Infrared channel low-temperature-difference object imaging method, device and circuit and storage medium

Abstract

The embodiment of the invention provides an infrared channel low-temperature-difference object imaging method, device and circuit and a storage medium. The method comprises the following steps: when an infrared detector detects an infrared signal of a to-be-detected object, converting the infrared signal into a voltage signal; the voltage signal is calibrated through the signal conditioning circuit to compensate the measurement error; performing isolation processing on the calibrated voltage signal through a first isolation circuit, and identifying the maximum voltage value in the isolated voltage signal through a peak detection circuit; an analog-to-digital converter matched with the signal acquisition circuit is determined according to the range where the maximum voltage value is located, so that the analog-to-digital converter of the signal acquisition circuit is switched; converting the voltage signal into a corresponding digital signal through a signal acquisition circuit; determining a gray value mapping function according to the maximum voltage value and the digital signal, and converting the digital signal into image gray value data based on the gray value mapping function; and generating a grayscale image of the to-be-measured object according to the image grayscale value data.

Description

Technical Field

[0001] The present application relates to the field of photoelectric detection technology, and specifically to an infrared channel low temperature difference object imaging method, device, circuit, storage medium and computer program product. Background Art

[0002] Infrared imaging technology is a non-contact imaging technology that uses infrared radiation naturally emitted or reflected by objects. This technology relies on infrared detectors to capture infrared energy emitted by objects of different temperatures and convert it into visual images. Infrared imaging technology has been widely used due to its unique advantages in normal or high temperature environments. For example, at night or in low light conditions, infrared imaging technology can be used for night vision monitoring to help security personnel identify potential security threats. In the industrial field, thermal imaging diagnostic technology uses infrared imaging to detect hot spots in equipment and predict potential failures and maintenance needs. In addition, infrared imaging also plays an important role in medical, scientific research, military and other fields.

[0003] However, when it comes to low-temperature environments, infrared imaging technology faces a series of challenges. In low-temperature environments, the temperature difference between objects is often very small, which poses a problem for traditional infrared imaging technology. Due to the small temperature gradient, the contrast of infrared images is reduced, resulting in reduced recognition of object details and boundaries. In this case, even small temperature changes may carry important information, but traditional infrared imaging systems cannot effectively capture and display this information. This low-contrast image limits the application of infrared imaging in cold chain logistics, food storage, transmission line icing monitoring and other fields, which often require accurate monitoring of low-temperature objects. For example, icing is a common phenomenon in transmission lines in cold climates, which can cause the weight of the conductors to increase, the elasticity to decrease, and even cause serious accidents such as line breakage. Therefore, real-time monitoring of icing conditions is of vital importance to ensure the stable operation of the power system. However, in the field of transmission line icing monitoring, due to the small temperature difference between the icing and the conductor, it is difficult for the infrared imaging system to clearly depict the outline and thickness of the icing, which affects the staff's accurate judgment of the icing condition. Secondly, in low-temperature environments, the thermal properties of ice and wires are similar, making it difficult for infrared imaging systems to distinguish between ice and wires, and thus unable to provide quantitative analysis of ice thickness. In addition, due to the influence of factors such as atmospheric humidity and wind speed in low-temperature environments, infrared images may be noisy, further reducing the reliability of monitoring data. Therefore, there is an urgent need to enhance the quality of infrared imaging, improve the contrast and resolution of infrared images, and contribute to safe production in industries such as power systems. Summary of the invention

[0004] The purpose of the embodiments of the present application is to provide an infrared channel low temperature difference object imaging method, device, circuit, storage medium and computer program product to solve the problem of difficulty in imaging objects with small temperature gradients between objects in a low temperature environment in the prior art infrared imaging technology.

[0005] In order to achieve the above-mentioned purpose, the first aspect of the present application provides an infrared channel low temperature difference object imaging method, which is applied to a low temperature difference object imaging circuit. The low temperature difference object imaging circuit includes an infrared detector, a signal conditioning circuit, a signal monitoring circuit and a signal acquisition circuit. The infrared detector is connected in series with the signal conditioning circuit. The signal monitoring circuit is connected in parallel with the signal acquisition circuit and then connected in series with the signal conditioning circuit. The signal monitoring circuit includes a first isolation circuit and a peak detection circuit. The first isolation circuit includes a voltage follower. The peak detection circuit includes an operational amplifier, a diode and a capacitor. The signal acquisition circuit includes a second isolation circuit and a digital-to-analog conversion module. The digital-to-analog conversion module includes a plurality of analog-to-digital converters connected in parallel and with different ranges. Each analog-to-digital converter is connected in series with an electronic switch. The method includes:

[0006] When the infrared detector detects the infrared signal of the object to be measured, the infrared signal is converted into a voltage signal;

[0007] inputting the voltage signal into a signal conditioning circuit so as to calibrate the voltage signal through the signal conditioning circuit to compensate for the measurement error;

[0008] Inputting the calibrated voltage signal into the signal monitoring circuit to isolate the voltage signal through the first isolation circuit, and identifying the maximum voltage value in the isolated voltage signal through the peak detection circuit;

[0009] Determine the analog-to-digital converter matched with the signal acquisition circuit according to the range where the maximum voltage value is located, so as to switch the analog-to-digital converter of the signal acquisition circuit by controlling the closing of an electronic switch connected in series with the matched analog-to-digital converter;

[0010] Inputting the voltage signal into the signal acquisition circuit so as to convert the voltage signal into a corresponding digital signal through the signal acquisition circuit;

[0011] Determine a grayscale value mapping function according to the maximum voltage value and the digital signal, so as to convert the digital signal into image grayscale value data based on the grayscale value mapping function;

[0012] Generate a grayscale image of the object to be measured based on the image grayscale value data.

[0013] In an embodiment of the present application, the infrared detector is equipped with a first reference power supply, which includes a voltage reference chip. The method also includes: when the infrared detector is in a dark environment or does not detect the infrared signal of the object to be measured, supplying voltage to the infrared detector through the first reference power supply; recording the output voltage of the infrared detector as a basic offset; and calculating the offset error based on the output voltage and a preset reference voltage to calibrate the voltage signal of the infrared detector to compensate for the measurement error.

[0014] In an embodiment of the present application, the signal conditioning circuit includes a second reference power supply and a compensation circuit, the second reference power supply includes a voltage reference chip, the compensation circuit includes a digital potentiometer with multiple series resistors and electronic switches built in, and the voltage signal is input into the signal conditioning circuit to calibrate the voltage signal through the signal conditioning circuit to compensate for the measurement error. The method includes: inputting the voltage signal into the signal conditioning circuit, periodically controlling any electronic switch in the compensation circuit to close, so as to connect each node of the multiple series resistors to the Uw terminal; obtaining the voltage between the Uw terminal and the Ul terminal, so as to calibrate the voltage signal through the voltage to compensate for the measurement error.

[0015] In an embodiment of the present application, a grayscale value mapping function is determined based on a maximum voltage value and a voltage signal, and converting a voltage signal into image grayscale value data based on the grayscale value mapping function includes: when the voltage signal is in an interval formed by a first voltage value and a second voltage value, converting the voltage signal into image grayscale value data by a preset logarithmic exchange function, wherein the first voltage value is less than the second voltage value, and the second voltage value is a first decimal multiple of the maximum voltage value; when the voltage signal is in an interval formed by a second voltage value and a third voltage value, converting the voltage signal into image grayscale value data by a preset linear transformation function, wherein the second voltage value is less than the third voltage value, and the third voltage value is a second decimal multiple of the maximum voltage value; when the voltage signal is in an interval formed by the third voltage value and the maximum voltage value, converting the voltage signal into image grayscale value data by a preset antilogarithmic transformation function.

[0016] In an embodiment of the present application, the method also includes: constructing a neighborhood based on a grayscale image; setting an upper threshold and a lower threshold of the neighborhood; traversing all pixels in the grayscale image to determine whether the grayscale value of each pixel among all pixels is greater than the upper threshold or less than the lower threshold; determining pixels whose grayscale values ​​are greater than the upper threshold or less than the lower threshold as noise points to remove the noise points.

[0017] In an embodiment of the present application, setting the upper threshold and the lower threshold of the neighborhood includes determining the upper threshold and the lower threshold according to formula (1):

[0018]

[0019] Among them, λ1 is the upper threshold, λ2 is the lower threshold, μ is the mean gray value of pixels in the neighborhood, σ is the standard deviation of the gray value of pixels in the neighborhood, and α is a constant.

[0020] The second aspect of the present application provides a device for imaging low temperature difference objects in an infrared channel, comprising:

[0021] a memory configured to store instructions;

[0022] The processor is configured to call the instructions from the memory and implement the above-mentioned infrared channel low temperature difference object imaging method when executing the instructions.

[0023] A third aspect of the present application provides an infrared channel low temperature difference object imaging circuit, comprising:

[0024] The infrared detector is connected in series with the signal conditioning circuit and is used to convert the infrared signal into a voltage signal when the infrared signal of the object to be detected is detected;

[0025] A signal conditioning circuit, used for calibrating the voltage signal to compensate for measurement errors;

[0026] The signal monitoring circuit is connected in parallel with the signal acquisition circuit and then in series with the signal conditioning circuit, and includes a first isolation circuit and a peak detection circuit. The first isolation circuit includes a voltage follower, and the peak detection circuit includes an operational amplifier, a diode and a capacitor. The signal monitoring circuit is used to isolate the voltage signal through the first isolation circuit, and identify the maximum voltage value in the isolated voltage signal through the peak detection circuit;

[0027] The signal acquisition circuit includes a second isolation circuit and a digital-to-analog conversion module, wherein the digital-to-analog conversion module includes a plurality of analog-to-digital converters connected in parallel and having different ranges, each analog-to-digital converter being connected in series with an electronic switch for converting a voltage signal into a corresponding digital signal;

[0028] The above-mentioned device for imaging low-temperature difference objects in the infrared channel.

[0029] A fourth aspect of the present application provides a machine-readable storage medium having instructions stored thereon, which, when executed by a processor, configures the processor to execute the above-mentioned infrared channel low temperature difference object imaging method.

[0030] A fifth aspect of the present application provides a computer program product, including a computer program, which, when executed by a processor, implements the above-mentioned infrared channel low temperature difference object imaging method.

[0031] The above technical solution converts the detected infrared signal into a voltage signal through an infrared detector, then identifies the maximum voltage value of the voltage signal through a signal monitoring circuit, adaptively selects an analog-to-digital converter with a suitable range, thereby improving the resolution of voltage acquisition, and matches the acquired digital signal with a predefined grayscale value mapping table to generate corresponding grayscale value data. This method improves the resolution of infrared imaging technology for low-temperature difference objects and can provide clear and reliable infrared images for various engineering fields.

[0032] Other features and advantages of the embodiments of the present application will be described in detail in the subsequent specific implementation section. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The accompanying drawings are used to provide a further understanding of the embodiments of the present application and constitute a part of the specification. Together with the following specific implementations, they are used to explain the embodiments of the present application, but do not constitute a limitation on the embodiments of the present application. In the accompanying drawings:

[0034] Figure 1 A schematic diagram of an application environment of an infrared channel low temperature difference object imaging method according to an embodiment of the present application is schematically shown;

[0035] Figure 2 A schematic diagram of a process of an infrared channel low temperature difference object imaging method according to an embodiment of the present application is schematically shown;

[0036] Figure 3 A schematic diagram of a compensation circuit according to an embodiment of the present application is shown;

[0037] Figure 4 A gray value mapping function diagram according to an embodiment of the present application is schematically shown;

[0038] Figure 5 A schematic diagram of a 3*3 neighborhood of an infrared grayscale image according to an embodiment of the present application is schematically shown;

[0039] Figure 6 The internal structure diagram of a computer device according to an embodiment of the present application is schematically shown. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. It should be understood that the specific implementation methods described herein are only used to illustrate and explain the embodiments of the present application, and are not used to limit the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0041] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present application, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of such features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0042] The infrared channel low temperature difference object imaging method provided in this application can be applied to Figure 1 In the application environment shown in the figure. Figure 1 As shown, a schematic diagram of an infrared channel low temperature difference object imaging circuit is provided, and the infrared channel low temperature difference object imaging circuit includes an infrared detector, a signal conditioning circuit, a signal monitoring circuit and a signal acquisition circuit. Among them, the infrared detector is connected in series with the signal conditioning circuit, and the signal monitoring circuit is connected in parallel with the signal acquisition circuit and then connected in series with the signal conditioning circuit. The infrared detector can be used to convert the infrared signal into a voltage signal when the infrared signal of the object to be measured is detected. The signal conditioning circuit can be used to calibrate the voltage signal to compensate for the measurement error. The signal monitoring circuit includes a first isolation circuit and a peak detection circuit, the first isolation circuit includes a voltage follower, the peak detection circuit includes an operational amplifier, a diode and a capacitor, and the signal monitoring circuit can be used to isolate and process the voltage signal through the first isolation circuit, and identify the maximum voltage value in the isolated voltage signal through the peak detection circuit. The signal acquisition circuit includes a second isolation circuit and a digital-to-analog conversion module, and the digital-to-analog conversion module includes a plurality of analog-to-digital converters in parallel with different ranges, each analog-to-digital converter is connected in series with an electronic switch, and can be used to convert the voltage signal into a corresponding digital signal.

[0043] It should be noted that the processor may be a microprocessor, which may be connected in series with the signal monitoring circuit and the signal acquisition circuit connected in parallel, and the processor may be an FPGA chip of model XC7A100T. An FPGA chip may refer to a programmable logic chip, which may realize various digital circuit functions such as digital signal processing, image processing, communication protocol, control system, etc. at the hardware level.

[0044] Figure 2 The following schematically shows a flow chart of a method for imaging low temperature difference objects in an infrared channel according to an embodiment of the present application. Figure 2 As shown, an embodiment of the present application provides an infrared channel low temperature difference object imaging method, which can be applied to an infrared channel low temperature difference object imaging circuit, and the method may include the following steps:

[0045] Step 201: When the infrared detector detects an infrared signal of the object to be detected, the infrared signal is converted into a voltage signal.

[0046] In the embodiments of the present application, it should be noted that an infrared detector may refer to a device that can convert an incident infrared radiation signal into an electrical signal output. Infrared radiation is an electromagnetic wave with a wavelength between visible light and microwaves, which is imperceptible to the human eye. In order to detect and measure the existence and intensity of this radiation, it is usually necessary to convert it into a measurable physical quantity. Modern infrared detectors mainly utilize infrared thermal effects and photoelectric effects, the output of which is usually electrical quantity, or can be converted into electrical quantity by appropriate methods. In the present technical solution, when the infrared detector detects the infrared signal of the object to be measured, it can convert the infrared signal into a voltage signal for output.

[0047] In an embodiment of the present application, the infrared detector is equipped with a first reference power supply, which includes a voltage reference chip. The method also includes: when the infrared detector is in a dark environment or does not detect the infrared signal of the object to be measured, supplying voltage to the infrared detector through the first reference power supply; recording the output voltage of the infrared detector as a basic offset; calculating the offset error based on the output voltage and the preset reference voltage to calibrate the voltage signal of the infrared detector to compensate for the measurement error.

[0048] In this embodiment, it should be noted that the infrared detector may have a measurement error, and the voltage signal output by the infrared detector may not be accurate. Therefore, in order to compensate for the measurement error caused by the infrared detector, the voltage signal output by the infrared detector can be calibrated by building a reference power supply into the infrared detector or by installing an external reference power supply. Among them, the reference power supply can refer to providing a relatively stable voltage or current in the circuit as a comparison benchmark for the stable operation of other components. The voltage reference chip is an integrated circuit that provides a stable and accurate reference voltage, which is mainly used to calibrate the voltage in other circuits to ensure that the voltage in the entire system remains stable and accurate. Therefore, in this technical solution, a voltage reference chip can be selected as a built-in reference power supply for the infrared detector. Specifically, when the infrared detector is in a dark environment or the infrared signal of the object to be measured is not detected, the voltage can be transmitted to the infrared detector through the voltage reference chip. The output voltage of the infrared detector is recorded as a basic offset. Thus, the processor can calculate the offset error based on the output voltage and the preset reference voltage to calibrate the voltage signal of the infrared detector to compensate for the measurement error.

[0049] Step 202 , inputting the voltage signal into a signal conditioning circuit, so as to calibrate the voltage signal through the signal conditioning circuit to compensate for the measurement error.

[0050] In the embodiments of the present application, it should be noted that the infrared detector may have measurement errors, and the voltage signal output by it may not be accurate. Therefore, in order to compensate for the measurement errors caused by the infrared detector, the voltage signal output by the infrared detector can be calibrated by building a reference power supply into the infrared detector or by installing an external reference power supply. In the present technical solution, the external reference power supply can be deployed in the signal conditioning circuit, so that the processor can input the voltage signal output by the infrared detector into the signal conditioning circuit, so as to calibrate the voltage signal through the signal conditioning circuit to compensate for the measurement error.

[0051] In an embodiment of the present application, the signal conditioning circuit includes a second reference power supply and a compensation circuit, the second reference power supply includes a voltage reference chip, the compensation circuit includes a digital potentiometer with multiple series resistors and electronic switches built in, and the voltage signal is input into the signal conditioning circuit to calibrate the voltage signal through the signal conditioning circuit to compensate for the measurement error. The method includes: inputting the voltage signal into the signal conditioning circuit, periodically controlling any electronic switch in the compensation circuit to close, so as to connect each node of the multiple series resistors to the Uw terminal; obtaining the voltage between the Uw terminal and the Ul terminal, so as to calibrate the voltage signal through the voltage to compensate for the measurement error.

[0052] In this embodiment, it should be noted that the signal conditioning circuit includes a second reference power supply and a compensation circuit. The second reference power supply may refer to a voltage reference chip, and the compensation circuit includes a digital potentiometer with multiple series resistors and electronic switches built in. The digital potentiometer may refer to an electronic component that controls the resistance value through a digital signal, also known as a digitally controlled programmable resistor or a resistive digital-to-analog converter (DAC).

[0053] like Figure 3As shown, a schematic diagram of a compensation circuit is provided. The compensation circuit can be selected as a digital potentiometer, and n resistors with the same resistance value are connected in series. The two ends of each resistor are connected through an electronic switch, and the electronic switches L1 to Ln can be MOSFET tubes. Among them, MOSFET tubes can refer to a semiconductor device, also known as metal oxide semiconductor field effect transistors or insulated gate field effect transistors. MOSFET tubes are mainly composed of metal (M), oxide (O) and semiconductor (S), and control the conduction and cutoff of current through electric field effects. Its working principle is to control the width of the conductive channel between the source and the drain by changing the gate voltage, thereby realizing the control of current. After the processor inputs the voltage signal to the signal conditioning circuit, only one electronic switch is closed at a time under the control of the digital signal, thereby connecting each node of the series resistor to the Uw terminal. The voltage between the Uw terminal and the Ul terminal is obtained, and the voltage between the Uw terminal and the Ul terminal is used as the compensation voltage of the voltage signal output by the infrared detector, thereby compensating for the measurement error of the infrared detector. Among them, the Uw terminal and the Ul terminal represent different wavelengths and transmission characteristics in optical fiber communication. The Uw end usually refers to a port that uses a longer wavelength optical signal for transmission, usually with a wavelength of around 1310nm. When an optical signal of this wavelength is transmitted in an optical fiber, it has a smaller attenuation, which is suitable for long-distance transmission and is often used in trunk transmission and metropolitan area network transmission. The Ul end refers to a port that uses a shorter wavelength optical signal for transmission, usually with a wavelength of around 1550nm. The optical signal of this wavelength has a greater attenuation in the optical fiber, but is suitable for short-distance transmission and high-speed transmission, and is often used in access network and local area network transmission.

[0054] Step 203, inputting the calibrated voltage signal into the signal monitoring circuit, isolating the voltage signal through the first isolation circuit, and identifying the maximum voltage value in the isolated voltage signal through the peak detection circuit.

[0055] In the embodiments of the present application, it should be noted that the isolation circuit may refer to a circuit that completely isolates the input and output circuits by physical means. It transmits the signal to the output end by using an isolation element and simultaneously blocks the conduction of current or interfering substances. The isolation circuit can achieve signal transmission and power isolation, thereby providing higher safety and reliability. In this technical solution, if Figure 2 As shown, the signal monitoring circuit includes a first isolation circuit and a peak detection circuit. The first isolation circuit may include a voltage follower. The voltage follower plays a role in isolating the signal, so that the signal monitoring circuit does not affect the voltage signal output by the infrared detector. The peak detection circuit may refer to an electronic circuit for measuring the maximum value (positive peak value) or minimum value (negative peak value) in a signal waveform, usually composed of a diode and a capacitor. In the present technical solution, if Figure 2As shown, the peak detection circuit includes an operational amplifier, a diode and a capacitor, and the operational amplifier can be an operational amplifier of model OPA350EA. The processor can input the calibrated voltage signal to the signal monitoring circuit to isolate the voltage signal through the first isolation circuit, and then identify the maximum voltage value in the isolated voltage signal through the peak detection circuit.

[0056] Step 204, determining the analog-to-digital converter matched with the signal acquisition circuit according to the range of the maximum voltage value, and switching the analog-to-digital converter of the signal acquisition circuit by controlling the electronic switch connected in series with the matched analog-to-digital converter to close.

[0057] In the embodiment of the present application, it should be noted that the digital-to-analog converter is also called a D / A converter, referred to as DAC, and may refer to a device that can convert digital quantities into analog. The D / A converter is basically composed of four parts, namely a weighted resistor network, an operational amplifier, a reference power supply and an analog switch. A digital-to-analog converter is generally used in an analog-to-digital converter, and the analog-to-digital converter is an A / D converter, referred to as ADC, which is a device that converts a continuous analog signal into a discrete digital signal. In the present technical solution, the signal acquisition circuit may include a second isolation circuit and a digital-to-analog conversion module, and the digital-to-analog conversion module includes a plurality of analog-to-digital converters ADC connected in parallel and with different ranges, and each analog-to-digital converter is connected in series with an electronic switch. The second isolation circuit may include a voltage follower, and the voltage follower plays the role of isolating the signal so that the signal monitoring circuit does not affect the voltage signal output by the infrared detector.

[0058] like Figure 2 As shown, in the present technical solution, the digital-to-analog conversion module can be composed of three 8-bit analog-to-digital converters ADC1, ADC2 and ADC3. The analog-to-digital converters ADC1, ADC2 and ADC3 are respectively connected in series with the electronic switches K1, K2 and K3. The electronic switches K1, K2 and K3 can be selected as MOSFET tubes. The ranges of the analog-to-digital converters ADC1, ADC2 and ADC3 are 0 to 2.5V, 0 to 3.3V and 0 to 5V respectively. Therefore, the resolutions of ADC1, ADC2 and ADC3 can be:

[0059]

[0060] If the range of the voltage signal to be collected is 0 to 2.5V, ADC1 can be selected to collect voltage data, which can increase the resolution by 1.3 times compared with selecting ADC2 to collect voltage signals, and can increase the resolution by 2 times compared with selecting ADC3 to collect voltage signals.

[0061] Therefore, after obtaining the maximum voltage value of the voltage signal output by the infrared detector, the processor can determine the analog-to-digital converter that matches the signal acquisition circuit according to the range of the maximum voltage value, so as to switch the analog-to-digital converter of the signal acquisition circuit by controlling the closing of the electronic switch in series with the matching analog-to-digital converter.

[0062] Step 205 , input the voltage signal to the signal acquisition circuit, so as to convert the voltage signal into a corresponding digital signal through the signal acquisition circuit.

[0063] In the embodiment of the present application, it should be noted that the voltage signal output by the infrared detector is a continuously changing analog signal, which can take an infinite number of values ​​within a range. In the present technical solution, discrete numerical values ​​are required for subsequent calculations, so the voltage signal needs to be converted into a corresponding digital signal. Specifically, after the processor switches the analog-to-digital converter of the signal acquisition circuit to respond according to the range of the maximum voltage value obtained, the processor can further input the voltage signal into the signal acquisition circuit to convert the voltage signal into a corresponding digital signal through the signal acquisition circuit.

[0064] Step 206 , determining a grayscale value mapping function according to the maximum voltage value and the digital signal, so as to convert the digital signal into image grayscale value data based on the grayscale value mapping function.

[0065] In the embodiment of the present application, it should be noted that the gray value data refers to the brightness or gray level of each pixel in the black and white image. In digital image processing, the gray value usually represents the brightness intensity of the pixel, which ranges from 0 to 255, where 0 represents the darkest black and 255 represents the brightest white. The higher the gray value, the brighter the pixel; the lower the gray value, the darker the pixel. After obtaining the maximum voltage value output by the signal monitoring circuit and the digital signal output by the signal acquisition circuit, the processor can further determine the gray value mapping function according to the maximum voltage value and the digital signal, thereby further converting the digital signal into image gray value data based on the gray value mapping function.

[0066] In an embodiment of the present application, a grayscale value mapping function is determined based on the maximum voltage value and the voltage signal, and converting the voltage signal into image grayscale value data based on the grayscale value mapping function includes: when the voltage signal is in an interval formed by a first voltage value and a second voltage value, converting the voltage signal into image grayscale value data through a preset logarithmic exchange function, wherein the first voltage value is less than the second voltage value, and the second voltage value is a first decimal multiple of the maximum voltage value; when the voltage signal is in an interval formed by the second voltage value and a third voltage value, converting the voltage signal into image grayscale value data through a preset linear transformation function, wherein the second voltage value is less than the third voltage value, and the third voltage value is a second decimal multiple of the maximum voltage value; when the voltage signal is in an interval formed by the third voltage value and the maximum voltage value, converting the voltage signal into image grayscale value data through a preset antilogarithmic transformation function.

[0067] In this embodiment, it should be noted that the first voltage value is less than the second voltage value, the second voltage value is the first decimal multiple of the maximum voltage value, the second voltage value is less than the third voltage value, the third voltage value is the second decimal multiple of the maximum voltage value, the first voltage value may refer to 0V, the first decimal multiple may refer to 0.3, and the second decimal multiple may refer to 0.7. Therefore, taking the maximum voltage value as M as an example, the second voltage value may be 0.3M, and the third voltage value may be 0.7M.

[0068] Specifically, when the voltage signal is in the range of [0, 0.3M), that is, when the voltage signal is greater than or equal to 0 and less than 0.3M, a preset logarithmic exchange function can be selected to convert the voltage signal into image grayscale value data. For example, if the depth of the grayscale image is 8 bits and the maximum value of the voltage signal is 2.5V, then when the voltage signal is 0 to 0.75V, the preset logarithmic exchange function is:

[0069]

[0070] The logarithmic transformation function can enhance the dark details of the grayscale image. The logarithmic base needs to be a real number greater than 1. The logarithmic base is selected according to the dark details of the grayscale image. Here, the base is 2.

[0071] When the voltage signal is in [0.3M, 0.7M], that is, when the voltage signal is greater than or equal to 0.3M and less than or equal to 0.7M, a preset linear transformation function can be selected to convert the voltage signal into image grayscale value data. Specifically, for example, if the depth of the grayscale image is 8 bits, the maximum value of the voltage signal is 2.5V, and when the voltage signal is 0.75 to 1.75V, the preset linear transformation function is:

[0072]

[0073] The linear transformation function can smooth the grayscale image and improve the image visual effect.

[0074] When the voltage signal is in (0.7M, M], that is, when the voltage signal is greater than 0.7M and less than or equal to M, a preset antilogarithmic transformation function can be selected to convert the voltage signal into image grayscale value data. Specifically, for example, if the depth of the grayscale image is 8 bits, the maximum value of the voltage signal is 2.5V, and when the voltage signal is 1.75 to 2.5V, the preset antilogarithmic transformation function is:

[0075]

[0076] The antilogarithmic transformation function can enhance the bright details of the grayscale image. The base of the antilogarithmic transformation function should be the same as the base of the logarithmic transformation function.

[0077] Step 207: Generate a grayscale image of the object to be measured according to the image grayscale value data.

[0078] In the embodiment of the present application, it should be noted that after the processor determines the grayscale value mapping function based on the maximum voltage value and the digital signal, and converts the digital signal into image grayscale value data based on the grayscale value mapping function, it can further generate a grayscale image of the object to be measured based on the image grayscale value data.

[0079] In an embodiment of the present application, the method also includes: constructing a neighborhood based on a grayscale image; setting an upper threshold and a lower threshold of the neighborhood; traversing all pixels in the grayscale image to determine whether the grayscale value of each pixel among all pixels is greater than the upper threshold or less than the lower threshold; determining pixels whose grayscale values ​​are greater than the upper threshold or less than the lower threshold as noise points to remove the noise points.

[0080] In the present embodiment, it should be noted that in image processing, a neighborhood generally refers to a set of pixels around a central pixel. In the present technical solution, there may be many noise points in the obtained grayscale image, thereby affecting the image clarity and quality. Therefore, after obtaining the grayscale image of the infrared image, the image noise points can be further identified and eliminated by the built-in noise reduction algorithm of the processor to improve the clarity and quality of the infrared grayscale image. Specifically, the processor can first construct a neighborhood according to the grayscale image, and set the upper and lower thresholds of the neighborhood, and then traverse all the pixels in the grayscale image to determine whether the grayscale value of each pixel in all the pixels is greater than the upper threshold or less than the lower threshold. If the pixel is greater than the upper threshold or less than the lower threshold, it can be considered as a noise point, and the noise point needs to be removed. If the pixel is greater than or equal to the lower threshold and less than or equal to the upper threshold, it can be considered not to be a noise point, and the pixel needs to be retained.

[0081] In the embodiment of the present application, setting the upper threshold and the lower threshold of the neighborhood includes determining the upper threshold and the lower threshold according to formula (1):

[0082]

[0083] Among them, λ1 is the upper threshold, λ2 is the lower threshold, μ is the mean gray value of pixels in the neighborhood, σ is the standard deviation of the gray value of pixels in the neighborhood, and α is a constant.

[0084] In this embodiment, it should be noted that Figure 5 As shown in Figure 1, a schematic diagram of a 3*3 neighborhood of an infrared grayscale image is provided. Figure 5 As shown in the figure, for a certain point in the infrared grayscale image and its 3*3 neighborhood, the mean, standard deviation, and median of the grayscale values ​​in the neighborhood are solved, and then the noise points are judged and eliminated according to the set threshold. If the grayscale values ​​of each point in the neighborhood are: a0=96, a1=68, a2=78, a3=88, a4=69, a5=92, a6=67, a7=81, a8=79, then the mean μ and standard deviation σ are obtained respectively:

[0085]

[0086] If α=2, the upper and lower thresholds are:

[0087] λ1=μ+α×σ=99.78,

[0088] λ2=μ-α×σ=59.78,

[0089] The gray value of the current pixel is λ1≥a0≥λ2, so the current pixel is not a noise point and is retained.

[0090] If the grayscale values ​​of each point in the neighborhood are: a0 = 128, a1 = 68, a2 = 78, a3 = 88, a4 = 69, a5 = 92, a6 = 67, a7 = 81, a8 = 79, then the mean μ and standard deviation σ are:

[0091]

[0092] If α=2, the upper and lower thresholds are:

[0093] λ1=μ+α×σ=118.93,

[0094] λ2=μ-α×σ=47.73,

[0095] The grayscale value of the current pixel a0≥λ1, so the current pixel is determined to be a noise point, and the grayscale value of the current pixel a0 is modified to the median value of the neighborhood, that is, a0=79.

[0096] Traverse all pixels in the image, execute the above noise reduction algorithm for all pixels whose neighbors can be found, and output the infrared grayscale image after removing the noise.

[0097] The above technical solution converts the detected infrared signal into a voltage signal through an infrared detector, then identifies the maximum voltage value of the voltage signal through a signal monitoring circuit, adaptively selects an analog-to-digital converter with a suitable range, thereby improving the resolution of voltage acquisition, and matches the acquired digital signal with a predefined grayscale value mapping table to generate corresponding grayscale value data. This method improves the resolution of infrared imaging technology for low-temperature difference objects and can provide clear and reliable infrared images for various engineering fields.

[0098] The embodiment of the present application provides a device for imaging low temperature difference objects in an infrared channel, comprising:

[0099] a memory configured to store instructions;

[0100] The processor is configured to call the instructions from the memory and implement the above-mentioned infrared channel low temperature difference object imaging method when executing the instructions.

[0101] An embodiment of the present application provides a machine-readable storage medium having instructions stored thereon. When the instructions are executed by a processor, the processor is configured to execute the above-mentioned infrared channel low temperature difference object imaging method.

[0102] In one embodiment, a computer device is provided. The computer device may be a server, and its internal structure diagram may be as follows: Figure 6 As shown. The computer device includes a processor A01, a network interface A02, a memory (not shown in the figure) and a database (not shown in the figure) connected through a system bus. Among them, the processor A01 of the computer device is used to provide computing and control capabilities. The memory of the computer device includes an internal memory A03 and a non-volatile storage medium A04. The non-volatile storage medium A04 stores an operating system B01, a computer program B02 and a database (not shown in the figure). The internal memory A03 provides an environment for the operation of the operating system B01 and the computer program B02 in the non-volatile storage medium A04. The database of the computer device is used to store infrared channel low temperature difference object imaging method data. The network interface A02 of the computer device is used to communicate with an external terminal through a network connection. When the computer program B02 is executed by the processor A01, an infrared channel low temperature difference object imaging method is implemented.

[0103] Those skilled in the art will understand that Figure 6 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0104] The present application provides a device, which includes a processor, a memory, and a program stored in the memory and executable on the processor. When the processor executes the program, the following steps are implemented:

[0105] The present application also provides a computer program product, which, when executed on a data processing device, is suitable for executing the program steps of the method for initializing infrared channel low temperature difference object imaging.

[0106] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0107] The present application is described with reference to flowcharts and / or block diagrams of methods, devices (systems) and computer program products according to embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0108] These computer program instructions may also be stored in a computer readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture including an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0109] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process in the computer or other programmable device. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0110] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0111] The memory may include non-permanent memory in a computer-readable medium, random access memory (RAM) and / or non-volatile memory in the form of read-only memory (ROM) or flash RAM. The memory is an example of a computer-readable medium.

[0112] Computer readable media include permanent and non-permanent, removable and non-removable media that can be implemented by any method or technology to store information. Information can be computer readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, compact disk read-only memory (CD-ROM), digital versatile disk (DVD) or other optical storage, magnetic cassettes, magnetic tape disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device. As defined herein, computer readable media does not include temporary computer readable media (transitory media), such as modulated data signals and carrier waves.

[0113] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0114] The above are only embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. 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. A method for imaging low temperature difference objects in an infrared channel, characterized in that: The invention is applied to an infrared channel low temperature difference object imaging circuit, wherein the infrared channel low temperature difference object imaging circuit comprises an infrared detector, a signal conditioning circuit, a signal monitoring circuit and a signal acquisition circuit, wherein the infrared detector is connected in series with the signal conditioning circuit, the signal monitoring circuit is connected in parallel with the signal acquisition circuit and then connected in series with the signal conditioning circuit, the signal monitoring circuit comprises a first isolation circuit and a peak detection circuit, the first isolation circuit comprises a voltage follower, the peak detection circuit comprises an operational amplifier, a diode and a capacitor, the signal acquisition circuit comprises a second isolation circuit and a digital-to-analog conversion module, the digital-to-analog conversion module comprises a plurality of analog-to-digital converters connected in parallel and having different ranges, each analog-to-digital converter is connected in series with an electronic switch, and the method comprises: When the infrared detector detects an infrared signal of the object to be detected, converting the infrared signal into a voltage signal; Inputting the voltage signal into the signal conditioning circuit so as to calibrate the voltage signal through the signal conditioning circuit to compensate for measurement errors; Inputting the calibrated voltage signal into the signal monitoring circuit, isolating the voltage signal through the first isolation circuit, and identifying the maximum voltage value in the isolated voltage signal through the peak detection circuit; Determine the analog-to-digital converter matched by the signal acquisition circuit according to the range of the maximum voltage value, so as to switch the analog-to-digital converter of the signal acquisition circuit by controlling the closing of an electronic switch connected in series with the matched analog-to-digital converter; Inputting the voltage signal into the signal acquisition circuit so as to convert the voltage signal into a corresponding digital signal through the signal acquisition circuit; Determine a grayscale value mapping function according to the maximum voltage value and the digital signal, so as to convert the digital signal into image grayscale value data based on the grayscale value mapping function; A grayscale image of the object to be measured is generated according to the image grayscale value data.

2. The infrared channel low temperature difference object imaging method according to claim 1, characterized in that: The infrared detector has a built-in first reference power supply, the first reference power supply includes a voltage reference chip, and the method further includes: When the infrared detector is in a dark environment or does not detect the infrared signal of the object to be detected, supplying voltage to the infrared detector through the first reference power supply; Recording the output voltage of the infrared detector as a basic offset; An offset error is calculated according to the output voltage and a preset reference voltage to calibrate the voltage signal of the infrared detector to compensate for the measurement error.

3. The infrared channel low temperature difference object imaging method according to claim 1, characterized in that: The signal conditioning circuit includes a second reference power supply and a compensation circuit, the second reference power supply includes a voltage reference chip, the compensation circuit includes a digital potentiometer with multiple series resistors and electronic switches built in, and the voltage signal is input into the signal conditioning circuit to calibrate the voltage signal through the signal conditioning circuit to compensate for the measurement error, including: Inputting the voltage signal to the signal conditioning circuit, and periodically controlling any electronic switch in the compensation circuit to close, so as to connect each node of the plurality of series resistors to the Uw terminal; The voltage between the Uw terminal and the Ul terminal is obtained to calibrate the voltage signal by the voltage to compensate for the measurement error.

4. The infrared channel low temperature difference object imaging method according to claim 1, characterized in that: The step of determining a grayscale value mapping function according to the maximum voltage value and the voltage signal, so as to convert the voltage signal into image grayscale value data based on the grayscale value mapping function comprises: When the voltage signal is in an interval formed by a first voltage value and a second voltage value, converting the voltage signal into image grayscale value data by using a preset logarithmic exchange function, wherein the first voltage value is less than the second voltage value, and the second voltage value is a first decimal multiple of the maximum voltage value; When the voltage signal is within the interval formed by the second voltage value and the third voltage value, converting the voltage signal into image grayscale value data by using a preset linear transformation function, wherein the second voltage value is less than the third voltage value, and the third voltage value is a second decimal multiple of the maximum voltage value; When the voltage signal is within the interval formed by the third voltage value and the maximum voltage value, the voltage signal is converted into image grayscale value data by using a preset inverse logarithmic transformation function.

5. The infrared channel low temperature difference object imaging method according to claim 1, characterized in that: The method further comprises: constructing a neighborhood based on the grayscale image; Setting an upper threshold and a lower threshold of the neighborhood; Traversing all pixels in the grayscale image to determine whether the grayscale value of each pixel among all the pixels is greater than the upper threshold or less than the lower threshold; Pixels whose grayscale values ​​are greater than the upper threshold or less than the lower threshold are determined as noise points, so as to remove the noise points.

6. The infrared channel low temperature difference object imaging method according to claim 5, characterized in that: The setting of the upper threshold and the lower threshold of the neighborhood includes determining the upper threshold and the lower threshold according to formula (1): Among them, λ1 is the upper threshold, λ2 is the lower threshold, μ is the mean gray value of pixels in the neighborhood, σ is the standard deviation of the gray value of pixels in the neighborhood, and α is a constant.

7. A device for imaging low temperature difference objects in an infrared channel, characterized in that: include: a memory configured to store instructions; A processor is configured to call the instruction from the memory and implement the infrared channel low temperature difference object imaging method according to any one of claims 1 to 6 when executing the instruction.

8. An infrared channel low temperature difference object imaging circuit, characterized in that: include: The infrared detector is connected in series with the signal conditioning circuit and is used to convert the infrared signal into a voltage signal when the infrared signal of the object to be detected is detected; The signal conditioning circuit is used to calibrate the voltage signal to compensate for measurement errors; A signal monitoring circuit, connected in parallel with the signal acquisition circuit and then in series with the signal conditioning circuit, comprises a first isolation circuit and a peak detection circuit, wherein the first isolation circuit comprises a voltage follower, and the peak detection circuit comprises an operational amplifier, a diode and a capacitor, and the signal monitoring circuit is used to isolate the voltage signal through the first isolation circuit, and identify the maximum voltage value in the isolated voltage signal through the peak detection circuit; The signal acquisition circuit includes a second isolation circuit and a digital-to-analog conversion module, wherein the digital-to-analog conversion module includes a plurality of analog-to-digital converters connected in parallel and having different ranges, each analog-to-digital converter being connected in series with an electronic switch for converting the voltage signal into a corresponding digital signal; The device for imaging low temperature difference objects in the infrared channel according to claim 7.

9. A machine-readable storage medium having instructions stored thereon, characterized in that: When the instruction is executed by a processor, the processor is configured to perform the infrared channel low temperature difference object imaging method according to any one of claims 1 to 6.

10. A computer program product, characterized in that It comprises a computer program, which, when executed by a processor, implements the infrared channel low temperature difference object imaging method as described in any one of claims 1 to 6.

Images