WO2021128534A1

WO2021128534A1 - Rod bionic vision sensor

Info

Publication number: WO2021128534A1
Application number: PCT/CN2020/073527
Authority: WO
Inventors: 施路平; 杨哲宇; 赵蓉; 裴京; 徐海峥
Original assignee: 清华大学
Priority date: 2019-12-24
Filing date: 2020-01-21
Publication date: 2021-07-01
Also published as: CN111031267A; CN111031267B

Abstract

A rod bionic vision sensor, comprising: a first subcircuit, the first subcircuit comprising a target first-type photosensitive component (31), a first current amplifier (32), a comparator (33), an adder (34), and a digital-to-analog converter (35); a first preset number of non-target first-type photosensitive components being provided around the target first-type photosensitive component, each non-target first-type photosensitive component being connected in series to one first-type control switch (M1, M2, M3, and M4). By mimicking the effects of rod cells, implemented is the effect of sensing light intensity gradient information in a target light signal, thus increasing the dynamic range of a bionic vision sensor image, and increasing photographing speed. With one first-type control switch being introduced for each non-target first-type photosensitive component, the light intensity gradient information obtained can be controlled to implement an adjustment of the dynamic range of the bionic vision sensor image, thus implementing an adjustment of the photographing speed.

Description

Rod Bionic Vision Sensor

Technical field

The present invention relates to the field of integrated circuit technology, and more specifically, to a rod bionic vision sensor.

Background technique

At present, with the continuous in-depth research on image sensors and image processing and recognition algorithms, image sensors dominated by CMOS technology are playing an increasingly important role in many application fields such as industrial manufacturing, intelligent transportation, and intelligent robots.

However, the current CMOS image sensor has some shortcomings that are difficult to overcome: the dynamic range of the CMOS sensor to acquire images is relatively small. Moreover, due to the low sub-sampling resolution of CMOS image sensors, saturation and distortion are likely to occur in scenes with strong, weak or high contrast. At the same time, because the CMOS image sensor acquires all the data in the light reflected by the external target object, it will cause image data redundancy and a large amount of data. Brings a lot of pressure to the subsequent image processing and storage. For row (column) scanning CMOS image sensors, the imaging speed is mainly limited by the conversion speed of the analog-to-digital converter (ADC). As the requirements for the scale of the photosensitive array continue to increase, The shooting speed of CMOS image sensors will become increasingly difficult to increase.

Based on the above-mentioned problems caused by the CMOS image sensor during the shooting process, there is an urgent need to provide a rod bionic vision sensor to solve the problems caused by the use of the CMOS image sensor for shooting.

Summary of the invention

In order to overcome the above-mentioned problems or at least partially solve the above-mentioned problems, an embodiment of the present invention provides a rod bionic vision sensor.

The embodiment of the present invention provides a rod bionic vision sensor, including: a first sub-circuit, the first sub-circuit includes a target first-type photosensitive device, a first current amplifier, a comparator, an adder, and a digital-to-analog converter ；

The target first-type photosensitive device is used to obtain a target light signal, and convert the target light signal into a first-type current signal;

The target first-type photosensitive device is connected to the first current amplifier, and the first current amplifier is connected to an input terminal of the comparator; the input terminals of the adder are respectively connected to the target first-type photosensitive device A first preset number of non-target type 1 photosensitive devices around the device are connected, and the output terminal of the adder is connected to the other input terminal of the comparator;

The output terminal of the comparator is connected to the digital-to-analog converter, and the digital-to-analog converter converts the input specified digital signal into a specified analog signal, and outputs the specified analog signal to the first current amplifier or The adder until the output terminal of the comparator outputs an event pulse signal, the first sub-circuit outputs the designated digital signal, and the designated digital signal is used to characterize the light intensity gradient information in the target optical signal ；

Wherein, each of the non-target first-type photosensitive devices is connected in series with a first-type control switch.

Preferably, the first sub-circuit further includes: a three-state gate circuit;

The tri-state gate circuit is respectively connected with the output terminal of the comparator and the input terminal of the digital-to-analog converter;

The three-state gate circuit is used to output the designated digital signal when the event pulse signal is output at the output terminal of the comparator.

Preferably, the first sub-circuit further includes: an addressing unit;

The addressing unit is respectively connected with the output terminal of the comparator and the input terminal of the digital-to-analog converter;

The addressing unit is used to output the designated digital signal when the event pulse signal is output at the output terminal of the comparator.

Preferably, the control circuit further includes: a second sub-circuit;

The second sub-circuit includes one non-target first-type photosensitive device and the second preset number of first-type current mirrors;

Each first-type current mirror is respectively connected in series with a target first-type photosensitive device around the non-target first-type photosensitive device.

Preferably, when the illuminance of the target light signal is greater than a first preset value, all the first-type control switches are turned on at the same time, and when the intensity of the target light signal is less than a second preset value, all the The first type of control switch is turned off at the same time.

Preferably, when at least one of the first-type control switches is turned on, the designated digital signal output by the first sub-circuit is a differential mode signal, and when all the first-type control switches are turned off, the The designated digital signal output by the first sub-circuit is a common mode signal.

Preferably, the first current amplifier is specifically a second type current mirror.

Preferably, the first sub-circuit further includes: a second current amplifier;

The second current amplifier is connected between the target first-type photosensitive device and the first current amplifier.

Preferably, the first sub-circuit further includes: a storage unit;

The storage unit is used to store the designated digital signal.

The rod bionic vision sensor provided by the embodiment of the present invention realizes the perception of light intensity gradient information in the target light signal by simulating the function of rod cells, thereby increasing the dynamic range of the bionic vision sensor image and increasing the shooting speed . Moreover, a first-type control switch is introduced for each non-target first-type photosensitive device, which can control the obtained light intensity gradient information, realize the adjustment of the dynamic range of the bionic vision sensor image, and then realize the adjustment of the shooting speed .

Description of the drawings

In order to explain the embodiments of the present invention or the technical solutions in the prior art more clearly, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the drawings in the following description These are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative work.

FIG. 1 is a schematic structural diagram of the arrangement of a pixel array in a bionic vision sensor according to an embodiment of the present invention;

2 is a schematic structural diagram of the arrangement of pixel arrays in a bionic vision sensor according to an embodiment of the present invention;

3 is a schematic structural diagram of a first sub-circuit in a rod bionic vision sensor provided by an embodiment of the present invention;

4 is a schematic diagram of the connection relationship between the target first-type photosensitive device and each non-target first-type photosensitive device in the first sub-circuit of the rod bionic vision sensor according to an embodiment of the present invention;

5 is a schematic diagram of a change form of a designated digital signal input to a digital-to-analog converter in a rod bionic vision sensor according to an embodiment of the present invention;

6 is a schematic diagram of a specific structure of a rod bionic vision sensor provided by an embodiment of the present invention;

7 is a schematic diagram of a specific structure of a rod bionic vision sensor provided by an embodiment of the present invention;

FIG. 8 is a schematic structural diagram of a second sub-circuit in a rod bionic vision sensor provided by an embodiment of the present invention.

Detailed ways

In order to make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments These are a part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present invention.

In the description of the embodiments of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" The orientation or positional relationship indicated by "" is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the embodiments of the present invention and simplifying the description, and does not indicate or imply that the pointed device or element must have a specific orientation, It is constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the embodiment of the present invention. In addition, the terms "first", "second", and "third" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance.

In the description of the embodiments of the present invention, it should be noted that, unless otherwise clearly defined and limited, the terms "installation", "connection", and "connection" should be interpreted broadly. For example, they may be fixed connections or Removable connection or integral connection; it can be mechanical connection or electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal communication between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present invention can be understood in specific situations.

Specifically, in the embodiment of the present invention, the pixel array of the bionic vision sensor includes a first type of photosensitive device and a second type of photosensitive device. Among them, the first type of photosensitive device is used to obtain the target light signal and convert the target light signal into the first type of current signal, and the second type of photosensitive device is used to obtain the target light signal, and extract the specified frequency band from the target light signal. Optical signal, and convert the optical signal of the specified frequency band into the second type current signal.

The target light signal refers to the light signal reflected on the surface of the target object. The target light signal can be directly irradiated on the first type of photosensitive device or the second type of photosensitive device, or it can be irradiated on the first type of photosensitive device or the second type of photosensitive device through a collimating lens. The type of photosensitive device can also be irradiated on the first type of photosensitive device or the second type of photosensitive device through the cover. The waveband of the target light signal may be a visible light waveband, that is, the target light signal may be a visible light signal. The target object refers to an object that needs to be observed by the human eye, which may be a real object, an image, or other forms, and the specific form of the target object is not limited in the present invention.

The first type of photosensitive device may specifically be a photo-diode (PD), or may be other devices that can convert an optical signal into a current signal, which is not specifically limited in the embodiment of the present invention. It should be noted that the first type of photosensitive device does not include a filter. The second type of photosensitive device is used to sense the color components in the target light signal. The second type of photosensitive device may specifically include a PD and a color filter (CF) arranged on the PD, which is finally obtained by a bionic vision sensor The image is a color image. Among them, CF is used to obtain the target optical signal, extract the optical signal of the specified frequency band from the target optical signal, and the PD converts the optical signal of the specified frequency band into the second type current signal. The color filter may specifically be a filter or a lens, which is used to transmit light signals of a specified wavelength. When the color filter is a lens, a Byron lens can be used specifically, and other types of lenses can also be used. The color filter can be divided into a red color filter, a blue color filter and a green color filter according to the wavelength of the transmitted light signal, and the transmitted light signals are respectively a red light signal, a blue light signal and a green light signal.

It should be noted that the second type of photosensitive device can also be directly composed of photodiodes. By selecting photodiodes with different response curves, the target light signal can be obtained, and the light signal of the specified wavelength band can be extracted from the target light signal, and the light The signal is converted into the role of the second type of current signal.

The rod bionic vision sensor provided in the embodiment of the present invention is mainly used to simulate the function of the rod cell in the human eye, so the rod bionic vision sensor can also be called a rod cell circuit. Rod cells can be equivalent to the first type of photosensitive device in the bionic vision sensor. Since rod cells can be divided into excitatory rod cells and inhibitory rod cells, correspondingly, the first type of photosensitive device can include the target Type 1 photosensitive devices and non-target type 1 photosensitive devices, excitatory rod cells can be equivalent to target type 1 photosensitive devices, and inhibitory rod cells can be equivalent to non-target type 1 photosensitive devices.

In the bionic vision sensor provided in the embodiment of the present invention, a schematic diagram of the arrangement of the pixel array structure can be shown in FIG. 1, which includes a first type of photosensitive device 11 and a second type of photosensitive device 12, and the first type of photosensitive device 11 The target type 1 photosensitive device is marked with "+", and the non-target type 1 photosensitive device is marked with "-". The second type photosensitive device 12 containing a red color filter is marked as "R", the second type photosensitive device 12 containing a blue color filter is marked as "B", and the second type photosensitive device containing a green color filter is marked as "R". Device 12 is labeled "G". Each target type 1 photosensitive device is surrounded by 4 non-target type 1 photosensitive devices and 4 type 2 photosensitive devices, and each non-target type 1 photosensitive device is surrounded by 4 target type 1 photosensitive devices and 4 The second type of photosensitive device.

The structure diagram of the arrangement of the pixel array can also be shown in Figure 2, which includes the first type of photosensitive device 21 and the second type of photosensitive device 22, the target first type of photosensitive device in the first type of photosensitive device 21 is marked as "+ ", non-target type 1 photosensitive devices are marked as "-". The second type photosensitive device 22 containing a red color filter is marked as "R", the second type photosensitive device 22 containing a blue color filter is marked as "B", and the second type photosensitive device containing a green color filter is marked as "R". Device 22 is labeled "G". Each target type 1 photosensitive device has 6 non-target type 1 photosensitive devices and 2 type 2 photosensitive devices, and each non-target type 1 photosensitive device is surrounded by 2 target type 1 photosensitive devices and 4 The second type photosensitive device, or each non-target first type photosensitive device is surrounded by 4 target first type photosensitive devices and 2 second type photosensitive devices. The arrangement of the pixel array may also be in other forms, which is not specifically limited in the embodiment of the present invention. Hereinafter, only the arrangement of the pixel array shown in FIG. 1 is taken as an example for description.

Since the first-type photosensitive device may include the target first-type photosensitive device, the rod bionic vision sensor specifically includes a first sub-circuit for controlling the target first-type photosensitive device. Among them, the first sub-circuit may specifically be a first-type current mode active pixel sensor circuit. As shown in FIG. 3, the first sub-circuit includes a target first-type photosensitive device 31, a first current amplifier 32, a comparator 33, an adder 34, and a digital to analog converter (Digital to Analog Converter, DAC) 35. The target first The type photosensitive device 31 is connected to the first current amplifier 32, and the first current amplifier 32 is used to _{amplify the first type current signal I 0} obtained by the conversion of the target first type photosensitive device 31, and the amplification factor is a first preset number, That is, the magnification is equal to the number of non-target first-type photosensitive devices around the target first-type photosensitive device 31 to ensure that the amplified first-type current signal is equal to the first preset number around the target first-type photosensitive device 31 The sum of the current signals converted by non-target second-type photosensitive devices is on the same order of magnitude. The pixel array shown in FIG. 1 corresponds to the first preset number of 4, and the pixel array shown in FIG. 2 corresponds to the first preset number of 6. In the embodiment of the present invention, the first preset number is equal to 4 as an example for description.

It should be noted that there is no color filter (CF) in the first type of photosensitive device provided in the embodiment of the present invention, so the response band of the photosensitive device is related to itself. Generally speaking, at this time, the image signal output by the rod bionic vision sensor controlled by the bionic vision sensor is a grayscale signal.

The first current amplifier 32 is connected to an input terminal of the comparator 33 and inputs the amplified first-type current signal into the comparator 33. The four non-target first-type photosensitive devices around the target first-type photosensitive device 31 are all connected to the input ends of the adder 34 respectively. Because each non-target first-type photosensitive device is connected in series with a first-type control switch. In the embodiment of the present invention, only the first-type control switches M ₁ , M ₂ , M ₃ , and M ₄ connected in series with each non-target first-type photosensitive device are shown. Among them, the first type of control switches may specifically be MOS transistors, and all the first type of control switches can be turned on at the same time, or they can be turned off at the same time, and can also be partially turned on and partially turned off, which can be specifically set as required. China does not make specific restrictions on this.

As shown in FIG. 4, the target first-type photosensitive device provided in the embodiment of the present invention and each surrounding non-target first-type photosensitive device are connected through a MOS tube to achieve connection control. When the MOS tube is turned on, the target type 1 photosensitive device is connected to the non-target type 1 photosensitive device through the conductive MOS tube. When the MOS tube is disconnected, the target type 1 photosensitive device is connected to the non-target type 1 photosensitive device. The device is disconnected.

The on and off of the first type of control switch can be set as required, so the first type of control switch is a configurable first type of control switch. Since the first type of control switch realizes whether the non-target type 1 photosensitive device around the target type 1 photosensitive device is effective, it can be understood that the first type of control switch can be used as a parameter configurable 1bit convolution check to check the first type of photosensitive device. The current signal converted by the device is subjected to convolution operation, the completion speed is very high, and the 1-bit convolution operation in the pixel can be completed to realize high-speed feature extraction.

The output terminal of the adder 34 is connected to the other input terminal of the comparator 33. _{The current signals I 1} , I ₂ , I ₃ , and I ₄ obtained by the conversion of the four non-target first-type photosensitive devices are respectively input to the adder 34, and the adder 34 calculates _{I 1} , I ₂ , I ₃ , and I ₄ And input the sum result to the comparator 33. The comparator 33 compares the amplified first-type current signal and the sum result of the adder 34. If the comparison result between the current moment and the current moment is consistent, no output is made. The DAC35 converts the input designated digital signal into a designated analog signal, and outputs the designated analog signal to the first current amplifier 32 or the adder 34, and then outputs it to the first current amplifier 32 or the adder 34. The designated analog signal of a current amplifier 32 is denoted as I _DA2 , and the designated analog signal output to the adder 34 is denoted as I _DA1 . The output is then compared by the comparator 33. When the comparison result at the current moment and the latter moment are opposite, the output terminal of the comparator 33 outputs the event pulse signal, that is, the comparator 33 is in the edge-triggered state. At this time, the first sub-circuit The specified digital signal is output, and the specified digital signal is used to characterize the light intensity gradient information in the target optical signal. Among them, the designated digital signal output by the first sub-circuit is a digital signal represented by 0 and 1.

Among them, the designated digital signal input to the DAC35 can be a designated digital signal that is manually inputted periodically. The change form of the designated digital signal is shown in Figure 5. The designated digital signal increases stepwise with time. In the case of N*step, the value of the designated digital signal is ΔI, and the comparator 33 outputs an event pulse signal, that is, the comparator 33 is in the edge-triggered state, and the ΔI at this time is used as the output of the first sub-circuit. Among them, N is the number of steps passed before, and step is the time length of each step.

It should be noted that the adder in the embodiment of the present invention can be an actual device or a functional module that realizes the addition function. For example, it can be achieved by combining the lines where the _{current signals I 1} , I ₂ , I ₃ , and I _{4 are located.} Realize as a line. Moreover, the first current amplifier may also be an actual device or a functional module that realizes the current amplifying function, which is not specifically limited in the embodiment of the present invention.

According to the arrangement of the pixel array, the target first-type photosensitive device and the non-target first-type photosensitive device in the rod bionic vision sensor provided in the embodiment of the present invention are multiplexed. For example, in the pixel array shown in Figure 1, any two adjacent target first-type photosensitive devices share two non-target first-type photosensitive devices, and each non-target second-type photosensitive device is surrounded by four surrounding The goal is to share the first type of photosensitive devices to realize the multiplexing of the first type of photosensitive devices.

The embodiment of the present invention provides a rod bionic vision sensor, which realizes the perception of light intensity gradient information in the target light signal by simulating the role of rod cells, thereby increasing the dynamic range of the bionic vision sensor image and improving shooting speed. Moreover, a first-type control switch is introduced for each non-target first-type photosensitive device, which can control the obtained light intensity gradient information, realize the adjustment of the dynamic range of the bionic vision sensor image, and then realize the adjustment of the shooting speed .

On the basis of the foregoing embodiment, in the rod bionic vision sensor provided in the embodiment of the present invention, the first sub-circuit further includes: a three-state gate circuit;

Specifically, the rod bionic vision sensor provided in the embodiment of the present invention further includes in the first sub-circuit: a three-state gate circuit, as shown in FIG. 6, which is a component of the rod bionic vision sensor provided in the embodiment of the present invention. Specific structure diagram. In FIG. 6, the circuit structure 61 simulates a rod cell circuit, and the circuit structure 62 simulates a ganglion cell and a bipolar cell. Vcc is the power supply of the control circuit. The target first-type photosensitive device 63 is connected to Vcc. The first-type current signal I ₀ converted by the target first-type photosensitive device 63 is amplified 4 times by the current mirror 64 and then compared with a comparator (Comparer, CP). ) 66 is connected to the input terminal, and the current signals converted by the four non-target first-type photosensitive devices around the target first-type photosensitive device 63 are respectively I ₁ , I ₂ , I ₃ , and I ₄ . Fig. 6 does not show the four non-target first-type photosensitive devices around the target first-type photosensitive device 63, only the first-type control switches M ₁ and M 1, which are connected in series with each non-target first-type photosensitive device are drawn. M ₂ , M ₃ , M ₄ . The lines where I ₁ , I ₂ , I ₃ , and I ₄ are located are merged into one line to realize the function of an adder. The combined line is connected to the input terminal of CP66. The CP66 compares the amplified first-type current signal and the sum of I ₁ , I ₂ , I ₃ , and I ₄ . If the comparison result between the current moment and the current moment is consistent, no output is made. The DAC65 converts the input designated digital signal into a designated analog signal, and outputs the designated analog signal to the target type 1 photosensitive device 63 or a non-target A type of photosensitive device. After the output, the CP66 is used for comparison. When the comparison result of the current time and the next time is opposite, the output terminal of the CP66 outputs the event pulse signal, that is, the CP66 is in the edge-triggered state. At this time, the three-state gate circuit 67 outputs the specified digital signal .

In FIG. 6, a capacitor 68 is also connected between CP66 and ground. The capacitor 68 may be an actual capacitor or a virtual parasitic capacitor in the first sub-circuit, which is not specifically limited in the embodiment of the present invention.

On the basis of the foregoing embodiment, in the rod bionic vision sensor provided in the embodiment of the present invention, the first sub-circuit further includes a storage unit. The storage unit is connected to the output terminal of the tri-state gate circuit and is used to store the designated digital signal output by the first sub-circuit. The storage unit may specifically be a register, a latch, SRAM, DRAM, memristor, etc. Taking a register as an example, the number of bits of the register can be selected according to the accuracy of the DAC35, and a 4-bit register can be selected in the embodiment of the present invention.

As shown in FIG. 7, on the basis of the foregoing embodiment, in the rod bionic vision sensor provided in the embodiment of the present invention, the first sub-circuit further includes an addressing unit 69.

The addressing unit 69 is respectively connected with the output terminal of CP68 and the input terminal of DAC65;

The addressing unit 69 is used for outputting an event pulse signal at the output terminal of the CP68, that is, when the CP68 is in an edge trigger state, outputting a designated digital signal. In other words, the tri-state gate circuit 67 in FIG. 6 can be replaced with an addressing unit to obtain the structure shown in FIG. 7.

On the basis of the foregoing embodiment, in the rod bionic vision sensor provided in the embodiment of the present invention, the first sub-circuit further includes a storage unit. The storage unit is connected to the output terminal of the addressing unit 69 and is used to store the designated digital signal output by the first sub-circuit. The storage unit may specifically be a register, a latch, SRAM, DRAM, memristor, etc. Taking a register as an example, the number of bits of the register can be selected according to the accuracy of the DAC35, and a 4-bit register can be selected in the embodiment of the present invention.

On the basis of the foregoing embodiment, in the rod bionic vision sensor provided in the embodiment of the present invention, the control circuit further includes: a second sub-circuit;

Each first-type current mirror is respectively connected in series with a second-type photosensitive device around the non-target first-type photosensitive device, and the second-type photosensitive device is used to obtain the target light signal from the target light signal Extracting the optical signal of the specified frequency band in the, and converting the optical signal of the specified frequency band into the second type current signal.

Specifically, as shown in FIG. 8, the rod bionic vision sensor provided in the embodiment of the present invention further includes a second sub-circuit for controlling the non-target type 1 photosensitive device. Wherein, the second sub-circuit may specifically be a second-type current mode active pixel sensor circuit. The second sub-circuit includes a non-target first-type photosensitive device 71 and four first-type current mirrors 72, 73, 74, 75. Each first-type current mirror is connected in series with a target first-type photosensitive device around the non-target first-type photosensitive device 71, that is, the current signal I ₁ obtained by the conversion of the non-target first-type photosensitive device 71 is copied into four I ₁ , Respectively used to include the first sub-circuit of each target first-type photosensitive device around the non-target first-type photosensitive device 71 to obtain the light intensity gradient information in the target light signal, so as to realize the non-target first-type photosensitive device Reuse.

On the basis of the above-mentioned embodiment, the rod bionic vision sensor provided in the embodiment of the present invention, when the illuminance of the target light signal is greater than the first preset value, all the first-type control switches are turned on at the same time, when When the intensity of the target optical signal is less than the second preset value, all the control switches of the first type are turned off at the same time.

Specifically, all the control switches of the first type are independent of each other, and one is turned on and off does not affect the other. The number of turns on and the number of turns off can be selected according to needs, and all of them can be turned on or off. . In the embodiment of the present invention, in order to obtain a better effect, when the illuminance of the target light signal is greater than the first preset value, all the control switches of the first type can be turned on at the same time, and when the intensity of the target light signal is less than the second preset value When the value is set, all the first type control switches are turned off at the same time. The first preset value and the second preset value may be determined according to the type, parameter, and ambient light intensity of the photosensitive device. For example, the first preset value may be 10klux, and the second preset value may be 50lux. That is, when the illuminance of the target light signal is greater than the first preset value, it is indicated as strong light. At this time, in order to prevent saturation of the DAC and comparator in the rod bionic vision sensor, all the first type control switches are turned on at the same time. All non-target type 1 photosensitive devices are valid, and the designated digital signal output by the first sub-circuit is a differential mode signal, which enables the bionic vision sensor to obtain the edge information of the image. When the intensity of the target light signal is less than the second preset value, it is indicated as weak illumination. At this time, the first type current signal I ₁ converted by the target first type photosensitive device is very small. Therefore, all the first-type control switches are turned off at the same time. At this time, all non-target first-type photosensitive devices are invalid, and the designated digital signal output by the first sub-circuit is a common mode signal, which enables the bionic vision sensor to obtain the original information of the image. The rod bionic vision sensor provided in the embodiment of the present invention better simulates the Gap Junction connection of the human eye, thereby realizing the improvement of the image dynamic range of the bionic vision sensor.

It should be noted that when the illuminance of the target light signal is greater than the first preset value and less than the second preset value, it indicates that the illumination is moderate. At this time, all the control switches of the first type may be partially turned on and partially turned off. When at least one type 1 control switch is turned on, the designated digital signal output by the first sub-circuit is a differential mode signal. When all the first type control switches are turned off, the designated digital signal output by the first sub-circuit is a common mode signal. signal.

On the basis of the foregoing embodiment, in the rod bionic vision sensor provided in the embodiment of the present invention, the first current amplifier is specifically a second type current mirror.

Specifically, as shown in FIGS. 6 and 7, the current mirror 64 is a second type of current mirror. The second type here is mainly used to distinguish from the first type of current mirror, and does not play a limiting role.

On the basis of the foregoing embodiment, in the rod bionic vision sensor provided in the embodiment of the present invention, the first sub-circuit further includes: a second current amplifier;

Specifically, in the embodiment of the present invention, since the current signal converted by the first-type photosensitive device is relatively small, a second current amplifier may be connected between the first current amplifier and the target first-type photosensitive device to serve as the target The first-type current signal converted by the first-type photosensitive device is preliminarily amplified. The second current amplifier may be an actual device or a functional module that realizes the current amplification function, which is not specifically limited in the embodiment of the present invention. Correspondingly, a second current amplifier is also provided between the non-target first-type photosensitive device around the target first-type photosensitive device and the adder, so that the current of the branch where each non-target first-type photosensitive device is located before the adder is The signal is in the same order of magnitude as the current signal of the branch where the target type 1 photosensitive device is located.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: The technical solutions recorded in the foregoing embodiments are modified, or some of the technical features thereof are equivalently replaced; these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

A rod bionic vision sensor, characterized by comprising: a first sub-circuit, the first sub-circuit including a target first-type photosensitive device, a first current amplifier, a comparator, an adder, and a digital-to-analog converter;

The target first-type photosensitive device is used to obtain a target light signal, and convert the target light signal into a first-type current signal;

The target first-type photosensitive device is connected to the first current amplifier, and the first current amplifier is connected to an input terminal of the comparator; the input terminals of the adder are respectively connected to the target first-type photosensitive device A first preset number of non-target type 1 photosensitive devices around the device are connected, and the output terminal of the adder is connected to the other input terminal of the comparator;

The output terminal of the comparator is connected to the digital-to-analog converter, and the digital-to-analog converter converts the input specified digital signal into a specified analog signal, and outputs the specified analog signal to the first current amplifier or The adder until the output terminal of the comparator outputs an event pulse signal, the first sub-circuit outputs the designated digital signal, and the designated digital signal is used to characterize the light intensity gradient information in the target optical signal ；

Wherein, each of the non-target first-type photosensitive devices is connected in series with a first-type control switch.
The rod bionic vision sensor according to claim 1, wherein the first sub-circuit further comprises: a three-state gate circuit;

The tri-state gate circuit is respectively connected with the output terminal of the comparator and the input terminal of the digital-to-analog converter;

The three-state gate circuit is used to output the designated digital signal when the event pulse signal is output at the output terminal of the comparator.
The rod bionic vision sensor according to claim 1, wherein the first sub-circuit further comprises: an addressing unit;

The addressing unit is respectively connected with the output terminal of the comparator and the input terminal of the digital-to-analog converter;

The addressing unit is used to output the designated digital signal when the event pulse signal is output at the output terminal of the comparator.
The rod bionic vision sensor according to claim 1, wherein the control circuit further comprises: a second sub-circuit;

The second sub-circuit includes one non-target first-type photosensitive device and the second preset number of first-type current mirrors;

Each first-type current mirror is respectively connected in series with a target first-type photosensitive device around the non-target first-type photosensitive device.
The rod bionic vision sensor according to any one of claims 1-4, wherein when the illuminance of the target light signal is greater than a first preset value, all the first-type control switches are turned on at the same time When the intensity of the target optical signal is less than the second preset value, all the first type control switches are turned off at the same time.
The rod bionic vision sensor according to any one of claims 1-4, wherein when at least one of the first-type control switches is turned on, the designated digital signal output by the first sub-circuit It is a differential mode signal. When all the first-type control switches are turned off, the designated digital signal output by the first sub-circuit is a common mode signal.
The rod bionic vision sensor according to any one of claims 1 to 4, wherein the first current amplifier is specifically a second type current mirror.
The rod bionic vision sensor according to any one of claims 1-4, wherein the first sub-circuit further comprises: a second current amplifier;

The second current amplifier is connected between the target first-type photosensitive device and the first current amplifier.
The rod bionic vision sensor according to any one of claims 1-4, wherein the first sub-circuit further comprises: a storage unit;

The storage unit is used to store the designated digital signal.