An infrared readout circuit

Abstract

The application provides an infrared readout circuit, for each pixel group of an infrared array, the infrared readout circuit comprises a readout unit corresponding to the pixel group, an analog-digital converter and a correction control unit, the analog-digital converter comprises a comparator; for a pixel in the pixel group: the readout unit is used for determining a voltage response value corresponding to the pixel based on an initial bias value corresponding to a to-be-corrected parameter value of the pixel; the comparator is used for comparing the voltage response value with a preset voltage value, obtaining a comparison result corresponding to the pixel, and inputting the comparison result to the correction control unit; the correction control unit is used for adjusting the to-be-corrected parameter value based on the comparison result, obtaining an adjusted parameter value; determining a correction parameter optimal value corresponding to the pixel based on the adjusted parameter value, and replacing the to-be-corrected parameter value by the correction parameter optimal value. Through the technical scheme, the non-uniformity correction does not need to be realized by an external processor, and the hardware resource overhead is reduced.

Description

Technical Field

[0001] This application relates to the field of infrared temperature measurement technology, and in particular to an infrared readout circuit. Background Technology

[0002] Thermal imaging temperature measurement is a non-contact temperature measurement method that can acquire the temperature value of a target object in a target scene. For example, an infrared array can include multiple pixels, each of which can be a thermistor, or sensor unit. For each pixel, after the infrared thermal radiation from the target scene reaches that pixel, the pixel can sense the ambient temperature, thereby changing the pixel's resistance value and controlling the current value passing through that pixel. Based on this current value, the corresponding voltage output value of the pixel can be determined and output. Based on this voltage output value, the corresponding temperature value of the pixel can be determined.

[0003] In thermal imaging temperature measurement, it is necessary to pre-calibrate the mapping relationship (i.e., functional relationship) between voltage and temperature values. Based on this, the mapping relationship can be queried based on the voltage output value corresponding to each pixel, thereby obtaining the temperature value corresponding to that pixel. In summary, the temperature value corresponding to each pixel can be obtained, and these temperature values ​​corresponding to these pixels are the temperature values ​​corresponding to the target objects in the target scene.

[0004] Due to manufacturing process variations, different pixels may respond differently to the same amount of infrared radiation. For example, if the voltage output values ​​for pixel 1 and pixel 2 differ when the same infrared radiation reaches them, it will cause image inhomogeneity. This difference needs to be corrected, and this correction method is called non-uniformity correction. However, there is currently no reasonable method for performing non-uniformity correction. It is mainly achieved through external processors, but the correction effect is relatively poor. Summary of the Invention

[0005] This application provides an infrared readout circuit. The infrared array includes K pixel groups, where K is a positive integer greater than 1. For each pixel group of the infrared array, the infrared readout circuit includes a readout unit corresponding to that pixel group, an analog-to-digital converter, and a correction control unit. The analog-to-digital converter includes a comparator. Specifically, for each pixel in the pixel group:

[0006] The readout unit is used to determine the voltage response value corresponding to the pixel based on the initial bias value corresponding to the parameter value to be corrected corresponding to the pixel, and input the voltage response value to the comparator;

[0007] The comparator is used to compare the voltage response value with the preset voltage value to obtain the comparison result corresponding to the pixel, and input the comparison result to the correction control unit;

[0008] The correction control unit is used to adjust the value of the parameter to be corrected based on the comparison result to obtain the adjusted parameter value; determine the optimal value of the correction parameter corresponding to the pixel based on the adjusted parameter value, and replace the value of the parameter to be corrected with the optimal value of the correction parameter.

[0009] As can be seen from the above technical solutions, the embodiments of this application design an infrared readout circuit, which realizes non-uniformity correction without the need for an external processor. This reduces the overhead of external hardware resources, lowers costs, simplifies development, and achieves better correction results. By providing different bias voltage values ​​to different pixels (different bias voltage values ​​are controlled by the optimal values ​​of different correction parameters), the differences in response of different pixels to the same infrared radiation are corrected, making the response of different pixels to the same infrared radiation consistent, thus realizing the non-uniformity correction of different pixels. By dividing all pixels of the infrared array into K pixel groups, parallel processing of the K pixel groups can be performed, thereby reducing the time required for the correction stage. Attached Figure Description

[0010] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments of this application or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings of the embodiments of this application.

[0011] Figure 1 This is a schematic diagram of the structure of an infrared array in one embodiment of this application;

[0012] Figure 2 This is a schematic diagram of the infrared readout circuit in one embodiment of this application;

[0013] Figure 3 This is a schematic diagram of the structure of an ADC in one embodiment of this application;

[0014] Figure 4 This is a schematic diagram of the infrared readout circuit in one embodiment of this application;

[0015] Figure 5 This is a schematic diagram of the structure of the readout unit in one embodiment of this application;

[0016] Figure 6 This is a schematic diagram illustrating the working principle of an ADC in one embodiment of this application;

[0017] Figure 7 This is a schematic diagram of the operation of the infrared readout circuit in one embodiment of this application;

[0018] Figure 8 This is a timing diagram of the infrared readout circuit in one embodiment of this application;

[0019] Figure 9 This is a timing diagram of the operation of each switch in the infrared readout circuit according to one embodiment of this application. Detailed Implementation

[0020] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to limit the application. The singular forms “a,” “the,” and “the” as used in this application and claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to any and all possible combinations comprising one or more of the associated listed items.

[0021] It should be understood that although the terms first, second, third, etc., may be used to describe various information in embodiments of this application, such information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, without departing from the scope of this application, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the word "if" may also be interpreted as "when," "when," or "in response to a determination."

[0022] Thermal imaging devices may include thermal imaging cameras (such as cameras and video cameras that use thermal imaging to measure temperature, such as infrared thermal imaging cameras), infrared arrays (also known as focal plane arrays, which are circuits composed of a large number of pixels), baffles, and external processors.

[0023] An infrared array can include multiple pixels, each of which can be a thermistor. For each pixel, after the infrared thermal radiation from the target scene reaches that pixel, the pixel can sense the ambient temperature, thereby changing the resistance value of the pixel and controlling the current value passing through the pixel. Based on this current value, the voltage output value corresponding to the pixel is determined and output to an external processor. In other words, the voltage output value corresponding to each pixel can be output to an external processor.

[0024] Based on the pre-calibrated mapping relationship between voltage and temperature values, after obtaining the voltage output value corresponding to each pixel, the external processor can query the mapping relationship to obtain the temperature value corresponding to each pixel. The temperature values ​​corresponding to these pixels are the actual target temperature values ​​of the target scene.

[0025] A baffle is a device used to block the lens of a thermal imaging device. When the baffle is open, it blocks the lens, and in this case, the temperature value sensed by each pixel in the infrared array is the temperature value of the baffle; different pixels will sense the same temperature value. When the baffle is closed, it does not block the lens, and in this case, the temperature value sensed by each pixel in the infrared array is the temperature value of the external target (i.e., the temperature value of the target object to be detected); different pixels may sense different temperature values.

[0026] Due to variations in the manufacturing process, different pixels may respond differently to the same infrared radiation, resulting in image inhomogeneity. This difference needs to be corrected before imaging; this correction method is called non-uniformity correction. In related technologies, non-uniformity correction is mainly achieved through an external processor, but the correction effect is poor and it consumes the resources of the external processor, wasting processing power.

[0027] To address the aforementioned issues, this application proposes an infrared readout circuit connected to an infrared array. This circuit corrects the temperature values ​​sensed by each pixel within the array, achieving non-uniformity correction directly from the infrared readout circuit, eliminating the need for an external processor. This reduces external hardware resource overhead, lowers costs, simplifies development, and provides better correction results. For example, the thermal imaging device may also include an infrared readout circuit capable of correcting the non-uniformity of the voltage output value corresponding to a pixel and outputting the corrected voltage output value to an external processor. The external processor then no longer needs to perform non-uniformity correction on the voltage output value and can directly determine the temperature value based on the voltage output value.

[0028] In this embodiment, all pixels of the infrared array can be divided into K pixel groups, where K is a positive integer greater than 1, so that the K pixel groups can be processed in parallel, thereby reducing the time required for the correction stage.

[0029] The structure and function of the infrared readout circuit of this embodiment will be described below with reference to specific embodiments.

[0030] See Figure 1 The diagram shown is a schematic of the structure of an infrared array, which includes a large number of pixels. Figure 1 Taking M*N pixels as an example, this means that there are N pixels in each row, for a total of M rows of pixels, and M pixels in each column, for a total of N columns of pixels. Based on this, all pixels of the infrared array can be divided into K pixel groups, where K is a positive integer greater than 1, and each pixel group includes multiple pixels.

[0031] For example, all pixels in the infrared array can be divided into M pixel groups (i.e., K equals M), meaning all pixels in each row of the infrared array are grouped into the same pixel group, and M rows of pixels constitute M pixel groups. Alternatively, all pixels in the infrared array can be divided into N pixel groups (i.e., K equals N), meaning all pixels in each column of the infrared array are grouped into the same pixel group, and N columns of pixels constitute N pixel groups. Of course, the above are just two examples of partitioning methods, and no limitation is imposed on this partitioning method.

[0032] In this embodiment, taking the division of all pixels of the infrared array into N pixel groups (i.e., K pixel groups) as an example, all pixels in each column of the infrared array are assigned to the same pixel group. In other words, each pixel group in the K pixel groups corresponds to all pixels in one column. In this case, see [link to relevant documentation]. Figure 1 As shown, all cells in each column (i.e., all cells in each cell group) correspond to the same analog-to-digital converter (ADC), meaning the number of ADCs can be N.

[0033] In this embodiment, for each pixel group of the infrared array, the infrared readout circuit may include a readout unit, ADC, correction control unit, digital to analog converter (DAC), and first register corresponding to that pixel group.

[0034] Since there are K pixel groups, each of the K pixel groups corresponds to one of the K readout units, and there is a one-to-one correspondence between the K readout units and the K pixel groups; each of the K pixel groups corresponds to one of the K ADCs, and there is a one-to-one correspondence between the K ADCs and the K pixel groups; each of the K pixel groups corresponds to one of the K correction control units, and there is a one-to-one correspondence between the K correction control units and the K pixel groups; each of the K pixel groups corresponds to one of the K DACs, and there is a one-to-one correspondence between the K DACs and the K pixel groups; each of the K pixel groups corresponds to one of the K first registers, and there is a one-to-one correspondence between the K first registers and the K pixel groups.

[0035] Since the processing procedure is the same for each pixel group, for ease of description, the following embodiments will use the processing procedure for one pixel group as an example. See Figure 2 As shown, this pixel group can correspond to a readout unit, an ADC, a correction control unit, a DAC, and a first register.

[0036] In this embodiment, for the ADC corresponding to each pixel group, see [link / reference]. Figure 3 The diagram shown is a schematic of the structure of an ADC, which may include, but is not limited to: a comparator, a first switch, a correction target value generator, a ramp generator, a counter, a second register, a second switch, and a data output unit.

[0037] See Figure 4 The diagram shows the structure of an infrared readout circuit. For each pixel group, the infrared readout circuit may include a readout unit, an ADC, a correction control unit, a DAC, and a first register corresponding to that pixel group. The ADC may include a comparator, a first switch, a correction target value generator, a ramp generator, a counter, a second register, a second switch, and a data output unit corresponding to that pixel group.

[0038] For example, an infrared array can also be called an infrared focal plane array or an uncooled infrared focal plane array. It is an array composed of infrared sensitive pixels (hereinafter referred to as pixels). These infrared sensitive pixels can absorb external infrared radiation and cause the pixels to heat up. The heating causes a change in the resistance of the heat-sensitive material. Moreover, this array can work in environments that are not absolute zero.

[0039] An infrared array may include a large number of pixels (e.g., M*N pixels), which can be divided into K pixel groups. For each pixel in a pixel group, since the processing method for each pixel is the same, for ease of description, the processing process of one pixel will be used as an example in the following embodiments.

[0040] For example, the infrared readout circuit supports two states: a correction state (also known as an automatic correction state) and a readout state (also known as a normal readout state). After the infrared readout circuit is powered on and reset, it first enters the correction state. In the correction state, the optimal values ​​of the correction parameters corresponding to each pixel are obtained and written to the first register. After the correction state ends, it enters the readout state. In the readout state, the optimal values ​​of the correction parameters in the first register can be used to correct the voltage output value of the pixel, and the corrected voltage output value is output. That is, the correction is completed in the infrared readout circuit.

[0041] The following combination Figure 4 The infrared readout circuit shown describes the functions of the readout unit, ADC, correction control unit, DAC, first register, comparator, first switch, correction target value generator, ramp generator, counter, second register, second switch, and data output unit.

[0042] When the infrared readout circuit is in the correction state, the functions of each component are as follows:

[0043] I. Readout Unit. The readout unit is used to determine the voltage response value corresponding to a pixel based on the initial bias voltage value corresponding to the parameter value to be corrected, and inputs the voltage response value to the comparator. For example, the readout unit can determine the voltage response value corresponding to a pixel based on the first current corresponding to the initial bias voltage value corresponding to the parameter value to be corrected and the second current output by the pixel response temperature value.

[0044] The second current output by the pixel in response to the temperature value refers to the change in the resistance value of the pixel when the temperature value of the test target sensed by the pixel changes. When the resistance value of the pixel changes, the second current corresponding to the pixel changes. In other words, the second current is related to the temperature value of the test target sensed by the pixel.

[0045] See Figure 5 The diagram shows the structure of the readout unit, which may include a resistor Rd, a first MOS (Metal Oxide Semiconductor Field Effect Transistor), a second MOS transistor, an integrating circuit, and a sample-and-hold circuit. It should be noted that... Figure 5 Although pixel Rs is placed inside the readout unit, this is only for ease of illustrating the connection between pixel Rs and the readout unit; pixel Rs is not actually a component of the readout unit. The integrating circuit consists of an operational amplifier, a switch rst, and an integrating capacitor Cint. The sample-and-hold circuit, also known as a sample-and-hold amplifier, is used to achieve this function. When converting an analog signal to a digital value, a certain conversion time is required. During this conversion time, the analog signal must remain essentially unchanged to ensure conversion accuracy.

[0046] See Figure 5 As shown, the input voltage of the first MOSFET is the bias value Vin. In the correction state, the bias value Vin is called the initial bias value Vin, which is determined based on the value of the parameter to be corrected. The determination process is described in subsequent embodiments. In the readout state, the bias value Vin is called the target bias value Vin, which is determined based on the optimal value of the correction parameter. The determination process is described in subsequent embodiments.

[0047] In the corrected state, the larger the initial bias value Vin, the smaller the current I1 (denoted as the first current I1) passing through the first MOSFET. That is, the initial bias value Vin is negatively correlated with the first current I1. Obviously, by controlling the size of the initial bias value Vin, the size of the first current I1 can be adjusted.

[0048] See Figure 5As shown, the input voltage of the second MOSFET is the voltage value VFID, which is a fixed voltage value. The working principle of this second MOSFET will not be described in detail in this embodiment.

[0049] See Figure 5 As shown, pixel Rs is a resistive element in the infrared array. For example, pixel Rs can be a MEMS (Micro-Electro-Mechanical Systems) thermistor; the type of pixel Rs is not limited. In practical applications, the number of pixels Rs can be multiple. Figure 5 In this example, we take a single pixel Rs. Pixel Rs is used to convert infrared signals into electrical signals. In other words, when infrared thermal radiation from the target scene reaches pixel Rs, pixel Rs can sense the ambient temperature, thereby changing the resistance value of pixel Rs and controlling the current value passing through pixel Rs, i.e., the current I2.

[0050] For example, in the corrected state, a baffle can be opened for the infrared array. The temperature value of each position on the baffle is the same. Thus, for each pixel in the pixel group, taking pixel Rs as an example, the ambient temperature sensed by pixel Rs is the temperature value of the baffle. For ease of distinction, the temperature value sensed by pixel Rs is recorded as the test target temperature value, that is, the test target temperature value is the temperature value of the baffle. Obviously, based on the test target temperature value sensed by pixel Rs, the current I2 passing through pixel Rs (referred to as the second current I2) can be controlled, that is, the second current I2 matches the test target temperature value sensed by pixel Rs.

[0051] See Figure 5 As shown, the integrator circuit can be connected to the first MOSFET and also to the sample-and-hold circuit. The input current Iint of the integrator circuit can also be called the integrating current Iint, and it can be determined based on the first current I1 and the second current I2. That is, the first current I1 corresponding to the initial bias value Vin and the second current I2 of the pixel Rs can be determined. Then, the input current Iint corresponding to the integrator circuit can be determined based on the first current I1 and the second current I2. For example, the input current Iint can be determined as follows: Iint = I1 - I2.

[0052] Given the input current Iint, an integrating circuit can be used to integrate it, without restrictions on the integration process, to obtain the voltage input value Vo_int corresponding to pixel Rs. For example, the integrating circuit can be used to integrate and amplify the weak electrical signal of pixel Rs, and the output of the integrated amplification is the voltage input value Vo_int. For instance, the voltage input value Vo_int can be determined as follows: Vo_int = Vref - Iint * Tint / Cint, where Vref is the input voltage of the operational amplifier, Iint is the input current, Tint is the on-time of the switch int (i.e., the integration time), and Cint is the integrating capacitor.

[0053] See Figure 5 As shown, the input of the sample-and-hold circuit is the voltage input value Vo_int, and the output of the sample-and-hold circuit is the voltage response value Vo. The voltage input value Vo_int can be sampled and held by the sample-and-hold circuit to obtain the voltage response value Vo corresponding to the pixel Rs. That is, Vo = Vo_int.

[0054] When performing analog-to-numerical conversion on an analog signal, a certain conversion time is required. During this conversion time, the analog signal must remain basically unchanged in order to ensure conversion accuracy. The sample-and-hold circuit is the circuit that implements this function. This embodiment does not restrict the operation of the sample-and-hold circuit.

[0055] In summary, for pixel Rs, the input voltage of the first MOSFET is the initial bias value Vin, and the current flowing through the first MOSFET is the first current I1 corresponding to the initial bias value Vin. The output of pixel Rs in response to the temperature value is the second current I2. The difference between the first current I1 and the second current I2 can be determined as the input current Iint of the integrator circuit. The input current Iint is input to the integrator circuit, and the integrator circuit integrates the input current Iint to obtain the voltage input value Vo_int corresponding to pixel Rs. Then, based on the voltage input value Vo_int corresponding to pixel Rs, the voltage response value Vo corresponding to pixel Rs is determined.

[0056] After obtaining the voltage response value Vo corresponding to pixel Rs, the voltage response value Vo can be input to the comparator in the ADC, and the comparator in the ADC will process it based on the voltage response value Vo.

[0057] II. Comparator. The comparator is used to compare the voltage response value Vo and the preset voltage value Vref to obtain the comparison result corresponding to pixel Rs, and input the comparison result corresponding to pixel Rs to the correction control unit.

[0058] Exemplarily, the comparison result (Result) may be a logic value. If the voltage response value Vo is greater than the preset voltage value Vref, the logic value may be a first value (e.g., 1), and the first value indicates that the voltage response value Vo is greater than the preset voltage value Vref; or, if the voltage response value Vo is less than the preset voltage value Vref, the logic value may be a second value (e.g., 0), and the second value indicates that the voltage response value Vo is less than the preset voltage value Vref.

[0059] Exemplarily, the voltage response value Vo may be a voltage value of an analog signal, and the preset voltage value Vref may be a voltage value of an analog signal. The preset voltage value Vref may also be referred to as a correction target value Vref. No limitation is imposed on the value of the preset voltage value Vref, and the value can be configured according to experience. On this basis, after obtaining the voltage response value Vo corresponding to the pixel Rs, the comparator can compare the voltage response value Vo with the preset voltage value Vref. If the voltage response value Vo is greater than the preset voltage value Vref (that is, Vo>Vref), the comparator determines that the logic value is the first value, and outputs the first value to the correction control unit. If the voltage response value Vo is less than the preset voltage value Vref (that is, Vo<Vref), the comparator determines that the logic value is the second value, and outputs the second value to the correction control unit. No limitation is imposed on the first value and the second value, for example, the first value is 1 and the second value is 0.

[0060] In a possible implementation, the correction control unit can determine the state corresponding to the infrared readout circuit. When the infrared readout circuit is in the correction state, the correction control unit can control the second end of the first switch to connect to the correction target value generator. Since the first end of the first switch is fixedly connected to the comparator, after controlling the second end of the first switch to connect to the correction target value generator, the comparator and the correction target value generator can be communicated. That is, when the infrared readout circuit is in the correction state, the comparator and the correction target value generator are communicated.

[0061] Exemplarily, the correction target value generator is configured to generate the preset voltage value Vref, and send the preset voltage value Vref to the comparator, that is, the comparator can obtain the preset voltage value Vref from the correction target value generator.

[0062] Third, the correction control unit. The correction control unit may also be referred to as a NUC control unit. The correction control unit is configured to adjust a parameter value to be corrected based on a comparison result of the voltage response value Vo and the preset voltage value Vref, to obtain an adjusted parameter value; determine an optimal correction parameter value corresponding to the pixel based on the adjusted parameter value, and replace the parameter value to be corrected corresponding to the pixel with the optimal correction parameter value corresponding to the pixel.

[0063] For example, in the process of adjusting the parameter value to be corrected based on the comparison result of the voltage response value Vo and the preset voltage value Vref to obtain the adjusted parameter value, if the comparison result is a first value, indicating that the voltage response value Vo is greater than the preset voltage value Vref, then the parameter value to be corrected is decreased to obtain the adjusted parameter value; or, if the comparison result is a second value, indicating that the voltage response value Vo is less than the preset voltage value Vref, then the parameter value to be corrected is increased to obtain the adjusted parameter value. Specifically, when the correction control unit decreases the parameter value to be corrected to obtain the adjusted parameter value, it can subtract 1 from the parameter value to obtain the adjusted parameter value; of course, it can also subtract other values ​​from the parameter value to obtain the adjusted parameter value, without limitation. When the correction control unit increases the parameter value to be corrected to obtain the adjusted parameter value, it can add 1 to the parameter value to obtain the adjusted parameter value; of course, it can also add other values ​​to the parameter value to obtain the adjusted parameter value, without limitation.

[0064] For example, in the process of determining the optimal value of the correction parameter corresponding to a pixel based on the adjusted parameter value, if the adjustment termination condition of the parameter value to be corrected has been met, the adjusted parameter value can be determined as the optimal value of the correction parameter corresponding to that pixel. Alternatively, if the adjustment termination condition of the parameter value to be corrected has not been met, the adjusted parameter value can be determined as the parameter value to be corrected corresponding to that pixel, and the parameter value to be corrected can be written into the first register to redetermine the voltage response value corresponding to that pixel based on the parameter value to be corrected.

[0065] The correction control unit can determine whether the comparison result of the current comparison cycle is the same as the comparison result of the previous comparison cycle. If the comparison result of the current comparison cycle is the same as the comparison result of the previous comparison cycle, it can be determined that the adjustment termination condition for the parameter value to be corrected has not been met. If the comparison result of the current comparison cycle is different from the comparison result of the previous comparison cycle, it can be determined that the adjustment termination condition for the parameter value to be corrected has been met. For example, if the comparison result of the current comparison cycle is the first value and the comparison result of the previous comparison cycle is the first value, it is determined that the adjustment termination condition for the parameter value to be corrected has not been met; or, if the comparison result of the current comparison cycle is the second value and the comparison result of the previous comparison cycle is the second value, it is determined that the adjustment termination condition for the parameter value to be corrected has been met; or, if the comparison result of the current comparison cycle is the second value and the comparison result of the previous comparison cycle is the first value, it is determined that the adjustment termination condition for the parameter value to be corrected has been met. The comparison result is: the first value indicates that the voltage response value Vo is greater than the preset voltage value Vref, and the second value indicates that the voltage response value Vo is less than the preset voltage value Vref.

[0066] The correction control unit performs an XOR operation between the comparison result of the current comparison cycle and the comparison result of the previous comparison cycle. If the XOR result is 0, it indicates that the adjustment termination condition for the parameter value to be corrected has not been met; if the XOR result is 1, it indicates that the adjustment termination condition for the parameter value to be corrected has been met. It is important to note that a XOR result of 0 indicates that the comparison result of the current comparison cycle is the same as the comparison result of the previous comparison cycle, while a XOR result of 1 indicates that the comparison result of the current comparison cycle is different from the comparison result of the previous comparison cycle. The comparison result of the current comparison cycle is either a first value or a second value; the comparison result of the previous comparison cycle is either a first value or a second value.

[0067] In this embodiment, in order to determine the optimal value of the correction parameter corresponding to the pixel, a target algorithm can be used to adjust the value of the parameter to be corrected corresponding to the pixel to obtain the optimal value of the correction parameter corresponding to the pixel. There are no restrictions on this target algorithm, as long as it can adjust the value of the parameter to be corrected to obtain the optimal value of the correction parameter.

[0068] For example, assuming the value of the parameter to be corrected is a 4-bit binary number, such as 1000, the process of adjusting the value of the parameter to be corrected corresponding to the pixel using the target algorithm may include:

[0069] In correction cycle 1 (i.e., the number of adjustments is 1): the value of the parameter to be corrected is 8 (1000). Based on the value of the parameter to be corrected 8, the initial bias value can be determined (see the following embodiments for the determination process). Based on the initial bias value, the voltage response value Vo is determined, and the comparison result between the voltage response value Vo and the preset voltage value Vref is determined.

[0070] If the voltage response value Vo is greater than the preset voltage value Vref, i.e., the comparison result is the first value 1, then the parameter value to be corrected 8 is decremented by 1 to obtain the adjusted parameter value 7 (0111); if the voltage response value Vo is less than the preset voltage value Vref, i.e., the comparison result is the first value 0, then the parameter value to be corrected 8 is incremented by 1 to obtain the adjusted parameter value 9 (1001). In summary, the adjusted parameter value can be obtained, and the adjusted parameter value is determined as the parameter value to be corrected corresponding to the pixel, and the parameter value to be corrected is written into the first register.

[0071] In correction cycle 1, the comparison result S1 between the voltage response value Vo and the preset voltage value Vref can also be stored. The comparison result S1 may be a first value of 1 or a second value of 0.

[0072] In correction cycle 2 (i.e., the number of adjustments is 2): the value of the parameter to be corrected may be 7 or 9. Assuming that the value of the parameter to be corrected is 9, the initial bias value is determined based on the value of the parameter to be corrected 9, the voltage response value Vo is determined based on the initial bias value, and the comparison result S2 between the voltage response value Vo and the preset voltage value Vref is determined.

[0073] If the voltage response value Vo is greater than the preset voltage value Vref, that is, the comparison result S2 is the first value 1, then the value of the parameter to be corrected 9 can be reduced by 1 to obtain the adjusted parameter value 8 (1000); if the voltage response value Vo is less than the preset voltage value Vref, that is, the comparison result S2 is the first value 0, then the value of the parameter to be corrected 9 can be increased by 1 to obtain the adjusted parameter value 10 (1010).

[0074] After obtaining comparison result S2, an XOR operation can be performed between comparison result S2 and comparison result S1. If the result of the XOR operation is 0, it is determined that the adjustment termination condition for the value of the parameter to be corrected has not been met. Therefore, the adjusted parameter value (such as adjusted parameter value 8 or adjusted parameter value 10) is determined as the value of the parameter to be corrected corresponding to the pixel, and the value of the parameter to be corrected is written into the first register. Alternatively, if the result of the XOR operation is 1, it is determined that the adjustment termination condition for the value of the parameter to be corrected has been met. Therefore, the adjusted parameter value (such as adjusted parameter value 8 or adjusted parameter value 10) is determined as the optimal value of the correction parameter corresponding to the pixel, and the optimal value of the correction parameter is written into the first register. Thus, the optimal value of the correction parameter is successfully obtained.

[0075] Assuming the result of the XOR operation is 0, meaning the adjustment termination condition for the parameter value to be corrected is not met, then in correction cycle 2, the comparison result S2 can also be stored, that is, the comparison result S1 can be replaced by the comparison result S2. The comparison result S2 may be the first value 1, or the comparison result S2 may be the second value 0.

[0076] In correction cycle 3 (i.e., the number of adjustments is 3): the value of the parameter to be corrected may be 8 or 10. Assuming that the value of the parameter to be corrected is 10, the initial bias value is determined based on the value of the parameter to be corrected 10, the voltage response value Vo is determined based on the initial bias value, and the comparison result S3 between the voltage response value Vo and the preset voltage value Vref is determined.

[0077] If the voltage response value Vo is greater than the preset voltage value Vref, that is, the comparison result S3 is the first value 1, then the value of the parameter to be corrected 10 can be decremented by 1 to obtain the adjusted parameter value 9; if the voltage response value Vo is less than the preset voltage value Vref, that is, the comparison result S3 is the first value 0, then the value of the parameter to be corrected 10 can be incremented by 1 to obtain the adjusted parameter value 11 (1011).

[0078] After obtaining comparison result S3, an XOR operation can be performed between comparison result S3 and comparison result S2. If the result of the XOR operation is 0, it is determined that the adjustment termination condition for the parameter value to be corrected has not been met. Therefore, the adjusted parameter value (such as adjusted parameter value 9 or adjusted parameter value 11) is determined as the parameter value to be corrected corresponding to the pixel, and the parameter value to be corrected is written into the first register. Alternatively, if the result of the XOR operation is 1, it is determined that the adjustment termination condition for the parameter value to be corrected has been met. Therefore, the adjusted parameter value (such as adjusted parameter value 9 or adjusted parameter value 11) is determined as the optimal value of the correction parameter corresponding to the pixel, and the optimal value of the correction parameter is written into the first register. Thus, the optimal value of the correction parameter is successfully obtained.

[0079] Assuming the result of the XOR operation is 1, which means the adjustment termination condition of the parameter to be corrected has been met, then the optimal value of the corrected parameter can be obtained, that is, the optimal value of the corrected parameter can be obtained after 3 correction cycles.

[0080] In summary, in this embodiment, during correction cycle 1, the correction control unit can store the parameter value D0 to be corrected in the first register, determine the initial bias voltage value Vin based on the parameter value D0, determine the voltage response value Vo based on the initial bias voltage value Vin, and correct the parameter value D0 to be corrected based on the comparison result of the voltage response value Vo and the preset voltage value Vref to obtain the parameter value D1 to be corrected. The correction control unit can store the parameter value D1 to be corrected in the first register. In this way, the correction control unit continuously updates the parameter value to be corrected in the first register and determines the initial bias voltage value Vin based on the latest parameter value to be corrected.

[0081] The correction control unit uses the parameter value D generated during the last correction to correct. i-1 (D i-1 When adjusting the value of the parameter to be corrected (corresponding to the current output voltage response value Vo of the readout unit), if Result = 1, then the value of the parameter to be corrected, D, will be adjusted. i-1 Subtract 1 to obtain the value of the parameter to be corrected, D. i Using the parameter value D to be corrected i Update the value of the parameter to be corrected, D, in the first register. i-1 If Result = 0, then the parameter value to be corrected, D, will be... i-1 Add 1 to get the value of the parameter to be corrected, D. i Using the parameter value D to be corrected i Update the value of the parameter to be corrected, D, in the first register. i-1 .

[0082] When the Result values ​​of the previous and subsequent correction cycles are different, it indicates that the voltage response value Vo output by the readout unit has reached the optimal correction value, and the update process of the parameter value to be corrected can be terminated. Based on this, a judgment unit can be added to the correction control unit to perform an XOR operation on the comparison result of the previous correction cycle and the comparison result of the current correction cycle. If the XOR operation result is 0, it indicates that the optimal result has not yet been reached; if the XOR operation result is 1, it indicates that the optimal result has been reached, and the correction process stops.

[0083] In this embodiment, the decision to exit the correction process can be based on the XOR operation result of the Result of two consecutive correction cycles, thereby reducing the duration and number of correction cycles. In other words, if the XOR operation result is 1, it indicates that the optimal result has been achieved, and the correction process is stopped, reducing the number of correction cycles. Referring to Table 1, assuming the preset voltage value Vref generated by the correction target value generator is near the analog voltage value corresponding to the parameter value to be corrected (11-12), and the initial value of the parameter value to be corrected is 8, the correction control unit can increment the parameter value by 1 according to the above method.

[0084] When the Result values ​​of the two consecutive correction cycles are different, it indicates that the voltage response value Vo output by the readout unit has reached the optimal correction value. The update process of the parameter value to be corrected can be skipped, thus stopping the correction in time and reducing unnecessary correction cycles. In other words, the correction process is completed in 5 correction cycles.

[0085] Table 1

[0086]

[0087]

[0088] In summary, for each pixel in the pixel group, the correction control unit can obtain the optimal value of the correction parameter corresponding to that pixel and write the optimal value of the correction parameter corresponding to that pixel into the first register.

[0089] In one possible implementation, the correction control unit can also determine the state of the infrared readout circuit. For example, after the infrared readout circuit is powered on, its corresponding correction state can be determined. After determining the optimal correction parameter value for each pixel, its corresponding readout state can be determined, thus automatically switching between the correction and readout states of the infrared readout circuit. Clearly, when the infrared readout circuit is in the correction state, the optimal correction parameter value for each pixel can be determined and written to the first register. When the infrared readout circuit is in the readout state, subsequent processes can be performed based on the optimal correction parameter value in the first register.

[0090] For example, when the infrared readout circuit is in the correction state, the correction control unit can control the second terminal of the first switch to connect to the correction target value generator, thereby connecting the comparator and the correction target value generator. This allows the comparator to obtain a preset voltage value Vref from the correction target value generator, and the infrared readout circuit is used to implement the correction state function based on the preset voltage value Vref. Furthermore, the correction control unit can control the second terminal of the second switch to connect to ground (GND). Although the first terminal of the second switch is connected to the counter, because the second terminal of the second switch is connected to ground, the counter can be stopped, meaning it cannot obtain the internal clock, thus stopping the counter and turning it off.

[0091] IV. First Register. The first register stores the parameter value to be corrected for each pixel. After the correction control unit obtains the optimal correction parameter value, the storage register stores the optimal correction parameter value for each pixel. For example, in correction mode, the first register can store the parameter value to be corrected for the pixel, and the parameter value can be updated in each correction cycle. After correction is complete, the first register can store the optimal correction parameter value for the pixel. In readout mode, the optimal correction parameter value can be read from the first register, and subsequent processes can be performed based on the optimal correction parameter value.

[0092] For example, the correction control unit can acquire the initial value of the parameter to be corrected corresponding to each pixel and write these initial values ​​into a first register, which stores these initial values. For multiple pixels in a pixel group, the initial values ​​of the parameters to be corrected corresponding to different pixels can be the same. In subsequent processes, the initial values ​​of the parameters to be corrected for different pixels can be adjusted. These initial values ​​can be understood as the first parameter value to be corrected. By continuously adjusting the parameter values, the optimal value of the correction parameter is obtained, which can be understood as the last parameter value to be corrected.

[0093] For example, after the correction control unit obtains the optimal value of the correction parameter corresponding to each pixel, it can write these optimal values ​​of the correction parameter into the first register, and the first register stores these optimal values ​​of the correction parameter.

[0094] 5. DAC (Digital-to-Analog Converter). The DAC is used to perform digital-to-analog conversion on the parameter value to be corrected corresponding to the pixel, to obtain an analog voltage signal. The voltage value corresponding to the analog voltage signal is determined as the initial bias voltage value Vin corresponding to the parameter value to be corrected, and the initial bias voltage value Vin is input to the readout unit.

[0095] For example, the DAC can read the parameter value to be corrected from the first register, perform digital-to-analog conversion on the parameter value of the digital signal to obtain an analog voltage signal, and determine the voltage value corresponding to the analog voltage signal as the initial bias value Vin. That is, the initial bias value Vin serves as the input voltage of the first MOSFET, which can control the current I1 passing through the first MOSFET. Obviously, different initial bias values ​​Vin can provide different biases for the readout unit. When the initial bias value Vin is larger, the voltage response value Vo corresponding to the pixel is larger, thereby eliminating the problem of readout units having different responses to the same radiation caused by manufacturing deviations. For example, in correction cycle 1, the initial bias value Vin is determined based on the parameter value to be corrected in correction cycle 1, and the fixed initial bias value Vin is input to the readout unit; in correction cycle 2, the initial bias value Vin is determined based on the parameter value to be corrected in correction cycle 2, and the fixed initial bias value Vin is input to the readout unit, and so on.

[0096] In summary, the correction state allows us to obtain the optimal correction parameter values ​​for each pixel and write them to the first register. After correction, we can proceed to the readout state. In readout, the baffle can be closed, ensuring that the sensed ambient temperature for each pixel is the actual target temperature of the target scene.

[0097] When the infrared readout circuit is in readout mode, the functions of each component are as follows:

[0098] I. Readout Unit. The readout unit determines the voltage response value corresponding to a pixel based on the target bias voltage value corresponding to the optimal value of the correction parameters for that pixel, and inputs this voltage response value to the comparator. For example, the readout unit can determine the voltage response value corresponding to a pixel based on the third current corresponding to the target bias voltage value corresponding to the optimal value of the correction parameters and the fourth current output from the pixel response temperature value.

[0099] The fourth current output by the pixel in response to the temperature value refers to the change in the pixel's resistance value when the actual target temperature value sensed by the pixel changes. When the pixel's resistance value changes, the corresponding fourth current of the pixel changes. In other words, the fourth current is related to the actual target temperature value sensed by the pixel.

[0100] See Figure 5 As shown, the input voltage of the first MOSFET is the bias value Vin. In readout mode, this bias value Vin is called the target bias value Vin, which is determined based on the optimal value of the correction parameter. The optimal value of the correction parameter is used to correct the actual target temperature value sensed by the pixel. That is, in readout mode, the actual target temperature value sensed by the pixel is corrected based on the optimal value of the correction parameter. By correcting the voltage response value Vo of the readout unit, the purpose of correcting the actual target temperature value sensed by the pixel is achieved.

[0101] See Figure 5 As shown, in the readout state, when the target bias value Vin is larger, the third current I1 passing through the first MOS transistor is smaller. That is, the target bias value Vin and the third current I1 are negatively correlated. Thus, the target bias value Vin is controlled by the optimal value of the correction parameter, and then the third current I1 is controlled by the target bias value Vin, thereby affecting the voltage response value Vo corresponding to the pixel Rs.

[0102] In readout mode, the baffles of the infrared array can be turned off. Thus, for each pixel, taking pixel Rs as an example, the ambient temperature sensed by pixel Rs is the actual target temperature value of the target scene. Based on the actual target temperature value sensed by pixel Rs, the current I2 passing through pixel Rs (denoted as the fourth current I2) can be controlled, meaning the fourth current I2 matches the actual target temperature value of the target scene sensed by pixel Rs.

[0103] In summary, for pixel Rs, the input voltage of the first MOSFET is the target bias value Vin, the current flowing through the first MOSFET is the third current I1 corresponding to the target bias value Vin, and the output of pixel Rs in response to the temperature value is the fourth current I2. The difference between the third current I1 and the fourth current I2 can be determined as the input current Iint of the integrator circuit. The input current Iint is input to the integrator circuit, and the integrator circuit integrates the input current Iint to obtain the voltage input value Vo_int corresponding to pixel Rs. Then, based on the voltage input value Vo_int corresponding to pixel Rs, the voltage response value Vo corresponding to pixel Rs is determined.

[0104] After obtaining the voltage response value Vo corresponding to pixel Rs, the voltage response value Vo can be input to the comparator in the ADC, and the comparator in the ADC will process it based on the voltage response value Vo.

[0105] II. Correction Control Unit. The correction control unit determines the state of the infrared readout circuit. For example, after the infrared readout circuit is powered on, it determines the corresponding correction state; after the optimal correction parameter value for the corresponding pixel is determined, it determines the corresponding readout state. In the correction state, the correction control unit controls the baffle to open, allowing each pixel in the infrared array to sense the baffle's temperature value. In the readout state, the correction control unit controls the baffle to close, allowing each pixel in the infrared array to sense the actual target temperature value of the target scene.

[0106] For example, when the infrared readout circuit is in the readout state, the correction control unit can control the second terminal of the first switch to connect to the ramp generator, thereby connecting the comparator and the ramp generator. This allows the comparator to obtain the ramp voltage value from the ramp generator, and the infrared readout circuit can be used to realize the readout state function based on the ramp voltage value. Furthermore, the correction control unit can control the second terminal of the second switch to connect to the internal clock, causing the counter to start counting. That is, the first terminal of the second switch is connected to the counter, and the second terminal of the second switch is connected to the internal clock, causing the counter to obtain the internal clock and start counting.

[0107] III. DAC. The DAC is used to perform digital-to-analog conversion on the optimal correction parameters corresponding to a pixel, obtaining an analog voltage signal. The voltage value corresponding to the analog voltage signal is determined as the target bias voltage value Vin corresponding to the optimal correction parameters. The target bias voltage value Vin is input to the readout unit, so that the readout unit can determine the voltage response value corresponding to the pixel based on the third current corresponding to the target bias voltage value Vin and the fourth current output by the pixel response temperature value. For example, if the first register already stores the optimal correction parameters corresponding to the pixel, the DAC can read the optimal correction parameters from the first register and then obtain the target bias voltage value Vin.

[0108] IV. ADC. For each pixel in the pixel group, the ADC determines the corresponding voltage output value and outputs this voltage output value externally, such as to an external processor, so that the external processor can determine the actual target temperature value of the target scene (i.e., the temperature value of the target object) based on this voltage output value. For example, the external processor can query a pre-calibrated mapping relationship between voltage and temperature values ​​to obtain the temperature value corresponding to the voltage output value. This temperature value is the temperature value of the target object, i.e., the final detected temperature value. This embodiment does not restrict the process of determining this temperature value.

[0109] In one possible implementation, when the infrared readout circuit is in the readout state, the first switch switches to the ramp generator, connecting the comparator and the ramp generator. The second switch switches to the internal clock, enabling the counter. The counter starts counting, the ADC works normally, performs analog-to-digital conversion, and outputs the voltage value.

[0110] For example, the ADC may include a first switch, a correction target value generator, and a ramp generator. The correction target value generator is used to generate a preset voltage value Vref, and the ramp generator is used to generate a ramp voltage value. The first terminal of the first switch is connected to a comparator, and the second terminal of the first switch is connected to either the correction target value generator or the ramp generator. When the second terminal of the first switch is connected to the correction target value generator, the infrared readout circuit is used to implement the correction state based on the preset voltage value Vref, as described in the above embodiment. When the second terminal of the first switch is switched from the correction target value generator to the ramp generator, the infrared readout circuit is used to implement the readout state based on the ramp voltage value, as described in subsequent embodiments.

[0111] For example, an ADC may include a ramp generator, a comparator, a counter, a second register, and a data output unit. These devices work together to achieve analog-to-digital conversion, and their functions are as follows:

[0112] A ramp generator. A ramp generator is used to generate ramp voltage values. For example, a ramp generator can generate multiple ramp voltage values ​​starting from an initial ramp voltage value (e.g., generating multiple ramp voltage values ​​with a stable slope starting from an initial ramp voltage value). The initial ramp voltage value can be configured empirically, such as being 0, and there are no restrictions on this.

[0113] A comparator is used to obtain the ramp voltage value from the ramp generator and compare it with the voltage response value Vo (i.e., the voltage response value Vo corresponding to the optimal value of the correction parameters) to obtain the comparison result for each pixel. This comparison result is used to determine the voltage output value corresponding to the pixel. For example, the comparator compares the voltage response value Vo with each ramp voltage value generated by the ramp generator to obtain the comparison result for each ramp voltage value. This comparison result can be that the voltage response value Vo is greater than the ramp voltage value, or that the voltage response value Vo is not greater than the ramp voltage value. For example, if the ramp generator sequentially generates ramp voltage values ​​W1, W2, ..., and so on, the comparator sequentially compares the voltage response value Vo with the ramp voltage value W1 to obtain the comparison result corresponding to ramp voltage value W1, compares the voltage response value Vo with the ramp voltage value W2 to obtain the comparison result corresponding to ramp voltage value W2, and so on. The comparison result corresponding to the ramp voltage value indicates that the voltage response value Vo is greater than the ramp voltage value, or the voltage response value Vo is equal to the ramp voltage value, or the voltage response value Vo is less than the ramp voltage value.

[0114] Counter. The counter is used to start counting when the second switch is switched to the internal clock. That is, the counter can count clock pulses to obtain a count value, and there are no restrictions on this counting process.

[0115] For example, the counter may include, but is not limited to, a Gray code counter. The working principle of a Gray code counter is that when the Gray code (i.e. the count value) is incremented, any two adjacent bits differ by only one bit, which is less than the number of flips of a binary encoder. Since the number of flips is less than that of a binary encoder, the power consumption is also lower. Based on this, a Gray code counter is used to implement the counting function in this embodiment.

[0116] The second register stores the target count value corresponding to the target ramp voltage value; wherein, the target ramp voltage value is the first ramp voltage value among all ramp voltage values ​​that is greater than the voltage response value Vo; the target count value is the count value when the ramp generator generates the target ramp voltage value.

[0117] For example, if the slope voltage value W i The voltage response value Vo is greater than the slope voltage value W. i-1 Not greater than the voltage response value Vo, and the ramp voltage value W i-1 It is the slope voltage value W i The previous ramp voltage value can then be used to calculate the ramp voltage value W. i Assuming the target ramp voltage value is W, and the ramp generator produces a ramp voltage value W... iIf the time is time i, then the count value i corresponding to time i (i.e., the count value generated by the counter at time i) can be used as the target count value. Based on this, the second register is used to store the count value i.

[0118] Data output unit. The data output unit is used to obtain the target count value from the second register, determine the voltage output value corresponding to the pixel based on the target count value, and output the voltage output value to the outside. The process of determining the voltage output value based on the target count value is not limited in this embodiment.

[0119] See Figure 6 The diagram illustrates the working principle of an ADC. Before the ADC begins analog-to-digital conversion, the counter's output value Count1 is reset to zero. During ADC operation, the ramp generator produces multiple ramp voltage values ​​Vramp with stable slopes, starting from an initial ramp voltage value. The comparator compares these ramp voltage values ​​Vramp with the voltage response value Vo. The counter counts clock pulses when it starts operating. When the ramp generator begins producing ramp voltage values ​​Vramp, the voltage response value Vo is greater than Vramp, and the comparator's output Vcomp is high. This continues until Vramp exceeds Vo, at which point the comparator flips, triggering the second register to save the current count value Count2. The second register transmits Count2 to the data output unit, which performs serial-to-parallel conversion on Count2 to obtain the voltage output value, which is then output to an external source (such as an external processor).

[0120] As can be seen from the above technical solutions, the embodiments of this application design an infrared readout circuit that achieves non-uniformity correction without the need for an external processor. This reduces the overhead of external hardware resources, lowers costs, simplifies development, and provides better correction results. By providing different bias values ​​to different pixels (different bias values ​​are controlled by the optimal values ​​of different correction parameters), the differences in response of different pixels to the same infrared radiation are corrected, making the response of different pixels to the same infrared radiation consistent, thus achieving non-uniformity correction of different pixels. By dividing all pixels of the infrared array into K pixel groups, parallel processing of the K pixel groups can be performed, thereby reducing the time required for the correction stage. The infrared readout circuit is an uncooled infrared readout circuit that realizes the automatic non-uniformity correction function and can complete the automatic non-uniformity correction of pixels. The comparator in the ADC can be directly reused, and only a few switching structures need to be added to reduce the circuit cost and the time required for the correction stage. It has the advantage of eliminating the non-uniformity deviation caused by the column-level integrator. During the correction comparison phase, each column comparator can be activated simultaneously, and the signals of all columns are compared in parallel, which greatly saves correction comparison time.

[0121] See Figure 7 The diagram shown illustrates the operation of an infrared readout circuit. This method may include:

[0122] Step 701: Power on and start the infrared readout circuit.

[0123] Step 702: After the infrared readout circuit is powered on, configuration information can be written to the correction control unit. For example, the configuration information may include line time, integration time, parameter value to be corrected, preset voltage value, etc.

[0124] The correction control unit can use the parameter value to be corrected as the parameter value to be corrected for each pixel and write the parameter value to be corrected for each pixel into the first register. Among the multiple pixels included in a pixel group, the parameter values ​​to be corrected for different pixels can be the same, that is, the same parameter value to be corrected is written into the first register.

[0125] The correction control unit can use the preset voltage value as the preset voltage value for each pixel and write the preset voltage value into the correction target value generator, that is, the correction target value generator obtains the preset voltage value.

[0126] Step 703: The correction control unit determines that it has entered the correction state and activates the baffle. The temperature value at each position of the baffle is the same, so that the test target temperature value sensed by each pixel is the temperature value of the baffle. The correction control unit controls the second terminal of the first switch to connect to the correction target value generator, thereby connecting the comparator and the correction target value generator. The correction control unit controls the second terminal of the second switch to connect to the ground terminal, causing the counter to stop working.

[0127] Step 704: In the correction state, the readout unit determines the voltage response value corresponding to the pixel based on the initial bias voltage value corresponding to the parameter value to be corrected corresponding to the pixel, and inputs the voltage response value to the comparator; the comparator compares the voltage response value with the preset voltage value, obtains the comparison result corresponding to the pixel, and inputs the comparison result to the correction control unit; the correction control unit adjusts the parameter value to be corrected based on the comparison result, obtains the adjusted parameter value, updates the adjusted parameter value to the first register, and replaces the parameter value to be corrected.

[0128] For a detailed explanation of the process in step 704, please refer to the above embodiments, which will not be repeated here.

[0129] Step 705: Determine whether the correction is complete. If complete, the adjusted parameter value updated in the first register is used as the optimal value of the correction parameter, and step 706 is executed. If incomplete, the adjusted parameter value updated in the first register is used as the parameter value to be corrected, and step 704 is executed based on the parameter value to be corrected.

[0130] Step 706: The correction control unit determines that it has entered the readout state and closes the baffle so that each pixel senses the actual target temperature value of the target scene. The correction control unit can control the second terminal of the first switch to connect to the ramp generator, thereby connecting the comparator and the ramp generator. The correction control unit can control the second terminal of the second switch to connect to the internal clock, thereby enabling the counter to start working normally.

[0131] Step 707: In readout mode, the readout unit determines the voltage response value corresponding to the pixel based on the target bias voltage value corresponding to the optimal value of the correction parameters corresponding to the pixel, and inputs the voltage response value to the comparator. The comparator compares the voltage response value and the ramp voltage value to obtain the comparison result corresponding to the pixel. After obtaining the comparison result, the voltage output value corresponding to the pixel can be determined based on the comparison result. Finally, the voltage output value corresponding to the pixel is output to the external processor to determine the temperature value corresponding to the pixel.

[0132] For a detailed explanation of step 707, please refer to the above embodiments, which will not be repeated here.

[0133] The following is a brief explanation of the timing sequence of the infrared readout circuit, based on specific application scenarios.

[0134] See Figure 8 The diagram shown is the timing diagram of the infrared readout circuit. The correction can be divided into two stages. In the first stage, the first register advances the value of the parameter to be corrected, D, which was updated in the previous frame, by one row. i-1 The data is written to the DAC, and the readout unit reads the updated parameter value D from the previous frame. i-1 The output voltage response value Vo is calculated. In the second stage, the unit output voltage response value Vo is read out, the correction target value generator outputs a preset voltage value Vref, the comparator compares the voltage response value Vo with the preset voltage value Vref, and the comparison result is input to the correction control unit. The correction control unit then calculates the correction parameter value D based on the comparison result. i-1 By performing an increment or decrement operation, the updated value of the parameter to be corrected, D, is obtained. i And the parameter value to be corrected, D i Stored in the first register.

[0135] When the results of two consecutive comparisons are inconsistent, it indicates that the value of the parameter D to be corrected is incorrect. i This is already the optimal value; the parameter value to be corrected is D. i As the optimal value of the correction parameters, the correction control unit will set the control signal to zero based on the judgment result, stop the correction process, turn on the ADC, and enter the readout state.

[0136] See Figure 9The diagram shows the timing of each switch in the infrared readout circuit. When the outputs of the two comparators are inconsistent, the XOR calculation result is 1, and the control signal is set to 0. At the falling edge of the clock CLK, the first switch S1 and the second switch S2 are triggered to flip, stopping the non-uniform correction, turning on the ADC, and performing normal analog-to-digital conversion, i.e., entering the readout state.

[0137] Based on the same concept as the infrared readout circuit described above, this application proposes another infrared readout circuit. The infrared array may include K pixel groups, where K is a positive integer greater than 1. For each pixel group of the infrared array, the infrared readout circuit includes a readout unit, an analog-to-digital converter, and a correction control unit corresponding to that pixel group. The analog-to-digital converter includes a comparator. Specifically, for each pixel in the pixel group: the readout unit is used to determine the voltage response value corresponding to the pixel based on the initial bias voltage value corresponding to the parameter value to be corrected, and inputs the voltage response value to the comparator; the comparator is used to compare the voltage response value with a preset voltage value to obtain a comparison result corresponding to the pixel, and inputs the comparison result to the correction control unit; the correction control unit is used to adjust the parameter value to be corrected based on the comparison result to obtain an adjusted parameter value; determine the optimal value of the correction parameter corresponding to the pixel based on the adjusted parameter value, and replace the parameter value to be corrected with the optimal value of the correction parameter.

[0138] For example, the analog-to-digital converter further includes a first switch, a correction target value generator, and a ramp generator. The correction target value generator is used to generate a preset voltage value, and the ramp generator is used to generate a ramp voltage value. The first terminal of the first switch is connected to a comparator, and the second terminal of the first switch is connected to either the correction target value generator or the ramp generator. Based on this, when the second terminal of the first switch is connected to the correction target value generator, the infrared readout circuit is used to realize the correction state based on the preset voltage value (i.e., the correction state is realized through the cooperation of the various modules of the infrared readout circuit); when the second terminal of the first switch is switched from the correction target value generator to the ramp generator, the infrared readout circuit is used to realize the readout state based on the ramp voltage value (i.e., the readout state is realized through the cooperation of the various modules of the infrared readout circuit).

[0139] For example, the correction control unit is further configured to determine the state corresponding to the infrared readout circuit; wherein, after the infrared readout circuit is powered on, the infrared readout circuit is in a correction state; and after the optimal values ​​of the correction parameters corresponding to all pixels have been determined, the infrared readout circuit is in a readout state. Based on this, when the infrared readout circuit is in a correction state, the correction control unit controls the second terminal of the first switch to connect to a correction target value generator, so that the comparator obtains a preset voltage value from the correction target value generator, and the infrared readout circuit is used to implement the correction state function based on the preset voltage value. When the infrared readout circuit is in a readout state, the correction control unit controls the second terminal of the first switch to connect to a ramp generator, so that the comparator obtains a ramp voltage value from the ramp generator, and the infrared readout circuit is used to implement the readout state function based on the ramp voltage value.

[0140] For example, when the infrared readout circuit is in the readout state, the readout unit is used to determine the voltage response value corresponding to the pixel based on the target bias voltage value corresponding to the optimal value of the correction parameter corresponding to the pixel, and input the voltage response value to the comparator; the comparator is used to obtain the ramp voltage value from the ramp generator, and compare the voltage response value and the ramp voltage value to obtain the comparison result corresponding to the pixel; wherein, the comparison result can be used to determine the voltage output value corresponding to the pixel.

[0141] For example, the analog-to-digital converter includes a counter, a second register, a second switch, and a data output unit; the first terminal of the second switch is connected to the counter, and when the infrared readout circuit is in the correction state, the second terminal of the second switch is connected to ground to stop the counter from working; when the infrared readout circuit is in the readout state, the second terminal of the second switch is connected to an internal clock to start the counter from counting. Based on this, a ramp generator is used to generate multiple ramp voltage values ​​starting from an initial ramp voltage value; a comparator is used to compare the voltage response value with each ramp voltage value to obtain a comparison result corresponding to each ramp voltage value, wherein the comparison result is that the voltage response value is greater than the ramp voltage value, or the voltage response value is not greater than the ramp voltage value; a counter is used to count clock pulses to obtain a count value; a second register is used to store the target count value corresponding to the target ramp voltage value; the target ramp voltage value is the first ramp voltage value among multiple ramp voltage values ​​that is greater than the voltage response value; the target count value is the count value when the ramp generator generates the target ramp voltage value; a data output unit is used to obtain the target count value from the second register, determine the voltage output value corresponding to the pixel based on the target count value, and output the voltage output value to the outside.

[0142] For example, when the readout unit determines the voltage response value of a pixel based on the initial bias value corresponding to the parameter value to be corrected corresponding to the pixel, it is specifically used to: determine the voltage response value of the pixel based on the first current corresponding to the initial bias value and the second current output by the pixel response temperature value.

[0143] For example, the infrared readout circuit may further include a digital-to-analog converter corresponding to the pixel group; the digital-to-analog converter is used to perform digital-to-analog conversion on the parameter value to be corrected corresponding to the pixel to obtain an analog voltage signal, and determine the voltage value corresponding to the analog voltage signal as the initial bias voltage value corresponding to the parameter value to be corrected, and input the initial bias voltage value to the readout unit.

[0144] For example, when the correction control unit adjusts the value of the parameter to be corrected based on the comparison result to obtain the adjusted parameter value, it specifically does the following: if the comparison result is a first value, which indicates that the voltage response value is greater than a preset voltage value, then the value of the parameter to be corrected is decreased to obtain the adjusted parameter value; if the comparison result is a second value, which indicates that the voltage response value is less than a preset voltage value, then the value of the parameter to be corrected is increased to obtain the adjusted parameter value. In one possible implementation, when the correction control unit decreases the value of the parameter to be corrected to obtain the adjusted parameter value, it specifically does the following: it performs a subtraction operation on the value of the parameter to be corrected by 1 to obtain the adjusted parameter value; when the correction control unit increases the value of the parameter to be corrected to obtain the adjusted parameter value, it specifically does the following: it performs an increment operation on the value of the parameter to be corrected by 1 to obtain the adjusted parameter value.

[0145] For example, when the correction control unit determines the optimal value of the correction parameter corresponding to the pixel based on the adjusted parameter value, it specifically does so as follows: if the adjustment end condition of the parameter value to be corrected has been met, the adjusted parameter value is determined as the optimal value of the correction parameter corresponding to the pixel; or, if the adjustment end condition of the parameter value to be corrected has not been met, the adjusted parameter value is determined as the parameter value to be corrected corresponding to the pixel.

[0146] In one possible implementation, the correction control unit is further configured to: determine that the adjustment termination condition for the parameter value to be corrected has not been met if the comparison result of the current comparison cycle is a first value and the comparison result of the previous comparison cycle is a first value; or, determine that the adjustment termination condition for the parameter value to be corrected has not been met if the comparison result of the current comparison cycle is a second value and the comparison result of the previous comparison cycle is a second value; or, determine that the adjustment termination condition for the parameter value to be corrected has been met if the comparison result of the current comparison cycle is a first value and the comparison result of the previous comparison cycle is a second value; or, determine that the adjustment termination condition for the parameter value to be corrected has been met if the comparison result of the current comparison cycle is a second value and the comparison result of the previous comparison cycle is a first value; a comparison result of a first value indicates that the voltage response value is greater than a preset voltage value, and a comparison result of a second value indicates that the voltage response value is less than a preset voltage value.

[0147] In another possible implementation, the correction control unit is further configured to perform an XOR operation on the comparison result of the current comparison cycle and the comparison result of the previous comparison cycle; if the result of the XOR operation is 0, it is determined that the adjustment termination condition for the value of the parameter to be corrected has not been met; if the result of the XOR operation is 1, it is determined that the adjustment termination condition for the value of the parameter to be corrected has been met. Here, the comparison result of the current comparison cycle is either a first value or a second value; the comparison result of the previous comparison cycle is either a first value or a second value.

[0148] For example, the infrared readout circuit may also include a first register corresponding to the pixel group; the first register is used to store the parameter value to be corrected corresponding to the pixel.

[0149] In one possible implementation, the infrared array may include multiple columns of pixels, each column may include multiple pixels, and based on this, all pixels in each column may be divided into the same pixel group; wherein, each pixel group in the K pixel groups corresponds to all pixels in a column.

[0150] As can be seen from the above technical solutions, the embodiments of this application design an infrared readout circuit, which realizes non-uniformity correction without the need for an external processor. This reduces the overhead of external hardware resources, lowers costs, simplifies development, and achieves better correction results. By providing different bias voltage values ​​to different pixels (different bias voltage values ​​are controlled by the optimal values ​​of different correction parameters), the differences in response of different pixels to the same infrared radiation are corrected, making the response of different pixels to the same infrared radiation consistent, thus realizing the non-uniformity correction of different pixels. By dividing all pixels of the infrared array into K pixel groups, parallel processing of the K pixel groups can be performed, thereby reducing the time required for the correction stage.

[0151] The systems, devices, modules, or units described in the above embodiments can be implemented by a computer entity or by a product with a certain function. A typical implementation device is a computer, which can be a personal computer, laptop computer, cellular phone, camera phone, smartphone, personal digital assistant, media player, navigation device, email sending and receiving device, game console, tablet computer, wearable device, or any combination of these devices.

[0152] For ease of description, the above devices are described separately by function as various units. Of course, in implementing this application, the functions of each unit can be implemented in one or more software and / or hardware.

[0153] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, embodiments of this application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0154] The above description is merely an embodiment of this application and is not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. An infrared readout circuit, characterized in that, The infrared array comprises K pixel groups, where K is a positive integer greater than 1. The infrared readout circuit includes K readout units corresponding to the K pixel groups, K analog-to-digital converters, and K correction control units. The analog-to-digital converters include comparators. Specifically, for each pixel group of the infrared array, for each pixel in the pixel group: The readout unit is used to determine the voltage response value corresponding to the pixel based on the initial bias value corresponding to the parameter value to be corrected corresponding to the pixel, and input the voltage response value to the comparator; The comparator is used to compare the voltage response value with the preset voltage value to obtain the comparison result corresponding to the pixel, and input the comparison result to the correction control unit; The correction control unit is used to adjust the value of the parameter to be corrected based on the comparison result to obtain the adjusted parameter value; determine the optimal value of the correction parameter corresponding to the pixel based on the adjusted parameter value, and replace the value of the parameter to be corrected with the optimal value of the correction parameter.

2. The infrared readout circuit according to claim 1, characterized in that, The analog-to-digital converter further includes a first switch, a correction target value generator, and a ramp generator. The correction target value generator is used to generate the preset voltage value, and the ramp generator is used to generate a ramp voltage value. Wherein, the first end of the first switch is connected to the comparator, and the second end of the first switch is connected to the correction target value generator or the ramp generator; When the correction target value generator is connected to the second terminal of the first switch, the infrared readout circuit is used to realize the correction state based on the preset voltage value; When the second terminal of the first switch is switched from the correction target value generator to the ramp generator, the infrared readout circuit is used to realize the function of reading out the state based on the ramp voltage value.

3. The infrared readout circuit according to claim 2, characterized in that, The correction control unit is also used to determine the state corresponding to the infrared readout circuit; wherein, after the infrared readout circuit is powered on, the infrared readout circuit corresponds to the correction state; after the optimal values ​​of the correction parameters corresponding to all pixels have been determined, the infrared readout circuit corresponds to the readout state. When the infrared readout circuit is in the corresponding correction state, the second terminal of the first switch is connected to the correction target value generator so that the comparator obtains the preset voltage value from the correction target value generator, and the infrared readout circuit is used to realize the correction state based on the preset voltage value. When the infrared readout circuit is in the corresponding readout state, the second terminal of the first switch is controlled to connect to the ramp generator, so that the comparator obtains the ramp voltage value from the ramp generator, and the infrared readout circuit is used to realize the readout state based on the ramp voltage value.

4. The infrared readout circuit according to claim 3, characterized in that, When the infrared readout circuit is in the corresponding readout state The readout unit is used to determine the voltage response value corresponding to the pixel based on the target bias voltage value corresponding to the optimal value of the correction parameter corresponding to the pixel, and input the voltage response value to the comparator; The comparator is used to obtain the ramp voltage value from the ramp generator and compare the voltage response value with the ramp voltage value to obtain a comparison result corresponding to the pixel; wherein the comparison result is used to determine the voltage output value corresponding to the pixel.

5. The infrared readout circuit according to claim 4, characterized in that, The analog-to-digital converter includes a counter, a second register, a second switch, and a data output unit. The first terminal of the second switch is connected to the counter. When the infrared readout circuit is in the correction state, the second terminal of the second switch is connected to ground to stop the counter from working. When the infrared readout circuit is in the readout state, the second terminal of the second switch is connected to an internal clock to start the counter from counting. The ramp generator is used to generate multiple ramp voltage values ​​starting from an initial ramp voltage value; the comparator is used to compare the voltage response value with each ramp voltage value to obtain a comparison result corresponding to each ramp voltage value, wherein the comparison result is that the voltage response value is greater than the ramp voltage value, or the voltage response value is not greater than the ramp voltage value; The counter is used to count clock pulses to obtain a count value; The second register is used to store the target count value corresponding to the target ramp voltage value; the target ramp voltage value is the first ramp voltage value among the plurality of ramp voltage values ​​that is greater than the voltage response value; the target count value is the count value when the ramp generator generates the target ramp voltage value; The data output unit is used to obtain the target count value from the second register, determine the voltage output value corresponding to the pixel based on the target count value, and output the voltage output value to the outside.

6. The infrared readout circuit according to any one of claims 1-5, characterized in that, When the readout unit determines the voltage response value corresponding to the pixel based on the initial bias value corresponding to the parameter value to be corrected corresponding to the pixel, it is specifically used to: determine the voltage response value corresponding to the pixel based on the first current corresponding to the initial bias value and the second current output by the pixel response temperature value; The infrared readout circuit includes a digital-to-analog converter corresponding to the pixel group; The digital-to-analog converter is used to perform digital-to-analog conversion on the parameter value to be corrected corresponding to the pixel to obtain an analog voltage signal, determine the voltage value corresponding to the analog voltage signal as the initial bias voltage value corresponding to the parameter value to be corrected, and input the initial bias voltage value to the readout unit.

7. The infrared readout circuit according to any one of claims 1-5, characterized in that, The correction control unit adjusts the value of the parameter to be corrected based on the comparison result to obtain the adjusted parameter value. Specifically, if the comparison result is a first value, which indicates that the voltage response value is greater than the preset voltage value, the value of the parameter to be corrected is decreased to obtain the adjusted parameter value; if the comparison result is a second value, which indicates that the voltage response value is less than the preset voltage value, the value of the parameter to be corrected is increased to obtain the adjusted parameter value.

8. The infrared readout circuit according to claim 7, characterized in that, When the correction control unit reduces the value of the parameter to be corrected to obtain the adjusted parameter value, it is specifically used to: subtract 1 from the value of the parameter to be corrected to obtain the adjusted parameter value; When the correction control unit adds the value of the parameter to be corrected to obtain the adjusted parameter value, it specifically performs the following operation: increments the value of the parameter to be corrected by 1 to obtain the adjusted parameter value.

9. The infrared readout circuit according to any one of claims 1-5, characterized in that, When the correction control unit determines the optimal value of the correction parameter corresponding to the pixel based on the adjusted parameter value, it is specifically used to: if the adjustment end condition of the parameter value to be corrected has been met, then the adjusted parameter value is determined as the optimal value of the correction parameter corresponding to the pixel; or, if the adjustment end condition of the parameter value to be corrected has not been met, then the adjusted parameter value is determined as the parameter value to be corrected corresponding to the pixel.

10. The infrared readout circuit according to claim 9, characterized in that, The correction control unit is further configured to determine that the adjustment termination condition of the parameter value to be corrected is not met if the comparison result of the current comparison cycle is the first value and the comparison result of the previous comparison cycle is the first value. Alternatively, if the comparison result of the current comparison cycle is the second value, and the comparison result of the previous comparison cycle is the second value, then it is determined that the adjustment termination condition of the parameter value to be corrected has not been met. Alternatively, if the comparison result of the current comparison cycle is the first value and the comparison result of the previous comparison cycle is the second value, then it is determined that the adjustment termination condition of the parameter value to be corrected has been met. Alternatively, if the comparison result of the current comparison cycle is the second value and the comparison result of the previous comparison cycle is the first value, then it is determined that the adjustment termination condition of the parameter value to be corrected has been met. The comparison result is a first value, which indicates that the voltage response value is greater than the preset voltage value, and a second value, which indicates that the voltage response value is less than the preset voltage value.

11. The infrared readout circuit according to claim 9, characterized in that, The correction control unit is also used to perform an XOR operation on the comparison result of the current comparison cycle and the comparison result of the previous comparison cycle; if the result of the XOR operation is 0, it is determined that the adjustment termination condition of the parameter value to be corrected has not been met. If the result of the XOR operation is 1, then the adjustment termination condition of the parameter value to be corrected has been met. The comparison result of the current comparison period is either the first value or the second value; The comparison result of the previous comparison cycle is either the first value or the second value.

12. The infrared readout circuit according to any one of claims 1-5, characterized in that, The infrared readout circuit includes a first register corresponding to the pixel group; The first register is used to store the parameter values ​​to be corrected corresponding to the pixel.

13. The infrared readout circuit according to any one of claims 1-5, characterized in that, The infrared array includes multiple columns of pixels, each column including multiple pixels, and all pixels in each column are divided into the same pixel group; wherein, each pixel group in the K pixel groups corresponds to all pixels in a column.

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