Self-adaptive exposure circuit for fusion type visual sensor

Abstract

The invention discloses a self-adaptive exposure circuit for a fusion type visual sensor. The self-adaptive exposure circuit comprises an event statistics module, an event quantity judgment module, an exposure time control module and a gray level statistics module, the event statistics module is used for performing statistics on event data generated by the fusion type visual sensor and outputting a statistical result to the event quantity judgment module; the event quantity judgment module judges the statistical result and transmits a judgment result to the exposure time control module; the gray level statistics module is used for performing statistics on gray level information and transmitting a statistical result to the exposure time control module; and the exposure time control module correspondingly adjusts the exposure time according to the judgment result and the gray information. According to the self-adaptive exposure circuit for the fusion type visual sensor provided by the embodiment of the invention, the phenomena of overexposure or insufficient exposure and the like caused by the change of external light intensity are prevented through the mutual cooperation of all the modules, so that the imaging quality of the fusion type visual sensor is improved.

Description

Technical Field

[0001] The invention belongs to the field of fusion type vision sensor exposure circuits, and in particular relates to an adaptive exposure circuit for a fusion type vision sensor. Background Art

[0002] Advances in fields such as artificial intelligence and autonomous driving have ushered in a new era of intelligent perception, while also placing higher demands on image sensors. In order to face more complex lighting scenarios and meet the needs of high-speed, low-power perception, the visual system has placed higher demands on the speed and dynamic range of image sensors. However, traditional COMS image sensors are limited by their perception methods, and their performance is difficult to continue to improve.

[0003] In order to solve the problems in the traditional image sensors mentioned above, people have proposed a new type of image sensor, namely, an event-based image sensor (EVS), with reference to the human neural visual system. An event-based vision sensor is a sensor that detects and outputs changes in external light intensity. Each pixel independently senses changes in light intensity and discretizes them into events of increased and decreased light intensity. Compared with traditional integral CMOS sensors, it outputs less data, has a faster response speed, and consumes less power. Therefore, event-based vision sensors are widely used in high-speed, high-real-time, and high-dynamic range situations. However, due to the lack of absolute light intensity information, the image visibility of event-based image sensors is generally poor. Therefore, people embed CIS pixels in EVS pixels to obtain a fusion vision sensor (RGBHybrid Event-Based Vision Sensor) that can output grayscale, which can better solve the difficult problems in the field of image processing. In order to better output grayscale and improve the imaging quality of fusion vision sensors. The present invention provides an adaptive exposure circuit for a fusion vision sensor. Summary of the invention

[0004] The technical problem to be solved by the present invention is that, in order to solve various deficiencies existing in the existing visual sensors, the present invention provides an adaptive exposure circuit for a fusion type visual sensor.

[0005] In order to solve the above technical problems, an embodiment of the present invention provides an adaptive exposure circuit for a fusion type visual sensor, comprising: an event statistics module, an event quantity judgment module, an exposure time control module and a grayscale statistics module;

[0006] The event statistics module is used to count the light intensity increase events and light intensity decrease events generated by the fusion type vision sensor, and output the statistical results to the event quantity judgment module;

[0007] The event quantity determination module is used to determine the statistical result and transmit the determination result to the exposure time control module;

[0008] The grayscale statistics module is used to count the grayscale information of the fusion type visual sensor and transmit the statistical results to the exposure time control module;

[0009] The exposure time control module is used to adjust the exposure time accordingly according to the judgment result and the grayscale information.

[0010] Preferably, the event quantity judgment module includes a first threshold and a second threshold; when the number of light intensity increase events minus the number of light intensity decrease events is greater than or equal to the first threshold, the event quantity judgment module outputs a first judgment result; when the number of light intensity decrease events minus the number of light intensity increase events is greater than or equal to the second threshold, the event quantity judgment module outputs a second judgment result; when the number of light intensity increase events minus the number of light intensity decrease events is less than the first threshold and the number of light intensity decrease events minus the number of light intensity increase events is less than the second threshold, the event quantity judgment module outputs a third judgment result.

[0011] Preferably, the grayscale statistics module includes a third threshold, a fourth threshold, a fifth threshold and a sixth threshold; when the grayscale information is less than the third threshold, the grayscale statistics module will determine that the grayscale information is low grayscale pixel information, and count the number of the low grayscale pixel information; when the grayscale information is greater than the fourth threshold, the grayscale statistics module will determine that the grayscale information is high grayscale pixel information, and count the number of the high grayscale pixel information; when the number of the low grayscale pixel information is greater than the fifth threshold, the first statistical result is output; when the number of the high grayscale pixel information is greater than the sixth threshold, the second statistical result is output;

[0012] The third threshold is smaller than the fourth threshold.

[0013] Preferably, the event quantity determination module includes a first subtractor, a second subtractor, a first comparator, a second comparator and an XOR gate;

[0014] The first subtractor input terminal and the second subtractor input terminal are connected to the event statistics module; the first subtractor output terminal is connected to the first comparator input terminal; the second subtractor output terminal is connected to the second comparator input terminal; the first comparator output terminal and the second comparator output terminal are connected to the XOR gate input terminal; the first comparator output terminal, the second comparator output terminal, and the XOR gate output terminal are connected to the exposure time control module as the event quantity judgment module output terminal.

[0015] Preferably, another input terminal of the first comparator is connected to a first threshold value; another input terminal of the second comparator is connected to a second threshold value.

[0016] Preferably, the grayscale statistics module includes: a third comparator, a fourth comparator, a fifth comparator, a sixth comparator, a first D flip-flop, a second D flip-flop, a first adder and a second adder;

[0017] The input terminals of the third comparator and the fourth comparator are connected to the grayscale information as the input terminals of the grayscale statistics module; the output terminal of the third comparator and the output terminal of the first D flip-flop are connected to the input terminal of the first adder; the output terminal of the first adder is connected to the input terminal of the first D flip-flop and the input terminal of the fifth comparator; the output terminal of the fourth comparator and the output terminal of the second D flip-flop are connected to the input terminal of the second adder; the output terminal of the second adder is connected to the input terminal of the second D flip-flop and the input terminal of the sixth comparator; the output terminal of the fifth comparator and the output terminal of the sixth comparator are used as the output terminals of the grayscale statistics module to output the statistical results.

[0018] Preferably, the other input terminal of the third comparator is connected to the third threshold; when the grayscale information is less than the third threshold, the first D flip-flop stores data with an increase of 1; the other input terminal of the fourth comparator is connected to the fourth threshold; when the grayscale information is greater than the fourth threshold, the second D flip-flop stores data with an increase of 1; the other input terminal of the fifth comparator is connected to the fifth threshold; the other input terminal of the sixth comparator is connected to the sixth threshold.

[0019] Preferably, the exposure time control module comprises: a third D flip-flop, a right shift register, a left shift register and a selector;

[0020] The output end of the third D flip-flop is connected to the right shift register input end, the left shift register input end, and the selector input end; the right shift register output end and the left shift register output end are connected to the selector input end; the selector output end is connected to the third D flip-flop input end; the selector selection end is connected to the grayscale statistics module output end and the event quantity judgment module input end as the exposure time control module input end.

[0021] Preferably, the event statistics module comprises: a first event buffer, a first adder group, a first accumulating register, a second event buffer, a second adder group and a second accumulating register;

[0022] The first event buffer is used to store the light intensity increase events generated by the fusion vision sensor, and the output end is connected to the input end of the first adder group; the first adder group is used to accumulate the light intensity increase events, and the output end is connected to the input end of the first accumulation register; the first accumulation register is used to store the statistical results of the light intensity increase events, and output the statistical results of the light intensity increase events to the event quantity judgment module.

[0023] Preferably, the second event buffer is used to store the light intensity reduction events generated by the fusion vision sensor, and the output end is connected to the input end of the second adder group; the second adder group is used to accumulate the light intensity reduction events, and the output end is connected to the input end of the second accumulation register; the second accumulation register is used to store the statistical results of the light intensity reduction events, and output the statistical results of the light intensity reduction events to the event quantity judgment module.

[0024] The implementation of the embodiments of the present invention has the following beneficial effects:

[0025] (1) Before the next exposure of the fusion vision sensor, the embodiment of the present invention uses an event statistics module to count light intensity increase events (ON events) and light intensity decrease events (OFF events), and then compares the number of ON and OFF events through the event quantity judgment module and outputs the comparison result. The grayscale statistics module counts the grayscale information of the fusion vision sensor and outputs the statistical result. Finally, the exposure time control module determines whether to increase, decrease or keep the exposure time unchanged according to the output of the event quantity judgment module and the grayscale statistics module, so as to prevent overexposure or underexposure caused by changes in external light intensity, thereby improving the imaging quality of the fusion vision sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 A schematic diagram of an adaptive exposure circuit structure for a fusion type vision sensor provided for the implementation of the present invention;

[0028] Figure 2 A schematic diagram of the connection structure between an adaptive exposure circuit and a pixel array for a fusion type vision sensor provided for the implementation of the present invention;

[0029] Figure 3A flow chart of an adaptive exposure circuit for a fusion type vision sensor provided for the implementation of the present invention;

[0030] Figure 4 A flow chart of an adaptive exposure circuit control algorithm for a fusion vision sensor provided for the implementation of the present invention;

[0031] Figure 5 A schematic diagram of the structure of an event quantity judgment module of an adaptive exposure circuit for a fusion type visual sensor provided for the implementation of the present invention;

[0032] Figure 6 A schematic diagram of the structure of a grayscale statistics module of an adaptive exposure circuit for a fusion-type visual sensor provided for the implementation of the present invention;

[0033] Figure 7 A schematic diagram of the structure of an exposure time control module of an adaptive exposure circuit for a fusion-type vision sensor provided for the implementation of the present invention. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0035] like Figure 1-Figure 7As shown, the present embodiment discloses an adaptive exposure circuit for a fusion type vision sensor. The adaptive exposure circuit for a fusion type vision sensor is used to connect to a fusion type vision sensor pixel array. The fusion type vision sensor pixel array is a 640×480 pixel array. Each pixel group includes 4 event pixels and 12 RGB pixels, forming a 4×4 structure. The fusion type vision sensor pixel array receives the external light intensity and generates a series of ON and OFF events according to the relative change of the external light intensity under the control of the EVS control circuit, and sends the series of ON and OFF events to the column sampling circuit. After receiving a series of ON and OFF events, the column sampling circuit will send them to the EVS signal processing circuit and the adaptive exposure circuit for the fusion type vision sensor. At the same time, the voltage information of the RGB pixels will be transmitted to the RGB signal processing circuit and the adaptive exposure circuit after being sampled by the column ADC. The adaptive exposure circuit for the fusion type vision sensor will flexibly adjust the exposure time according to the difference in the number of ON and OFF events and the amount of grayscale information of the fusion type vision sensor, and transmit the adjusted exposure time to the RGB control circuit. The exposure of the fusion-type visual sensor pixel array is then controlled, and finally the ON and OFF event data together with the grayscale information data are transmitted to the outside of the chip via the output interface circuit.

[0036] Specifically, the adaptive exposure circuit for the fusion type vision sensor includes: an event statistics module 10, an event quantity judgment module 20, a grayscale statistics module 30 and an exposure time control module 40. The event statistics module 10 is used to count the ON events and OFF events generated by the fusion type vision sensor, and output the statistical results to the event quantity judgment module 20. The event quantity judgment module 20 is used to judge the statistical results and transmit the judgment results to the exposure time control module 40. The grayscale statistics module 30 is used to count the grayscale information of the fusion type vision sensor and transmit the statistical results to the exposure time control module 40. The exposure time control module 40 is used to adjust the exposure time accordingly according to the judgment results and grayscale information.

[0037] Among them, the event quantity judgment module 20 includes a first threshold (Umax_1) and a second threshold (Umax_2). When the number of ON events minus the number of OFF events is greater than or equal to the first threshold, the event quantity judgment module outputs a first judgment result (Flag_ON>>OFF); when the number of OFF events minus the number of ON events is greater than or equal to the second threshold, the event quantity judgment module outputs a second judgment result (Flag_ON<<OFF); when the number of ON events minus the number of OFF events is less than the first threshold and the number of OFF events minus the number of ON events is less than the second threshold, the event quantity judgment module outputs a third judgment result (Flag_ON≈OFF). The first threshold and the second threshold can be set as needed. When the external light is dim, the first threshold can be appropriately increased and the second threshold can be appropriately decreased. When the external light is bright, the first threshold can be appropriately decreased and the second threshold can be appropriately increased.

[0038] The gray scale statistics module 30 has a third threshold (Gray_thr1), a fourth threshold (Gray_thr2), a fifth threshold (max_1), and a sixth threshold (max_2). When the gray scale information is less than the third threshold, the gray scale statistics module 30 will judge that the gray scale information is low gray scale pixel information and count the number of low gray scale pixel information. When the gray scale information is greater than the fourth threshold, the gray scale statistics module 30 will judge that the gray scale information is high gray scale pixel information and count the number of high gray scale pixel information. When the number of low gray scale pixel information is greater than the fifth threshold, a first statistical result (Flag_dark) is output. When the number of high gray scale pixel information is greater than the sixth threshold, a second statistical result (Flag_bright) is output. The third threshold, the fourth threshold, the fifth threshold, and the sixth threshold can be set as needed. In different situations, different sizes can be set. Among them, the third threshold is less than the fourth threshold.

[0039] The adaptive exposure circuit for the fusion type vision sensor determines how to adjust the exposure time by counting the number of ON and OFF events generated by the pixel array of the fusion type vision sensor and the number of high and low gray scale pixel information. The ON and OFF events generated by the EVS pixels carry the change information of the external light intensity, and the time required to generate an event pulse is very short, reaching the nanosecond level, which is much lower than the gray scale information data. Therefore, it is possible to use the ON and OFF event data to help adjust the exposure time. In this way, the fusion type vision sensor using the adaptive exposure circuit for the fusion type vision sensor has a large dynamic range and can handle exposure problems under various different external illuminations.

[0040] Please refer to Figure 3The adaptive exposure circuit of the fusion vision sensor specifically includes the following working steps:

[0041] S1: pixel array response;

[0042] S2: row and column control circuit regulation;

[0043] S3: the event counting module 10 and the event quantity determination module 20 cache the ON and OFF events, and count the number of ON and OFF events;

[0044] S4: The grayscale statistics module 30 performs statistics on the grayscale information;

[0045] S5: The exposure time control module 40 adjusts the exposure time accordingly according to the number of ON and OFF events and the grayscale information.

[0046] Specifically, after the pixel array of the fusion-type visual sensor generates an event in response to changes in external light intensity, it will be regulated by the row and column control circuit, and the event data will be read into the event buffer. Subsequently, the event statistics module 10 and the event quantity judgment module 20 will count the ON and OFF event data, obtain the total number of ON and OFF events, and calculate their difference. At the same time, the grayscale statistics module 30 will count the number of high and low grayscale pixel information. The exposure time control module 40 will selectively increase or decrease the exposure time or keep it unchanged according to the number of ON and OFF events and the grayscale statistics information, thereby realizing adaptive exposure.

[0047] See also Figure 4 , the algorithm flow chart of the adaptive exposure circuit for the fusion type vision sensor is as follows: when the accumulator register of the event statistics module 10 transmits the addition result of the ON and OFF event data to the event quantity judgment module 20. The event quantity judgment module 20 will calculate the difference between the two, and compare the calculation result with its own first threshold and its own second threshold. At the same time, the grayscale statistics module 30 will also compare the number of high and low grayscale pixel information with its own sixth threshold and fifth threshold. When the difference between the number of ON and OFF event data is greater than or equal to the first threshold, and the number of high grayscale pixel information exceeds the sixth threshold, the adaptive exposure circuit for the fusion type vision sensor will reduce the exposure time. When the difference is greater than or equal to the second threshold, and the number of low grayscale pixel information exceeds the fifth threshold, the adaptive exposure circuit for the fusion type vision sensor will increase the exposure time. In other cases, the exposure time remains unchanged.

[0048] In this embodiment, Frame 1 generates 4783 ON events and 238 OFF events, and the difference between the number of ON and OFF events is greater than Umax_1. At this time, if the number of high grayscale pixel information exceeds the sixth threshold, the adaptive exposure circuit for the fusion type visual sensor will reduce the exposure time, otherwise the exposure time remains unchanged. This embodiment achieves the purpose of reducing exposure by shifting the original exposure time data to the right by one position. Frame 6 has 2314 ON events and 1984 OFF events, and the difference between the two numbers is not large, and the exposure time remains unchanged. Frame 9 generates 478 ON events and 5874 OFF events, and the number of OFF events is much greater than the number of ON events. At this time, if the number of low grayscale pixel information exceeds the fifth threshold, the adaptive exposure circuit for the fusion type visual sensor will increase the exposure time, and the exposure time data will be shifted to the left by one position, otherwise the exposure time remains unchanged.

[0049] Each time the exposure time is updated, the new data will be transmitted to the RGB control circuit to control the exposure of the pixel array of the fusion vision sensor. In this way, by flexibly adjusting the exposure time according to the difference in the number of ON and OFF events and the number of high and low grayscale pixel information, the adaptive exposure circuit for the fusion vision sensor can solve the exposure time problem of the fusion vision sensor under different external light intensities and improve its imaging quality.

[0050] See also Figure 1 and Figure 5-Figure 7 The event statistics module 10 includes: a first event buffer 110, a first adder group 120, a first accumulating register 130, a second event buffer 140, a second adder group 150 and a second accumulating register 160. The first event buffer 110, the first adder group 120 and the first accumulating register 130 are used to count ON event data. The second event buffer 140, the second adder group 150 and the second accumulating register 160 are used to count OFF event data.

[0051] The first event buffer 110 is used to store the ON event data generated by the fusion type vision sensor, and the output end is connected to the input end of the first adder group 120. The first adder group 120 is used to accumulate the ON event data, and the output end is connected to the input end of the first accumulation register 130. The first accumulation register 130 is used to store the statistical results of the ON event data, and output the statistical results of the ON event data to the event quantity judgment module 20.

[0052] The second event buffer 140 is used to store the OFF event data generated by the fusion type vision sensor, and the output end is connected to the input end of the second adder group 150. The second adder group 150 is used to accumulate the OFF event data, and the output end is connected to the input end of the second accumulation register 160. The second accumulation register 160 is used to store the OFF event data statistics, and output the OFF event data statistics to the event quantity judgment module 20.

[0053] Specifically, the event buffer is grouped into 16 bits, and 16 bits of data are sent to the adder group at one time. The adder counts the number of "1"s in the 16 bits of data, that is, the number of ON and OFF events, thereby obtaining a 5-bit statistical data. This 5-bit data will be stored in the accumulator register, reflecting the number of events generated by the pixel array. When the event accumulation of the ON and OFF event data is completed, the accumulator register will transmit the addition result to the event quantity judgment module 20. The event quantity judgment module 20 will output a 3-bit flag signal, that is, the judgment result, based on the difference between the number of ON and OFF event data and the size relationship between its own first and second thresholds.

[0054] See also Figure 5 , the event quantity judgment module 20 includes a first subtractor 210, a second subtractor 220, a first comparator 230, a second comparator 240 and an XOR gate 250. The input end of the first subtractor 210 and the input end of the second subtractor 220 are connected to the event statistics module 10. Specifically, the input end of the first subtractor 210 and the input end of the second subtractor 220 are respectively connected to the output end of the first accumulator register 130 and the output end of the second accumulator register 160. The output end of the first subtractor 210 is connected to the input end of the first comparator 230. The output end of the second subtractor 220 is connected to the input end of the second comparator 240. The output end of the first comparator 230 and the output end of the second comparator 240 are connected to the input end of the XOR gate 250. The output end of the first comparator 230, the output end of the second comparator 240, and the output end of the XOR gate 250 are connected to the exposure time control module 40 as the output end of the event quantity judgment module 20, and output the first judgment result, the second judgment result, and the third judgment result to the exposure time control module 40 respectively. The other input end of the first comparator 230 is connected to the first threshold. The other input end of the second comparator 240 is connected to the second threshold. The input data of the subtrahend and minuend ends of the first subtractor 210 are opposite to the input data of the subtrahend and minuend ends of the second subtractor 220, that is, the output of the first subtractor 210 is the ON event number minus the OFF event number, and the output of the second subtractor 220 is the OFF event number minus the ON event number.

[0055] See also Figure 6 The grayscale statistics module 30 includes: a third comparator 310, a fourth comparator 320, a fifth comparator 330, a sixth comparator 340, a first D flip-flop 350, a second D flip-flop 360, a first adder 370 and a second adder 380. The input ends of the third comparator 310 and the fourth comparator 320 are connected to the grayscale information as the input ends of the grayscale statistics module 30. The output end of the third comparator 310 and the output end of the first D flip-flop 350 are connected to the input end of the first adder 370. The output end of the first adder 370 is connected to the input end of the first D flip-flop 350 and the input end of the fifth comparator 330. The output end of the fourth comparator 320 and the output end of the second D flip-flop 360 are connected to the input end of the second adder 380. The output end of the second adder 380 is connected to the input end of the second D flip-flop 360 and the input end of the sixth comparator 340. The output end of the fifth comparator 330 and the output end of the sixth comparator 340 serve as output ends of the grayscale statistics module 30 to output the first statistical result and the second statistical result.

[0056] Among them, the other input end of the third comparator 310 is connected to the third threshold value, which is used to determine whether the input grayscale information is low grayscale pixel information. When the grayscale information is less than the third threshold value, the grayscale information is low grayscale pixel information, and the first D flip-flop 350 stores data with the number 1 added. The other input end of the fourth comparator 320 is connected to the fourth threshold value, which is used to determine whether the input grayscale information is high grayscale pixel information. When the grayscale information is greater than the fourth threshold value, the grayscale information is high grayscale pixel information, and the second D flip-flop 360 stores data with the number 1 added. The other input end of the fifth comparator 330 is connected to the fifth threshold value. The other input end of the sixth comparator 340 is connected to the sixth threshold value. The fifth comparator 330 and the sixth comparator 340 are used to determine whether the number of high and low grayscale pixel information counted by the first D flip-flop 350 and the second D flip-flop 360 reaches the required number.

[0057] See also Figure 7, the exposure time control module 40 includes: a third D flip-flop 410, a right shift register 420, a left shift register 430, and a selector 440. The output terminal of the third D flip-flop 410 is connected to the input terminals of the right shift register 420, the left shift register 430, and the selector 440. The output terminals of the right shift register 420 and the left shift register 430 are connected to the input terminal of the selector 440. The output terminal of the selector 440 is connected to the input terminal of the third D flip-flop 410. The selection terminal of the selector 440 serves as the input terminal of the exposure time control module 40 and is connected to the output terminal of the grayscale statistics module 30 and the input terminal of the event quantity judgment module 20. Among them, the right shift register 420 serves as branch 1. The third D flip-flop 410 is directly connected to the selector 440 as branch 2. The left shift register 430 serves as branch 3.

[0058] In this embodiment, the data of the 5-bit Flag signal received by the selection terminal of the selector 440 includes a first judgment result, a second judgment result, a third judgment result, a first statistical result, and a second statistical result. The first judgment result, the second judgment result, the third judgment result, the first statistical result, and the second statistical result are all 1-bit data. The exposure event control module will flexibly control the amount of exposure time according to this 3-bit judgment result and 2-bit statistical result to prevent problems such as overexposure or underexposure.

[0059] Specifically, when the value of the Flag signal data is 5’b10001, it indicates that the Flag_bright signal and the Flag_ON>>OFF signal are pulled high, and the selector 440 selects the data of branch 1 as the new exposure time data and stores it in the third D flip-flop group 410. When the value of the Flag signal data is 5’b01010, the Flag_dark signal and the Flag_ON<<OFF signal are pulled high, and the selector 440 selects the data of branch 3 as the new exposure time data and stores it in the third D flip-flop group 410. Except for the above two cases, the selector 440 will select the data of branch 2 as the new exposure time data and store it in the third D flip-flop group 410.

[0060] In summary, in the embodiment of the present invention, the event statistics module is used to count the ON events and OFF events, and then the event quantity judgment module compares the quantities of ON and OFF events and outputs a comparison result. And the grayscale statistics module integrates the grayscale information of the statistical fusion type vision sensor and outputs a statistical result. Finally, the exposure time control module will decide to increase the exposure time, decrease the exposure time, or keep it unchanged according to the outputs of the event quantity judgment module and the grayscale statistics module, so as to prevent phenomena such as overexposure or underexposure caused by changes in the external light intensity, thereby improving the imaging quality of the fusion type vision sensor.

[0061] What is disclosed above is only a preferred embodiment of the present invention, and it certainly cannot be used to limit the scope of rights of the present invention. Ordinary technicians in this field can understand that all or part of the processes of the above embodiment and equivalent changes made according to the claims of the present invention still fall within the scope of the invention.

Claims

1. An adaptive exposure circuit for a fusion type visual sensor, characterized in that: include: Event statistics module, event quantity judgment module, exposure time control module and grayscale statistics module; The event statistics module is used to count the light intensity increase events and light intensity decrease events generated by the fusion type vision sensor, and output the statistical results to the event quantity judgment module; The event quantity determination module is used to determine the statistical result and transmit the determination result to the exposure time control module; The grayscale statistics module is used to count the grayscale information of the fusion type visual sensor and transmit the statistical results to the exposure time control module; The exposure time control module is used to adjust the exposure time accordingly according to the judgment result and the grayscale information.

2. The adaptive exposure circuit for a fusion type visual sensor according to claim 1, characterized in that: The event quantity judgment module includes a first threshold and a second threshold; when the number of light intensity increase events minus the number of light intensity decrease events is greater than or equal to the first threshold, the event quantity judgment module outputs a first judgment result; when the number of light intensity decrease events minus the number of light intensity increase events is greater than or equal to the second threshold, the event quantity judgment module outputs a second judgment result; when the number of light intensity increase events minus the number of light intensity decrease events is less than the first threshold and the number of light intensity decrease events minus the number of light intensity increase events is less than the second threshold, the event quantity judgment module outputs a third judgment result.

3. The adaptive exposure circuit for a fusion type visual sensor according to claim 1, characterized in that: The grayscale statistics module includes a third threshold, a fourth threshold, a fifth threshold and a sixth threshold; when the grayscale information is less than the third threshold, the grayscale statistics module determines that the grayscale information is low grayscale pixel information, and counts the number of low grayscale pixel information; When the grayscale information is greater than a fourth threshold, the grayscale statistics module determines that the grayscale information is high-grayscale pixel information, and counts the number of low-grayscale pixel information; When the number of low-grayscale pixel information is greater than a fifth threshold, a first statistical result is output; when the number of high-grayscale pixel information is greater than a sixth threshold, a second statistical result is output; The third threshold is smaller than the fourth threshold.

4. The adaptive exposure circuit for a fusion type visual sensor according to claim 1, characterized in that: The event quantity determination module includes a first subtractor, a second subtractor, a first comparator, a second comparator and an XOR gate; The first subtractor input terminal and the second subtractor input terminal are connected to the event statistics module; the first subtractor output terminal is connected to the first comparator input terminal; the second subtractor output terminal is connected to the second comparator input terminal; the first comparator output terminal and the second comparator output terminal are connected to the XOR gate input terminal; the first comparator output terminal, the second comparator output terminal, and the XOR gate output terminal are connected to the exposure time control module as the event quantity judgment module output terminal.

5. The adaptive exposure circuit for a fusion type visual sensor according to claim 4, characterized in that: Another input terminal of the first comparator is connected to a first threshold; another input terminal of the second comparator is connected to a second threshold.

6. The adaptive exposure circuit for a fusion type visual sensor according to claim 1, characterized in that: The grayscale statistics module includes: a third comparator, a fourth comparator, a fifth comparator, a sixth comparator, a first D flip-flop, a second D flip-flop, a first adder and a second adder; The input terminals of the third comparator and the fourth comparator are connected to the grayscale information as the input terminals of the grayscale statistics module; the output terminal of the third comparator and the output terminal of the first D flip-flop are connected to the input terminal of the first adder; the output terminal of the first adder is connected to the input terminal of the first D flip-flop and the input terminal of the fifth comparator; the output terminal of the fourth comparator and the output terminal of the second D flip-flop are connected to the input terminal of the second adder; the output terminal of the second adder is connected to the input terminal of the second D flip-flop and the input terminal of the sixth comparator; the output terminal of the fifth comparator and the output terminal of the sixth comparator are used as the output terminals of the grayscale statistics module to output the statistical results.

7. The adaptive exposure circuit for a fusion type visual sensor according to claim 6, characterized in that: The other input terminal of the third comparator is connected to the third threshold; when the grayscale information is less than the third threshold, the first D flip-flop stores data with the number 1 increased; the other input terminal of the fourth comparator is connected to the fourth threshold; when the grayscale information is greater than the fourth threshold, the second D flip-flop stores data with the number 1 increased; the other input terminal of the fifth comparator is connected to the fifth threshold; the other input terminal of the sixth comparator is connected to the sixth threshold.

8. The adaptive exposure circuit for a fusion type visual sensor according to claim 1, characterized in that: The exposure time control module includes: a third D flip-flop, a right shift register, a left shift register and a selector; The output end of the third D flip-flop is connected to the right shift register input end, the left shift register input end, and the selector input end; the right shift register output end and the left shift register output end are connected to the selector input end; the selector output end is connected to the third D flip-flop input end; the selector selection end is connected to the grayscale statistics module output end and the event quantity judgment module input end as the exposure time control module input end.

9. The adaptive exposure circuit for a fusion type visual sensor according to claim 1, characterized in that: The event statistics module includes: a first event buffer, a first adder group, a first accumulating register, a second event buffer, a second adder group and a second accumulating register; The first event buffer is used to store the light intensity increase events generated by the fusion vision sensor, and the output end is connected to the input end of the first adder group; the first adder group is used to accumulate the light intensity increase events, and the output end is connected to the input end of the first accumulation register; the first accumulation register is used to store the statistical results of the light intensity increase events, and output the statistical results of the light intensity increase events to the event quantity judgment module.

10. The adaptive exposure circuit for a fusion type visual sensor according to claim 9, characterized in that: The second event buffer is used to store the light intensity reduction events generated by the fusion vision sensor, and the output end is connected to the input end of the second adder group; the second adder group is used to accumulate the light intensity reduction events, and the output end is connected to the input end of the second accumulation register; the second accumulation register is used to store the statistical results of the light intensity reduction events, and output the statistical results of the light intensity reduction events to the event quantity judgment module.

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