from the smaller to the larger order, which is not limited in this embodiment.

In one embodiment, when the SPAD array is divided into 2×2 pixels and 4 TDC units are configured, the 1 pixel is connected to 1 TDC unit, and as the frame number increases, the pixel and the TDC unit are sequentially turned on in order of increasing numbers.

In this embodiment, as shown in fig. 2, in the initial configuration, the serial numbers of all SPAD units in the SPAD array are configured to be 1, 4 TDC units are configured, and the SPAD units in the four region representation regions with different gray scales are respectively connected with the corresponding TDC units. During detection, the enabling signals of all the SPAD units with the number of 1 are set to be 1 in one frame, namely all the SPAD units are opened to form a pixel, 4 TDC units are simultaneously opened, then the data of all the TDC units are added together, and a histogram is output to perform single-point detection.

On the basis of the initial configuration, if the number of pixels of the SPAD array is desired to be increased to 2×2, as shown in fig. 3, numbers 1 to 4 are respectively configured for SPAD units in four regions of different gray scales, all SPAD unit forming pixels 1 with number 1, all SPAD unit forming pixels 2 with number 2, all SPAD unit forming pixels 3 with number 3, and all SPAD unit forming pixels 4 with number 4, and at this time, the pixels 1 to 4 are respectively connected with 1 TDC unit. During detection, as the frame number increases, the pixels and the TDC units are sequentially started in the order of increasing the sequence, namely, the enabling signal of the pixel 1 is initially set to be 1, the enabling signals of other pixels are set to be 0, and after the state machine starts to work, the complete detection data is automatically output once with 4 frames as a period according to the frame number. The method comprises the steps of automatically opening only the SPAD unit with the serial number of 1 in a 1 st frame, automatically opening only the SPAD unit with the serial number of 2 in a 2 nd frame, automatically opening only the SPAD unit with the serial number of 3 in a 3 rd frame, automatically opening only the SPAD unit with the serial number of 4 in a 4 th frame, outputting 4 histograms after 4 frames, and further obtaining depth values of 4 pixels.

In one embodiment, when the SPAD array is divided into 4*4 pixels and 4 TDC units are configured, the 4 pixels are connected with 1 TDC unit, and the pixels and the TDC units are sequentially turned on in order of increasing number as the number of frames increases; wherein, the pixels with the serial numbers of 1, 5, 9 and 13 are connected with the first TDC unit; the pixels with the serial numbers of 2, 6, 10 and 14 are connected with a second TDC unit; the pixels with the serial numbers of 3, 7, 11 and 15 are connected with a third TDC unit; the pixels numbered 4, 8, 12 and 16 are connected to a fourth TDC unit.

In this embodiment, as shown in fig. 4, if the number of pixels of the SPAD array is increased to 4*4, the numbers 1-16 are respectively configured for the SPAD units in the four areas with different gray scales, and the TDC units are still fixed to 4, so that every 4 pixels are connected with 1 TDC unit. Preferably, the positions of the numbers 1 to 16 may be arranged based on the priority rule of the TDC units, for example, the four areas are the connection areas corresponding to the first TDC unit, the second TDC unit, the third TDC unit and the fourth TDC unit, respectively, in order of gray values from high to low, then the numbers 1, 5, 9 and 13 may be arranged in the area corresponding to the first TDC unit, the numbers 2, 6, 10 and 14 may be arranged in the area corresponding to the second TDC unit, the numbers 3, 7, 11 and 15 may be arranged in the area corresponding to the third TDC unit, and the numbers 4, 8, 12 and 16 may be arranged in the area corresponding to the third TDC unit, so that the sequence of the numbers of the pixels corresponds to the priority sequence of the TDC units.

During detection, the pixels and the TDC units are sequentially started in the sequence of increasing the number of frames. That is, the enable signal of the pixel 1 is initially set to 1, the enable signals of other pixels are set to 0, and after the state machine is started to work, the complete detection data is automatically output once with 16 frames as a period according to the frame number. And automatically opening only the SPAD unit with the sequence number of 1 in the 1 st frame, automatically opening only the SPAD unit with the sequence number of 2 in the 2 nd frame, automatically opening only the SPAD unit with the sequence number of 3 in the 3 rd frame, and so on, automatically opening only the SPAD unit with the sequence number of 16 in the 16 th frame, outputting 16 histograms after 16 frames, and further obtaining the depth value of 16 pixels. And the positions of pixels 1-4, 5-8, 9-12 and 13-16 in the detection process are circulated according to the priority order of the first TDC unit to the fourth TDC unit, so that the pixels in the area with the highest priority of the TDC unit are opened during each frame, and the detection efficiency is ensured.

Further, if the number of pixels of the SPAD array is increased to 8×8, as shown in fig. 5, the SPAD units in the four areas with different gray scales are respectively configured with numbers 1 to 64, and each SPAD unit is independently used as a pixel. The TDC units are still fixed to 4, so every 16 pixels is connected to 1 TDC unit. The positions of the serial numbers 1-64 can be configured based on the priority rule of the TDC units, for example, the four areas are respectively the connection areas corresponding to the first TDC unit, the second TDC unit, the third TDC unit and the fourth TDC unit according to the order of the gray values from high to low, and the corresponding serial numbers are configured for each SPAD unit in the four areas in a circulating manner according to the order of the gray values from high to low, until the configuration is completed, so that the serial number sequence of the pixels corresponds to the priority sequence of the TDC units. The positions of the numbers 1-64 in the four areas in fig. 5 can be seen specifically, and will not be described here.

During detection, the pixels and the TDC units are sequentially started in the sequence of increasing the number of frames. That is, the enable signal of the pixel 1 is initially set to 1, the enable signals of other pixels are set to 0, and after the state machine is started to work, the complete detection data is automatically output once with 64 frames as a period according to the frame number. And automatically opening only the SPAD unit with the sequence number of 1 in the 1 st frame, automatically opening only the SPAD unit with the sequence number of 2 in the 2 nd frame, automatically opening only the SPAD unit with the sequence number of 3 in the 3 rd frame, and so on, automatically opening only the SPAD unit with the sequence number of 64 in the 64 th frame, outputting 64 histograms after 64 frames, and further obtaining the depth value of 64 pixels.

Therefore, under the fixed configuration and limited number of TDC units, pixel division and pixel opening sequence control are performed on the SPAD array through simple and efficient sequence number configuration, and further, the distribution positions of pixels are controlled based on factors such as the connection area of each TDC unit and the priority sequence of the TDC unit, so that data of single pixels at corresponding positions can be output by using different frames, the number of frames corresponds to the priority sequence of the TDC unit connected with the opening pixel, each frame accurately and efficiently outputs data of only opening pixels by the TDC unit with the highest priority, and depth values of all pixels can be output when the period frame number is completed, thereby realizing the pixel mapping function of 1*1- >2 x 2- >4*4- >8 x 8 in the embodiment, realizing dynamic depth detection of pixel resolution, and improving the flexibility of depth detection.

It should be noted that, there is not necessarily a certain sequence between the steps, and those skilled in the art will understand that, in different embodiments, the steps may be performed in different orders, that is, may be performed in parallel, may be performed interchangeably, or the like.

The present invention also provides a depth sensor chip configured dynamically, as shown in fig. 6, fig. 6 is a structural diagram of the depth sensor chip in an embodiment of the present invention, which includes a SPAD array 601, a state machine 602, a TDC array 603, a histogram module 604, and a data processing module 605, where the SPAD array 601, the TDC array 603, the histogram module 604, and the data processing module 605 are sequentially connected, and the SPAD array 601 is further connected to the state machine 602. The SPAD array 601 is divided into m×n pixels based on the obtained pixel configuration information and configures an initial on position, where each pixel includes at least one SPAD unit, and one or more pixels are correspondingly connected to one TDC unit; the state machine 602 is configured to control one pixel at a corresponding position to be sequentially turned on at each frame in a specified order from an initial on position according to the number of frames and the pixel configuration information; the TDC array 603 includes a plurality of TDC units, each of which is configured to receive a photon signal output by one pixel connected thereto in response to an incident photon, and output TDC data corresponding to the photon signal for each frame; the histogram module 604 is configured to correspondingly generate m×n histograms according to the output m×n frame TDC data when the state machine 602 completes each round of m×n frames; the data processing module 605 is configured to calculate depth values of m×n pixels according to the m×n histograms. Since the foregoing method embodiments have been described in detail for the dynamically configured depth detection process, reference may be made specifically to the foregoing corresponding method embodiments, which are not described herein in detail.

In summary, the invention provides a dynamically configured depth detection method and a depth sensing chip, the method comprises the following steps: acquiring pixel configuration information, dividing the SPAD array into m x n pixels according to the pixel configuration information, and configuring an initial starting position, wherein each pixel comprises at least one SPAD unit, and one or more pixels are correspondingly connected with one TDC unit; setting a state machine, and starting from an initial starting position according to the frame number and pixel configuration information of the state machine, and sequentially controlling one pixel at a corresponding position to be sequentially opened in each frame according to a designated sequence; outputting the TDC data of each frame through a TDC unit connected to one pixel that is turned on; when the state machine completes one round of m x n frames, correspondingly generating m x n histograms according to the output m x n frames of TDC data; and calculating the depth values of the m x n pixels according to the m x n histograms. The depth detection of different pixel resolutions is realized by dynamically dividing pixel configuration and flexibly using the frame number of a state machine to dynamically open and close each pixel.

The foregoing is a further detailed description of the invention in connection with the preferred embodiments, and it is not intended that the invention be limited to the specific embodiments described. It will be apparent to those skilled in the art that several equivalent substitutions and obvious modifications can be made without departing from the spirit of the invention, and the same should be considered to be within the scope of the invention.

Claims (13)

1. A dynamically configured depth detection method, comprising the steps of:

acquiring pixel configuration information, dividing a SPAD array into m-n pixels according to the pixel configuration information, and configuring an initial starting position, wherein each pixel comprises at least one SPAD unit, one or more pixels are correspondingly connected with one TDC unit, and only one pixel is started at the same time;

setting a state machine, and controlling one pixel at a corresponding position to be sequentially opened in each frame according to a designated sequence from an initial opening position according to the frame number of the state machine and the pixel configuration information;

outputting the TDC data of each frame through a TDC unit connected to one pixel that is turned on;

when the state machine completes one round of m x n frames, correspondingly generating m x n histograms according to the output m x n frames of TDC data;

and calculating the depth values of the m x n pixels according to the m x n histograms.

2. The method for dynamically configuring depth detection according to claim 1, wherein the obtaining pixel configuration information, dividing the SPAD array into m×n pixels according to the pixel configuration information, and configuring an initial on position, comprises:

acquiring pixel configuration information, wherein the pixel configuration information comprises the number of pixels, the serial numbers of the pixels and the distribution of the pixels;

dividing the SPAD units with the same serial numbers in the SPAD array into the same pixel to obtain m x n pixels; the SPAD array comprises m×n SPAD units, M can be divided by M, and N can be divided by N.

3. The method of dynamically configurable depth detection of claim 1, wherein,

and setting the enabling signals of the SPAD units corresponding to the pixels to be started to be 1, and setting the enabling signals of the SPAD units corresponding to other pixels to be 0.

4. The method according to claim 2, wherein the step of sequentially controlling the pixel at the corresponding position to be turned on in the designated order includes:

in order of sequence numbers from small to large, one pixel at the position of sequence number 1 is turned on at the 1 st frame, one pixel at the position of sequence number 2 is turned on at the 2 nd frame, and so on, and one pixel at the position of sequence number m is turned on at the m x n frame.

5. The method of dynamically configured depth detection of claim 2, wherein the obtaining pixel configuration information, before dividing a SPAD array into m x n pixels and configuring an initial on position according to the pixel configuration information, further comprises:

k TDC units and the priority of each TDC unit are configured, each TDC unit is connected to one or more pixels, k=m or n or other integer dividing m×n.

6. The dynamically configurable depth sounding method of claim 5, wherein said configuring the priority of each TDC unit is specifically:

the priority of the first TDC unit is highest at frame 1, the priority of the second TDC unit is highest at frame 2, …, the priority of the kth TDC unit is highest at the kth frame, the priority of the first TDC unit is highest at the k+1th frame, and so on until the detection output is stopped.

7. The method of dynamically configurable depth probe of claim 6, wherein the pixel configuration information comprises a connection of m x n pixels to k TDC units.

8. The method for dynamically configuring depth detection according to claim 7, wherein the connection relation is specifically:

the pixels sequentially connected to the first to kth TDC units are arranged in a cyclic manner with k as a period in the order of decreasing numbers.

9. The dynamically configured depth detection method of claim 1, wherein when the SPAD array is divided into 2 x 2 pixels and 4 TDC units are configured, the 1 pixel is connected to 1 TDC unit, and the pixels and TDC units are sequentially turned on in order of increasing sequence number as the number of frames increases.

10. The dynamically configured depth detection method of claim 1, wherein when the SPAD array is divided into 4*4 pixels and 4 TDC units are configured, the 4 pixels are connected with 1 TDC unit, and the pixels and TDC units are sequentially turned on in order of increasing sequence as the number of frames increases; wherein, the pixels with the serial numbers of 1, 5, 9 and 13 are connected with the first TDC unit; the pixels with the serial numbers of 2, 6, 10 and 14 are connected with a second TDC unit; the pixels with the serial numbers of 3, 7, 11 and 15 are connected with a third TDC unit; the pixels numbered 4, 8, 12 and 16 are connected to a fourth TDC unit.

11. The method for dynamically configuring depth detection according to claim 1, wherein from a sequence number of 1 to a sequence number of m, every k sequence number of pixels are distributed in the same partition, the pixels in the same partition are connected to the same TDC unit, and k is the number of TDC units; pixels of adjacent sequence numbers are distributed in different partitions.

12. The dynamically configurable depth detection method of claim 11, wherein from sequence number 1 to sequence number m pixels, every k consecutive sequence number pixels are distributed in different k partitions clockwise in SPAD array;

m n/k pixels in the same partition are also distributed clockwise in the partition in the order of the sequence from small to large, and k is the number of TDC units.

13. A depth sensing chip, comprising:

the SPAD array is divided into m x n pixels based on the acquired pixel configuration information and configures an initial starting position, wherein each pixel comprises at least one SPAD unit, and one or more pixels are correspondingly connected with one TDC unit;

a state machine configured to control one pixel at a corresponding position to be sequentially turned on at each frame in a specified order from an initial on position according to a frame number and the pixel configuration information;

the TDC array comprises a plurality of TDC units, wherein each TDC unit is used for receiving photon signals output by one pixel connected with the TDC unit in response to incident photons and outputting TDC data corresponding to the photon signals according to each frame;

the histogram module is used for correspondingly generating m x n histograms according to the output m x n frame TDC data when the state machine completes each round of m x n frames;

and the data processing module is used for calculating and obtaining depth values of m x n pixels according to the m x n histograms.