CN115876331A

CN115876331A - Infrared reading circuit

Info

Publication number: CN115876331A
Application number: CN202211711894.6A
Authority: CN
Inventors: 何佳; 刘俊
Original assignee: Hangzhou Hikmicro Sensing Technology Co Ltd
Current assignee: Hangzhou Hikmicro Sensing Technology Co Ltd
Priority date: 2022-12-29
Filing date: 2022-12-29
Publication date: 2023-03-31

Abstract

The application provides an infrared reading circuit, aiming at each image element group of an infrared array, the infrared reading circuit comprises a reading unit, an analog-digital converter and a correction control unit, wherein the reading unit, the analog-digital converter and the correction control unit correspond to the image element group; for a pixel in a pixel group: the reading unit is used for determining a voltage response value corresponding to the pixel based on an initial bias value corresponding to a parameter value to be corrected corresponding to the pixel; the comparator is used for comparing the voltage response value with a preset voltage value to obtain 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 parameter value to be corrected based on the comparison result to obtain an adjusted parameter value; and determining the optimal value of the correction parameter corresponding to the pixel based on the adjusted parameter value, and replacing the parameter value to be corrected by the optimal value of the correction parameter. According to the technical scheme, the non-uniformity correction is not required to be realized by an external processor, and the hardware resource overhead is reduced.

Description

Infrared reading circuit

Technical Field

The application relates to the technical field of infrared temperature measurement, in particular to an infrared reading circuit.

Background

Thermal imaging temperature measurement is a non-contact temperature measurement mode, and can acquire a temperature value of a target object in a target scene. For example, the infrared array may include a plurality of pixels, each of which may be a thermistor, that is, a sensor unit, and for each pixel, after infrared radiation of the target scene reaches the pixel, the pixel may sense an external environment temperature, thereby changing a resistance value of the pixel, and controlling a current value passing through the pixel, and based on the current value, a voltage output value corresponding to the pixel may be determined, and the voltage output value may be output, and based on the voltage output value, a temperature value corresponding to the pixel may be determined.

In the thermal imaging temperature measurement process, the mapping relationship (i.e. the functional relationship) between the voltage value and the temperature value needs to be calibrated in advance, and based on this, the mapping relationship can be inquired based on the voltage output value corresponding to each pixel, so as to obtain the temperature value corresponding to the pixel. In summary, the temperature value corresponding to each pixel can be obtained, and the temperature values corresponding to these pixels are the temperature values corresponding to the target object of the target scene.

Due to the manufacturing process deviation, the response of different pixels to the same infrared radiation is different, for example, when the same infrared radiation reaches the pixel 1 and the pixel 2, if the voltage output value output for the pixel 1 is different from the voltage output value output for the pixel 2, the imaging non-uniformity is caused, and the difference of the pixels needs to be corrected, which is called non-uniformity correction. However, there is no reasonable way to correct the non-uniformity, and the non-uniformity correction is mainly realized by an external processor, which is poor in correction effect.

Disclosure of Invention

The application provides an infrared reading circuit, an infrared array comprises K image element groups, K is a positive integer larger than 1, aiming at each image element group of the infrared array, the infrared reading circuit comprises a reading unit, an analog-digital converter and a correction control unit, which correspond to the image element group, and the analog-digital converter comprises a comparator; wherein, for a pel in the group of pels:

the reading unit is used for determining a voltage response value corresponding to the pixel based on an initial bias value corresponding to a parameter value to be corrected corresponding to the pixel and inputting the voltage response value to the comparator;

the comparator is used for comparing the voltage response value with a preset voltage value to obtain 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 parameter value to be corrected based on the comparison result to obtain an adjusted parameter value; and determining the optimal value of the correction parameter corresponding to the pixel based on the adjusted parameter value, and replacing the parameter value to be corrected by the optimal value of the correction parameter.

According to the technical scheme, the infrared reading circuit is designed in the embodiment of the application, the non-uniformity correction is realized by the infrared reading circuit, an external processor is not needed to realize the non-uniformity correction, the expenditure of external hardware resources is reduced, the cost is reduced, the development is simple, and the correction effect is good. By providing different bias values for different pixels (different bias values are controlled by different optimum values of correction parameters), the response difference of different pixels to the same infrared radiation is corrected, so that the response of different pixels to the same infrared radiation is consistent, and the non-uniformity correction of different pixels is realized. All pixels of the infrared array are divided into K pixel groups, so that the K pixel groups can be processed in parallel, and time required by a correction stage is reduced.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments of the present application or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments described in the present application, and other drawings can be obtained by those skilled in the art according to the drawings of the embodiments of the present application.

FIG. 1 is a schematic diagram of an infrared array in one embodiment of the present application;

FIG. 2 is a schematic diagram of an IR read circuit according to one embodiment of the present application;

FIG. 3 is a schematic diagram of an ADC in an embodiment of the present application;

FIG. 4 is a schematic diagram of an IR read circuit according to one embodiment of the present application;

FIG. 5 is a schematic diagram of a read-out unit according to an embodiment of the present application;

FIG. 6 is a schematic diagram of the operation of an ADC in an embodiment of the present application;

FIG. 7 is a schematic flow chart of an infrared readout circuit according to an embodiment of the present application;

FIG. 8 is a timing diagram illustrating operation of an IR readout circuit according to one embodiment of the present application;

fig. 9 is an operation timing diagram of each switch of the infrared readout circuit according to an embodiment of the present application.

Detailed Description

The terminology used in the embodiments of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used in this application and the claims, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should also be understood that the term "and/or" as used herein is meant to encompass any and all possible combinations of one or more of the associated listed items.

It should be understood that although the terms first, second, third, etc. may be used in the embodiments of the present application to describe various information, the information should not be limited to these terms. These terms are only used to distinguish one type of information from another. For example, first information may also be referred to as second information, and similarly, second information may also be referred to as first information, without departing from the scope of the present application. Depending on the context, moreover, the word "if" may be used to be interpreted as "at 8230; \8230when" or "when 8230; \8230when" or "in response to a determination".

The thermal imaging device may include a thermal imaging camera (e.g., a camera and a video camera for measuring temperature by thermal imaging, such as an infrared thermal imaging camera), and the thermal imaging device may include an infrared array (also referred to as a focal plane array, where the infrared array is a circuit composed of a large number of pixels), a blocking plate, an external processor, and the like.

The infrared array may include a plurality of pixels, each of which may be a thermistor, and for each of which, after infrared thermal radiation of the target scene reaches the pixel, the pixel may sense an external ambient temperature to change a resistance value of the pixel and control a value of current passing through the pixel, to determine a voltage output value corresponding to the pixel based on the current value and output the voltage output value to the external processor, that is, the voltage output value corresponding to each of the pixels may be output to the external processor.

Based on the mapping relationship between the pre-calibrated voltage value and the temperature value, the external processor may query the mapping relationship after obtaining the voltage output value corresponding to each pixel, to obtain the temperature value corresponding to each pixel, where the temperature values corresponding to the pixels are the actual target temperature value of the target scene.

The separation blade is used for sheltering from the device of thermal imaging equipment's camera lens, and when opening the separation blade, the separation blade shelters from thermal imaging equipment's camera lens, and under this condition, the temperature value that each pixel perception in the infrared array all is the temperature value of separation blade, and the temperature value that different pixels perception was the same. When the blocking sheet is closed, the blocking sheet does not block the lens of the thermal imaging device, under the condition, the temperature value sensed by each pixel in the infrared array is an external target temperature value (namely the temperature value of the target object to be detected), and the temperature values sensed by different pixels can be different.

Due to the deviation of the manufacturing process, the response of different pixels to the same infrared radiation is different, so that the imaging nonuniformity is caused, and the difference of the pixels needs to be corrected before imaging, and the correction mode is called nonuniformity correction. In the related art, the non-uniformity correction is mainly realized through an external processor, the correction effect is poor, the resources of the external processor are occupied, and the processing resources are wasted.

In view of the above problems, an embodiment of the present application provides an infrared readout circuit, where the infrared readout circuit is connected to an infrared array and is used to correct a temperature value sensed by each pixel in the infrared array, that is, the infrared readout circuit realizes non-uniformity correction, and does not need an external processor to realize non-uniformity correction, so that overhead of external hardware resources is reduced, cost is reduced, development is simple, and a correction effect is good. For example, the thermal imaging device may further include an infrared readout circuit, where the infrared readout circuit may perform non-uniformity correction on the voltage output value corresponding to the pixel, and output the corrected voltage output value to the external processor, and the external processor may no longer perform non-uniformity correction on the voltage output value, and may determine the temperature value directly based on the voltage output value.

In this embodiment, all pixels of the infrared array may be divided into K pixel groups, where K is a positive integer greater than 1, so that the K pixel groups may be processed in parallel, and the time required for the correction stage may be reduced.

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

Referring to fig. 1, a schematic structural diagram of an infrared array is shown, where the infrared array includes a large number of pixels, and in fig. 1, M × N pixels are taken as an example, that is, N pixels exist in each row, M rows of pixels coexist, M pixels exist in each column, and N columns of pixels coexist. On the basis, all image elements of the infrared array can be divided into K image element groups, wherein K is a positive integer larger than 1, and each image element group comprises a plurality of image elements.

For example, all pixels of the infrared array may be divided into M pixel groups (i.e., K equals to M), that is, all pixels of each row of the infrared array are divided into the same pixel group, and the M pixel groups are M pixel groups. Alternatively, all pixels of the infrared array may be divided into N pixel groups (i.e., K equals to N), that is, all pixels of each column of the infrared array are divided into the same pixel group, and the N columns of pixels are N pixel groups. Of course, the above are only two examples of the dividing manner, and the dividing manner is not limited.

In this embodiment, taking the example of dividing all the pixels of the infrared array into N pixel groups (i.e., K pixel groups), that is, all the pixels in each column of the infrared array are divided into the same pixel group, that is, each pixel group in the K pixel groups corresponds to all the pixels in one column. In this case, referring to fig. 1, all the pixels in each column (i.e., all the pixels in each pixel group) correspond to the same Analog-to-Digital Converter (ADC), i.e., the number of ADCs may be N.

In this embodiment, for each pixel group of the infrared array, the infrared readout circuit may include a readout unit, an ADC, a correction control unit, a Digital-to-Analog Converter (DAC), and a first register corresponding to the pixel group.

Due to the existence of K pixel groups, the K pixel groups correspond to the K reading units, and the K reading units correspond to the K pixel groups one by one; k pixel groups correspond to K ADCs, and the K ADCs correspond to the K pixel groups one by one; k pixel groups correspond to K correction control units, and the K correction control units correspond to the K pixel groups one by one; k pixel groups correspond to K DACs, and the K DACs correspond to the K pixel groups one by one; k pixel groups correspond to K first registers, and the K first registers correspond to the K pixel groups one by one.

Since the processing procedure for each pixel group is the same, for convenience of description, the following embodiments will be described by taking the processing procedure of one pixel group as an example. Referring to fig. 2, the group of pixels may correspond to a readout unit, an ADC, a rectification control unit, a DAC, and a first register.

In this embodiment, for the ADC corresponding to each pixel group, see fig. 3, which is a schematic structural diagram of the ADC, the ADC may include but is not limited to: the correction device comprises a comparator, a first switch, a correction target value generator, a slope generator, a counter, a second register, a second switch and a data output unit.

Referring to fig. 4, which is a schematic structural diagram of the infrared readout circuit, for each pixel group, the infrared readout circuit may include a readout unit, an ADC, a rectification control unit, a DAC, and a first register corresponding to the pixel group. The ADC may include a comparator, a first switch, a rectification target value generator, a ramp generator, a counter, a second register, a second switch, and a data output unit corresponding to the pixel group.

For example, the infrared Array, which may also be referred to as an infrared Focal Plane Array (uncooled Focal Plane Array) or an uncooled infrared Focal Plane Array, is an Array composed of infrared sensitive pixels (herein, simply referred to as pixels) capable of absorbing external infrared radiation and causing temperature rise of the pixels, the temperature rise causing resistance change of the thermal sensitive material, and such an Array may operate in a non-absolute zero-degree environment.

The infrared array may include a large number of pixels (e.g., M × N pixels), and the pixels may be divided into K pixel groups, and for each pixel in the pixel groups, since the processing manner of each pixel is the same, for convenience of description, in the following embodiments, the processing procedure of one pixel is taken as an example.

Illustratively, the infrared readout circuit supports two states: a correction state (which may also be referred to as an auto-correction state) and a readout state (which may also be referred to as a normal readout state). After the infrared reading circuit is powered on and reset, the infrared reading circuit enters a correction state, obtains the optimum value of the correction parameter corresponding to each pixel in the correction state, and writes the optimum value of the correction parameter into the first register. And after the correction state is finished, entering a reading state, correcting the voltage output value of the pixel by using the optimum value of the correction parameter in the first register in the reading state, and outputting the corrected voltage output value, namely finishing correction in the infrared reading circuit.

The functions of the devices such as the readout unit, the ADC, the correction control unit, the DAC, the first register, the comparator, the first switch, the correction target value generator, the ramp generator, the counter, the second register, the second switch, and the data output unit will be described below with reference to the infrared readout circuit shown in fig. 4.

When the infrared readout circuit is in the corrected state, the functions of the devices are as follows:

1. and a readout unit. The reading unit is used for determining a voltage response value corresponding to the pixel based on an initial bias value corresponding to the parameter value to be corrected corresponding to the pixel, and inputting the voltage response value to the comparator. For example, the reading unit may determine the voltage response value corresponding to the pixel based on a first current corresponding to the initial bias voltage value corresponding to the parameter value to be corrected and a second current output by the response temperature value of the pixel.

The second current output by the pixel in response to the temperature value means that when the temperature value of the test target sensed by the pixel changes, the resistance value of the pixel is changed, and when the resistance value of the pixel changes, the second current corresponding to the pixel changes, that is, the second current is related to the temperature value of the test target sensed by the pixel.

Referring to fig. 5, which is a schematic structural diagram of a readout unit, the readout unit may include a resistor Rd, a first MOS (Metal Oxide Semiconductor Field Effect Transistor) Transistor, a second MOS Transistor, an integrating circuit, and a sample-and-hold circuit. It should be noted that, although the pixel Rs is disposed inside the readout unit in fig. 5, the connection relationship between the pixel Rs and the readout unit is only described here for convenience, and the pixel Rs does not belong to a device of the readout unit. The integrating circuit is composed of an operational amplifier, a switch rst and an integrating capacitor Cint. The sample-and-hold circuit is also called a sample-and-hold amplifier, and when analog-to-digital conversion is performed on an analog signal, a certain conversion time is required, and in the conversion time, the analog signal needs to be kept basically unchanged, so that the conversion precision can be ensured, and the sample-and-hold circuit is a circuit for realizing the function.

Referring to fig. 5, the input voltage of the first MOS transistor is a bias voltage value Vin, in the correction state, the bias voltage value Vin is referred to as an initial bias voltage value Vin, the initial bias voltage value Vin is determined based on the value of the parameter to be corrected, and the determination process is described in the following embodiments. In the read state, the bias voltage value Vin is referred to as a target bias voltage value Vin, which is determined based on the optimal value of the correction parameter, as described in the following embodiments.

In the rectification state, when the initial bias value Vin is larger, the current I1 (denoted as the first current I1) passing through the first MOS transistor is smaller, that is, the initial bias value Vin is inversely related to the first current I1, and obviously, by controlling the magnitude of the initial bias value Vin, the magnitude of the first current I1 can be adjusted.

Referring to fig. 5, the input voltage of the second MOS transistor is a voltage value VFID, and the voltage value VFID is a fixed voltage value, and the working principle of the second MOS transistor is not described in detail in this embodiment.

Referring to fig. 5, the pixel Rs is a resistor element in an infrared array, for example, the pixel Rs may be a MEMS (micro electro Mechanical Systems) thermistor, and the type of the pixel Rs is not limited. In practical applications, the number of the image elements Rs may be multiple, and in fig. 5, one image element Rs is taken as an example. The pixel Rs is used for converting an infrared signal into an electric signal, namely, after infrared heat radiation of a target scene reaches the pixel Rs, the pixel Rs can sense the temperature of the external environment, so that the resistance value of the pixel Rs is changed, and the current value passing through the pixel Rs, namely the current I2, is controlled.

For example, in the correction state, the blocking sheet may be opened for the infrared array, and the temperature values at the positions of the blocking sheet are the same, so that, for each pixel in the pixel group, the pixel Rs is taken as an example for explanation, the external environment temperature sensed by the pixel Rs is the temperature value of the blocking sheet, and for convenience of distinction, the temperature value sensed by the pixel Rs is recorded as a test target temperature value, that is, the test target temperature value is the temperature value of the blocking sheet. Obviously, based on the test target temperature value sensed by the pixel Rs, the current I2 (denoted as the second current I2) passing through the pixel Rs can be controlled, that is, the second current I2 is matched with the test target temperature value sensed by the pixel Rs.

Referring to fig. 5, the integration circuit may be connected to the first MOS transistor, and the integration circuit may be connected to the sample-and-hold circuit. Here, the input current Iint of the integration circuit may also be referred to as an integrated current Iint, and the input current Iint may 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 may be determined, and then the input current Iint corresponding to the integration circuit may be determined based on the first current I1 and the second current I2, for example, the input current Iint may be determined in the following manner: iint = I1-I2.

On the basis of the known input current Iint, the input current Iint can be integrated through an integration circuit, the integration operation process is not limited, and the voltage input value Vo _ int corresponding to the pixel element Rs is obtained. For example, the integrating circuit is used to integrate and amplify the weak electrical signal of the pixel Rs, and the output result of the integration and amplification is the voltage input value Vo _ int. For example, the voltage input value Vo _ int may be determined as follows: vo _ int = Vref-Iint × Tint/Cint, in the above formula, 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 integration capacitance.

Referring to fig. 5, the input end of the sample-and-hold circuit is the voltage input value Vo _ int, and the output end of the sample-and-hold circuit is the voltage response value Vo, and the sample-and-hold circuit performs sample-and-hold operation on the voltage input value Vo _ int to obtain the voltage response value Vo corresponding to the pixel Rs, that is, vo = Vo _ int.

When analog-to-digital conversion is performed on an analog signal, a certain conversion time is required, and in this conversion time, the analog signal needs to be kept basically unchanged, so that the conversion precision can be ensured, the sample-and-hold circuit is a circuit for realizing this function, and the working process of the sample-and-hold circuit is not limited in this embodiment.

In summary, for the pixel Rs, the input voltage of the first MOS transistor is the initial bias value Vin, the current passing through the first MOS transistor is the first current I1 corresponding to the initial bias value Vin, the pixel Rs outputs the second current I2 in response to the temperature value, the difference between the first current I1 and the second current I2 is determined as the input current Iint of the integrating circuit, and the input current Iint is input to the integrating circuit to perform an integrating operation on the input current Iint through the integrating circuit, so as to obtain the voltage input value Vo _ int corresponding to the pixel Rs. Then, a voltage response value Vo corresponding to the pixel Rs is determined based on the voltage input value Vo _ int corresponding to the pixel Rs.

After the voltage response value Vo corresponding to the pixel Rs is obtained, the voltage response value Vo may be input to a comparator in the ADC, and the comparator in the ADC performs processing based on the voltage response value Vo.

2. A comparator. The comparator is used for comparing the voltage response value Vo with the preset voltage value Vref to obtain a comparison result corresponding to the pixel Rs, and the comparison result corresponding to the pixel Rs is input to the correction control unit.

For example, the comparison Result (Result) may be a logic value, and 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), where 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 smaller 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 smaller than the preset voltage value Vref.

For example, the voltage response value Vo may be a voltage value of the analog signal, the preset voltage value Vref may also be referred to as a correction target value Vref, and a value of the preset voltage value Vref is not limited and may be configured empirically. On the basis, after the comparator obtains the voltage response value Vo corresponding to the pixel Rs, the voltage response value Vo and the preset voltage value Vref can be compared. If the voltage response value Vo is greater than the preset voltage value Vref (i.e., vo > Vref), the logic value is determined to be a first value, and the first value is output to the correction control unit. And if the voltage response value Vo is smaller than the preset voltage value Vref (i.e. Vo < Vref), determining that the logic value is a second value, and outputting the second value to the correction control unit. The first value and the second value are not limited, if the first value is 1, the second value is 0.

In one possible embodiment, the correction control unit may determine a corresponding state of the infrared readout circuit, and may control the second terminal of the first switch to be connected to the correction target value generator when the infrared readout circuit corresponds to the correction state, and since the first terminal of the first switch is fixedly connected to the comparator, the comparator and the correction target value generator may be communicated after the second terminal of the first switch is controlled to be connected to the correction target value generator, that is, the comparator and the correction target value generator may be communicated when the infrared readout circuit corresponds to the correction state.

For example, the correction target value generator is configured to generate a preset voltage value Vref and send the preset voltage value Vref to the comparator, i.e., the comparator may obtain the preset voltage value Vref from the correction target value generator.

3. A correction control unit. The correction control unit can also be called as a NUC control unit, and is used for 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; and determining the optimal value of the correction parameter corresponding to the pixel based on the adjusted parameter value, and replacing the parameter value to be corrected corresponding to the pixel with the optimal value of the correction parameter corresponding to the pixel.

Illustratively, 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, which indicates that the voltage response value Vo is greater than the preset voltage value Vref, the parameter value to be corrected is reduced to obtain the adjusted parameter value; or if the comparison result is a second value, and the second value indicates that the voltage response value Vo is smaller than the preset voltage value Vref, increasing the parameter value to be corrected to obtain the adjusted parameter value. The correction control unit reduces the parameter value to be corrected, and when the adjusted parameter value is obtained, the correction control unit can perform 1 reduction operation on the parameter value to be corrected to obtain the adjusted parameter value; of course, the parameter value to be corrected may be subtracted from the other values to obtain the adjusted parameter value, which is not limited to this. The correction control unit increases the parameter value to be corrected, and when the adjusted parameter value is obtained, the correction control unit can perform the operation of adding 1 to the parameter value to be corrected to obtain the adjusted parameter value; of course, other values may be added to the parameter value to be corrected to obtain the adjusted parameter value, which is not limited to this.

For example, in the process of determining the optimal value of the correction parameter corresponding to the pixel based on the adjusted parameter value, if the adjustment end condition of the parameter value to be corrected is met, the adjusted parameter value may be 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 is not satisfied, the adjusted parameter value may be 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, so as to re-determine the voltage response value corresponding to the pixel based on the parameter value to be corrected.

Wherein, the rectification control unit may determine whether the comparison result of the current comparison period is the same as the comparison result of the previous comparison period. If the comparison result of the current comparison period is the same as the comparison result of the previous comparison period, it can be determined that the adjustment end condition of the parameter value to be corrected is not met. If the comparison result of the current comparison period is different from the comparison result of the previous comparison period, it can be determined that the adjustment end condition of the parameter value to be corrected is met. For example, if the comparison result of the current comparison period is the first value and the comparison result of the previous comparison period is the first value, it is determined that the adjustment end condition of the parameter value to be corrected is not met; or if the comparison result of the current comparison period is the second value and the comparison result of the last comparison period is the second value, determining that the adjustment end condition of the parameter value to be corrected is not met; or if the comparison result of the current comparison period is a first value and the comparison result of the last comparison period is a second value, determining that the adjustment end condition of the parameter value to be corrected is met; or if the comparison result of the current comparison period is the second value and the comparison result of the last comparison period is the first value, determining that the adjustment end condition of the parameter value to be corrected is met. And the comparison result is that the first value-taking representation voltage response value Vo is greater than the preset voltage value Vref, and the comparison result is that the second value-taking representation voltage response value Vo is less than the preset voltage value Vref.

The correction control unit can perform exclusive-or operation on the comparison result of the current comparison period and the comparison result of the previous comparison period; if the result of the XOR operation is 0, determining that the adjustment end condition of the parameter value to be corrected is not met; and if the result of the exclusive-or operation is 1, determining that the adjustment end condition of the parameter value to be corrected is met. It should be noted that, when the result of the xor operation is 0, it may indicate that the comparison result of the current comparison period is the same as the comparison result of the previous comparison period, and when the result of the xor operation is 1, it may indicate that the comparison result of the current comparison period is different from the comparison result of the previous comparison period. Wherein, the comparison result of the current comparison period is a first value or a second value; the comparison result of the last comparison period is the first value or the second value.

In this embodiment, in order to determine the optimal value of the correction parameter corresponding to the pixel, a target algorithm may 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, and the target algorithm is not limited as long as the value of the parameter to be corrected can be adjusted to obtain the optimal value of the correction parameter.

For example, assuming that the value of the parameter to be corrected is a 4-bit binary value, for example, 1000, in this case, the process of adjusting the value of the parameter to be corrected corresponding to the pixel by using the target algorithm may include:

in the correction period 1 (i.e., the number of adjustments is 1): the value of the parameter to be corrected is 8 (1000), an initial bias voltage value may be determined based on the value of the parameter to be corrected 8 (see the subsequent embodiment for the determination process), the voltage response value Vo is determined based on the initial bias voltage value, and the comparison result of the voltage response value Vo and the preset voltage value Vref is determined.

If the voltage response value Vo is greater than the preset voltage value Vref, that is, the comparison result is a first value 1, subtracting 1 from the parameter value 8 to be corrected to obtain an adjusted parameter value 7 (0111); if the voltage response value Vo is smaller than the preset voltage value Vref, that is, the comparison result is the first value 0, then 1 is added to the parameter value 8 to be corrected, and an adjusted parameter value 9 is obtained (1001). In conclusion, the adjusted parameter value can be obtained, 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.

In the correction period 1, a comparison result S1 of the voltage response value Vo and the preset voltage value Vref may be stored, where the comparison result S1 may be a first value 1, and the comparison result S1 may also be a second value 0.

In correction period 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, an initial bias value is determined based on the value of the parameter to be corrected 9, a voltage response value Vo is determined based on the initial bias value, and a comparison result S2 of the voltage response value Vo and a preset voltage value Vref is determined.

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, subtracting 1 from the to-be-corrected parameter value 9 to obtain an adjusted parameter value 8 (1000); if the voltage response value Vo is smaller than the preset voltage value Vref, that is, the comparison result S2 is the first value 0, then 1 may be added to the to-be-corrected parameter value 9, so as to obtain an adjusted parameter value 10 (1010).

After the comparison result S2 is obtained, an exclusive or operation may be performed on the comparison result S2 and the comparison result S1, and if the result of the exclusive or operation is 0, it is determined that the adjustment end condition of the parameter value to be corrected is not satisfied, so that the adjusted parameter value (for example, the adjusted parameter value 8 or the adjusted parameter value 10) 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. Or, if the result of the xor operation is 1, determining that the adjustment end condition of the parameter value to be corrected is met, and therefore, determining the adjusted parameter value (for example, the adjusted parameter value 8 or the adjusted parameter value 10) as the optimal value of the correction parameter corresponding to the pixel, and writing the optimal value of the correction parameter into the first register, so as to successfully obtain the optimal value of the correction parameter.

Assuming that the result of the xor operation is 0, that is, the adjustment ending condition of the parameter value to be corrected is not satisfied, in the correction period 2, the comparison result S2 may be further stored, that is, the comparison result S2 is used to replace the comparison result S1, where the comparison result S2 may be the first value 1, and the comparison result S2 may also be the second value 0.

In correction period 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, an initial bias voltage value is determined based on the value of the parameter to be corrected 10, a voltage response value Vo is determined based on the initial bias voltage value, and a comparison result S3 of the voltage response value Vo and a preset voltage value Vref is determined.

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, subtracting 1 from the to-be-corrected parameter value 10, so as to obtain an adjusted parameter value 9; if the voltage response value Vo is smaller than the preset voltage value Vref, that is, the comparison result S3 is the first value 0, then 1 may be added to the parameter value 10 to be corrected, so as to obtain an adjusted parameter value 11 (1011).

After the comparison result S3 is obtained, an exclusive or operation may be performed on the comparison result S3 and the comparison result S2, and if the result of the exclusive or operation is 0, it is determined that the adjustment end condition of the parameter value to be corrected is not satisfied, so that the adjusted parameter value (for example, the adjusted parameter value 9 or the 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. Or, if the result of the xor operation is 1, determining that the adjustment end condition of the parameter value to be corrected is met, and therefore, determining the adjusted parameter value (such as the adjusted parameter value 9 or the adjusted parameter value 11) as the optimal value of the correction parameter corresponding to the pixel, and writing the optimal value of the correction parameter into the first register, so as to successfully obtain the optimal value of the correction parameter.

Assuming that the result of the xor operation is 1, that is, the adjustment ending condition of the parameter value to be corrected is satisfied, then the optimal value of the correction parameter may be obtained, that is, the optimal value of the correction parameter may be obtained through 3 correction cycles.

In summary, in the embodiment, in the calibration cycle 1, the calibration control unit may store the parameter value D to be calibrated in the first register ₀ Based on the value D of the parameter to be corrected ₀ Determining an initial bias value Vin, determining a voltage response value Vo based on the initial bias value Vin, and treating a correction parameter value D based on a comparison result of the voltage response value Vo and a preset voltage value Vref ₀ Correcting to obtain a value D of a parameter to be corrected ₁ The correction control unit may store the value of the parameter to be corrected D in the first register ₁ In this way, the correction control unit continuously updates the value of the parameter to be corrected in the first register, and determines the initial bias value Vin based on the latest value of the parameter to be corrected.

The correction control unit generates a value D of a parameter to be corrected for the last correction _i-1 (D _i-1 A to-be-corrected parameter value corresponding to the voltage response value Vo currently output by the sensing unit) is adjusted, if Result =1, the to-be-corrected parameter value D is adjusted _i-1 Subtracting 1 to obtain a parameter value D to be corrected _i Using the value of the parameter D to be corrected _i Updating the value D of the parameter to be corrected in the first register _i-1 . If Result =0, the value D of the parameter to be corrected is calculated _i-1 Adding 1 to obtain the parameter value D to be corrected _i Using the value of the parameter D to be corrected _i Updating the value D of the parameter to be corrected in the first register _i-1 。

When results of the two previous and next correction periods are different, the Result indicates that the voltage response value Vo output by the reading unit has reached the optimal correction value, and the updating process of the parameter value to be corrected can be skipped. If the result of the exclusive-or operation is 0, indicating that the optimal result is not corrected; if the result of the exclusive-or operation is 1, the optimal result is corrected, and the correction process is stopped.

In this embodiment, whether to jump out of the correction process may be determined based on the Result of the exclusive or operation of results of the two correction periods before and after, so that the duration of the correction period may be reduced, and the number of the correction periods may be reduced, that is, if the Result of the exclusive or operation is 1, it is known that the optimal Result has been corrected, the correction process is stopped, and the number of the correction periods is reduced. Referring to table 1, assuming that the preset voltage Vref generated by the correction target value generator is near the analog voltage value corresponding to the parameter value 11-12 to be corrected, and the initial value of the parameter value to be corrected is 8, the correction control unit may add 1 to the parameter value to be corrected according to the above-mentioned manner.

When results of the two correction periods are different, the Result shows that the voltage response value Vo output by the reading unit reaches the optimum correction value, and the updating process of the value of the parameter to be corrected can be skipped, so that correction is stopped in time, unnecessary correction periods are reduced, and the correction process is completed through 5 correction periods.

TABLE 1

To sum up, for each pixel in the pixel group, the correction control unit may obtain the optimum value of the correction parameter corresponding to the pixel, and write the optimum value of the correction parameter corresponding to the pixel into the first register.

In one possible embodiment, the rectification control unit may also determine a corresponding state of the infrared readout circuit. For example, after the infrared reading circuit is powered on and started, the corresponding correction state of the infrared reading circuit can be determined, and after the optimal value of the correction parameter corresponding to each pixel is determined, the corresponding reading state of the infrared reading circuit can be determined, so that the correction state and the reading state of the infrared reading circuit can be automatically switched. Obviously, when the infrared reading circuit corresponds to the correction state, the optimum value of the correction parameter corresponding to each pixel may be determined, and the optimum value of the correction parameter corresponding to each pixel is written into the first register. When the infrared reading circuit corresponds to the reading state, the subsequent process can be carried out based on the optimal value of the correction parameter in the first register.

For example, when the infrared readout circuit corresponds to the correction state, the correction control unit may control the second terminal of the first switch to connect the correction target value generator, so as to connect the comparator and the correction target value generator, so that the comparator obtains the preset voltage value Vref from the correction target value generator, and the infrared readout circuit is configured to implement the function of correcting the state based on the preset voltage value Vref. And the rectification control unit may control the second terminal of the second switch to be connected to a Ground (GND), and although the first terminal of the second switch is connected to the counter, since the second terminal of the second switch is connected to the ground, the counter may be stopped, that is, the counter may not acquire the internal clock, so that the counter may be stopped, that is, the counter may be turned off.

4. A first register. The first register is used for storing the value of the parameter to be corrected corresponding to each pixel, and after the correction control unit obtains the optimal value of the correction parameter, the storage pixel is used for storing the optimal value of the correction parameter corresponding to each pixel. For example, in the correction state, the first register may store a value of a parameter to be corrected corresponding to the pixel, and in each correction cycle, the value of the parameter to be corrected may be updated. After the correction state is completed, the first register may store the optimal value of the correction parameter corresponding to the pixel. In the read-out state, the optimum value of the correction parameter may be read from the first register, and a subsequent process may be performed based on the optimum value of the correction parameter.

For example, the correction control unit may obtain initial values of parameters to be corrected corresponding to each pixel, write the initial values of the parameters to be corrected into the first register, and store the initial values of the parameters to be corrected by the first register; for a plurality of pixels in the pixel group, initial values of parameters to be corrected corresponding to different pixels can be the same. In the subsequent process, initial values of parameters to be corrected of different pixels can be adjusted, the initial values of the parameters to be corrected are understood as the first parameter values to be corrected, the optimal values of the correction parameters are obtained by continuously adjusting the parameter values to be corrected, and the optimal values of the correction parameters can be understood as the last parameter values to be corrected.

For example, after the correction control unit obtains the optimum value of the correction parameter corresponding to each pixel, the optimum values of the correction parameters may be written into the first register, and the first register stores the optimum values of the correction parameters.

5. DAC (digital-to-analog converter). The DAC is used for carrying out digital-to-analog conversion on the parameter value to be corrected corresponding to the pixel to obtain an analog voltage signal, determining a voltage value corresponding to the analog voltage signal as an initial bias voltage value Vin corresponding to the parameter value to be corrected, and inputting the initial bias voltage value Vin to the reading unit.

For example, the DAC may read a value of a parameter to be corrected from the first register, perform digital-to-analog conversion on the value of the parameter to be corrected of the digital signal to obtain an analog voltage signal, and determine a voltage value corresponding to the analog voltage signal as an initial bias value Vin, that is, the initial bias value Vin serves as an input voltage of the first MOS transistor, and may control a current I1 passing through the first MOS transistor. Obviously, different initial bias values Vin can provide different biases for the reading unit, and when the initial bias value Vin is larger, the voltage response value Vo corresponding to the pixel is larger, so that the problem that the reading unit has response difference to the same radiation caused by manufacturing deviation can be solved. For example, in the correction period 1, an initial bias value Vin is determined based on the value of the parameter to be corrected in the correction period 1, and the determined initial bias value Vin is input to the reading unit; in the correction period 2, an initial bias value Vin is determined based on the parameter value to be corrected in the correction period 2, the initial bias value Vin is input to the readout unit, and so on.

In summary, the description of the correction state is completed, and in the correction state, the optimum value of the correction parameter corresponding to each pixel may be obtained, and the optimum value of the correction parameter may be written into the first register. After the correction state is complete, a readout state may be performed. In the reading state, the blocking sheet can be closed, so that the sensed external environment temperature is the actual target temperature value of the target scene for each pixel.

When the infrared readout circuit is in the readout state, the functions of the devices are as follows:

1. and a readout unit. The reading unit is used for determining a voltage response value corresponding to the pixel based on a target bias voltage value corresponding to the optimal value of the correction parameter corresponding to the pixel, and inputting the voltage response value to the comparator. For example, the readout unit may determine the voltage response value corresponding to the pixel based on the third current corresponding to the target bias voltage value corresponding to the optimal value of the correction parameter and the fourth current output by the response temperature value of the pixel.

The fourth current output by the pixel in response to the temperature value means that when the actual target temperature value sensed by the pixel changes, the resistance value of the pixel is changed, and when the resistance value of the pixel changes, the fourth current corresponding to the pixel changes, that is, the fourth current is related to the actual target temperature value sensed by the pixel.

Referring to fig. 5, the input voltage of the first MOS transistor is a bias voltage value Vin, and in the read state, the bias voltage value Vin is referred to as a target bias voltage value Vin, and the target bias voltage value Vin is determined based on the optimal value of the correction parameter. The optimal value of the correction parameter is used for correcting the actual target temperature value sensed by the pixel, namely, in a reading state, the actual target temperature value sensed by the pixel is corrected based on the optimal value of the correction parameter, and the purpose of correcting the actual target temperature value sensed by the pixel is achieved through correcting the voltage response value Vo of the reading unit.

Referring to fig. 5, in the readout state, when the target bias voltage value Vin is larger, the third current I1 passing through the first MOS transistor is smaller, that is, the target bias voltage value Vin is inversely related to the third current I1, so that the target bias voltage value Vin is controlled by the optimal value of the correction parameter, and then the third current I1 is controlled by the target bias voltage value Vin, so as to affect the voltage response value Vo corresponding to the pixel Rs.

In a reading state, the blocking sheet can be closed for the infrared array, so that for each pixel, taking the pixel Rs as an example, the external environment temperature sensed by the pixel Rs is an actual target temperature value of a target scene. Based on the actual target temperature value sensed by the pixel Rs, the current I2 (denoted as the fourth current I2) passing through the pixel Rs may be controlled, that is, the fourth current I2 matches the actual target temperature value of the target scene sensed by the pixel Rs.

In summary, for the pixel Rs, the input voltage of the first MOS transistor is the target bias value Vin, the current passing through the first MOS transistor is the third current I1 corresponding to the target bias value Vin, the pixel Rs outputs the fourth current I2 in response to the temperature value, a difference between the third current I1 and the fourth current I2 can be determined as the input current Iint of the integrating circuit, and the input current Iint is input to the integrating circuit, so as to perform an integrating operation on the input current Iint through the integrating circuit, and obtain the voltage input value Vo _ int corresponding to the pixel Rs. Then, a voltage response value Vo corresponding to the pixel Rs is determined based on the voltage input value Vo _ int corresponding to the pixel Rs.

After the voltage response value Vo corresponding to the pixel Rs is obtained, the voltage response value Vo can be input to a comparator in the ADC, and the comparator in the ADC performs processing based on the voltage response value Vo.

2. A correction control unit. The correction control unit may determine a state corresponding to the infrared reading circuit, for example, after the infrared reading circuit is powered on and started, determine a correction state corresponding to the infrared reading circuit; and after the optimal value of the correction parameter corresponding to the pixel is determined, determining the corresponding reading state of the infrared reading circuit. When the infrared reading circuit corresponds to the correction state, the correction control unit controls the blocking piece to be opened so that each pixel in the infrared array can sense the temperature value of the blocking piece. When the infrared reading circuit is in a corresponding reading state, the correction control unit controls the blocking sheet to be closed so that each pixel in the infrared array can sense the actual target temperature value of the target scene.

Illustratively, when the infrared readout circuit corresponds to the readout state, the rectification control unit may control the second terminal of the first switch to connect to the ramp generator, so as to connect the comparator and the ramp generator, so that the comparator obtains the ramp voltage value from the ramp generator, and the infrared readout circuit may be configured to implement the function of reading out the state based on the ramp voltage value. And the rectification control unit may control the second terminal of the second switch to be connected to the internal clock, so as to enable 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, so as to enable the counter to acquire the internal clock and start counting.

3. A DAC. The DAC is used for carrying out digital-to-analog conversion on the optimal value of the correction parameter corresponding to the pixel to obtain an analog voltage signal, determining the voltage value corresponding to the analog voltage signal as a target bias voltage value Vin corresponding to the optimal value of the correction parameter, and inputting the target bias voltage value Vin to the reading unit, so that the reading unit determines a voltage response value corresponding to the pixel based on a third current corresponding to the target bias voltage value Vin and a fourth current output by the pixel response temperature value. For example, the first register already stores the optimal value of the correction parameter corresponding to the image element, and the DAC may read the optimal value of the correction parameter from the first register to obtain the target bias value Vin.

4. An ADC. For each pixel in the pixel group, the ADC is configured to determine a voltage output value corresponding to the pixel, and output the voltage output value to the external device, for example, output the voltage output value to the external processor, so that the external processor determines an actual target temperature value of the target scene (i.e., a temperature value of the target object) based on the voltage output value. For example, the external processor may query a mapping relationship between a pre-calibrated voltage value and a temperature value to obtain a temperature value corresponding to the voltage output value, where the temperature value is a temperature value of the target object, that is, a finally detected temperature value.

In a possible implementation mode, when the infrared reading circuit corresponds to a reading state, the first switch is switched to the ramp generator to connect the comparator and the ramp generator, the second switch is switched to the internal clock to enable the counter, the counter starts counting, the ADC works normally, analog-to-digital conversion is carried out, and a voltage output value is output.

Illustratively, the ADC may include a first switch, a corrected target value generator for generating a preset voltage value Vref, and a ramp generator for generating a ramp voltage value; the first end of the first switch is connected with the comparator, and the second end of the first switch is connected with the correction target value generator or the slope 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 function of correcting the state based on the preset voltage value Vref, and the implementation process is as in the above embodiment. When the second terminal of the first switch is switched from the corrected target value generator to the ramp generator, the infrared readout circuit is used to implement a function of reading out the state based on the ramp voltage value, and the implementation process is described in the following embodiments.

Illustratively, the ADC may include a ramp generator, a comparator, a counter, a second register, and a data output unit, and the analog-to-digital conversion is implemented by cooperation of these devices, and the functions of these devices are as follows:

a ramp generator. The ramp generator is configured to generate a ramp voltage value, for example, the ramp generator is configured to generate a plurality of ramp voltage values starting from an initial ramp voltage value (for example, the ramp generator is configured to generate a plurality of ramp voltage values of stable slope starting from the initial ramp voltage value). The initial ramp voltage value may be configured empirically, for example, the initial ramp voltage value may be 0, and the like, which is not limited thereto.

A comparator. The comparator is used for acquiring a ramp voltage value from the ramp generator, and comparing the voltage response value Vo (namely the voltage response value Vo corresponding to the optimal value of the correction parameter) with the ramp voltage value to obtain a comparison result corresponding to the pixel, wherein the comparison result is used for determining a voltage output value corresponding to the pixel. For example, the comparator is configured to compare the voltage response value Vo with each ramp voltage value generated by the ramp generator, and obtain a comparison result corresponding to each ramp voltage value, where the comparison result may 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, the ramp generator sequentially generates a ramp voltage value W1 and ramp voltage values W2, \8230, and so on, the comparator sequentially compares the voltage response value Vo with the ramp voltage value W1 to obtain a comparison result corresponding to the ramp voltage value W1, compares the voltage response value Vo with the ramp voltage value W2 to obtain a comparison result corresponding to the 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.

A counter. The counter is used for starting to count when the second switch is switched to the internal clock, that is, the counter can count the clock pulse to obtain a count value, and the counting process is not limited.

Illustratively, the counter may include, but is not limited to, a gray code counter, whose operating principle is: when the gray code (i.e., the count value) is incremented, only one bit of any two adjacent bits is different, and the number of times of the flipping is less than that of the binary encoder.

A second register. The second register is used for storing a target count value corresponding to the target ramp voltage value; wherein the target ramp voltage value is a ramp voltage value of which the first one of all the ramp voltage values is greater than the voltage response value Vo; the target count value is the count value at which the ramp generator generates the target ramp voltage value.

For example, if the ramp voltage value W _i Is greater than the voltage response value Vo and has a ramp voltage value W _i-1 Not greater than the voltage response value Vo, the ramp voltage value W _i-1 Is a slopeVoltage value W _i The previous ramp voltage value of (2), the ramp voltage value W can be set _i As the target ramp voltage value. Suppose that the ramp generator generates a ramp voltage value W _i If the time point of (d) is time point i, the count value i corresponding to the time point i (i.e., the count value generated by the counter at the time point i) may be set as the target count value. On this basis, the second register is used to store the count value i.

And a data output unit. And the data output unit is used for acquiring a target counting value from the second register, determining a voltage output value corresponding to the pixel based on the target counting value, and outputting 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.

Referring to fig. 6, which is a schematic diagram illustrating the operation principle of the ADC, the output value Count1 of the counter is reset to zero before the ADC starts to perform analog-to-digital conversion. When the ADC works, the ramp generator generates a plurality of ramp voltage values Vramp with stable slope from an initial ramp voltage value, and the comparator compares the plurality of ramp voltage values Vramp with the voltage response value Vo. The counter starts to count clock pulses. When the ramp generator starts to generate the ramp voltage value Vramp, the voltage response value Vo is greater than the ramp voltage value Vramp, the output Vcomp of the comparator is at a high level, until the ramp voltage value Vramp is greater than the voltage response value Vo, the comparator is turned over, and the second register is triggered to store the current Count value Count2. The second register transmits the Count value Count2 to the data output unit, and the data output unit performs serial-parallel conversion on the Count value Count2 to obtain a voltage output value, and outputs the voltage output value to the outside (such as an external processor).

According to the technical scheme, the infrared reading circuit is designed in the embodiment of the application, the non-uniformity correction is realized by the infrared reading circuit, an external processor is not needed for realizing the non-uniformity correction, the expenditure of external hardware resources is reduced, the cost is reduced, the development is simple, and the correction effect is good. By providing different bias values for different pixels (different bias values are controlled by different optimum values of correction parameters), the response difference of different pixels to the same infrared radiation is corrected, so that the response of different pixels to the same infrared radiation is consistent, and the non-uniformity correction of different pixels is realized. All pixels of the infrared array are divided into K pixel groups, so that the K pixel groups can be processed in parallel, and time required by a correction stage is reduced. The infrared reading circuit is a non-refrigeration type infrared reading circuit which realizes the automatic non-uniformity correction function and can finish the automatic non-uniformity correction of the pixels. The comparator in the ADC can be directly multiplexed, only a plurality of switch structures are needed to be added, the time required by a correction stage can be reduced while the circuit cost is reduced, and the method has the advantage that non-uniform deviation brought by a column-level integrator can be eliminated. In the correction comparison stage, each column of comparators can be started simultaneously, and signals of all columns are compared in parallel, so that the correction comparison time is greatly saved.

Referring to fig. 7, which is a schematic diagram illustrating a working flow of the infrared readout circuit, the method may include:

step 701, the infrared reading circuit is powered on and started.

In step 702, after the infrared readout circuit is powered on and started, configuration information may be written in the correction control unit, for example, the configuration information may include a line time, an integration time, a value of a parameter to be corrected, a preset voltage value, and the like.

The correction control unit may use the value of the parameter to be corrected as the value of the parameter to be corrected of each pixel, and write the value of the parameter to be corrected of each pixel into the first register. For a plurality of pixels included in the pixel group, the values of the to-be-corrected parameters corresponding to different pixels may be the same, that is, the same value of the to-be-corrected parameter is written into the first register.

The correction control unit may use the preset voltage value as the preset voltage value of 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.

And 703, the correction control unit determines that the correction state is entered, and starts the blocking sheet, wherein the temperature value of each position of the blocking sheet is the same, so that the test target temperature value sensed by each pixel is the temperature value of the blocking sheet. The correction control unit controls the second end of the first switch to be connected with the correction target value generator, so that the comparator is communicated with the correction target value generator. The correction control unit controls the second end of the second switch to be connected with the ground end, so that the counter stops working.

Step 704, in the correction state, the reading unit determines a voltage response value corresponding to the pixel based on an initial bias value corresponding to a 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 a preset voltage value to obtain a comparison result corresponding to the pixel, and inputs the comparison result to the correction control unit; and the correction control unit adjusts the parameter value to be corrected based on the comparison result to obtain an adjusted parameter value, updates the adjusted parameter value to the first register and replaces the parameter value to be corrected.

For the detailed processing procedure of step 704, refer to the above embodiments, and are not described herein.

Step 705, determining whether the rectification is completed. If the correction parameter is completed, the adjusted parameter value updated to the first register is used as the optimal value of the correction parameter, and step 706 is executed. If not, the adjusted parameter value updated to the first register is used as the value of the parameter to be corrected, and step 704 is executed based on the value of the parameter to be corrected.

Step 706, the correction control unit determines to enter a read-out state, and closes the blocking sheet, so that each pixel element senses an actual target temperature value of the target scene. The rectification control unit may control the second end of the first switch to be connected to the ramp generator, thereby communicating the comparator and the ramp generator. The rectification control unit can control the second end of the second switch to be connected with the internal clock, so that the counter starts to work normally.

Step 707, in a reading state, the reading unit determines a voltage response value corresponding to the pixel based on a target bias voltage value corresponding to the optimal value of the correction parameter corresponding to the pixel, and inputs the voltage response value to the comparator; the comparator can compare the voltage response value with the slope voltage value to obtain a 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. And finally, outputting the voltage output value corresponding to the pixel to an external processor so as to determine the temperature value corresponding to the pixel.

For the detailed processing procedure of step 707, refer to the above embodiments, and are not described herein again.

The following briefly describes the operation timing sequence of the infrared readout circuit in conjunction with a specific application scenario.

Referring to fig. 8, a timing diagram of the operation of the infrared readout circuit is shown, and the correction can be divided into two stages. In the first stage, the first register updates the value D of the parameter to be corrected of the previous frame one line in advance _i-1 Writing in DAC, reading out the updated parameter value D to be corrected according to previous frame _i-1 The voltage response value Vo is output. In the second stage, the reading unit outputs a voltage response value Vo, 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 inputs the comparison result to the correction control unit, and the correction control unit treats a correction parameter value D according to the comparison result _i-1 Adding one or subtracting one to obtain the updated value D of the parameter to be corrected _i And the value D of the parameter to be corrected is corrected _i And storing the data into a first register.

When the results of the two comparisons are inconsistent, the value D of the parameter to be corrected is shown _i Already at the optimum value, the value D of the parameter to be corrected _i And as the optimal value of the correction parameter, the correction control unit sets the control signal to zero according to the judgment result, stops the correction process, starts the ADC and enters a read-out state.

Referring to fig. 9, it is a working timing diagram of each switch of the infrared reading circuit, when the results output by the two comparators are inconsistent, the result of the xor calculation is 1, the control signal is set to 0, when the clock CLK falls, the first switch S1 and the second switch S2 are triggered to be turned over, the non-uniform correction is stopped, the ADC is started, and the normal analog-to-digital conversion is performed, that is, the infrared reading circuit enters the reading state.

Based on the same application concept as the infrared readout circuit, the embodiment of the present application provides another infrared readout circuit, where the infrared array may include K pixel groups, where K is a positive integer greater than 1, and 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 the pixel group, and the analog-to-digital converter includes a comparator; wherein, aiming at the pixel in the pixel group: the reading unit is used for determining a voltage response value corresponding to the pixel based on an initial bias value corresponding to a parameter value to be corrected corresponding to the pixel and inputting the voltage response value to the comparator; the comparator is used for comparing the voltage response value with a preset voltage value to obtain 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 parameter value to be corrected based on the comparison result to obtain an adjusted parameter value; and determining the optimal value of the correction parameter corresponding to the pixel based on the adjusted parameter value, and replacing the parameter value to be corrected by the optimal value of the correction parameter.

Illustratively, the analog-to-digital converter further includes a first switch, a corrective target value generator for generating a preset voltage value, and a ramp generator for generating a ramp voltage value; wherein, the first end of the first switch is connected with the comparator, and the second end of the first switch is connected with the correction target value generator or the slope generator. On the basis, when the second end of the first switch is connected with the correction target value generator, the infrared reading circuit is used for realizing the function of correcting the state based on the preset voltage value (namely, the function of correcting the state is realized through the cooperation of all modules of the infrared reading circuit); when the second end of the first switch is switched from the corrected target value generator to the ramp generator, the infrared readout circuit is used for realizing a function of reading out the state based on the ramp voltage value (namely, the function of reading out the state is realized through the cooperation of all modules of the infrared readout circuit).

Illustratively, the correction control unit is further used for determining the corresponding state of the infrared reading circuit; after the infrared reading circuit is powered on and started, the infrared reading circuit is correspondingly corrected; and after the optimal values of the correction parameters corresponding to all the pixels are determined, the infrared reading circuit correspondingly reads the state. Based on this, when the infrared readout circuit corresponds to the correction state, the correction control unit controls the second end of the first switch to be connected with 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 for realizing the function of correcting the state based on the preset voltage value. When the infrared reading circuit is in a corresponding reading state, the correction control unit controls the second end of the first switch to be connected with the ramp generator, so that the comparator obtains a ramp voltage value from the ramp generator, and the infrared reading circuit is used for achieving a state reading function based on the ramp voltage value.

Illustratively, when the infrared readout circuit corresponds to a readout state, the readout unit is configured to determine a voltage response value corresponding to the pixel based on a target bias 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 for acquiring a ramp voltage value from the ramp generator, and comparing the voltage response value with the ramp voltage value to obtain a comparison result corresponding to the pixel; wherein the comparison result can be used to determine the voltage output value corresponding to the pixel.

Illustratively, the analog-to-digital converter includes a counter, a second register, a second switch, and a data output unit; and the first end of the second switch is connected with the counter, when the infrared reading circuit corresponds to the correction state, the second end of the second switch is connected with the ground end so as to stop the counter, and when the infrared reading circuit corresponds to the reading state, the second end of the second switch is connected with the internal clock so as to start the counter to count. Based on this, the ramp generator is used for generating a plurality of ramp voltage values from the initial ramp voltage value; the comparator is used for comparing the voltage response value with each ramp voltage value to obtain a comparison result corresponding to each ramp voltage value, and 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 for counting the clock pulse to obtain a count value; the second register is used for storing a target count value corresponding to the target ramp voltage value; the target ramp voltage value is a first one of the plurality of ramp voltage values that is greater than the voltage response value; the target count value is a count value when the ramp generator generates the target ramp voltage value; and the data output unit is used for acquiring the target count value from the second register, determining a voltage output value corresponding to the pixel based on the target count value and outputting the voltage output value to the outside.

For example, 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, the readout unit is specifically configured to: and determining a voltage response value corresponding to the pixel based on a first current corresponding to the initial bias voltage value and a second current output by the response temperature value of the pixel.

Illustratively, the infrared readout circuit may further include a digital-to-analog converter corresponding to the pixel group; and the digital-to-analog converter is used for performing digital-to-analog conversion on the parameter value to be corrected corresponding to the pixel to obtain an analog voltage signal, determining a voltage value corresponding to the analog voltage signal as an initial bias voltage value corresponding to the parameter value to be corrected, and inputting the initial bias voltage value to the reading unit.

Illustratively, the correction control unit adjusts the parameter value to be corrected based on the comparison result, and when obtaining the adjusted parameter value, the correction control unit is specifically configured to: if the comparison result is a first value which indicates that the voltage response value is greater than the preset voltage value, reducing the parameter value to be corrected to obtain an adjusted parameter value; and if the comparison result is a second value which indicates that the voltage response value is smaller than the preset voltage value, increasing the parameter value to be corrected to obtain the adjusted parameter value. In a possible embodiment, the correction control unit reduces the value of the parameter to be corrected, and when obtaining the adjusted parameter value, the correction control unit is specifically configured to: subtracting 1 from the parameter value to be corrected to obtain an adjusted parameter value; the correction control unit increases the value of the parameter to be corrected, and when the adjusted parameter value is obtained, the correction control unit is specifically used for: and adding 1 to the parameter value to be corrected to obtain the adjusted parameter value.

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, the correction control unit is specifically configured to: if the adjustment finishing condition of the parameter value to be corrected is met, determining the adjusted parameter value as the optimal value of the correction parameter corresponding to the pixel; or if the adjustment ending condition of the parameter value to be corrected is not met, determining the adjusted parameter value as the parameter value to be corrected corresponding to the pixel.

In a possible implementation manner, the correction control unit is further configured to determine that an adjustment end condition of the parameter value to be corrected is not met if the comparison result of the current comparison period is the first value and the comparison result of the previous comparison period is the first value; or, if the comparison result of the current comparison period is the second value and the comparison result of the previous comparison period is the second value, determining that the adjustment end condition of the parameter value to be corrected is not met; or if the comparison result of the current comparison period is a first value and the comparison result of the last comparison period is a second value, determining that the adjustment end condition of the parameter value to be corrected is met; or if the comparison result of the current comparison period is the second value and the comparison result of the last comparison period is the first value, determining that the adjustment end condition of the parameter value to be corrected is met; and the comparison result is that the first value-taking represents that the voltage response value is greater than the preset voltage value, and the comparison result is that the second value-taking represents that the voltage response value is less than the preset voltage value.

In another possible embodiment, the rectification control unit is further configured to perform an exclusive-or operation on the comparison result of the current comparison period and the comparison result of the previous comparison period; if the result of the XOR operation is 0, determining that the adjustment end condition of the parameter value to be corrected is not met; and if the result of the exclusive-or operation is 1, determining that the adjustment end condition of the parameter value to be corrected is met. Wherein, the comparison result of the current comparison period is a first value or a second value; the comparison result of the last comparison period is the first value or the second value.

Illustratively, the infrared readout circuit may further include a first register corresponding to the pixel group; and the first register is used for storing the parameter value to be corrected corresponding to the pixel.

In one possible embodiment, the infrared array may comprise a plurality of columns of picture elements, each column may comprise a plurality of picture elements, based on which all picture elements of each column may be divided into the same group of picture elements; each pixel group in the K pixel groups corresponds to all pixels in one column.

The systems, devices, modules or units illustrated in the above embodiments may be specifically implemented by computer entities or by products with certain functions. A typical implementation device is a computer, which may take the form of a personal computer, laptop computer, cellular telephone, camera phone, smart phone, personal digital assistant, media player, navigation device, email messaging device, game console, tablet computer, wearable device, or a combination of any of these devices.

For convenience of description, the above devices are described as being divided into various units by function, respectively. Of course, the functionality of the units may be implemented in one or more software and/or hardware when implementing the present application.

As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, embodiments of the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.

The above description is only an example of the present application and is not intended to limit the present application. Various modifications and changes may occur to those skilled in the art to which the present application pertains. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the claims of the present application.

Claims

1. An infrared reading circuit is characterized in that an infrared array comprises K image element groups, K is a positive integer greater than 1, the infrared reading circuit comprises a reading unit, an analog-digital converter and a correction control unit which correspond to the image element groups, and the analog-digital converter comprises a comparator; wherein, for a pixel in the pixel group:

the reading unit is used for determining a voltage response value corresponding to the pixel based on an initial bias value corresponding to the parameter value to be corrected corresponding to the pixel and inputting the voltage response value to the comparator;

2. The infrared readout circuit according to claim 1, wherein said analog-to-digital converter further comprises a first switch, a correction target value generator for generating said preset voltage value, and a ramp generator for generating a ramp voltage value;

wherein a first end of the first switch is connected with the comparator, and a second end of the first switch is connected with the correction target value generator or the slope generator;

when the second end of the first switch is connected with the correction target value generator, the infrared reading circuit is used for realizing the function of correcting the state based on the preset voltage value;

and when the second end of the first switch is switched from the correction target value generator to the ramp generator, the infrared reading circuit is used for realizing a function of reading a state based on the ramp voltage value.

3. The infrared readout circuit of claim 2,

the correction control unit is also used for determining the corresponding state of the infrared reading circuit; after the infrared reading circuit is powered on and started, the infrared reading circuit is correspondingly corrected; after the optimal values of the correction parameters corresponding to all the pixels are determined, the infrared reading circuit correspondingly reads the states;

when the infrared reading circuit corresponds to a correction state, controlling a second end of the first switch to be connected with the correction target value generator so that the comparator obtains the preset voltage value from the correction target value generator, wherein the infrared reading circuit is used for realizing the function of correcting the state based on the preset voltage value;

and when the infrared reading circuit corresponds to a reading state, controlling the second end of the first switch to be connected with the ramp generator so as to enable the comparator to obtain the ramp voltage value from the ramp generator, wherein the infrared reading circuit is used for realizing the function of reading the state based on the ramp voltage value.

4. The infrared readout circuit of claim 3,

when the infrared readout circuit corresponds to a readout state,

the reading unit is used for determining a voltage response value corresponding to the pixel based on a target bias voltage value corresponding to the optimal value of the correction parameter corresponding to the pixel, and inputting the voltage response value to the comparator;

the comparator is used for acquiring the ramp voltage value from the ramp generator and comparing the voltage response value with the ramp voltage value to obtain a comparison result corresponding to the pixel; and the comparison result is used for determining the voltage output value corresponding to the pixel.

5. The infrared readout circuit according to claim 4, wherein said analog-to-digital converter comprises a counter, a second register, a second switch, and a data output unit; the first end of the second switch is connected with the counter, when the infrared reading circuit corresponds to a correction state, the second end of the second switch is connected with a ground end so as to stop the counter, and when the infrared reading circuit corresponds to a reading state, the second end of the second switch is connected with an internal clock so as to start the counter to count;

the ramp generator is used for generating a plurality of ramp voltage values from an initial ramp voltage value; the comparator is used for comparing 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 for counting the clock pulse to obtain a count value;

the second register is used for storing a target count value corresponding to the target ramp voltage value; the target ramp voltage value is a ramp voltage value for which a first one of the plurality of ramp voltage values is greater than the voltage response value; the target count value is a count value at which the ramp generator generates the target ramp voltage value;

and the data output unit is used for acquiring the target count value from the second register, determining a voltage output value corresponding to the pixel based on the target count value, and outputting the voltage output value to the outside.

6. An infrared readout circuit according to any of claims 1 to 5, wherein the readout unit is specifically configured to, when determining the voltage response value corresponding to the picture element based on the initial bias voltage value corresponding to the value of the parameter to be corrected corresponding to the picture element: determining the voltage response value corresponding to the pixel based on a first current corresponding to the initial bias voltage value and a second current output by the response temperature value of the pixel;

the infrared reading circuit comprises a digital-to-analog converter corresponding to the pixel group;

the digital-to-analog converter is used for performing digital-to-analog conversion on the parameter value to be corrected corresponding to the pixel to obtain an analog voltage signal, determining a voltage value corresponding to the analog voltage signal as an initial bias voltage value corresponding to the parameter value to be corrected, and inputting the initial bias voltage value to the reading unit.

7. Infrared readout circuit according to one of claims 1 to 5,

the correction control unit adjusts the parameter value to be corrected based on the comparison result, and when the adjusted parameter value is obtained, the correction control unit is specifically configured to: if the comparison result is a first value which indicates that the voltage response value is greater than the preset voltage value, reducing the parameter value to be corrected to obtain an adjusted parameter value; and if the comparison result is a second value which indicates that the voltage response value is smaller than the preset voltage value, increasing the parameter value to be corrected to obtain an adjusted parameter value.

8. The infrared readout circuit of claim 7,

the correction control unit reduces the parameter value to be corrected, and when the adjusted parameter value is obtained, the correction control unit is specifically used for: subtracting 1 from the parameter value to be corrected to obtain an adjusted parameter value;

the correction control unit increases the parameter value to be corrected, and when the adjusted parameter value is obtained, the correction control unit is specifically used for: and adding 1 to the parameter value to be corrected to obtain an adjusted parameter value.

9. Infrared readout circuit according to one of claims 1 to 5,

the correction control unit is specifically configured to, when determining the optimum value of the correction parameter corresponding to the pixel based on the adjusted parameter value: if the adjustment ending condition of the parameter values to be corrected is met, determining the adjusted parameter values as the optimal values of the correction parameters corresponding to the pixels; or if the adjustment ending condition of the parameter value to be corrected is not met, determining the adjusted parameter value as the parameter value to be corrected corresponding to the pixel.

10. The infrared readout circuit of claim 9, wherein the correction control unit is further configured to determine that an adjustment end condition of the parameter value to be corrected is not satisfied if the comparison result of the current comparison period is the first value and the comparison result of the previous comparison period is the first value; or, if the comparison result of the current comparison period is the second value and the comparison result of the previous comparison period is the second value, determining that the adjustment end condition of the parameter value to be corrected is not met; or if the comparison result of the current comparison period is a first value and the comparison result of the last comparison period is a second value, determining that the adjustment end condition of the parameter value to be corrected is met; or if the comparison result of the current comparison period is the second value and the comparison result of the last comparison period is the first value, determining that the adjustment end condition of the parameter value to be corrected is met;

and the comparison result is that a first value is taken to indicate that the voltage response value is greater than the preset voltage value, and the comparison result is taken to indicate that the voltage response value is less than the preset voltage value.

11. The infrared readout circuit of claim 9, wherein the calibration control unit is further configured to perform an exclusive-or operation on the comparison result of the current comparison period and the comparison result of the previous comparison period; if the result of the XOR operation is 0, determining that the adjustment end condition of the parameter value to be corrected is not met; if the result of the XOR operation is 1, determining that the adjustment end condition of the parameter value to be corrected is met;

wherein, the comparison result of the current comparison period is a first value or a second value;

the comparison result of the last comparison period is the first value or the second value.

12. Infrared readout circuit according to one of claims 1 to 5,

the infrared reading circuit comprises a first register corresponding to the pixel group;

and the first register is used for storing the parameter value to be corrected corresponding to the pixel.

13. The infrared readout circuit of any of claims 1-5 wherein the infrared array comprises a plurality of columns of picture elements, each column comprising a plurality of picture elements, all picture elements of each column being divided into the same group of picture elements; wherein each pixel group in the K pixel groups corresponds to all pixels in a column.