WO2024050947A1

WO2024050947A1 - Light intensity change detection module and image sensor

Info

Publication number: WO2024050947A1
Application number: PCT/CN2022/129069
Authority: WO
Inventors: 陈守顺; 郭梦晗; 杨文磊
Original assignee: 豪威芯仑传感器(上海)有限公司
Priority date: 2022-09-06
Filing date: 2022-11-01
Publication date: 2024-03-14
Also published as: CN115474008A

Abstract

A light intensity change detection module (120), an image sensor (100), and a method for detecting a periodic light intensity change. The light intensity change detection module (120) comprises: a plurality of light intensity change detection pixel units (200), which are suitable for responding to a light intensity change in a field of view, and when the light intensity change meets a predetermined condition, entering a triggered state, and outputting current pulse signals; and a light intensity change detection control unit (400), which is coupled to each light intensity change detection pixel unit (200), and is suitable for determining, on the basis of the current pulse signals, whether a total pulse current is greater than a threshold value, and generating a pulse signal when the total pulse current is greater than the threshold value, wherein the light intensity change detection pixel units (200) are further suitable for being set after entering the triggered state, so as to respond to the light intensity change in the field of view again and continuously output the current pulse signals, and the light intensity change detection control unit (400) is further suitable for determining, on the basis of the pulse signals, whether the light intensity change is a periodic light intensity change, and generating and outputting frequency information of the light intensity change when the light intensity change is a periodic light intensity change.

Description

A light intensity change detection module and image sensor

Technical field

The present invention relates to the technical field of image sensors, and in particular, to a light intensity change detection module and an image sensor.

Background technique

In recent years, a dynamic visual image sensor that only senses dynamic information in the field of view has attracted more and more attention due to its advantages in the field of motion detection. As a bionic device, its basic working principle is very different from mainstream active pixel sensors. The dynamic vision image sensor abandons the concept of image frames. It only focuses on the dynamic components in the field of view that cause light intensity changes and automatically filters out useless background information. Specifically, each pixel unit in the sensor no longer passively senses the external light intensity, but actively monitors light intensity changes in real time and outputs its own position information when the light intensity changes meet certain conditions. Through this working method, useless background information is automatically filtered out at the sensor level, and the dynamic vision image sensor only outputs data stream information of useful pixel units, thus saving output bandwidth. In this way, the back-end image processing system can directly obtain and process useful dynamic information in the field of view, which can greatly reduce its storage and computing power requirements and achieve better real-time performance.

However, on the other hand, short-term light intensity changes such as "flash" existing in the field of view can also cause changes in light intensity in the corresponding area of the pixel unit and cause the dynamic vision image sensor to output data. In some scenes, this "flash" has nothing to do with the movement of the object but is just an instantaneous or periodic change in light intensity at certain locations in the field of view. For example, there is an LED light that flashes at a fixed frequency indoors. Periodic flashes appear in all areas of the field of view, causing all pixel units to detect changes in light intensity and output them by the sensor. However, this part of the data output by the sensor, It cannot accurately represent the motion information of the object. If data is not differentiated, the performance of various motion detection algorithms executed by the back-end processor will decrease, which limits the application scenarios of dynamic vision sensors. .

Based on the above pain points, a solution is needed that can detect light intensity changes in the field of view that do not represent object motion information.

Contents of the invention

The present invention provides a light intensity change detection module and an image sensor, in an attempt to solve or at least alleviate at least one of the above problems.

According to an aspect of the present invention, a light intensity change detection module is provided, including: a plurality of light intensity change detection pixel units, the light intensity change detection pixel unit being adapted to respond to light intensity changes in the field of view and detect the light intensity change in the field of view. When the light intensity change meets the predetermined conditions, it enters the trigger state and outputs a current pulse signal; the light intensity change detection control unit is coupled to each light intensity change detection pixel unit and is adapted to be based on the current pulse signal from each light intensity change detection pixel unit. , determine whether the total pulse current is greater than the threshold, and generate a pulse signal when the total pulse current is greater than the threshold; the light intensity change detection pixel unit is also adapted to be set after entering the trigger state to re-respond to light intensity changes in the field of view and Continuously output the current pulse signal to the light intensity change detection control unit; and the light intensity change detection control unit is also adapted to determine whether the light intensity change is a periodic light intensity change based on the pulse signal, and when the light intensity change is a periodic light intensity change, When, the frequency information of the light intensity change is generated and output.

Optionally, in the light intensity change detection module according to the present invention, the light intensity change detection control unit includes: a light intensity change determination subunit, adapted to receive current pulses from all light intensity change detection units via the current pulse output signal line signal, and when the total pulse current is greater than the threshold, a pulse signal is generated; the pulse frequency judgment subunit is suitable for judging whether the pulse signal is a periodic signal by calculating the time difference between multiple pulse signals. If the pulse signal is Periodic signal, then the light intensity changes are periodic light intensity changes.

Optionally, in the light intensity change detection module according to the present invention, the pulse frequency judgment subunit is also adapted to calculate the time difference between adjacent pulses, and when the time difference between adjacent pulse signals is the same, The pulse signal is determined to be a periodic signal; and the pulse frequency determination subunit is also adapted to calculate the frequency information of the light intensity change based on the time difference when it is determined that the light intensity change is a periodic light intensity change.

Optionally, in the light intensity change detection module according to the present invention, the light intensity change detection pixel unit includes: a photoelectric detection subunit, suitable for real-time monitoring of the light signal irradiated on it, and outputting a corresponding electrical signal; triggering generation A subunit, a first input end of which is coupled to the photodetection subunit, and a first output end of which is coupled to the logic subunit, and the trigger generation subunit is adapted to generate a trigger generation signal to the logic when the electrical signal meets a predetermined condition. Subunit; a logic subunit, the input end of which is coupled to the trigger generation subunit, the output end is coupled to the current pulse generation subunit, and the logic subunit is adapted to output a signal to the current pulse generation subunit when receiving the trigger generation signal; The current pulse generating subunit is adapted to generate and output the current pulse signal when receiving the output signal of the logic subunit.

Optionally, in the light intensity change detection module according to the present invention, the logic subunit includes a latch and a delay circuit. When the trigger generation signal is received, the latch is set and delayed. After the delay of the circuit, the latch is restored to the reset state; and the output signal of the latch is the reset signal of the trigger generation subunit, so that during the latch setting period, the trigger generation subunit is reset.

Optionally, in the light intensity change detection module according to the present invention, the current pulse generation subunit includes: a current source; a transistor, its gate is connected to the output of the logic subunit, its source is connected to the current source, and its drain passes the current The pulse output signal line is coupled with the light intensity change detection control unit.

Optionally, in the light intensity change detection module according to the present invention, the light intensity change determination subunit includes: a reference current source; a current comparator, the non-inverting input terminal of which is connected to the current pulse output signal line, and the inverting input terminal is connected to the reference current source, the output end of which is connected to the pulse frequency confirmation subunit, and is suitable for outputting a pulse signal to the pulse frequency judgment subunit when it is judged that the total pulse current from the current pulse output signal line exceeds the reference current source.

Optionally, in the light intensity change detection module according to the present invention, the light intensity change determination subunit includes: a current analog-to-digital converter, the input terminal of which is connected to the current pulse output signal line, and the output terminal of which is connected to a digital comparator, suitable for Quantize the total current pulse into a digital signal and output it to a digital comparator; the input terminal of the digital comparator is connected to the current analog-to-digital converter, and its output terminal is connected to the pulse frequency judgment subunit, which is suitable for confirming the output of the current analog-to-digital converter. After exceeding the threshold, the pulse signal is output to the pulse frequency judgment subunit.

Optionally, in the light intensity change detection module according to the present invention, the threshold value is determined based on at least the number of light intensity change detection pixel units.

Optionally, in the light intensity change detection module according to the present invention, a plurality of light intensity change detection pixel units are arranged around the main pixel array, and the main pixel array is adapted to trigger the corresponding response when the light intensity change in the field of view reaches a predetermined condition. main pixel unit, and output at least the address information of the triggered main pixel unit; and the number of light intensity change detection pixel units is determined based on the main pixel array.

According to yet another aspect of the present invention, a method for detecting periodic light intensity changes is provided, which is suitable for execution in the light intensity change detection module as described above, including: generating a current by monitoring light intensity changes in the field of view. Pulse signal, wherein the current pulse signal is generated when the light intensity change meets a predetermined condition; determine whether to generate a pulse signal by judging the size of the current pulse signal; repeat the steps of iteratively monitoring changes in light intensity and judging the size of the current pulse signal to generate Multi-segment pulse signals; and determining whether the light intensity change is a periodic light intensity change by calculating the time difference between the multi-segment pulse signals.

Optionally, the method according to the present invention further includes: when it is determined that the light intensity change is a periodic light intensity change, outputting frequency information of the light intensity change.

Optionally, in the method according to the present invention, determining whether to generate a pulse signal by judging the size of the current pulse signal includes: when the total instantaneous current of the received current pulse signal is greater than the threshold, confirming that the pulse signal is generated.

According to another aspect of the present invention, an image sensor is provided, including: core circuit components, adapted to trigger the corresponding main pixel unit when the light intensity change in the field of view meets a predetermined condition, and at least output the triggered main pixel unit The address information; the light intensity change detection module as described above is arranged around the main pixel array and is suitable for detecting periodic light intensity changes based on light intensity changes in the field of view.

Optionally, in the image sensor according to the present invention, the core circuit component includes a main pixel array, and the main pixel array includes a plurality of main pixel units; the number of light intensity change detection pixel units in the light intensity change detection module is determined by the main pixel array. Determine the number of rows and columns.

In summary, according to the solution of the present invention, without changing the structure of the original dynamic vision sensor, by adding an independent light intensity change detection module, the detection of periodic light intensity changes in the field of view can be realized, and the changes in the visual field can be detected. When there are periodic light intensity changes in the field, the frequency information of the light intensity changes is output to the back-end processing unit. According to the solution of the present invention, the interference of such periodic light intensity changes in the field of view on the output data of the dynamic vision sensor can be effectively reduced, and the performance of motion detection can be improved.

At the same time, the light intensity change detection module does not need to be coupled to the core circuit components. On the one hand, the core circuit components and the light intensity change detection module can independently complete their respective tasks without affecting each other, improving the working efficiency of the image sensor; on the other hand, the light intensity change detection module The change detection module is easy to deploy by simply determining the number of light intensity change detection pixel units based on the main pixel array in the core circuit assembly.

Description of the drawings

To carry out the above and related purposes, certain illustrative aspects are described herein in conjunction with the following description and accompanying drawings, which are indicative of various ways in which the principles disclosed herein may be practiced, and all aspects and their equivalents are intended to within the scope of the claimed subject matter. The above and other objects, features and advantages of the present disclosure will become more apparent by reading the following detailed description in conjunction with the accompanying drawings. Throughout this disclosure, the same reference numbers generally refer to the same parts or elements.

Figure 1 shows a schematic diagram of an image sensor 100 according to some embodiments of the invention;

Figure 2 shows a schematic diagram of a light intensity change detection module 200 according to some embodiments of the present invention;

Figure 3 shows a schematic diagram of a current pulse generation subunit 240 according to some embodiments of the present invention;

Figure 4 shows a schematic diagram of a light intensity change detection control unit 400 according to some embodiments of the present invention;

5A and 5B respectively show a schematic diagram of the light intensity change determination subunit 410 according to some embodiments of the present invention;

Figure 6 shows a schematic flowchart of a method 600 for detecting periodic light intensity changes according to some embodiments of the present invention.

Detailed ways

Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a thorough understanding of the disclosure, and to fully convey the scope of the disclosure to those skilled in the art.

As mentioned above, the dynamic vision image sensor (hereinafter referred to as the dynamic vision sensor) detects dynamic information in the field of view at the pixel level. Each pixel unit in the dynamic vision sensor monitors changes in light intensity in real time, and confirms that a pixel event occurs after the change reaches a predetermined condition (the predetermined condition is, for example, a preset value or a preset interval, etc., but is not limited to this), and Output pixel event information (for example, position information of the pixel unit). Since the movement of the object will cause the light intensity of the corresponding area in the field of view perceived by the corresponding pixel unit to change, the moving object in the field of view can be detected. However, on the other hand, there are some light intensity changes in the field of view that do not represent object motion information, but can cause light intensity changes in pixel units and cause the dynamic vision sensor to output data. Especially when this type of light intensity change is a global light intensity change (for example, when a vehicle enters/exits a tunnel), the dynamic vision sensor will output a full range of useless data, which will occupy a high output bandwidth and have a negative impact on subsequent Image processing, etc. cause interference.

The applicant found through research that when there are periodic light intensity changes in the field of view, if the dynamic vision sensor can give the frequency of light intensity changes in some way, then the back-end processor can extract valid objects in a variety of ways Events generated by motion improve the signal-to-noise ratio of event signals. For example, the back-end processing unit can extract events generated by object movement within this period of time by differencing the corresponding event frames according to the light intensity conversion frequency. Due to the periodicity of light intensity changes, it will generate irrelevant events at fixed times and locations. This redundant information can be easily removed by making a difference between the previous and later event frames. In addition, for light intensity changes with a short change time, the back-end processing unit can also periodically reset the dynamic vision sensor for a short period of time according to the frequency of light intensity changes to block out the light intensity changes.

In view of this, according to embodiments of the present invention, a solution for detecting periodic light intensity changes in the field of view is provided. When a periodic light intensity change is detected in the field of view, the frequency information of the light intensity change can be provided to the back-end processing unit for processing by the back-end processing unit.

Figure 1 shows a schematic diagram of an image sensor 100 according to some embodiments of the invention.

The image sensor 100 adds an independent circuit component to the existing structure of the dynamic vision sensor for detecting periodic light intensity changes in the field of view. According to an implementation manner, the image sensor 100 is coupled to an external image acquisition system and transmits the output data to the external image acquisition system for further calculation and processing. The embodiments of the present invention are not limited to this.

As shown in FIG. 1 , the image sensor 100 at least includes: a core circuit component 110 and a light intensity change detection module 120 . Among them, the core circuit component 110 completes the core function of the image sensor 100: detecting changes in light intensity and outputting pixel event information. In some embodiments, the core circuit component 110 mainly includes a plurality of main pixel units. When the light intensity change in the field of view reaches a predetermined condition, the main pixel unit in the corresponding area will be triggered, and the output of the core circuit component 110 will be triggered. Address information of the pixel unit. In some embodiments, the core circuit component 110 can also output time information of the triggered main pixel unit. The light intensity change detection module 120 is arranged around the core circuit component 110 and is used to detect and determine periodic light intensity changes in the field of view. At the same time, the light intensity change detection module 120 will also detect periodic light when it detects periodic light. When the intensity changes, calculate the frequency of light intensity changes.

According to the embodiment of the present invention, the core circuit component 110 detects and outputs dynamic information in the field of view. Further, the core circuit component 110 further includes: a main pixel array 112, a readout unit 114, and a main pixel array control unit 116. 1 , the main pixel array 112 is composed of multiple identical pixel acquisition circuits (or “main pixel units”) in one or two dimensions. A 3×3 main pixel array is shown in Figure 1, but is not limited thereto. Each main pixel unit independently and real-time monitors the light intensity changes in the corresponding area of the field of view, and enters the trigger state when it senses that the light intensity changes meet predetermined conditions (for example, the light intensity changes exceed a preset value). Optionally, the preset value of the light intensity change that can be determined by the main pixel unit can be adjusted according to different application scenarios through a filter (such as a high-pass filter) arranged in the main pixel unit to ensure that only a certain preset value is reached. Changes in light intensity at the set value are considered "movement" and are monitored. When the main pixel unit enters the trigger state, it sends a request signal to the peripheral readout unit 114. When it is selected by the readout unit 114, the readout unit 114 sends the address information (including row address and column address) of the main pixel unit 200. ) is encoded and output. The main pixel array control unit 116 is coupled to each main pixel unit through a global reset signal line, and sends a global reset signal to the main pixel unit to control the state of each main pixel unit.

According to the embodiment of the present invention, the working state of the core circuit component 110 depends on the global reset signal sent by the main pixel array control unit 116 . During initialization, the main pixel array control unit 116 sends a global reset signal to each main pixel unit in the main pixel array 112 through the global reset signal line to turn off the main pixel unit so that it no longer responds to changes in light intensity in the field of view. The entire main pixel array 112 is initialized. At the same time, while the global reset signal is valid, the readout unit 114 is also reset, and the core circuit component 110 enters the light intensity detection reset state, does not respond to light intensity changes in the field of view, and does not output data. When the global reset signal is cancelled, the core circuit component 110 of the image sensor 100 enters the light intensity detection enable state and begins to operate normally.

According to the embodiment of the present invention, the light intensity change detection module 120 arranged on the periphery of the core circuit component 110 is mainly used to detect periodic light intensity changes in the field of view that are not related to the movement of objects. According to an embodiment of the invention, the light intensity change is global.

With reference to FIG. 1 , the light intensity change detection module 120 further includes a plurality of light intensity change detection pixel units 200 and a light intensity change detection control unit 400 . Specifically, the light intensity change detection pixel unit 200 is used to detect whether there is a global light intensity change phenomenon in the field of view. The light intensity change detection control unit 400 serves as the global light intensity change determiner of the dynamic vision sensor, used to manage the light intensity change detection pixel unit 200, and obtains the result by calculating the interval time of the light intensity change when determining that the global light intensity change phenomenon occurs. The frequency of light intensity changes.

According to some embodiments of the present invention, the light intensity change detection pixel units 200 are distributed in the form of an array on the periphery of the main pixel array 112 . In one embodiment, at least one row/column of light intensity change detection pixel units 200 are respectively arranged in the four directions of upper, lower, left and right of the main pixel array 112, that is, light intensity change detection pixel rows or light intensity Change detection pixel column. Furthermore, the number of light intensity change detection pixel units 200 is determined by the number of rows and columns of the main pixel units in the main pixel array. More specifically, the number of light intensity change detection pixel units 200 in the light intensity change detection pixel row is consistent with the number of columns of the main pixel array 112; the number of light intensity change detection pixel units 200 in the light intensity change detection pixel column is consistent. , consistent with the number of rows of the main pixel array 112 . For example, the number of rows and columns of the main pixel array in FIG. 1 are both 3, then the number of corresponding light intensity change detection pixel units 200 is 3*4=12. That is to say, one row/column of light intensity change detection pixel units 200 are respectively arranged in the four directions of the main pixel array 112 in the upper, lower, left, and right directions, and the number of light intensity change detection pixel units 200 in each row/column is Both are 3. It should be noted that, to simplify the description, FIG. 1 only shows that the light intensity change detection pixel units 200 are distributed above and to the right of the main pixel array 112, and three light intensity change detection pixel units 200 form a light intensity change unit. The detection pixel row consists of three light intensity change detection pixel units 200 forming a light intensity change detection pixel column. It should be understood that FIG. 1 is only for illustration, and only shows part of the light intensity change detection pixel unit 200 .

The basic function of the light intensity change detection pixel unit 200 is basically the same as that of the main pixel unit, which is to detect light intensity in a corresponding area in the field of view. The light intensity change detection pixel unit 200 can respond to the light intensity change in the corresponding area of the field of view and enter the trigger state and generate a current pulse signal after the change meets a predetermined condition.

The light intensity change detection control unit 400 is connected to all the light intensity change detection pixel units 200 through current pulse output signal lines. In this way, the light intensity change detection control unit 400 determines whether there is a global light intensity change in the field of view through the received current pulse signal; and when it is confirmed that there is a global light intensity change, it continues to determine the global light intensity change. Is it cyclical? When it is a periodic light intensity change, the light intensity change detection control unit 400 calculates and outputs the frequency information of the light intensity change to the back-end processing unit.

In summary, according to the image sensor 100 of the present invention, without changing the structure of the original dynamic vision sensor, it is possible to detect periodic light intensity changes in the field of view by adding a set of pixel units for detecting changes in light intensity. detection, and when there are periodic light intensity changes in the field of view, the frequency information of the light intensity changes is output to the back-end processing unit. According to the solution of the present invention, the interference of such periodic light intensity changes in the field of view on the output data of the dynamic vision sensor can be effectively reduced, and the performance of motion detection can be improved.

At the same time, the light intensity change detection module 120 does not need to be coupled to the core circuit component 110. On the one hand, the core circuit component 110 and the light intensity change detection module 120 can independently complete their respective tasks without affecting each other, improving the working efficiency of the image sensor; on the other hand, In one aspect, the light intensity change detection module 120 is easy to deploy, and only the number of light intensity change detection pixel units is determined according to the main pixel array in the core circuit component 110 .

Regarding the specific structure of the core circuit component 110, please refer to the relevant content of the dynamic vision sensor, and there will not be too many restrictions here.

The light intensity change detection module 120 in the image sensor 100 will be further explained below with reference to the figures.

FIG. 2 shows a schematic diagram of the light intensity change detection pixel unit 200 in the light intensity change detection module 120 according to an embodiment of the present invention. As shown in FIG. 2 , the light intensity change detection pixel unit 200 includes a photodetection subunit 210 , a trigger generation subunit 220 , a logic subunit 230 and a current pulse generation subunit 240 .

Among them, the structures and functions of the photodetection subunit 210 and the trigger generation subunit 220 are completely consistent with those of the main pixel unit. Specifically, the photodetection subunit 210 monitors the light signal irradiated thereon in real time and outputs a corresponding electrical signal. As shown in FIG. 2 , the photodetection subunit 210 is a logarithmic photodetector, which includes a photodiode PD1 with an anode grounded, a first transistor T1 and a first amplifier A1 . The source of the first transistor T1 is connected to the cathode of the photodiode PD1, and the drain of the first transistor T1 is connected to the power supply VDD. The first amplifier A1 is connected between the cathode of the photodiode PD1 and the gate of the first transistor T1. Here, A1 can improve the response speed of voltage changes between the source and gate of T1.

The first input end of the trigger generation subunit 220 is coupled to the photodetection subunit 210, and its first output end is coupled to the logic subunit 230. When the electrical signal meets the predetermined condition, the trigger generation subunit 220 generates a trigger generation signal to Logic subunit 230. According to an embodiment, the trigger generation subunit 220 further includes a preprocessing module 221 and a threshold comparison module 222. As shown in Figure 2, the preprocessing module 221 in the trigger generation subunit 220 includes an amplifier A2. The threshold comparison module 222 in the trigger generation sub-unit 220 includes a first voltage comparator VC1, a second voltage comparator VC2 and an OR logic unit. The inverting input terminal of the first voltage comparator VC1 is connected to a fixed level, which is the first threshold of the threshold comparison module 222, and the non-inverting input terminal of the first voltage comparator VC1 is connected to the output of the preprocessing module 221. The non-inverting input terminal of the second voltage comparator VC2 is connected to a fixed level, which is the second threshold of the threshold comparison module 222 , and its inverting input terminal is connected to the output of the preprocessing module 221 . The OR logic unit ORs the outputs of the two voltage comparators. When the output signal of the preprocessing module 221 is greater than the first threshold or less than the second threshold (that is, the light intensity change meets the predetermined condition), the OR logic unit outputs a valid trigger generation signal and sends it to the back-end logic sub-unit 230 .

The input terminal of the logic subunit 230 is coupled to the trigger generation subunit 220 , and the output terminal is coupled to the current pulse generation subunit 240 . When receiving the trigger generation signal, the logic subunit 230 outputs a signal to the current pulse generation subunit 240 . In one embodiment, when receiving the trigger generation signal, the logic subunit 230 outputs a high level to the current pulse generation subunit 240; otherwise, the logic subunit 230 outputs a low level to the current pulse generation subunit 240. After receiving the output signal of the logic subunit 230, the current pulse generating subunit 240 generates and outputs a current pulse signal.

According to some embodiments of the invention, logic subunit 230 includes a latch and delay circuit. When the trigger generation signal is received, the latch is set, and after the delay of the delay circuit, the latch is restored to the reset state. At the same time, the output signal of the latch serves as a reset signal for the trigger generation subunit 220, so that during the latch setting period, the trigger generation subunit is reset to prepare for the next detection of light intensity change. In some embodiments, the output signal of the latch serves as a reset signal for the amplifier in the preprocessing module 221 to reset the trigger generation subunit 220 .

The current pulse generating subunit 240 receives the output signal of the logic subunit 230, converts it into a current pulse signal, and sends it to the current pulse output signal line. Specifically, during the period when the light intensity change detection pixel unit 200 detects a change in light intensity and sets the latch, the current pulse generation subunit 240 generates a fixed current to the current pulse output signal line; conversely, when there is no change in light intensity When detected, there is no current on the current pulse output signal line.

Figure 3 shows a schematic diagram of a current pulse generation subunit 240 according to some embodiments of the present invention.

The current pulse generation subunit 240 includes a transistor M1 and a current source I1. As shown in FIG. 3 , the gate of the transistor M1 is connected to the output of the logic subunit 230 , the source is connected to the current source I1 , and the drain is coupled to the light intensity change detection control unit 400 through the current pulse output signal line. It should be noted that the current pulse output signal line is coupled to all the light intensity change detection pixel units 200 in the light intensity change detection module 120 to automatically realize the current summation function. When the light intensity change detection pixel unit 200 is not triggered, the logic subunit 230 outputs a low level, the transistor M1 is turned off, and the current of the current source I1 will not flow through the current pulse output signal line; when the light intensity change detection pixel unit 200 is triggered When triggered, the logic subunit 230 outputs a high level, the transistor M1 is turned on, and the current of the current source I1 flows through the current pulse output signal line.

It should be noted that each sub-unit in the light intensity change detection pixel unit 200 has multiple implementation methods, and embodiments of the present invention are not limited thereto.

Figure 4 shows a schematic diagram of a light intensity change detection control unit 400 according to some embodiments of the present invention. The light intensity change detection control unit 400 resets all light intensity change detection pixel units 200 at the initial moment of power-on, and then monitors the current magnitude on the current pulse output signal line in real time. In some embodiments, at the initial power-on moment, the light intensity change detection control unit 400 resets the trigger generation sub-unit 220 and the logic sub-unit 230 in the light intensity change detection pixel unit 200 through the initial reset signal line (see Figure 2).

As shown in Figure 4, the light intensity change detection control unit 400 mainly includes: a light intensity change judgment sub-unit 410 and a pulse frequency judgment sub-unit 420.

The light intensity change determination subunit 410 receives current pulse signals from all light intensity change detection pixel units 200 through the current pulse output signal line. As mentioned above, the current pulse output signal line is coupled to all light intensity change detection pixel units 200 , can automatically realize the function of current summation. Therefore, the light intensity change determination subunit 410 obtains the total pulse current at the current moment, that is, the total instantaneous current, through the current pulse output signal line. The total instantaneous current represents the number of light intensity change detection pixel units 200 triggered in the light intensity change detection module 120 at the current moment, that is, the global light intensity change in the field of view. When the total pulse current is greater than the threshold, it outputs a pulse signal to the pulse frequency determination subunit 420.

5A and 5B respectively show schematic diagrams of the light intensity change determination subunit according to some embodiments of the present invention.

As shown in FIG. 5A , the light intensity change determination subunit 410 includes a current comparator and a reference current source. The non-inverting input terminal of the current comparator is connected to the current pulse output signal line, the inverting input terminal is connected to the reference current source, and the output terminal of the current comparator is connected to the pulse frequency confirmation subunit 420 . In this way, the current comparator determines the size of the total pulse current from the current pulse output signal line and the reference current source, and outputs the pulse signal to the pulse frequency determination subunit 420 when the total pulse current exceeds the reference current source. where the reference current source indicates the threshold. The threshold is determined based on at least the number of light intensity change detection pixel units 200. Generally speaking, while keeping other conditions unchanged, the greater the number of light intensity change detection pixel units 200 in the light intensity change detection module 120, the greater the threshold value. The bigger.

As shown in Figure 5B, the light intensity change determination subunit 410 includes a current analog-to-digital converter (ADC, Analog-to-Digital Converter) and a digital comparator. The current ADC quantizes the input total current pulse into a digital signal, and the back-end digital The comparator determines whether the output of the current ADC exceeds the threshold, and after confirming that the output of the current ADC exceeds the threshold, outputs a pulse signal to the pulse frequency determination subunit 420 . Regarding the selection of the threshold, please refer to the relevant description of Figure 5A.

The pulse frequency determination subunit 420 determines whether the pulse signal output by the light intensity change determination subunit 410 is a periodic signal. According to one embodiment, the pulse frequency determination subunit 420 calculates the time difference between adjacent pulses, and determines that the received pulse signal is a periodic signal when the time difference between adjacent pulses is the same.

When it is confirmed that the pulse signal is a periodic signal, the pulse frequency determination subunit 420 confirms that the corresponding light intensity change is a periodic light intensity change. At this time, the pulse frequency determination subunit 420 calculates the frequency of light intensity change based on the time difference between adjacent pulses. Specifically, the time difference between adjacent pulses is the light intensity change period, and the frequency of light intensity change can also be obtained through conversion. According to some embodiments, the pulse frequency determination subunit 420 outputs the frequency of light intensity changes to the back-end processing unit as a detection output of periodic light intensity. The pulse frequency determination subunit 420 can adopt a general period detection method, such as a counter-based detection method, which will not be described again here.

According to the solution of the present invention, without changing the structure of the original dynamic vision sensor, by adding an independent light intensity change detection module, the detection of periodic light intensity changes in the field of view can be realized. And the light intensity change detection module does not need to be coupled to the core circuit components. On the one hand, the core circuit components and the light intensity change detection module can independently complete their respective tasks without affecting each other, improving the working efficiency of the image sensor; on the other hand, the light intensity change detection module The detection module is easy to deploy, just determine the number of light intensity change detection pixel units according to the main pixel array in the core circuit component.

At the same time, the light intensity change detection module will also output the frequency information of the light intensity change to the back-end processing unit when it detects periodic light intensity changes in the field of view. According to the solution of the present invention, the interference of such periodic light intensity changes in the field of view on the output data of the dynamic vision sensor can be effectively reduced, and the performance of motion detection can be improved.

Correspondingly, the present invention also provides a method for detecting periodic light intensity changes using the above-mentioned image sensor 100 or the light intensity change detection module 120 . Figure 6 shows a schematic flowchart of a method 600 for detecting periodic light intensity changes according to some embodiments of the present invention. According to some embodiments of the present invention, the method 600 is performed in the light intensity change detection module 120.

As shown in Figure 6, method 600 begins at 610. In 610, the light intensity change detection pixel unit 200 generates a current pulse signal by monitoring the light intensity change in the field of view, where the current pulse signal is generated when the light intensity change meets a predetermined condition.

In 620, the light intensity change detection control unit 400 determines whether to generate a pulse signal by judging the size of the current pulse signal. According to some embodiments, when the total instantaneous current of the received current pulse signal is greater than the threshold, it is considered that a global light intensity change has occurred, and a pulse signal is generated.

In 630, the steps of monitoring changes in light intensity (ie 610) and the steps of judging the size of the current pulse signal (ie 620) are iteratively repeated to generate multi-segment pulse signals.

In 640, by calculating the time difference between multiple pulse signals, it is determined whether the light intensity change is a periodic light intensity change. According to some embodiments, when the time difference between adjacent pulses is the same, the light intensity change is determined to be a periodic light intensity change.

In addition, according to some embodiments of the present invention, when it is determined that the light intensity change is a periodic light intensity change, frequency information of the light intensity change is output.

It should be understood that the method 600, the aforementioned image sensor 100 and the light intensity change detection module 120 are mutually illustrative, and repeated descriptions will not be repeated.

The various techniques described here may be implemented in conjunction with hardware or software, or a combination thereof. Therefore, the methods and devices of the present disclosure, or certain aspects or parts of the methods and devices of the present disclosure, may be embedded in tangible media, such as removable hard disks, USB disks, floppy disks, CD-ROMs or any other machine-readable storage media. In the form of program code (ie, instructions), wherein when the program is loaded into a machine, such as a computer, and executed by the machine, the machine becomes an apparatus for practicing the present disclosure.

In the case where the program code executes on a programmable computer, the computing device generally includes a processor, a storage medium readable by the processor (including volatile and non-volatile memory and/or storage elements), at least one input device, and at least one output device. Wherein, the memory is configured to store the program code; the processor is configured to execute the method of detecting periodic light intensity changes of the present disclosure according to instructions in the program code stored in the memory.

By way of example, and not limitation, readable media includes readable storage media and communication media. Readable storage media store information such as computer-readable instructions, data structures, program modules or other data. Communication media typically embodies computer readable instructions, data structures, program modules or other data in a modulated data signal such as a carrier wave or other transport mechanism and includes any information delivery media. Combinations of any of the above are also included within the scope of readable media.

In the description provided herein, the algorithms and displays are not inherently associated with any particular computer, virtual system, or other device. Various general-purpose systems may also be used with examples of the present disclosure. From the above description, the structure required to construct such a system is obvious. Furthermore, this disclosure is not directed to any specific programming language. It should be understood that the disclosure described herein may be implemented using a variety of programming languages, and that the above descriptions of specific languages are for the purpose of disclosing preferred embodiments of the disclosure.

In the instructions provided here, a number of specific details are described. However, it is understood that embodiments of the present disclosure may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this description.

Similarly, it should be understood that in the above description of exemplary embodiments of the disclosure, various features of the disclosure are sometimes grouped together into a single embodiment in order to streamline the disclosure and assist in understanding one or more of the various disclosed aspects. figure, or its description. This method of disclosure, however, is not to be interpreted as reflecting an intention that the claimed disclosure requires more features than are expressly recited in each claim. Rather, as the following claims reflect, disclosed aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the claims following the Detailed Description are hereby expressly incorporated into this Detailed Description, with each claim standing on its own as a separate embodiment of this disclosure.

Those skilled in the art will understand that the modules or units or components of the device in the examples disclosed herein may be arranged in the device as described in this embodiment, or may alternatively be located in a different device than in this example. in one or more devices. The modules in the preceding examples can be combined into one module or further divided into sub-modules.

Those skilled in the art will understand that modules in the devices in the embodiment can be adaptively changed and arranged in one or more devices different from that in the embodiment. The modules or units or components in the embodiments may be combined into one module or unit or component, and furthermore they may be divided into a plurality of sub-modules or sub-units or sub-components. All features disclosed in this specification (including accompanying claims, abstract and drawings) and any method so disclosed may be employed in any combination, except that at least some of such features and/or processes or units are mutually exclusive. All processes or units of the equipment are combined. Each feature disclosed in this specification (including accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise.

Furthermore, those skilled in the art will understand that although some embodiments described herein include certain features included in other embodiments but not other features, combinations of features of different embodiments are meant to be within the scope of the present disclosure. within and form different embodiments. For example, in the following claims, any of the claimed embodiments may be used in any combination.

Furthermore, some of the described embodiments are described herein as methods or combinations of method elements that may be implemented by a processor of a computer system or by other means of performing the recited functions. Thus, a processor having the necessary instructions for implementing the method or method elements forms a means for implementing the method or method elements. Furthermore, elements of the apparatus embodiments described herein are examples of means for performing the functions performed by the elements for carrying out the purposes of this disclosure.

As used herein, unless otherwise specified, use of the ordinal words "first," "second," "third," etc., to describe common objects merely means reference to different instances of similar objects and is not intended to imply that The objects being described must have a given order in time, space, ordination, or in any other way.

Although the present disclosure has been described in terms of a limited number of embodiments, those skilled in the art will, having the benefit of the above description, appreciate that other embodiments are contemplated within the scope of the disclosure thus described. Furthermore, it should be noted that the language used in this specification was selected primarily for readability and teaching purposes, and was not selected to explain or define the subject matter of the present disclosure. Accordingly, many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the appended claims. This disclosure is illustrative and not restrictive with respect to the scope of the present disclosure, which is defined by the appended claims.

Claims

A light intensity change detection module, including:

A plurality of light intensity change detection pixel units, the light intensity change detection pixel unit is adapted to respond to light intensity changes in the field of view and enter a trigger state when the light intensity changes meet predetermined conditions, and output a current pulse signal;

The light intensity change detection control unit is coupled to each light intensity change detection pixel unit and is adapted to determine whether the total pulse current is greater than the threshold based on the current pulse signal from each light intensity change detection pixel unit, and when the total pulse current is greater than the threshold, Generate pulse signals;

The light intensity change detection pixel unit is further adapted to be set after entering the trigger state to re-respond to light intensity changes in the field of view and continue to output current pulse signals to the light intensity change detection control unit; and

The light intensity change detection control unit is further adapted to determine whether the light intensity change is a periodic light intensity change based on the pulse signal, and when the light intensity change is a periodic light intensity change, generate and output the light intensity change. Describes the frequency information of light intensity changes.
The light intensity change detection module according to claim 1, wherein the light intensity change detection control unit includes:

The light intensity change determination subunit is adapted to receive current pulse signals from all light intensity change detection units via the current pulse output signal line, and generate a pulse signal when the total pulse current is greater than the threshold;

The pulse frequency judgment subunit is suitable for judging whether the pulse signal is a periodic signal by calculating the time difference between multiple pulse signals. If the pulse signal is a periodic signal, the light intensity change is periodic light. Strong changes.
The light intensity change detection module according to claim 2, wherein,

The pulse frequency judgment subunit is also adapted to calculate the time difference between adjacent pulses, and when the time difference between adjacent pulse signals is the same, determine that the pulse signal is a periodic signal; and, the pulse The frequency determination subunit is also adapted to calculate the frequency information of the light intensity change based on the time difference when it is determined that the light intensity change is a periodic light intensity change.
The light intensity change detection module according to any one of claims 1 to 3, wherein the light intensity change detection pixel unit includes:

The photoelectric detection subunit is suitable for real-time monitoring of the light signal shining on it and outputting corresponding electrical signals;

A trigger generation subunit, a first input end of which is coupled to the photodetection subunit, and a first output end of which is coupled to a logic subunit, where the trigger generation subunit is adapted to generate when the electrical signal meets a predetermined condition. Generate trigger generation signals to logic subunits;

a logic subunit, the input end of which is coupled to the trigger generation subunit, and the output end is coupled to the current pulse generation subunit, and the logic subunit is adapted to output a signal to current pulse generation when receiving the trigger generation signal subunit;

The current pulse generating subunit is adapted to generate and output a current pulse signal when receiving the output signal of the logic subunit.
The light intensity change detection module according to claim 4, wherein the logic subunit includes a latch and a delay circuit,

The latch is set when the trigger generation signal is received, and after the delay of the delay circuit, the latch is restored to the reset state; and, the output of the latch The signal is a reset signal of the trigger generation subunit, so as to reset the trigger generation subunit during the setting period of the latch.
The light intensity change detection module according to claim 4 or 5, wherein the current pulse generating subunit includes:

Battery;

The transistor has a gate connected to the output of the logic subunit, a source connected to the current source, and a drain coupled to the light intensity change detection control unit through a current pulse output signal line.
The light intensity change detection module according to any one of claims 2 to 6, wherein the light intensity change decision subunit includes:

Reference current source;

A current comparator, the non-inverting input end of which is connected to the current pulse output signal line, the inverting input end of which is connected to the reference current source, and the output end of which is connected to the pulse frequency confirmation subunit, which is suitable for determining the signal from the current pulse output signal line. When the total pulse current exceeds the reference current source, a pulse signal is output to the pulse frequency judgment subunit.
The light intensity change detection module according to any one of claims 2 to 6, wherein the light intensity change decision subunit includes:

A current analog-to-digital converter, the input terminal of which is connected to the current pulse output signal line, and the output terminal of which is connected to a digital comparator, which is suitable for quantizing the total current pulse into a digital signal and outputting it to the digital comparator;

A digital comparator, the input terminal of which is connected to the current analog-to-digital converter, and the output terminal of which is connected to the pulse frequency judgment subunit, and is suitable for outputting a pulse signal to the pulse frequency judgment subunit after confirming that the output of the current analog-to-digital converter exceeds the threshold. Frequency judgment subunit.
The light intensity change detection module according to any one of claims 1-8, wherein,

The threshold is determined based on at least the number of the light intensity change detection pixel units.
The light intensity change detection module according to any one of claims 1-9, wherein,

The plurality of light intensity change detection pixel units are arranged around a main pixel array, and the main pixel array is adapted to trigger the corresponding main pixel unit when the light intensity change in the field of view reaches a predetermined condition, and output at least the triggered main pixel The address information of the unit; and the number of the light intensity change detection pixel units is determined based on the main pixel array.
A method for detecting periodic light intensity changes, the method is suitable for execution in the light intensity change detection module according to any one of claims 1-10, including:

Generate a current pulse signal by monitoring changes in light intensity in the field of view, wherein the current pulse signal is generated when the change in light intensity meets a predetermined condition;

Determine whether to generate a pulse signal by judging the size of the current pulse signal;

Repeat the steps of iteratively monitoring changes in light intensity and judging the size of the current pulse signal to generate multi-segment pulse signals; and

By calculating the time difference between the multiple pulse signals, it is determined whether the light intensity change is a periodic light intensity change.
The method of claim 11, further comprising:

When it is determined that the light intensity change is a periodic light intensity change, the frequency information of the light intensity change is output.
The method of claim 11 or 12, wherein determining whether to generate a pulse signal by judging the size of the current pulse signal includes:

When the total instantaneous current of the received current pulse signal is greater than the threshold, it is confirmed that the pulse signal is generated.
An image sensor including:

The core circuit component is adapted to trigger the corresponding main pixel unit when the light intensity change in the field of view meets the predetermined condition, and output at least the address information of the triggered main pixel unit;

The light intensity change detection module according to any one of claims 1 to 10 is arranged around the main pixel array and is adapted to detect periodic light intensity changes based on light intensity changes in the field of view.
The image sensor of claim 14, wherein

The core circuit component includes a main pixel array, and the main pixel array includes a plurality of main pixel units;

The number of light intensity change detection pixel units in the light intensity change detection module is determined by the number of rows and columns of the main pixel array.