Vision sensor, and operating method thereof

Abstract

A vision sensor and a method of operating the vision sensor are disclosed. A vision sensor according to an exemplary embodiment of the present disclosure includes a pixel array comprising a plurality of pixels, a voltage generator that generates a reset bias voltage provided to each of the plurality of pixels, a temperature comparison module that outputs a switching setting value according to the result of comparing temperature information and at least one reference temperature value, and a voltage level controller that generates a reset bias setting signal that adjusts the voltage level of the reset bias voltage based on the switching setting value.

Description

Technology Field

[0001] The technical concept of the present disclosure relates to a vision sensor, and more specifically, to a vision sensor that operates based on temperature information and a method of operating the same. Background Technology

[0002] Human-computer interaction (HCI) manifests and operates within user interfaces. Various user interfaces that recognize user input can provide natural interaction between humans and computers. Various sensors can be utilized to recognize user input.

[0003] Vision sensors, such as dynamic vision sensors, generate information about an event—namely, an event signal—when an event (e.g., a change in light intensity) occurs, and transmit this event signal to a processor. The operating characteristics of the pixels included in the vision sensor can change depending on the temperature. The problem to be solved

[0004] The problem that the technical concept of the present disclosure aims to solve is to provide a vision sensor that detects temperature information and controls operation according to the temperature information, and a method of operating the same. means of solving the problem

[0005] A vision sensor for solving the above technical problem may include a pixel array comprising a plurality of pixels, a voltage generator that generates a reset bias voltage provided to each of the plurality of pixels, a temperature comparison module that outputs a switching setting value according to the result of comparing temperature information and at least one reference temperature value, and a voltage level controller that generates a reset bias setting signal that adjusts the voltage level of the reset bias voltage based on the switching setting value.

[0006] A vision sensor for solving the above technical problem may include a pixel array comprising a plurality of pixels, a voltage generator that generates a reset bias voltage provided to each of the plurality of pixels, a temperature sensor controller that generates temperature information, a temperature comparison module that outputs a switching setting value according to the temperature information, and a voltage level controller that generates a reset bias setting signal that adjusts the voltage level of the reset bias voltage based on the switching setting value.

[0007] A method of operating a vision sensor comprising a plurality of pixels to solve the above technical problem comprises the steps of detecting the temperature of the vision sensor and generating temperature information at different points in time, acquiring a specified number of temperature information, and adjusting the voltage level of a reset switching signal provided to the plurality of pixels based on the acquired temperature information, wherein the plurality of pixels can be reset according to the reset switching signal. Effects of the invention

[0008] A vision sensor according to the present disclosure can adjust the voltage level of a reset switching signal provided to a pixel according to detected temperature information. Accordingly, leakage current that may occur in the reset switch at high temperatures, e.g., leakage current in the channel, can be prevented, and errors that may occur in the vision sensor detecting whether an event has occurred can be prevented.

[0009] Furthermore, various technical effects can be derived from embodiments of the technical concept of the present disclosure. Such unmentioned technical effects will be easily derived or inferred by those skilled in the art from the description below. Brief explanation of the drawing

[0010] FIG. 1 is a block diagram showing an image processing device according to an exemplary embodiment of the present disclosure. FIG. 2 is a block diagram showing a vision sensor according to an exemplary embodiment of the present disclosure. FIG. 3 is a flowchart for explaining the operation method of a vision sensor according to an exemplary embodiment of the present disclosure. FIG. 4 is a circuit diagram showing an example of an implementation of a pixel of a vision sensor according to an exemplary embodiment of the present disclosure. Figure 5a is a diagram illustrating the change in output voltage of a pixel amplifier according to temperature. Figure 5b is a diagram illustrating the change in gain of the pixel amplifier with respect to frequency according to temperature. FIG. 6 is a block diagram showing a temperature comparison module of a vision sensor according to an exemplary embodiment of the present disclosure. Figure 7 is a block diagram illustrating the counters included in the temperature comparison module of Figure 6. FIG. 8 is a block diagram illustrating the selection signal generator and register included in the temperature comparison module of FIG. 6. FIG. 9 is a block diagram showing a temperature comparison module of a vision sensor according to an exemplary embodiment of the present disclosure. FIG. 10 is a block diagram showing a voltage level controller of a vision sensor according to an exemplary embodiment of the present disclosure. FIG. 11 is a block diagram showing an image processing device according to an exemplary embodiment of the present disclosure. FIG. 12 is a block diagram exemplarily showing an electronic device to which a vision sensor according to an exemplary embodiment of the present disclosure is applied. Specific details for implementing the invention

[0011] Hereinafter, various embodiments of the present disclosure are described in conjunction with the accompanying drawings.

[0012] FIG. 1 is a block diagram showing an image processing device according to an exemplary embodiment of the present disclosure.

[0013] An image processing device (10) according to an exemplary embodiment of the present disclosure may be mounted on an electronic device having an image or light sensing function. For example, the image processing device (10) may be mounted on an electronic device such as a camera, a smartphone, a wearable device, an Internet of Things (IoT) device, a tablet PC (Personal Computer), a PDA (Personal Digital Assistant), a PMP (Portable Multimedia Player), a navigation system, a drone, an Advanced Driver Assistance System (ADAS), etc. Additionally, the image processing device (10) may be provided as a component in a vehicle, furniture, manufacturing equipment, a door, various measuring instruments, etc.

[0014] Referring to FIG. 1, the image processing device (10) may include a vision sensor (100) and a processor (200).

[0015] A vision sensor (100) can detect a change in the intensity of incident light and output event data (EDT). The vision sensor (100) may be a dynamic vision sensor that outputs event data (EDT) based on pixels (e.g., PX in FIG. 2) where a change in light is detected, i.e., pixels (PX) where an event occurred. The change in light intensity may be caused by the movement of an object being captured by the vision sensor (100), or by the movement of the vision sensor (100) or the image processing device (10) itself. The vision sensor (100) may transmit the event data (EDT) to a processor (200) periodically or non-periodically. The vision sensor (100) may transmit the event data (EDT) to the processor (200) in packets or frames.

[0016] The vision sensor (100) can selectively transmit event data (EDT) to the processor (200). The vision sensor (100) can transmit event data (EDT) generated from pixels (PX) corresponding to a region of interest set on the pixel array (PA) among the event signals generated in correspondence with the pixel array (PA) to the processor (200).

[0017] In an exemplary embodiment, the vision sensor (100) may include a temperature comparison module (150). The temperature comparison module (150) of the vision sensor (100) may adjust the voltage level of a reset switching signal (e.g., SWS of FIG. 3) provided to each of the pixels (PX) based on temperature information detected by the temperature sensor. For example, it may adjust the voltage level when the reset switching signal (SWS) is logic high.

[0018] When the temperature of the environment in which the vision sensor (100) operates increases excessively, the leakage current, e.g., the leakage current in the channel, may increase in the reset switch (e.g., SW in FIG. 3) included in each of the pixels (PX). Accordingly, the vision sensor (100) can control the leakage current of the reset switch (SW) included in each of the pixels (PX) by adjusting the voltage level of the reset switching signal (SWS) provided to the reset switch (SW) based on temperature information.

[0019] The processor (200) can process event data (EDT) received from the vision sensor (100) and can detect the movement of an object (or the movement of an object in an image recognized by the image processing device (10). The processor (200) may include an ASIC (application specific integrated circuit), an FPGA (field-programmable gate array), a dedicated microprocessor, a microprocessor, a general purpose processor, etc. In an exemplary embodiment, the processor (200) may be an application processor or an image processing processor.

[0020] The vision sensor (100) and the processor (200) can each be implemented as an integrated circuit (IC). For example, the vision sensor (100) and the processor (200) can be implemented as separate semiconductor chips. Alternatively, the vision sensor (100) and the processor (200) can be implemented as a single chip. For example, the vision sensor (100) and the processor (200) can be implemented as a system on chip (SoC).

[0021] FIG. 2 is a block diagram showing a vision sensor (100) according to an exemplary embodiment of the present disclosure. FIG. 3 is a flowchart for explaining the operation method of a vision sensor (100) according to an exemplary embodiment of the present disclosure.

[0022] Referring to FIG. 2, the vision sensor (100) may include a pixel array (PA), an event detection circuit (110), an interface (120), and a voltage generator (130).

[0023] A pixel array (PA) may include a plurality of pixels (PX) arranged in a matrix form. Each of the plurality of pixels (PX) can detect events in which the intensity of the received light increases or decreases. For example, each of the plurality of pixels (PX) may be connected to an event detection circuit (110) through a column line extending in the column direction and a row line extending in the row direction. A signal indicating that an event has occurred and polarity information of the event (i.e., whether it is an on-event where the intensity of light increases or an off-event where the intensity of light decreases) may be output from the pixel (PX) where the event occurred to the event detection circuit (110).

[0024] The event detection circuit (110) can read events from the pixel array (PA) and process the events. The event detection circuit (110) can generate an event signal (EVS) including polarity information of the event that occurred, the address of the pixel where the event occurred, and a timestamp. The event detection circuit (110) can process the events that occurred in the pixel array (PA) on a pixel-by-pixel basis, on a pixel group basis including multiple pixels, on a column basis, or on a frame basis.

[0025] The event detection circuit (110) may include a row AER (Address Event Representation), a column AER, and an event processing signal unit. The row AER may generate a row address of the pixel (PX) where the event occurred by receiving a signal indicating that an event has occurred, for example, a request (e.g., REQ of FIG. 4), from the pixel (PX) where the event occurred. The column AER (122) may generate a column address of the pixel (PX) where the event occurred by receiving a signal indicating that an event has occurred, for example, a request (e.g., REQ of FIG. 4), from the pixel (PX) where the event occurred.

[0026] The event processing signal unit can generate an event signal (EVS) based on row addresses and column addresses received from row AER and column AER, a polarity signal generated at a pixel (PX) (e.g., a signal indicating the occurrence of an on-event or off-event), and a timestamp (e.g., information about the time at which the event occurred). The event processing signal unit can remove noise events and generate event signals (EVS) for valid events. For example, if the amount of events that occurred during a predetermined period is less than a set threshold, the event processing signal unit may determine the events as noise and not generate an event signal (EVS) for the noise events.

[0027] The interface (120) receives event signals (EVS) and can transmit event data (EDT) to a processor (e.g., 200 in FIG. 1) according to a set protocol. The interface (120) can generate event data (EDT) by packing the event signals (EVS) into individual signal units, packet units, or frame units according to a set protocol, and can transmit the event data (EDT) to the processor (200). For example, the interface (120) may include one of an AER interface, a MIPI (Mobile Industry Processor Interface) interface, and parallel interfaces.

[0028] A voltage generator (130) can generate voltages provided to a pixel array (PA). For example, the voltage generator (130) can generate reference voltages or bias voltages used to detect on-events and off-events in a pixel (PX). The voltage generator (130) can change the voltage level of the reference voltages (or bias voltages) under the control of a voltage level controller (140). In an exemplary embodiment, the voltage generator (130) can generate a reset bias voltage (VIASR) that determines the voltage level of a reset switching signal (SWS) provided to a reset switch (e.g., SW in FIG. 3) of a pixel (PX).

[0029] The vision sensor (100) may include a voltage level controller (140). The voltage level controller (140) may generate a reset bias setting signal (RVS) that changes the reset bias voltage (VIASR) to a specific level. In an exemplary embodiment, the voltage level controller (140) may provide a reset bias setting signal (RVS) corresponding to a preset register value within the voltage level controller (140) to a voltage generator (130). Alternatively, in an exemplary embodiment, the voltage level controller (140) may receive a switching setting value (SSV) from a temperature comparison module (150) and provide a reset bias setting signal (RVS) that changes according to temperature information (TI) to a voltage generator (130).

[0030] The vision sensor (100) may include a temperature comparison module (150) and a temperature sensor controller (160). The temperature sensor controller (160) may provide temperature information (TI) corresponding to the temperature of the environment in which the vision sensor (100) operates to the temperature comparison module (150). In an exemplary embodiment, the vision sensor (100) may include a temperature sensor, and temperature information (TI) corresponding to the temperature detected by the temperature sensor may be provided to the temperature comparison module (150).

[0031] The temperature comparison module (150) receives temperature information (TI) and can output a switching setting value (SSV) based on the result of comparing the temperature information (TI) with a reference temperature value (RTV). For example, a plurality of reference temperature values ​​(RTV) may be set in the temperature comparison module (150), and the switching setting value (SSV) based on the result of comparing the temperature information (TI) with each of the plurality of reference temperature values ​​(RTV) can be provided to the voltage level controller (140). The voltage level controller (140) can generate a reset bias setting signal (RVS) based on the switching setting value (SSV).

[0032] Referring to FIGS. 2 and FIGS. 3, the vision sensor (100) can detect the temperature and generate temperature information (TI) in step S10. At this time, the temperature information (TI) may be generated by detecting the temperature of the vision sensor (100) at different points in time.

[0033] The vision sensor (100) can acquire a specified number of temperature information (TI) in step S20. For example, the temperature sensor controller (160) can periodically transmit the temperature information (TI) to the temperature comparison module (150), and the temperature comparison module (150) can acquire a specified number of temperature information (TI).

[0034] In step S30, the vision sensor (100) can adjust the voltage level of the reset switching signal provided to the pixels (PX) based on the acquired temperature information. For example, the temperature comparison module (150) can perform a specified number of comparison operations comparing the reference temperature value (RTV) with the acquired temperature information (TI), and can generate a switching setting value (SSV) based on the result of performing the comparison operations. The voltage level controller (140) can generate a reset bias setting signal (RVS) that changes the reset bias voltage (VIASR) to a set specific level based on the switching setting value (SSV), and the voltage generator (130) can generate a reset bias voltage (VIASR) that determines the voltage level of the reset switching signal (SWS) according to the reset bias setting signal (RVS). At this time, the reset bias voltage (VIASR) can be used to generate a reset switching signal (SWS) to turn off the reset switch.

[0035] The vision sensor (100) according to the present disclosure adjusts the voltage level of the reset switching signal according to temperature information (TI), thereby compensating for leakage current that may occur in the reset transistor under high temperature conditions. Accordingly, errors in the polarity information of the event detected by the vision sensor (100) at high temperature (i.e., whether it is an on-event where the light intensity increases or an off-event where the light intensity decreases) can be prevented.

[0036] FIG. 4 is a circuit diagram showing an example of an implementation of a pixel of a vision sensor according to an exemplary embodiment of the present disclosure.

[0037] Referring to FIG. 4, the pixel (PX) may include a photoelectric conversion element (PD), a first amplifier (A1), a second amplifier (A2), a first comparator (111), a second comparator (112), an on-event holder (113), an off-event holder (114), output logic (115), reset logic (116), a buffer (117), and a reset switch (SW). The pixel (PX) may further include transistors (MN, MP), capacitors (C1, C2), and a current source (ISF), etc.

[0038] A photoelectric conversion device (PD) can convert incident light, i.e., an optical signal, into an electrical signal, for example, an electric current (IPD). The photoelectric conversion device (PD) may include, for example, a photodiode, a phototransistor, a photogate, or a pinned photodiode. The photoelectric conversion device (PD) can generate an electrical signal having a higher level as the intensity of the incident light increases.

[0039] The photoelectric conversion element (PD) can generate a current (IPD). The transistor (MN) and the first amplifier (A1) can convert the current (IPD) into a voltage (VLOG) as an example of a current-voltage converter. The current-voltage converter may be implemented differently from that shown in FIG. 4. The transistor (MN) may be an NMOS (n-type metal-oxide-semiconductor) to which a power supply voltage (VDD) is applied at one end.

[0040] The current source (ISF) and the transistor (MP) can operate as a source follower to output a source follower voltage (VSF). The transistor (MP) may be a p-type metal-oxide-semiconductor (PMOS) to which a ground voltage is applied to one end. However, the source follower may include a current source (ISF) and an NMOS transistor to which a power supply voltage (VDD) is applied to one end.

[0041] The capacitors (C1, C2) and the second amplifier (A2) operate as amplifiers to amplify the source follower voltage (VSF) at a predetermined ratio to generate an output voltage (VOUT). The output voltage (VOUT) can be provided to the first comparator (111) and the second comparator (112).

[0042] A reset switch (SW) may be connected between the input and output terminals of the second amplifier (A2). The reset switch (SW) may be turned on or off in response to a reset switching signal (SWS), and by connecting the input and output terminals of the second amplifier (A2), the output voltage (VOUT) may be reset so that the voltages at both ends of the second amplifier (A2) become equal. In an exemplary embodiment, the reset switch (SW) may be a PMOS transistor, but is not limited thereto, and the reset switch (SW) may be implemented in various ways.

[0043] The first comparator (111) can compare the output voltage (VOUT) with the on-threshold voltage (VREF_ON) and generate an on signal (E_ON) based on the comparison result. The second comparator (112) can compare the output voltage (VOUT) of the amplifier with the off-threshold voltage (VREF_OFF) and generate an off signal (E_OFF) based on the comparison result. The first comparator (111) and the second comparator (112) can generate an on signal (E_ON) or an off signal (E_OFF) when the amount of change in light received by the photoelectric conversion element (PD) is greater than a certain change level.

[0044] For example, the ON signal (E_ON) may become a high level when the amount of light received by the photoelectric conversion element (PD) increases above a certain level, and the OFF signal (E_OFF) may become a high level when the amount of light received by the photoelectric conversion element (PD) decreases above a certain level. The ON-event holder (113) and the OFF-event holder (114) may each hold the ON signal (E_ON) and the OFF signal (E_OFF), respectively, and then output them. The ON-event holder (113) and the OFF-event holder (114) may output the ON signal (E_ON) and the OFF signal (E_OFF) when the pixel (PX) is scanned.

[0045] The output logic (115) receives an ON signal (E_ON) and an OFF signal (E_OFF), and can output a signal indicating a state in which a signal can be output based on the ON signal (E_ON) and the OFF signal (E_OFF), i.e., a request (REQ), and can transmit the request (REQ) to an event detection circuit (e.g., 110 in FIG. 2). When the event detection circuit (110) receives the request (REQ), it can transmit an acknowledgment signal (ACK) to the pixel (PX). The acknowledgment signal (ACK) may be a signal indicating that the event detection circuit (110) has read polarity information (e.g., a signal indicating the occurrence of an ON-event or an OFF-event) from the pixel (PX).

[0046] The reset logic (116) can receive an acknowledgment signal (ACK) and generate a reset signal (RST), and can transmit the reset signal (RST) to a buffer (117). The buffer (117) can generate a reset switching signal (SWS) to control a reset switch (SW) in response to the reset signal (RST). The reset signal (RST) may be a signal to individually reset a pixel (PX) included in a pixel array (e.g., PA in FIG. 2).

[0047] The buffer (117) may receive a global reset signal (GRST) and generate a reset switching signal (SWS). The global reset signal (GRST) may be a signal to reset all pixels in the pixel array (PA), and the buffer (117) may generate a reset switching signal (SWS) to control the reset switch (SW) in response to the global reset signal (GRST). That is, the global reset signal (GRST) may be a signal to reset the pixels (PX) included in the pixel array (PA) in common.

[0048] The buffer (117) receives a reset bias voltage (VIASR) from the voltage generator (130) and can generate a reset switching signal (SWS) using the reset bias voltage (VIASR). For example, the reset switch (SW) may be a PMOS transistor, and the buffer (117) can generate a reset switching signal (SWS_OFF) to turn off the reset switch (SW) using the reset bias voltage (VIASR). As the voltage level of the reset bias voltage (VIASR) changes, the voltage level of the reset switching signal (SWS_OFF) to turn off the reset switch (SW) may also change. In an exemplary embodiment, the voltage level of the reset bias voltage (VIASR) may change depending on the temperature at which the vision sensor operates.

[0049] FIG. 5a is a diagram illustrating the change in output voltage (VOUT) of a pixel amplifier according to temperature. FIG. 5b is a diagram illustrating the change in gain of a pixel amplifier with respect to frequency according to temperature. FIG. 5a is a diagram illustrating the change in output voltage (VOUT) when a reset switching signal (SWS) of the same voltage level is applied to a reset switch (SW) at different temperatures according to a comparative example. FIG. 5b is a diagram illustrating the change in gain of a pixel amplifier when a reset switching signal (SWS) of the same voltage level is applied to a reset switch (SW) at different temperatures according to a comparative example.

[0050] Referring to FIGS. 4 and 5a, as an on-event occurs, the voltage of the source follower voltage (VSF) may increase, and the first output voltage (VOUT1) may decrease. At this time, the first output voltage (VOUT_NT1) at normal temperatures remains in a decreased state, whereas the first output voltage (VOUT_HT1) at high temperatures may decrease and then gradually increase due to leakage current generated in the reset switch (SW). Since the first output voltage (VOUT1) must maintain a level lower than the on-threshold voltage (VREF_ON) for the pixel (PX) to detect the on-event, the time available to detect the on-event may decrease at high temperatures.

[0051] As an off-event occurs, the voltage of the source follower voltage (VSF) may decrease, and the second output voltage (VOUT2) may increase. At this time, while the second output voltage (VOUT_NT2) at normal temperatures remains in an increased state, the second output voltage (VOUT_HT2) at high temperatures may increase and then gradually decrease due to leakage current generated in the reset switch (SW). Since the second output voltage (VOUT2) must maintain a level higher than the off-threshold voltage (VREF_OFF) for the pixel (PX) to detect the off-event, the time required to detect the off-event may decrease at high temperatures.

[0052] A vision sensor according to the present disclosure can control the leakage current flowing through a reset switch (SW) by adjusting the voltage level of a reset switching signal (SWS) applied to a reset switch (SW) differently according to temperature, and can reduce the degree to which the levels of a first output voltage (VOUT1) corresponding to an on-event and a second output voltage (VOUT2) corresponding to an off-event change over time. Accordingly, the vision sensor can increase the time for detecting on-events and off-events and increase the detection accuracy of on-events and off-events.

[0053] Referring to FIGS. 4 and FIGS. 5b, the first temperature (T1) may be lower than the second temperature (T2), and the second temperature (T2) may be lower than the third temperature (T3). In a relatively low frequency region, as the temperature increases, the gain of the amplifier including capacitors (C1, C2) and the second amplifier (A2) may decrease rapidly, and an error may occur in detecting an on-event or an off-event when the vision sensor according to the comparative example is operating at a low frequency in a high-temperature state. Accordingly, the vision sensor according to the present disclosure can adjust the voltage level of the reset switching signal (SWS) applied to the reset switch (SW) according to the temperature, and by adjusting the operating frequency according to the adjusted voltage level of the reset switching signal (SWS), the detection accuracy of on-events and off-events can be increased.

[0054] FIG. 6 is a block diagram showing a temperature comparison module (150) of a vision sensor (100) according to an exemplary embodiment of the present disclosure. FIG. 7 is a block diagram for explaining counters (154 to 156) included in the temperature comparison module (150) of FIG. 6.

[0055] Referring to FIG. 6, the temperature comparison module (150) can receive temperature information (TI) generated at different times and can output a switching setting value (SSV) using a specified number of temperature information (TI). The temperature comparison module (150) may include a plurality of comparison circuits (151 to 153), a plurality of counters (154 to 156), a selection signal generator (157), a register (158), and a selector (159).

[0056] A plurality of comparison circuits (151 to 153) may include a first comparison circuit (151), a second comparison circuit (152), and a third comparison circuit (153). The first comparison circuit (151) may receive temperature information (TI) from a temperature sensor controller (160) and output a first result value (TR1) by comparing the temperature information (TI) with a first reference temperature value (RTV1). The second comparison circuit (152) may receive temperature information (TI) from a temperature sensor controller (160) and output a second result value (TR2) by comparing the temperature information (TI) with a second reference temperature value (RTV2). The third comparison circuit (153) may receive temperature information (TI) from a temperature sensor controller (160) and output a third result value (TR3) by comparing the temperature information (TI) with a third reference temperature value (RTV3). In FIG. 6, three comparison circuits are shown, but this is just an example, and the number of comparison circuits included in the temperature comparison module (150) can be configured in various ways.

[0057] At this time, since the multiple comparison circuits (151 to 153) periodically receive temperature information (TI), they can compare each of the multiple reference temperature values ​​(RTV1 to RTV3) with the periodically received temperature information (TI). Accordingly, the first comparison circuit (151) can periodically output first result values ​​(TR1), the second comparison circuit (152) can periodically output second result values ​​(TR2), and the third comparison circuit (153) can periodically output third result values ​​(TR3).

[0058] The first to third reference temperature values ​​(RTV1 to RTV3) may be pre-set in the temperature comparison module (150). Alternatively, in an exemplary embodiment, a plurality of comparison circuits (151 to 153) may receive the first to third reference temperature values ​​(RTV1 to RTV3) from the temperature sensor controller (160).

[0059] The temperatures corresponding to each of the first to third reference temperature values ​​(RTV1 to RTV3) may gradually increase. For example, the temperature corresponding to the first reference temperature value (RTV1) may be lower than the temperature corresponding to the second reference temperature value (RTV2), and the temperature corresponding to the second reference temperature value (RTV2) may be lower than the temperature corresponding to the third reference temperature value (RTV3).

[0060] Referring to FIGS. 6 and 7, the plurality of counters (154 to 156) may include a first counter (154), a second counter (155), and a third counter (156). The number of counters included in the temperature comparison module (150) may correspond to the number of comparison circuits.

[0061] The first counter (154) can receive a first result value (TR1) from the first comparison circuit (151) and output a first counting bit (CB1) that counts the first result value (TR1) using a clock signal (CLK). The second counter (155) can receive a second result value (TR2) from the second comparison circuit (152) and output a second counting bit (CB2) that counts the second result value (TR2) using a clock signal (CLK). The third counter (156) can receive a third result value (TR3) from the third comparison circuit (153) and output a third counting bit (CB3) that counts the third result value (TR3) using a clock signal.

[0062] At this time, the first counter (154) can periodically receive first result values ​​(TR1) from the first comparison circuit (151), and can periodically count the received first result values ​​(TR1) to output first counting bits (CB1). The second counter (155) can periodically receive second result values ​​(TR2) from the second comparison circuit (152), and can periodically count the received second result values ​​(TR2) to output second counting bits (CB2). The third counter (156) can periodically receive third result values ​​(TR3) from the third comparison circuit (153), and can periodically count the received third result values ​​(TR3) to output third counting bits (CB3).

[0063] Multiple counters (154 to 156) can receive a clock signal (CLK) from the temperature sensor controller (160) and can receive a clock enable signal (CLKEN). When the clock enable signal (CLKEN) is activated, the multiple counters (154 to 156) can perform a counting operation. However, unlike as shown in FIG. 7, the clock signal (CLK) may be generated within the temperature comparison module (150) without receiving the clock signal (CLK) from the temperature sensor controller (160).

[0064] Referring again to FIG. 6, the selection signal generator (157) receives first counting bits (CB1), second counting bits (CB2), and third counting bits (CB3) that are generated periodically, and can generate a selection signal (SS) based on a specific number of first counting bits (CB1), second counting bits (CB2), and third counting bits (CB3).

[0065] In an exemplary embodiment, the selection signal generator (157) may generate a selection signal (SS) after receiving a preset number of first counting bits (CB1), second counting bits (CB2), and third counting bits (CB3). For example, the selection signal generator (157) may receive the first to third counting bits (CB1 to CB3) generated by each of the plurality of comparison circuits (151 to 153) performing a comparison operation and each of the plurality of counters (154 to 156) performing a counting operation, sequentially in a specified number of comparisons according to time order. The selection signal generator (157) may output a selection signal (SS) based on the first counting bits (CB1) generated at different times, the second counting bits (CB2) generated at different times, and the third counting bits (CB3) generated at different times.

[0066] The selector (159) can receive a first setting value (SV1), a second setting value (SV2), and a third setting value (SV3) that are preset in the register (158) from the register (158), and in response to a selection signal (SS), can output one of the first to third setting values ​​(SV1~SV3) to the outside of the temperature comparison module (150) as a switching setting value (SSV). For example, the selector (159) may be a multiplexer.

[0067] Each of the first setting value (SV1), the second setting value (SV2), and the third setting value (SV3) can be transmitted to the voltage level controller (140), and the voltage level controller (140) can generate a reset bias setting signal (RVS) corresponding to each of the first setting value (SV1), the second setting value (SV2), and the third setting value (SV3). Accordingly, the voltage generator (130) can generate a reset bias voltage (VIASR) corresponding to each of the first setting value (SV1), the second setting value (SV2), and the third setting value (SV3).

[0068] FIG. 8 is a block diagram illustrating the selection signal generator and register included in the temperature comparison module (150) of FIG. 6.

[0069] Referring to FIG. 8, the selection signal generator (157) can receive level count number information (LCN) received from the temperature sensor controller (160). Based on the level count number information (LCN), the number of first counting bits (CB1) (e.g., n), the number of second counting bits (CB1) (n), and the number of third counting bits (CB3) (n) received by the selection signal generator (157) to generate a selection signal (SS) can be set.

[0070] For example, to generate a selection signal (SS) according to level count number information (LCN), the number of times counting bits are received at different points in time can be set to n. The selection signal generator (157) can receive a first counting bit (CB11), a second counting bit (CB21), and a third counting bit (CB31) at a first point in time, receive a first counting bit (CB12), a second counting bit (CB22), and a third counting bit (CB32) at a second point in time, and receive a first counting bit (CB1n), a second counting bit (CB2n), and a third counting bit (CB3n) at an n-th point in time. The selection signal generator (157) can generate a selection signal (SS) based on the received first counting bits (CB11~CB1n), second counting bits (CB21~CB2n), and third counting bits (CB31~CB3n).

[0071] The register (158) can receive a register setting signal (RSS) received from the temperature sensor controller (160). By the register setting signal (RSS), a first setting value (SV1), a second setting value (SV2), and a third setting value (SV3) can be set in the register (158). The values ​​of the first setting value (SV1), the second setting value (SV2), and the third setting value (SV3) can be changed according to the control of the temperature sensor controller (160). The register (158) can output the set first setting value (SV1), second setting value (SV2), and third setting value (SV3) to the selector (159).

[0072] FIG. 9 is a block diagram showing a temperature comparison module (150a) of a vision sensor (100) according to an exemplary embodiment of the present disclosure. In the description of FIG. 9, redundant descriptions of the same reference numerals as in FIG. 6 will be omitted.

[0073] Referring to FIG. 9, the temperature comparison module (150a) can receive temperature information (TI) from the on / SS temperature sensor controller (160) and output a switching setting value (SSV) based on the result of comparing it with a plurality of reference temperature values ​​(RTV1 to RTV3). The temperature comparison module (150a) can receive a frame end signal (FE) from the temperature sensor controller (160) indicating that the frame has ended. The temperature comparison module (150a) can output the switching setting value (SSV) in response to the frame end signal (FE). Accordingly, the voltage level of the reset switching signal provided to the reset switch of the pixel, for example, the voltage level of the reset switching signal to turn off the reset switch, can be determined when the next frame starts after one frame has ended.

[0074] In an exemplary embodiment, the temperature comparison module (150a) may include a plurality of comparison circuits (151–153), a plurality of counters (154–156), a selection signal generator (157), a register (158), a selector (159), and an AND gate (ANDG). The AND gate (ANDG) may receive a frame end signal (FE) from the temperature sensor controller (160) and receive a switching setting value (SSV) from the selector (159). When the frame end signal (FE) is activated (e.g., high level), the AND gate (ANDG) may output the switching setting value (SSV) to the outside of the temperature comparison module (150a) (e.g., the voltage level controller (140) of FIG. 2).

[0075] FIG. 10 is a block diagram showing a voltage level controller (140) of a vision sensor (100) according to an exemplary embodiment of the present disclosure.

[0076] Referring to FIG. 10, the voltage level controller (140) can receive a switching setting value (SSV) from a temperature comparison module (e.g., 150 in FIG. 6 or 150A in FIG. 9) and can generate a reset bias setting signal (RVS) that changes the reset bias voltage (e.g., VIASR in FIG. 2) to a set specific level. The voltage level controller (140) may include a register (141) and a selector (143).

[0077] A reference setting value (RSV) may be pre-set in the register (141), and the register (141) may output the reference setting value (RSV) to the selector (143). The selector (143) may receive the reference setting value (RSV) from the register (141) and receive the switching setting value (SSV) from the temperature comparison module (150, 150A). The selector (143) may receive a voltage level control signal (VCS) and, in response to the voltage level control signal (VCS), output one of the reference setting value (RSV) and the switching setting value (SSV) as a reset bias setting signal (RVS). Accordingly, the voltage level controller (140) may provide a reference setting value (RSV), which is a preset register value, to a voltage generator (e.g., 130 in FIG. 2) as a reset bias setting signal (RVS), or provide a switching setting value (SSV), which changes according to temperature information (TI), to the voltage generator (130) as a reset bias setting signal (RVS).

[0078] In an exemplary embodiment, a voltage level control signal (VCS) may be received from outside the vision sensor to a selector (143). For example, the voltage level control signal (VCS) may be received from a processor (e.g., 200 in FIG. 1) and may be received via an I2C (inter-integrated circuit). The processor (200) may control the vision sensor so that, depending on the operating environment of the vision sensor, the vision sensor generates a reset signal of a constant value according to a preset value, or generates a reset signal in which the voltage level is adjusted according to temperature.

[0079] In an exemplary embodiment, when the processor (200) determines that the temperature of the image processing device (e.g., 10 in FIG. 1) is in a high-temperature state exceeding a threshold value, it transmits a voltage level control signal (VCS) to the voltage level controller (140) of the vision sensor, thereby controlling the voltage level controller (140) to output a switching setting value (SSV) that changes according to temperature information (TI) as a reset bias setting signal (RVS). At this time, the processor (200) can detect that the image processing device (10) is in a high-temperature state through a temperature sensor outside the vision sensor, and the processor (200) can reduce unnecessary power consumption by controlling the temperature sensor inside the vision sensor not to operate.

[0080] In an exemplary embodiment, when the vision sensor operates at a high frequency exceeding a threshold value, the processor (200) can transmit a voltage level control signal (VCS) to the voltage level controller (140) of the vision sensor to control the output of a reference setting value (RSV), which is a preset register value, as a reset bias setting signal (RVS). In addition, in an exemplary embodiment, when the vision sensor operates at a low frequency below a threshold value, the processor (200) can transmit a voltage level control signal (VCS) to the voltage level controller (140) of the vision sensor to control the voltage level controller (140) to output a switching setting value (SSV), which changes according to temperature information (TI), as a reset bias setting signal (RVS). As described in FIG. 5b, when the vision sensor operates at a low frequency, the difference in amplifier gain due to temperature change may increase. Therefore, when operating at a low frequency, the voltage level controller (140) can be controlled to output a switching setting value (SSV) that changes according to temperature information (TI) as a reset bias setting signal (RVS).

[0081] FIG. 11 is a block diagram showing an image processing device (10b) according to an exemplary embodiment of the present disclosure.

[0082] Referring to FIG. 11, the image processing device (10b) may include a first sensor, i.e., a vision sensor (100b), a processor (200), and a second sensor (300). For example, the second sensor (300) may detect the external environment when the image processing device (10b) is operating, for example, the illuminance around an object or the brightness of an object, or detect the position of the image processing device (10b). For example, the second sensor (300) may be a gyroscope sensor or an illuminance sensor.

[0083] The second sensor (300) may provide the sensed signal to the vision sensor (100b) through the processor (200) or directly to the vision sensor (100b). The vision sensor (100b) may control the operation of the vision sensor (100b) based on the signal received from the second sensor (300). In an exemplary embodiment, the vision sensor (100b) may determine the levels of voltages provided to the pixel array (e.g., PA of FIG. 2) based on the signal received from the second sensor (300). For example, the vision sensor (100b) may adjust the voltage level of the reset bias voltage (VIASR) provided to the pixel array (PA) based on the signal received from the second sensor (300).

[0084] FIG. 12 is a block diagram exemplarily showing an electronic device (1000) to which a vision sensor (1100) according to an exemplary embodiment of the present disclosure is applied.

[0085] Referring to FIG. 12, the electronic device (1000) may include a vision sensor (1100), a main processor (1200), a working memory (1300), a storage (1400), a display device (1500), a communication unit (1600), and a user interface (1700).

[0086] The vision sensor (100, 100b) described with reference to FIGS. 1 to 11 can be applied as a vision sensor (1100). The vision sensor (1100) can sense an object to generate event signals and transmit the generated event signals to a main processor (1200). The vision sensor (1100) can improve the detection accuracy of the vision sensor (1100) by changing the voltage level of the reset signal provided to the pixel according to the temperature.

[0087] The main processor (1200) can control the overall operation of the electronic device (1000) and can detect the movement of an object by processing event data, i.e., event signals, received from the vision sensor (1100).

[0088] The working memory (1300) can store data used for the operation of the electronic device (1000). For example, the working memory (1300) can temporarily store packets or frames processed by the processor (1120). For example, the working memory (1300) may include volatile memory such as DRAM (Dynamic RAM), SDRAM (Synchronous RAM), and / or non-volatile memory such as PRAM (Phase-change RAM), MRAM (Magneto-resistive RAM), ReRAM (Resistive RAM), FRAM (Ferro-electric RAM).

[0089] Storage (1400) can store data requested for storage from the main processor (1200) or other components. Storage (1400) may include non-volatile memory such as flash memory, PRAM, MRAM, ReRAM, FRAM, etc.

[0090] The display device (1500) may include a display panel, a display driving circuit, and a DSI (display serial interface). For example, the display panel may be implemented as various devices such as an LCD (Liquid Crystal Display) device, an LED (Light Emitting Diode) display device, an OLED (Organic LED) display device, an AMOLED (Active Matrix OLED) display device, etc. The display driving circuit may include a timing controller, a source driver, etc., necessary to drive the display panel. A DSI host embedded in the main processor (1200) can perform serial communication with the display panel through the DSI.

[0091] The communication unit (1600) can exchange signals with an external device / system through an antenna (1630). The transceiver (1610) and MODEM (Modulator / Demodulator, 1620) of the communication unit (1600) can process signals exchanged with an external device / system according to wireless communication protocols such as LTE (Long Term Evolution), WIMAX (Worldwide Interoperability for Microwave Access), GSM (Global System for Mobile communication), CDMA (Code Division Multiple Access), Bluetooth, NFC (Near Field Communication), Wi-Fi (Wireless Fidelity), RFID (Radio Frequency Identification), etc.

[0092] The user interface (1700) may include at least one of input interfaces such as a keyboard, mouse, keypad, button, touch panel, touch screen, touchpad, touch ball, gyroscope sensor, vibration sensor, accelerometer sensor, etc.

[0093] Components of an electronic device (1000), such as a vision sensor (1100), a main processor (1200), a working memory (1300), a storage (1400), a display device (1500), a communication unit (1600), and a user interface (1700), can exchange data based on one or more of various interface protocols such as USB (Universal Serial Bus), SCSI (Small Computer System Interface), MIPI, I2C, PCIe (Peripheral Component Interconnect Express), M-PCIe (Mobile PCIe), ATA (Advanced Technology Attachment), PATA (Parallel ATA), SATA (Serial ATA), SAS (Serial Attached SCSI), IDE (Integrated Drive Electronics), EIDE (Enhanced IDE), NVMe (Nonvolatile Memory Express), UFS (Universal Flash Storage), etc.

[0094] As described above, exemplary embodiments have been disclosed in the drawings and specification. Although specific terms have been used to describe the embodiments in this specification, they are used only for the purpose of explaining the technical concept of this disclosure and are not intended to limit the meaning or the scope of this disclosure as defined in the claims. Therefore, those skilled in the art will understand that various modifications and equivalent alternative embodiments are possible therefrom. Accordingly, the true technical scope of protection of this disclosure should be determined by the technical concept of the appended claims.

Claims

Claim 1 A vision sensor comprising a plurality of pixels configured to generate first signals related to the movement of an object in response to a change in light intensity, wherein each of the plurality of pixels comprises: an amplifier including an input terminal and an output terminal; a reset switch connecting the input terminal and the output terminal in response to a reset switching signal; a first comparator configured to generate on-signals based on the first signals; and a second comparator configured to generate off-signals based on the first signals, wherein the reset switch is configured to receive the reset switching signal of a first voltage and the reset switching signal of a second voltage based on temperature information of the vision sensor. Claim 2 A vision sensor configured to compare the temperature information and a reference temperature in claim 1, and to determine the voltage level of the reset switching signal based on the comparison result. Claim 3 A vision sensor according to claim 2, further comprising an event detection circuit configured to generate event signals based on the on-signals and the off-signals. Claim 4 A vision sensor characterized by further including a temperature sensor configured to detect the temperature information in claim 3. Claim 5 A vision sensor according to claim 3, wherein the event detection circuit is configured to generate event signals based on some on-signals and some off-signals, and the some on-signals and the some off-signals are generated based on pixels related to the region of interest among the plurality of pixels. Claim 6 In claim 4, the temperature sensor is a vision sensor configured to periodically detect the temperature information. Claim 7 A vision sensor according to claim 6, wherein the temperature sensor is configured to detect the temperature of the vision sensor and generate multiple temperature information at different points in time, and is configured to reset the multiple pixels based on the multiple temperature information. Claim 8 A vision sensor according to claim 3, further comprising a processor configured to receive the event signal and characterized by being implemented as a system-on-chip. Claim 9 A vision sensor characterized in that, in claim 6, it is configured to compare the temperature information with each of a plurality of reference temperature values ​​and determine the voltage level of the reset switching signal based on the comparison result. Claim 10 A vision sensor comprising: a plurality of pixels configured to generate first signals related to the movement of an object in response to a change in light intensity; a temperature sensor configured to detect the temperature of the vision sensor and generate temperature information; and an event detection circuit configured to generate event signals based on the first signals, wherein each of the plurality of pixels includes an amplifier comprising an input terminal and an output terminal; and a reset switch connecting the input terminal and the output terminal in response to a reset switching signal, wherein the reset switch is configured to receive the reset switching signal of a first voltage and the reset switching signal of a second voltage based on the temperature information of the vision sensor. Claim 11 A vision sensor according to claim 10, wherein the temperature sensor is configured to detect the temperature of the vision sensor and generate multiple temperature information at different points in time, and each of the multiple pixels is reset based on the multiple temperature information. Claim 12 A vision sensor according to claim 11, characterized in that the event detection circuit is configured to reset the plurality of pixels to the first voltage or the second voltage based on the plurality of temperature information. Claim 13 A vision sensor according to claim 12, characterized in that it is configured to compare the plurality of temperature information and reference temperature values ​​and determine the first voltage or the second voltage based on the comparison result. Claim 14 A vision sensor configured to determine the first voltage or the second voltage by comparing the plurality of temperature information and the plurality of reference temperature values ​​in claim 13. Claim 15 A vision sensor according to claim 10, wherein the event detection circuit is configured to generate event signals based on second signals generated from pixels related to a region of interest among the plurality of pixels. Claim 16 A vision sensor according to claim 10, further comprising a processor configured to receive the event signals and characterized by being implemented as a system-on-chip. Claim 17 A vision sensor comprising: a plurality of pixels configured to generate first signals related to the movement of an object in response to a change in light intensity; and an event detection circuit configured to generate event signals based on the first signals, wherein each of the plurality of pixels comprises: an amplifier including an input terminal and an output terminal; and a reset switch connecting the input terminal and the output terminal in response to a reset switching signal, wherein the reset switch is configured to receive the reset switching signal of a first voltage and the reset switching signal of a second voltage based on temperature information of the vision sensor, and wherein the temperature information of the vision sensor is generated from a temperature sensor by detecting the temperature of the vision sensor. Claim 18 A vision sensor according to claim 17, characterized in that the plurality of pixels are configured to generate the first signals atypically. Claim 19 A vision sensor configured to compare the temperature information and a reference temperature value in claim 18, and to determine the first voltage or the second voltage based on the result of the comparison. Claim 20 A vision sensor according to claim 19, wherein the plurality of pixels are reset based on a plurality of temperature information generated from the temperature sensor by detecting the temperature of the vision sensor at a plurality of points in time.

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