EVS pixel operation method and related apparatus

Abstract

The present application provides an operating method of an EVS pixel and a related device, the method including: recording an output voltage generated by an EVS pixel in response to an incident light intensity at a first time to obtain a first voltage; taking the first voltage as a reference voltage, integrating the output voltage within a preset integration time after the first time to obtain a voltage change value; comparing the voltage change value with a preset voltage threshold range, and outputting an event signal when the voltage change value exceeds the voltage threshold range. By implementing the solution of the present application, the voltage change value generated by an EVS pixel in response to a change in light intensity within a certain time can be amplified and processed, and the voltage change value can be more clearly represented as increasing in a forward direction or decreasing in a reverse direction, which effectively ensures the accuracy of the event signal output by the EVS image sensor.

Description

[Technical Field]

[0001] This application relates to the field of sensor technology, and more particularly to an operating method for EVS pixels and related devices. [Background technology]

[0002] With the continuous advancement of science and technology, computer vision technology is also becoming increasingly mature. The emergence of event-based vision sensors (EVS) has attracted increasing attention in the field of vision. By simulating the human retina and responding to pixel point pulses of brightness changes due to motion, it can capture brightness changes in a scene at a very high frame rate, record events at specific points in time and specific locations in the image, and form an event stream rather than a frame stream, thereby solving problems such as information redundancy, large amounts of data storage and real-time processing in conventional cameras. However, current EVS image sensors have limited accuracy in measuring voltage changes due to factors such as noise and misalignment between circuits, and can also cause errors in the output of event signals. [Overview of the project] [Problems that the invention aims to solve]

[0003] The embodiments of this application provide an EVS pixel operation method and related apparatus that can solve the problem of low accuracy in outputting event signals by EVS image sensors, at least according to related technologies. [Means for solving the problem]

[0004] A first embodiment of the present invention provides a method for operating an EVS pixel used in an EVS pixel, the method for operating the EVS pixel is: The output voltage generated by the EVS pixel in response to the incident light intensity at a first time point is recorded, and a first voltage is obtained. Using the first voltage as a reference voltage, the output voltage is integrated within a predetermined integration time after the first time to obtain a voltage change value, This includes comparing the voltage change value with a preset voltage threshold range and outputting an event signal if the voltage change value exceeds the voltage threshold range.

[0005] A second embodiment of the present invention provides an EVS pixel, the EVS pixel comprising an input unit, a sampling unit, an integration unit, a comparison unit, and an output unit, wherein The input unit is used to generate an output voltage in response to the incident light intensity. The sampling unit is used to record the output voltage at a first time as a first voltage. The integration unit is used to obtain a voltage change value by integrating the output voltage within a preset integration time after the first time, using the first voltage as the reference voltage. The comparison unit is used to compare the voltage change value with a preset voltage threshold range. The output unit is used to output an event signal when the voltage change value exceeds the voltage threshold range.

[0006] A third embodiment of the present invention provides a terminal device comprising a memory and a processor for executing a computer program stored in the memory, wherein the processor, upon executing the computer program, implements each step in the method for operating an EVS pixel according to the first embodiment of the present invention.

[0007] A fourth embodiment of the present invention provides a computer-readable storage medium that stores a computer program which, when executed by a processor, implements each step in the method of operating an EVS pixel according to the first embodiment of the present invention. [Effects of the Invention]

[0008] As can be seen from the above, according to the EVS pixel operation method and related apparatus of the present invention, the output voltage generated by the EVS pixel in response to the incident light intensity at a first time is recorded to obtain a first voltage, the output voltage is integrated within a preset integration time after the first time using the first voltage as a reference voltage to obtain a voltage change value, the voltage change value is compared with a preset voltage threshold range, and an event signal is output if the voltage change value exceeds the voltage threshold range. By implementing the present invention's solution, the voltage change value is amplified by integrating the voltage change value generated by the EVS pixel in response to the change in light intensity within a certain time, making it possible to more clearly represent whether the voltage change is increasing in the forward direction or decreasing in the reverse direction, and effectively guaranteeing the accuracy of the event signal output by the EVS image sensor. [Brief explanation of the drawing]

[0009] [Figure 1] This is a basic flowchart of the operation method of the EVS pixel according to the first embodiment of the present application. [Figure 2] This is a schematic diagram of a step signal according to the first embodiment of the present application. [Figure 3] This is a schematic diagram of the structure of an EVS pixel according to the second embodiment of the present application. [Figure 4] This is a schematic diagram of the signal change according to the second embodiment of the present application. [Figure 5] This is a schematic diagram of the structure of a terminal device according to the third embodiment of the present application. [Modes for carrying out the invention]

[0010] To make the purpose, features, and advantages of the present invention clearer and easier to understand, the following clearly and completely describes the technical solutions in the embodiments of the present invention, with reference to the drawings of the embodiments. It is obvious that the embodiments described are only a selection of embodiments of the present invention, not all embodiments. All other embodiments that can be obtained based on the embodiments of the present invention without the creative effort of a person skilled in the art are all within the scope of protection of the present invention.

[0011] In the description of the embodiments of the present application, the orientation or positional relationship indicated by terms such as "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is the orientation or positional relationship shown based on the drawings, and is merely for facilitating the description of the embodiments of the present application and simplifying the description, and does not indicate or imply that the shown device or element must have a specific orientation, be configured and operated in a specific orientation, and thus should not be understood as a limitation to the present invention.

[0012] Furthermore, terms such as "first", "second", etc. are used only for the purpose of description, and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, the features limited by "first" and "second" can explicitly or implicitly include one or more of such features. In the description of the embodiments of the present application, "a plurality" means two or more unless otherwise clearly and specifically limited.

[0013] In the embodiments of the present application, unless otherwise clearly specified and limited, the meanings of terms such as "attachment", "connection", "connection", "fixation", etc. should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection, a mechanical connection, an electrical connection, a direct connection, an indirect connection through an intermediate medium, the interiors of two elements communicating with each other, or there being an interaction relationship between two elements. Those skilled in the art can understand the specific meanings of the above terms in the embodiments of the present application according to specific situations.

[0014] The above description is only a preferred embodiment of the present application and is not intended to limit the present invention. All modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present application should be included within the protection scope of the present application.

[0015] To address the problem of low accuracy in event signal output by EVS image sensors using related technologies, the first embodiment of the present invention provides a method for operating EVS pixels used in an EVS image sensor, the EVS image sensor includes a pixel array consisting of a plurality of EVS pixels, and as shown in Figure 1, Figure 1 is a basic flowchart of the method for operating EVS pixels according to this embodiment, the method for operating EVS pixels includes the following steps.

[0016] In step 101, the output voltage generated by the EVS pixel in response to the incident light intensity at the first time is recorded to obtain the first voltage.

[0017] Specifically, in this embodiment, each EVS pixel in the EVS pixel array is an integrated circuit, in which a photodiode can be integrated as a capacitor that accumulates charge, and in response to the incident light intensity, the photodiode generates an electrical signal including a current signal or a voltage signal, and in the case of a current signal, a current / voltage conversion unit further converts the photocurrent into a logarithmic voltage, that is, it realizes the conversion from a current signal to a voltage signal.

[0018] In step 102, the voltage change is obtained by integrating the output voltage within a predetermined integration time after the first time, using the first voltage as the reference voltage.

[0019] Specifically, in related technologies, the voltage change value is generally obtained by directly subtracting the voltage sampled at the previous time from the voltage at the next time, and the numerical accuracy of this voltage change value is generally limited. Therefore, this embodiment improves the numerical accuracy of the voltage change value by obtaining the voltage change value amplified using an integral method.

[0020] In one selectable embodiment of this embodiment, prior to the above step of integrating the output voltage over a preset integration time after a first time, using a first voltage as a reference voltage, to obtain a voltage change value, the embodiment further includes obtaining an image quality demand index of the EVS image sensor and setting the integration time based on the image quality demand index.

[0021] Specifically, the integration time in this embodiment is determined according to the actual usage requirements, and the above image quality requirement indicators include at least one of the following: image output frame rate, image resolution, etc. In actual applications, a longer integration time means that it takes longer to output a single frame of event image, which results in a lower image output frame rate, but at the same time, the image detail of the resulting event image becomes richer, i.e., the resolution becomes higher. As can be seen from this, the integration time is negatively correlated with the image output frame rate and positively correlated with the image resolution. By flexibly setting the integration time, this embodiment can effectively guarantee different image quality requirements and response speed requirements.

[0022] In one selectable embodiment of this embodiment, the above step of obtaining a voltage change value by integrating the output voltage within a preset integration time after a first time, with the first voltage as the reference voltage, includes obtaining a voltage change value by integrating the output voltage within a preset integration time after a first time, with the first voltage as the reference voltage, using a preset first integral calculation formula.

[0023] Furthermore, the integrating unit that performs the integrating operation is equipped with an operational amplifier, and when the currents at the input terminal and output terminal of the operational amplifier are equal, the following equation is satisfied.

[0024]

number

[0025]

number

[0026] In another selectable embodiment of this embodiment, the above step of integrating the output voltage within a preset integration time after a first time, using the first voltage as a reference voltage, to obtain a voltage change value, includes, when the first voltage is a step signal of the second voltage, integrating the output voltage within a preset integration time after a first time, using a preset second integral calculation formula, using the first voltage as a reference voltage, as shown in Figure 2, which is a schematic diagram of the step signal according to this embodiment, showing that the output voltage at the first time is a step signal with amplitude V2.

[0027] Specifically, the second integral formula is:

number

[0028] Furthermore, in one selectable embodiment of this embodiment, the operation method of the EVS pixel further includes statistically calculating the rate of event signals occurring in a unit of time prior to the current time of the EVS pixel, and adjusting the time constant accordingly based on the rate of event signals if the rate of event signals exceeds a preset threshold range of rates.

[0029] Specifically, the event signal occurrence rate in this embodiment is the level of event quantity output by the EVS pixel within a specific time. In this embodiment, considering that the amplification of the voltage change may be insufficient or excessive due to an unreasonable setting of the integration parameters, and that the accuracy of the event signal output may still not be guaranteed, the level of the historical event signal output is evaluated in real time based on this to determine whether the behavior of the event signal output is normal. If not, the integration operation is modified to ensure accurate output of the event signal by adjusting the time constants R and / or C of the integration model described above.

[0030] In step 103, the voltage change value is compared with a preset voltage threshold range, and an event signal is output if the voltage change value exceeds the voltage threshold range.

[0031] Specifically, in this embodiment, the event signal of each EVS pixel is a binary vector (i.e., a 2-bit vector), and this 2-bit vector is used to represent whether the incident light is becoming stronger or weaker. The voltage threshold range in this embodiment is limited by a first voltage threshold and a second voltage threshold, where the first voltage threshold is greater than 0 and the second voltage threshold is less than 0. Preferably, the first and second voltage thresholds are reciprocals of each other. For example, if the value of the first voltage threshold is 0.1V, the value of the second voltage threshold is -0.1V, and the voltage threshold range limited by both is [-0.1, 0.1]. In actual applications, situations in which the voltage change value exceeds the voltage threshold range include two situations: when the above voltage change value is greater than the first voltage threshold, the image sensor detects that the light intensity has increased and outputs a 2-bit vector [1,0] which is an UP event signal; and when the above voltage change value is less than the second voltage threshold, the image sensor detects that the light intensity has decreased and outputs a 2-bit vector [0,1] which is a DN event signal.

[0032] In one selectable embodiment of this embodiment, after the above step of comparing the voltage change value with a preset voltage threshold range, if the voltage change value does not exceed the voltage threshold range, the further steps include statistically calculating the occurrence rate of event signals in a unit of time prior to the current time of the EVS pixel, and updating the reference voltage if the occurrence rate of event signals is lower than a preset first occurrence rate threshold.

[0033] Specifically, in actual applications, when an event signal is output at a second time, reached after integration time from the first time, it is necessary to update the reference voltage. For example, the reference voltage can be updated to the output voltage at the second time, i.e., the recorded first voltage can be updated to the second voltage. If no event signal is output at the second time, it is possible to choose not to update the reference voltage. However, in actual application scenarios, there may be situations where the EVS pixel cannot generate an event signal for a long period of time, and the normal output of the event image cannot be guaranteed. In this scenario, this embodiment can actively choose to update the reference voltage when it is determined that no event signal will be generated for a long period of time based on the statistical results of the event signal occurrence rate. This adjusts the voltage change value used for threshold comparison in the subsequent sensor operation process, dynamically increasing the sensitivity of the EVS pixel to changes in light intensity and improving the event signal occurrence rate. Furthermore, in actual applications, in addition to the method of updating the reference voltage described above, this embodiment may also use a method of updating the voltage threshold range to improve the event signal occurrence rate, and this embodiment is not uniquely limited to this.

[0034] In another optional embodiment of this embodiment, after the above step of outputting an event signal when the voltage change value exceeds a voltage threshold range, the further steps include statistically calculating the rate of event signals occurring in a unit of time prior to the current time for the EVS pixel, and updating the reference voltage if the rate of event signals is higher than a preset second threshold rate.

[0035] Specifically, in actual applications, the data generated by the EVS image sensor is an asynchronous event stream, not a conventional image frame stream. While event streams have the advantage of high temporal resolution, errors and data overload can occur during event stream data transmission, potentially leading to slow or error-filled readouts from the event camera. One solution involves updating the reference voltage and dynamically reducing the sensitivity of the EVS pixel to changes in light intensity when the event rate is high within the historical time, thereby filtering low-frequency signals, limiting the event rate per unit time thereafter, and controlling the bandwidth.

[0036] According to the technical solution of the embodiment of the present invention described above, the output voltage generated by the EVS pixel in response to the incident light intensity at a first time is recorded to obtain a first voltage, the output voltage is integrated within a preset integration time after the first time using the first voltage as a reference voltage to obtain a voltage change value, the voltage change value is compared with a preset voltage threshold range, and an event signal is output if the voltage change value exceeds the voltage threshold range. By implementing the solution of the present invention, the voltage change value is amplified by integrating the voltage change value generated by the EVS pixel in response to the change in light intensity within a certain time, making it possible to more clearly represent whether the voltage change is increasing in the forward direction or decreasing in the reverse direction, and effectively guaranteeing the accuracy of the event signal output by the EVS image sensor.

[0037] Figure 3 is a schematic diagram of the structure of an EVS pixel according to a second embodiment of the present application. The EVS pixel may be used to realize the operation method of the EVS pixel in the embodiment described above. As shown in Figure 3, the EVS pixel 30 mainly includes an input unit 31, a sampling unit 32, an integration unit 33, a comparison unit 34, and an output unit 35, where, The input unit 31 is used to generate an output voltage in response to the incident light intensity. The sampling unit 32 is used to record the output voltage at a first time as the first voltage. The integration unit 33 is used to obtain a voltage change value by integrating the output voltage within a preset integration time after a first time, using the first voltage as the reference voltage. The comparison unit 34 is used to compare the voltage change value with a preset voltage threshold range. The output unit 35 is used to output an event signal when the voltage change value exceeds the voltage threshold range.

[0038] Specifically, in this embodiment, the input unit includes a photoelectric conversion device which may be a photodiode, phototransistor, clamp photodiode, or any other similar device, and the input unit may further include a current / voltage conversion unit configured to convert the photocurrent corresponding to incident light into a logarithmic voltage. A sampling unit is provided with a sampling capacitor, which samples the output voltage generated at a previous time in the input unit and stores it in the sampling capacitor. The EVS pixel may further include a voltage buffer connected to the input unit and the integration unit, respectively, and configured to transmit the voltage of the input unit to the integration unit.

[0039] Referring again to Figure 3, in one selectable embodiment of this embodiment, a first switch 36 is installed between the input unit 31 and the sampling unit 32, the integration unit 33 includes a feedback capacitor 331 and an operational amplifier 332, the operational amplifier includes a first input terminal connected to the input unit 31, a second input terminal connected to the sampling unit 32 and an output terminal connected to the comparison unit 34, the second switch 37 is installed between the first input terminal and the output terminal, the comparison unit 34 is connected to the output unit 35, where both the first switch 36 and the second switch 37 are ON before the first time, the first switch 36 is OFF at the first time, the second switch 37 is OFF after the first time, and when the integration time is reached, the second switch 37 is ON.

[0040] Specifically, if both the first and second switches are turned on before time t1, the feedback capacitor is short-circuited, the integration unit is reset, and at time t1, the pixels are sampled, the incident light is photoelectrically converted to form a voltage V1 at point A, i.e., V A When = V1, the first switch turns off and the voltage V1 is stored in the sampling unit, then the second switch turns off and the integrating unit is V A Starting the integration, the amplification factor of op-amp 332 is sufficiently large to create a virtual short circuit at the input terminal, satisfying the condition that the voltages at points B and C are V1, and at time t2, the voltage corresponding to the incident light is V2, i.e., V A =V2, the second switch is turned on, the integration unit stops integrating and resets it, and the integration unit returns the voltage V obtained by the integration. out The system compares the result with a preset voltage threshold range and outputs an event based on the comparison result. Conventional EVS image sensors generally directly compare the comparison result with a set threshold and output an event signal (i.e., an UP event or DN event). However, this method may result in insufficient accuracy of the event output due to the insufficient numerical accuracy of the comparison result. In this embodiment, the original comparison result is integrated by a second switch, and the integration time can be set according to the demand. Since the comparison result can be amplified by integration, the accuracy of the event output can be improved.

[0041] In this embodiment, based on the fact that the currents across the left and right ends of the operational amplifier 332 are equal, the following equation can be satisfied.

[0042]

number

[0043]

number

Number

[0044] As shown in FIG. 4, FIG. 4 is a schematic diagram of signal changes according to this embodiment. At time t1, when the EVS pixel is sampled and the voltage corresponding to the incident light is V1, the output voltage of the output unit is denoted as V A and V A = V1. Then the first switch turns off, and the voltage V1 is stored in the sampling unit. Next, the second switch turns off, and the integration unit starts integrating V A . Since the amplification factor of the operational amplifier is sufficiently large, the input terminals are in a virtual short circuit state, satisfying V + = V - = V1 (that is, the voltages at points B and C are V1). At time t2, the voltage corresponding to the incident light is V2, and V A = V2. Then the second switch turns on, the integration unit stops integrating and resets it. The integration time is t (that is, t2 - t1). According to the first integration formula, V out is output. Through the comparator, V out is compared with a preset threshold value, and a corresponding event signal is output based on the comparison result. When V A (t)>V1, that is, V out <V1, a UP event is output. When V A (t)<V1 and V out >V1, a DN event is output. According to the second integration formula, when V2 > V1, V out <V1, and a UP event is output. When V2 < V1, Vout >V1 is generated, and a DN event is output. After integration time t, the second switch is turned on, resetting the voltage of the feedback capacitor, and the voltage change at the next time point is integrated. It should be understood that each integration time can be set according to the requirements.

[0045] Furthermore, the operation methods of the EVS pixels in the first embodiment can all be implemented based on the EVS pixels according to this embodiment, and as will be obvious to those skilled in the art, for the sake of clarity and simplicity, the specific operation processes of the EVS pixels described in this embodiment can be explained by referring to the corresponding processes in the embodiments of the methods described above, and will not be explained again here.

[0046] According to this embodiment, the EVS pixel records the output voltage generated by the EVS pixel in response to the incident light intensity at a first time, obtains a first voltage, and uses the first voltage as a reference voltage to integrate the output voltage within a preset integration time after the first time to obtain a voltage change value. This voltage change value is compared with a preset voltage threshold range, and an event signal is output if the voltage change value exceeds the voltage threshold range. By implementing the solution of this invention, the voltage change value is amplified by integrating the voltage change value generated by the EVS pixel in response to the change in light intensity within a certain time, making it possible to more clearly indicate whether the voltage change is increasing in the forward direction or decreasing in the reverse direction, and effectively guaranteeing the accuracy of the event signal output by the EVS image sensor.

[0047] Figure 5 shows a terminal device according to a third embodiment of the present application. This terminal device may be used to realize the operation method of the EVS pixels in the embodiments described above, and mainly, The system includes a memory 501, a processor 502, and a computer program 503 stored in the memory 501 and executable by the processor 502, with the memory 501 and the processor 502 connected by communication. When the processor 502 executes the computer program 503, it realizes the method of the first embodiment described above. Here, the number of processors may be one or more.

[0048] Memory 501 may be high-speed random access (RAM) memory, or it may be non-volatile memory such as magnetic disk memory. Memory 501 is used to store executable program code, and the processor 502 is coupled to memory 501.

[0049] Furthermore, embodiments of the present application further provide a computer-readable storage medium that may be installed in the electronic device in each of the above embodiments, and the computer-readable storage medium may be the memory in the embodiment shown in Figure 5 described above.

[0050] A computer program is stored in the computer-readable storage medium, and when the program is executed by the processor, the operation method of the EVS pixels in the above-described embodiment is realized. Furthermore, this computer-readable storage medium may be a medium capable of storing various program codes, such as a USB memory, removable hard disk, read-only memory (ROM), RAM, magnetic disk, or optical disk.

[0051] In some embodiments of this application, it should be understood that the disclosed apparatus and methods may be implemented in other forms. For example, the apparatus embodiments described above are illustrative only, and the modularization, for example, is merely a logical functional division. In actual implementation, other division methods may be used, for example, multiple modules or components may be combined or integrated into another system, or some features may be ignored or not implemented. Furthermore, the coupling, direct coupling or communication connection between the indicated or considered components may be an indirect coupling or communication connection via some interface, apparatus or module, and may be in an electrical, mechanical or other form.

[0052] Modules described as separate components may or may not be physically separate, and components shown as modules may or may not be physical modules, that is, they may be located in one place or distributed across multiple network modules. Depending on the actual requirements, some or all of these modules can be selected to achieve the objectives of the solution of this embodiment.

[0053] Furthermore, each functional module in each embodiment of the present application may be integrated into a single processing module, each module may exist physically independently, or two or more modules may be integrated into a single module. The aforementioned integrated module can be implemented in hardware or as a software functional module.

[0054] If an integrated module is implemented as a software functional module and sold or used as an independent product, it may be recorded on a single computer-readable storage medium. Based on this understanding, an essential or prior art contribution to the technical solution of the present application, or all or part of the technical solution, may be implemented in the form of a software product, which is stored on a readable storage medium containing a plurality of instructions for causing a computer device (which may be a personal computer, server, or network device, etc.) to perform all or part of the steps of each embodiment of the present application. The aforementioned readable storage medium includes various media capable of storing program code, such as USB disks, removable hard disks, ROMs, RAMs, magnetic disks, or optical disks.

[0055] Furthermore, while the embodiments of each method described above have been expressed as a combination of a series of operations for the sake of simplicity, those skilled in the art should understand that this application is not limited to the sequence of operations described, and that some steps may be performed in other order or simultaneously. Also, those skilled in the art should understand that the embodiments described in the specification are all preferred embodiments, and that such operations and modules are not necessarily required for this application.

[0056] In the above embodiments, each description is given with emphasis, and for parts not detailed in one embodiment, you can refer to the relevant descriptions in other embodiments.

[0057] The above is a description of the operation method of the EVS pixel and related apparatus according to the present application. Those skilled in the art can modify the specific embodiments and scope of application based on the concept of the embodiments of the present application, and therefore, the contents of this specification should not be understood as limitations on the present application.

Claims

1. A method for operating an EVS pixel used in an EVS pixel, wherein the method for operating the EVS pixel is: The output voltage generated by the EVS pixel in response to the incident light intensity at a first time point is recorded to obtain a first voltage. Using the first voltage as a reference voltage, the output voltage is integrated within a predetermined integration time after the first time to obtain a voltage change value, The process includes comparing the voltage change value with a preset voltage threshold range and outputting an event signal if the voltage change value exceeds the voltage threshold range. The step of obtaining a voltage change value by integrating the output voltage within a predetermined integration time after the first time, using the first voltage as a reference voltage, is as follows: The process includes obtaining a voltage change value by integrating the output voltage within a predetermined integration time after the first time, using a predetermined first integral calculation formula, with the first integral calculation formula being: [Math 1] It is expressed as, Here, V ｏｕｔ V represents the voltage change value, Ａ (t) represents the output voltage at time t, V １ A method for operating an EVS pixel, characterized in that represents the first voltage, t1 represents the first time, t2 represents the second time reached after the integration time from the first time, and R and C are time constants.

2. The step of obtaining a voltage change value by integrating the output voltage within a predetermined integration time after the first time, using the first voltage as a reference voltage, is as follows: If the output voltage is a step signal in which the voltage changes from the first voltage to the second voltage, the method includes integrating the output voltage within a predetermined integration time after the first time, using the first voltage as the reference voltage, using a predetermined second integral calculation formula, to obtain a voltage change value, wherein the second integral calculation formula is: [Math 2] It is expressed as, Here, V ｏｕｔ V represents the voltage change value, １ represents the first voltage, V ２ The method for operating an EVS pixel according to claim 1, characterized in that represents the second voltage at time t2, t1 represents the first time, t2 represents the second time reached after the integration time from the first time, R and C are time constants, and Δt represents the integration time.

3. Before the step of obtaining a voltage change value by integrating the output voltage within a predetermined integration time after the first time, using the first voltage as a reference voltage, The image quality demand index of the EVS image sensor is obtained, and the image quality demand index includes at least one of the image output frame rate and image resolution. The method for operating an EVS pixel according to claim 1, further comprising setting the integration time based on the image quality demand index.

4. To statistically determine the occurrence rate of event signals in a unit of time prior to the current time for the aforementioned EVS pixel, The method for operating an EVS pixel according to claim 1 or 2, further comprising adjusting the time constant based on the occurrence rate of the event signal in response to the occurrence rate of the event signal exceeding a preset threshold range of occurrence rates.

5. After the step of comparing the voltage change value with a preset voltage threshold range, If the voltage change value does not exceed the voltage threshold range, the occurrence rate of event signals in a unit of time prior to the current time of the EVS pixel is statistically calculated. The method for operating an EVS pixel according to any one of claims 1 to 3, further comprising updating the reference voltage when the occurrence rate of the event signal is lower than a preset first occurrence rate threshold.

6. After the step of outputting an event signal when the voltage change value exceeds the voltage threshold range, To statistically determine the occurrence rate of event signals in a unit of time prior to the current time for the aforementioned EVS pixel, The method for operating an EVS pixel according to any one of claims 1 to 3, further comprising updating the reference voltage when the occurrence rate of the event signal is higher than a preset threshold for a second occurrence rate.

7. An EVS pixel comprising an input unit, a sampling unit, an integration unit, a comparison unit, and an output unit, wherein, The input unit is used to generate an output voltage in response to the incident light intensity. The sampling unit is used to record the output voltage at a first time as a first voltage. The integration unit is used to obtain a voltage change value by integrating the output voltage within a predetermined integration time after the first time, using the first voltage as a reference voltage, using a predetermined first integration calculation formula. The comparison unit is used to compare the voltage change value with a preset voltage threshold range. The output unit is used to output an event signal when the voltage change value exceeds the voltage threshold range. The first integral calculation formula is, [Math 3] It is expressed as, Here, V ｏｕｔ represents the voltage change value, V Ａ (t) represents the output voltage at time t, V １ represents the first voltage, t1 represents the first time, t2 represents the second time reached after passing the integration time from the first time, and R and C are used because they are time constants. The EV S pixel is characterized by this.

8. A first switch is installed between the input unit and the sampling unit, the integration unit includes a first input terminal connected to the input unit, a second input terminal connected to the sampling unit, and an output terminal connected to the comparison unit, a second switch is installed between the first input terminal and the output terminal, the comparison unit is connected to the output unit, and here, The EVS pixel according to claim 7, characterized in that, before the first time, both the first switch and the second switch are in the ON state, at the first time, the first switch is in the OFF state, after the first time, the second switch is in the OFF state, and when the integration time is reached, the second switch is in the ON state.

9. Terminal device, Memory and The system includes a processor for executing computer programs stored in the aforementioned memory, The terminal device is characterized in that, when the processor executes the computer program, it realizes the steps of the method according to any one of claims 1 to 3.

10. A computer-readable storage medium in which a computer program is stored, wherein the computer program, when executed by a processor, realizes a step according to any one of claims 1 to 3.

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