CN108871590B

CN108871590B - Method and device for correcting non-uniform response rate of uncooled infrared focal plane detector

Info

Publication number: CN108871590B
Application number: CN201811101237.3A
Authority: CN
Inventors: 侯莅聪; 朱荣华; 李世杰
Original assignee: Iray Technology Co Ltd
Current assignee: Iray Technology Co Ltd
Priority date: 2018-09-20
Filing date: 2018-09-20
Publication date: 2019-12-17
Anticipated expiration: 2038-09-20
Also published as: CN108871590A

Abstract

The embodiment of the invention discloses a method, a device and equipment for correcting the non-uniform response rate of an uncooled infrared focal plane detector and a computer readable storage medium. The method comprises the steps of calibrating the uncooled infrared focal plane detector at two target calibration temperature points respectively to obtain corresponding responsivity, and determining a responsivity prediction straight line according to two pairs of temperature values and responsivity values; calculating a response rate prediction curve according to the response rate prediction straight line and the response rate error value at each calibration temperature point; calculating the response rate of the uncooled infrared focal plane detector at the current temperature according to the response rate prediction curve; and finally, calculating a response rate correction coefficient of the current temperature according to the response rate and the average response rate of the current temperature. The calibration method provided by the application has the advantages that the working environment is limited, the calibration effect is poor, a large amount of calibration is needed, the time and cost consumption is large, the mass production efficiency of the uncooled infrared focal plane detector is improved, and the universality is high.

Description

method and device for correcting non-uniform response rate of uncooled infrared focal plane detector

Technical Field

the embodiment of the invention relates to the technical field of image processing of uncooled infrared focal plane detectors, in particular to a method, a device and equipment for correcting the non-uniform response rate of an uncooled infrared focal plane detector and a computer readable storage medium.

background

With the development of infrared technology, infrared focal plane array technology has come into play. The detector (including refrigeration type infrared focal plane detector and non-refrigeration infrared focal plane detector) prepared by the technology is one of the infrared detectors with the most advanced technical performance at present, and has wide application in military and civil fields.

The refrigeration type infrared focal plane detector has the advantages of high sensitivity, capability of distinguishing more subtle temperature difference and long detection distance, but has a complex structure and high cost, and is mainly applied to high-end military equipment. The uncooled infrared focal plane detector does not need a refrigerating device, can work at room temperature, and has the advantages of quick start, low power consumption, small volume, light weight, long service life, low cost and the like. Although the uncooled infrared focal plane detector has certain difference with a refrigerating device in sensitivity, through development of more than ten years, the uncooled infrared focal plane detector is obviously superior to a refrigerating detector in cost performance, and has wider application prospect.

However, due to the limitations of the semiconductor materials and the processing technology for manufacturing the devices, the output responses of the uncooled infrared focal plane detectors are different, and the non-uniformity of the infrared focal plane array response is caused. The non-uniformity of the response directly affects the definition of the final output image of the detector, which becomes a bottleneck for further improving the image quality and limits the application of the infrared imaging system to a certain extent.

In essence, to thoroughly solve the non-uniformity problem of the uncooled infrared focal plane array response, the level of the processing technology of the uncooled infrared focal plane array must be improved. However, it is difficult to ensure the uniformity of the response output of each detection unit of the uncooled infrared focal plane array under the current development of various disciplines. The nonuniformity is effectively reduced or removed through the nonuniformity correction technology, and the method becomes the key point for improving the imaging quality of the uncooled infrared focal plane array.

The existing non-uniformity correction method is generally based on an algorithm of a calibration technology, that is, a method for calibrating an infrared focal plane by using uniform high-temperature and low-temperature blackbodies in a laboratory so as to calculate a gain and an offset coefficient, such as a two-point method, an extended two-point method, a multi-point calibration look-up table method and a multi-point calibration fitting method.

the two-point method and the extended two-point method calculate the correction parameters of the linear function of each detector unit according to calibration data by calibrating two-point output voltages with different input energies. When the detector is used, each detector unit is output after being corrected by the first-order function. Although the algorithm is simple in structure and easy to implement by hardware, the algorithm has no capability of compensating the differential drift of each detection element, and the uncooled focal plane detector has no capability of compensating the drift caused by the temperature change of the detector, so that the working temperature range of the detector is narrow, and the temperature of the working environment of the detector is generally limited in order to reduce the error of the algorithm.

The multi-point calibration lookup table method is to put the uncooled infrared detector into a high-low temperature control box, perform calibration once at intervals of temperature (for example, the temperature is less than 5 ℃), and record the temperature value and calibration value of the detector. When the temperature sensor is used, the calibration value is searched according to the temperature value of the detector for compensation calculation. The multipoint calibration fitting method is to put the uncooled infrared detector into a high-low temperature control box, perform calibration once at intervals of temperature (for example, the temperature is less than 5 ℃), record the temperature value and the calibration value of the detector, and then fit the calibration data to obtain a fitting curve. When the temperature compensation device is used, the compensation value of the current temperature detector is calculated according to the temperature value of the detector and the fitted curve, and then compensation calculation is carried out. Because each detector needs to calibrate a large amount of data in advance, a large amount of external storage Flash and internal storage DDR are occupied, and calibration test also needs long time and a plurality of high and low temperature control boxes and blackbody equipment. The large-capacity external memory Flash and the internal memory DDR can improve the cost of the whole system, the mass production efficiency of the detector is low due to the calibration of a large amount of data, the production cost efficiency is improved if multiple sets of equipment are added, and the efficiency is not improved.

disclosure of Invention

the embodiment of the invention aims to provide a method, a device, equipment and a computer readable storage medium for correcting the non-uniform response rate of an uncooled infrared focal plane detector, which not only overcome the defects of limited working environment and poor correction effect of the existing two-point calibration method and the extended two-point calibration method, but also solve the problem of large time and cost consumption caused by the large amount of calibration required by the multi-point calibration method, do not limit the working environment temperature of the uncooled infrared focal plane detector, are favorable for improving the mass production efficiency of the uncooled infrared focal plane detector and have strong universality.

in order to solve the above technical problems, embodiments of the present invention provide the following technical solutions:

The embodiment of the invention provides a method for correcting the non-uniform response rate of an uncooled infrared focal plane detector, which comprises the following steps:

Obtaining the response rates of the uncooled infrared focal plane detector calibrated at two target calibration temperature points, and calculating a response rate prediction straight line of the response rate changing along with the temperature;

Calculating a response rate prediction curve according to the response rate prediction straight line and pre-stored response rate error values of all calibration temperature points;

Calculating the response rate of the uncooled infrared focal plane detector at the current temperature of a working interval determined by the two target calibration temperature points according to the response rate prediction curve;

calculating a response rate correction coefficient of the current temperature according to the response rate and the average response rate of the current temperature;

the response rate error value is a difference value between the response rate predicted by the response rate prediction straight line and the corresponding actual response rate at the same calibration temperature point, and is uniquely corresponding to the characteristic of the uncooled infrared focal plane detector; the average response rate is obtained by summing and averaging the response rates of all pixels of the uncooled infrared focal plane detector at the current temperature.

Optionally, the calculating a response rate correction coefficient of the current temperature according to the response rate of the current temperature and the average response rate includes:

Calculating a response rate correction coefficient for the current temperature according to the following formula:

K_[ij]＝SiTF_avg/SiTF_[ij]；

wherein, K_[ij]is the response rate correction factor for the current temperature, SiTF _ avg is the average response rate, SiTF_[ij]and i and j are coordinate values of the pixel element.

Optionally, the calculating process of the response error value of each calibration temperature point includes:

Obtaining the response rate of the non-refrigeration infrared focal plane detector calibrated at each calibration temperature point, and fitting an actual relation curve of the response rate changing along with the temperature according to the temperature value of each calibration temperature point and the corresponding response rate value;

Respectively calculating a temperature-response rate straight line positioned in each temperature subinterval according to the response rate values of two nonadjacent calibration temperature points in each temperature subinterval;

Respectively calculating the response rate error value of each calibration temperature point according to the actual relation curve and the temperature-response rate straight line of each temperature subinterval;

And each temperature subinterval forms a normal working interval of the uncooled infrared focal plane detector, and the test uncooled infrared focal plane detector has the same characteristics as the uncooled infrared focal plane detector.

Optionally, the obtaining and testing the response rate of the uncooled infrared focal plane detector calibrated at each calibration temperature point, and fitting an actual relationship curve of the response rate changing with the temperature according to the temperature value of each calibration temperature point and the corresponding response rate value includes:

acquiring the response rate of each pixel of the non-refrigeration infrared focal plane detector to be tested at each preset temperature point, and fitting an actual relation curve of the response rate changing along with the temperature for each pixel according to the temperature value of each calibrated temperature point and the corresponding response rate value;

Correspondingly, the step of respectively calculating the response rate error value of each calibration temperature point according to the actual relationship curve and the temperature-response rate straight line of each temperature subinterval comprises:

calculating the response rate error value of the pixel at each calibration temperature point according to the actual relation curve of each pixel and the temperature-response rate straight line of each temperature subinterval;

And for each calibration temperature point, calculating the sum of the response rate error values of all the pixels at the same calibration temperature point and taking the average value of the sum as the response rate error value of the calibration temperature point.

Optionally, after the calculating the response rate error value of each calibration temperature point according to the actual relationship curve and the temperature-response rate straight line of each temperature subinterval, the method further includes:

Obtaining response rate error values of a plurality of test uncooled infrared focal plane detectors with the same characteristics as the test uncooled infrared focal plane detectors at the same calibration temperature points;

And for each calibration temperature point of the same uncooled infrared focal plane detector, calculating the sum of the response rate error values of the pixels at the same calibration temperature point and taking the average value of the sum to serve as the response rate error value of the uncooled infrared focal plane detector array of the calibration temperature point.

Optionally, after the calculating a response rate correction coefficient of the current temperature according to the response rate of the current temperature and the average response rate, the method further includes:

calculating imaging data of the uncooled infrared focal plane detector by using the following formula to output an infrared image after non-uniformity correction:

Y_[ij]＝K_[ij](X_[ij]-B_[ij])+Bavr；

In the formula, X_[ij]Is the original data of each pixel of the uncooled infrared focal plane detector, B_[ij]The output value of each pixel body of the uncooled infrared focal plane detector is Bavr is the mean value of the output values of the pixel bodies of the uncooled infrared focal plane detector, K_[ij]And the response rate correction coefficient of each pixel, i and j are coordinate values of the pixels.

optionally, the calculating process of the output value of each pixel body of the uncooled infrared focal plane detector includes:

Acquiring a first body output value and a corresponding first temperature value, a second body output value and a corresponding second temperature value, a third body output value and a corresponding third temperature value when a shutter of the uncooled infrared focal plane detector triggers updating at three continuous same-interval temperature points;

Judging a working temperature interval in which the current working temperature of the uncooled infrared focal plane detector is positioned, and calculating a body output value of the current working temperature according to a slope corresponding to the working temperature interval;

the first working temperature interval is smaller than the first temperature value, the second working temperature interval is larger than the first temperature value and smaller than the second temperature value, the third working temperature interval is larger than the second temperature value and smaller than the third temperature value, and the fourth working temperature interval is larger than the third temperature value; calculating a second slope of a temperature-body output value straight line of the second working temperature interval according to the first body output value, the first temperature value, the second body output value and the second temperature value, and calculating a third slope of the third working temperature interval according to the second body output value, the second temperature value, the third body output value and the third temperature value; and predicting the slopes of the first working temperature interval and the fourth working temperature interval according to the second slope, the third slope and a preset slope adjusting value.

The embodiment of the invention also provides a non-uniform response rate correction device for the uncooled infrared focal plane detector, which comprises the following components:

the calibration module is used for acquiring the response rates of the uncooled infrared focal plane detector calibrated at two preset calibration temperature points and calculating a response rate prediction straight line of the response rate changing along with the temperature;

the response rate prediction curve calculation module is used for calculating to obtain a response rate prediction curve according to the response rate prediction straight line and pre-stored response rate error values of all calibration temperature points; the response rate error value is a difference value between the response rate predicted by the response rate prediction straight line and the corresponding actual response rate at the same calibration temperature point, and is uniquely corresponding to the characteristic of the uncooled infrared focal plane detector;

the response rate calculation module is used for calculating the response rate of the uncooled infrared focal plane detector at the current temperature of a working interval determined by the two target calibration temperature points according to the response rate prediction curve;

the response rate correction coefficient calculation module is used for calculating the response rate correction coefficient of the current temperature according to the response rate and the average response rate of the current temperature; the average response rate is obtained by summing and averaging the response rates of all pixels of the uncooled infrared focal plane detector at the current temperature.

The embodiment of the invention also provides non-uniform response rate correction equipment for the uncooled infrared focal plane detector, which comprises a processor, wherein the processor is used for realizing the steps of the non-uniform response rate correction method for the uncooled infrared focal plane detector when executing the computer program stored in the memory.

the embodiment of the present invention finally provides a computer-readable storage medium, where a non-uniform response rate correction program of an uncooled infrared focal plane detector is stored in the computer-readable storage medium, and when the non-uniform response rate correction program of the uncooled infrared focal plane detector is executed by a processor, the method for correcting the non-uniform response rate of the uncooled infrared focal plane detector is implemented as any one of the foregoing methods.

The embodiment of the invention provides a correction method for the non-uniform response rate of an uncooled infrared focal plane detector, which comprises the steps of calibrating the uncooled infrared focal plane detector at two target calibration temperature points respectively to obtain corresponding response rates, and determining a response rate prediction straight line according to two pairs of temperature values and the response rates; calculating a response rate prediction curve according to the response rate prediction straight line and the response rate error value at each calibration temperature point; calculating the response rate of the uncooled infrared focal plane detector at the current temperature according to the response rate prediction curve; and finally, calculating a response rate correction coefficient of the current temperature according to the response rate and the average response rate of the current temperature. The response rate error value is the difference value between the response rate predicted by using the response rate prediction curve and the corresponding actual response rate at the same calibration temperature point; the average response rate is obtained by summing and averaging the response rates of all pixels of the uncooled infrared focal plane detector at the current temperature.

The technical scheme provided by the application has the advantages that aiming at the uncooled infrared focal plane detector with the same characteristic, the uncooled infrared focal plane detector to be corrected is calibrated twice only by using two temperature values in a working environment temperature range to obtain a response rate prediction straight line, and the same temperature point obtains the response rate by using the same response rate error value, so that the nonuniformity of the pixel response rate of the uncooled infrared focal plane detector is accurately corrected. The method not only solves the defects that the working environment of the existing two-point calibration method and the existing extended two-point calibration method is limited and the correction effect is poor, but also solves the problem that the consumption of time and production cost is large due to the fact that a large amount of calibration is needed by a multi-point calibration method, does not limit the working environment temperature of the non-refrigeration infrared focal plane detector, is simple and easy to realize, is beneficial to improving the mass production efficiency of the non-refrigeration infrared focal plane detector, and has strong universality.

in addition, the embodiment of the invention also provides a corresponding implementation device, equipment and a computer readable storage medium for the non-uniformity response rate correction method of the uncooled infrared focal plane detector, so that the method has higher practicability, and the device, the equipment and the computer readable storage medium have corresponding advantages.

Drawings

in order to more clearly illustrate the embodiments or technical solutions of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained based on these drawings without creative efforts.

FIG. 1 is a schematic diagram of a relationship between operating temperature and response rate of a single pixel of an uncooled infrared focal plane detector provided by an embodiment of the invention;

FIG. 2 is a schematic diagram illustrating a comparison between a response rate prediction curve and an actual response rate curve of an uncooled infrared focal plane detector provided by an embodiment of the present invention;

FIG. 3 is a block diagram of a non-refrigerated infrared focal plane imaging system according to an embodiment of the present invention;

Fig. 4 is a schematic flow chart of a method for correcting the non-uniform response rate of the uncooled infrared focal plane detector according to the embodiment of the present invention;

FIG. 5 is a diagram illustrating a response rate with temperature according to an embodiment of the present invention;

Fig. 6 is a schematic flow chart of another non-uniform response rate correction method for an uncooled infrared focal plane detector according to an embodiment of the present invention;

Fig. 7 is a schematic flowchart of a non-uniform response rate correction method for an uncooled infrared focal plane detector according to an embodiment of the present invention;

fig. 8 is a structural diagram of a specific implementation manner of the non-uniform responsivity correction apparatus for the uncooled infrared focal plane detector according to the embodiment of the present invention;

fig. 9 is a structural diagram of another specific implementation of the non-uniformity responsivity correcting apparatus for the uncooled infrared focal plane detector according to the embodiment of the present invention.

Detailed Description

in order that those skilled in the art will better understand the disclosure, the invention will be described in further detail with reference to the accompanying drawings and specific embodiments. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The terms "first," "second," "third," "fourth," and the like in the description and claims of this application and in the above-described drawings are used for distinguishing between different objects and not for describing a particular order. Furthermore, the terms "comprising" and "having," as well as any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, article, or apparatus that comprises a list of steps or elements is not limited to only those steps or elements but may include other steps or elements not expressly listed.

the inventor of the application finds that the non-uniformity of the pixel response rate of the uncooled infrared focal plane detector has a certain relation with the temperature through research, in order to research the relation between the response rate of the uncooled infrared focal plane detector and the working temperature of the detector, firstly, the response rate of a large number of detectors is tested at different working temperatures to obtain the relation data of the working temperatures and the response rates, and an actual response rate curve is obtained according to the obtained data in a fitting mode, as shown in fig. 1. Two temperature points A (such as any one of a normal temperature value) and B (a high temperature value of the normal working temperature of the uncooled infrared focal plane detector) can be selected uniformly, a response rate prediction straight line of an AB temperature interval can be obtained, the difference between the actual response rate and the linear prediction response rate at a plurality of temperatures is obtained through calculation, all pixel difference values of the same temperature point are averaged, the difference values of the same temperature point of all detectors are averaged again, and the average difference value of the temperature point is obtained.

Randomly selecting a part of non-refrigeration infrared focal plane detectors, and calculating a response rate prediction straight line of an AB work temperature interval according to two measured A, B temperature points. And calculating to obtain a response rate prediction curve through the average difference value of the response rate prediction straight line and a plurality of temperature points calculated before. Comparing the response rate prediction curve with the actual response rate curve, as shown in fig. 2, it can be seen that the maximum error between the response rate prediction curve and the actual response rate curve does not exceed 1%.

According to the calculation scheme, the actual response rate curve can be accurately reduced, and the non-uniformity of the pixel response rate of the uncooled infrared focal plane detector can be accurately corrected.

Based on the technical solutions of the embodiments of the present invention, some possible application scenarios related to the technical solutions of the embodiments of the present invention are described below by way of example with reference to fig. 3, and fig. 3 is a schematic frame diagram of an uncooled infrared focal plane imaging system according to an embodiment of the present invention.

As shown in fig. 3, the uncooled infrared focal plane imaging system may include an optical lens, an uncooled infrared focal plane detector, an image processing chip, a memory, a shutter, and a motor drive thereof.

The optical lens is used for collecting optical signals of a target and transmitting the optical signals to the uncooled infrared focal plane detector; when the shutter is closed, the optical signal is used for providing uniform optical signals for the uncooled infrared focal plane detector, and the interference of external optical signals is avoided; the uncooled focal plane detector is used for converting the received optical signal into an analog voltage signal and converting the analog voltage signal into a digital signal through digital-to-analog conversion and outputting the digital signal; the image processing chip is used for carrying out image effect algorithm processing (namely, the application provides a non-uniform response rate correction method of the uncooled infrared focal plane detector) and image data format conversion processing on the received image digital signals, obtaining a desired image effect and an image data format and transmitting the image effect and the image data format; the nonvolatile memory Flash is used for storing response rate SiTF calibration data, and the volatile memory DDR is used for storing data of an image processing chip algorithm.

The image processing chip respectively calibrates the uncooled infrared focal plane detector at two target calibration temperature points to obtain corresponding responsivity, and determines a responsivity prediction line according to the two pairs of temperature values and the responsivity value; calculating a response rate prediction curve according to the response rate prediction straight line and the response rate error value at each calibration temperature point; calculating the response rate of the uncooled infrared focal plane detector at the current temperature according to the response rate prediction curve; and finally, calculating a response rate correction coefficient of the current temperature according to the response rate and the average response rate of the current temperature.

Correcting coefficient K of the obtained responsivity of detector pixel_[ij](i and j are coordinates of the pixel), and the output value of the pixel body of the uncooled infrared focal plane detector can calculate the image after the nonuniformity correction according to an imaging formula of the nonuniformity correction method of the uncooled infrared focal plane detector. The imaging formula of the uncooled infrared focal plane detector non-uniformity correction method is as follows:

Y_[ij]＝K_[ij](X_[ij]-B_[ij])+Bavr；

In the formula, X_[ij]As raw data of an uncooled infrared focal plane detector, B_[ij]Is the output value of the pixel body of the uncooled infrared focal plane detector, Bavr is the average value of the output values of the pixel body of the uncooled infrared focal plane detector, K_[ij]the non-uniform response rate correction coefficient is used, and i and j are coordinate values of the pixel.

wherein, the detector pixel outputs B_[ij]The calculation process (i, j are coordinates of the pixel) can be that the image processing chip firstly obtains three pairs of temperature-body output values of the uncooled infrared focal plane detector shutter when triggered and updated at three continuous same interval temperature points, respectively calculates the linear slopes of the second working temperature interval and the third working temperature interval according to the 6 values, predicts the linear slopes of the first working temperature interval and the fourth working temperature interval according to the two calculated linear slopes, and finally calculates the corresponding body output value according to the linear slope of the working temperature interval where the current working environment temperature of the detector is located. It should be noted that the above application scenarios are only shown for facilitating understanding of the ideas and principles of the present application, and the embodiments of the present application are not limited in any way in this respect. Rather, embodiments of the present application may be applied to any scenario where applicable.

Having described the technical solutions of the embodiments of the present invention, various non-limiting embodiments of the present application are described in detail below.

referring to fig. 4, fig. 4 is a schematic flow chart of a non-uniform response rate correction method for an uncooled infrared focal plane detector according to an embodiment of the present invention, where the embodiment of the present invention includes the following:

S401: and obtaining the response rates of the uncooled infrared focal plane detector calibrated at two target calibration temperature points, and calculating a response rate prediction straight line of the response rate changing along with the temperature.

two target calibration temperature points (first target calibration temperature T)_aAnd a second target calibration temperature T_b) The temperature values are different for different detector operating temperatures, i.e. the two temperature values are different. Optionally, the two target calibration temperature points are the highest temperature and the lowest temperature of the current working interval. Of course, any two temperature values in the working interval can be adopted, which does not affect the implementation of the present application.

The specific calibration process may be:

The uncooled infrared focal plane detector is placed in a high-low temperature control box, the temperature control box is set to a specified temperature (a first target calibration temperature), the temperature stability of the temperature control box and the detector is confirmed, the whole area array of the detector is aligned to a black body, the black body is respectively provided with two times of energy temperatures (the energy temperatures are respectively set to be high-low temperature areas in the working range of the energy receiving temperature of the detector), and the output value of a detector unit is read after the energy temperatures of the black body are required to be stable. Through two tests, two energy temperature points (Q) of the detector unit are obtained_T1，Q_T2) Output value (D)_a1，D_a2) Then the response rate value calibrated at the first target calibration temperature is:

SiTFa＝(D_a2-D_a1)/(Q_T2–Q_T1)。

And after the temperature control box is changed to be at a temperature (the second target calibration temperature), testing according to the process to obtain another response rate value (SiTFb).

based on two sets of data (calibration temperature, calibration responsivity), i.e. (T)_aSiTFa) and (T)_bSiTFb), using two pointsthe mathematical basic knowledge of a straight line is determined to obtain a straight line relational expression (the abscissa is the temperature value and the ordinate is the response rate value) of the response rate of the working interval along with the temperature change, and the obtained straight line relational expression is the response rate prediction straight line.

s402: and calculating a response rate prediction curve according to the response rate prediction straight line and the pre-stored response rate error value of each calibration temperature point.

One temperature value corresponds to one response error value, and the response rate error values of a plurality of temperature values can form a response rate error value set. The characteristic of the responsivity error value set uniquely corresponds to that of the uncooled infrared focal plane detector to be corrected currently, that is, the same group of responsivity error value sets can be used by the uncooled infrared focal plane detectors of the same batch with the same type. Each calibration temperature point belongs to any temperature in the normal working environment temperature range of the uncooled infrared focal plane detector.

The calculation process of the response error value of each calibration temperature point may be:

Acquiring the response rate of the test uncooled infrared focal plane detector with the same characteristics as the uncooled infrared focal plane detector to be corrected at calibration temperature points, and fitting an actual relation curve of the response rate changing along with the temperature according to the temperature value of each calibration temperature point and the corresponding response rate value; calculating a temperature-response rate straight line positioned in a plurality of preset temperature subintervals according to response rate values of two nonadjacent calibration temperature points in the temperature subintervals; and respectively calculating the response rate error value of each calibration temperature point according to the actual relation curve and the temperature-response rate straight line of each temperature subinterval.

Each temperature sub-interval constitutes a normal operating interval of the entire uncooled infrared focal plane detector, for example, the normal operating range of the uncooled infrared focal plane detector is-40 ° to 85 °, so each temperature sub-interval may be three temperature sub-intervals, for example (-40 °, 0 °), (0 °, 40 °), and (40 °, 85 °).

when calculating the temperature-responsivity straight line of each temperature subinterval, the temperature points for calculating the temperature-responsivity straight line are spaced as far as possible, the greater the difference between the two temperature points, the higher the accuracy of the calculated temperature-responsivity straight line, and preferably, the responsivity at the end point of the temperature subinterval can be selected for calculation, for example, when calculating the temperature-responsivity straight line of the (40 ° and 85 °) temperature subinterval, the responsivity value of 40 ° and the responsivity value of 85 ° can be used for calculation.

It should be noted that the above calculation processes are all calculated by taking pixel points as units, that is, each pixel point has a temperature-response rate straight line in a temperature sub-interval.

The response rate error value is a difference value between the response rate predicted by the response rate prediction straight line and the corresponding actual response rate at the same calibration temperature point, and the response rate prediction straight line can be obtained by the method of S401. That is to say, for the uncooled infrared focal plane detector, within a working temperature interval, a response rate prediction straight line can be obtained by using the method of S401, then, each temperature point in the working temperature interval is calibrated for a response rate, for each temperature point, there is a response rate obtained by using the response rate prediction straight line of S401, and a response rate obtained by calibration, and the difference value of the two response rates is a response rate error value.

For the uncooled infrared focal plane detector to be corrected, after a response rate prediction straight line is obtained, adding the response rate error value of each temperature point in the temperature subinterval corresponding to the response rate prediction straight line to the response rate error value of the temperature point on the basis of the corresponding response rate value to obtain a corrected response rate value, sequentially carrying out the same correction treatment on each temperature point, and fitting each corrected response rate to obtain a curve, namely a response rate prediction curve.

And splicing the response rate prediction intervals of the temperature subintervals in the normal working range to obtain a response rate prediction curve in the working range of the whole detector.

s403: and calculating the response rate of the uncooled infrared focal plane detector at the current temperature of the working interval determined by the two target calibration temperature points according to the response rate prediction curve.

S404: and calculating a response rate correction coefficient of the current temperature according to the response rate and the average response rate of the current temperature.

The average response rate is obtained by summing and averaging the response rates of all pixels of the uncooled infrared focal plane detector at the current temperature. And for a certain temperature point, summing the response rates of all the pixels corresponding to the temperature point, and then taking the average value as the average response rate of the temperature point.

alternatively, the response rate correction coefficient for the current temperature may be calculated according to the following formula:

K_[ij]＝SiTF_avg/SiTF_[ij]；

Wherein, K_[ij]The coefficient for correcting the response rate of the current temperature is SiTF _ avg which is the average response rate, SiTF_[ij]As the response rate of the current temperature,

It should be noted that, in the embodiment of the present invention, only for any one pixel body of the uncooled infrared focal plane detector, the technical solution provided by the embodiment of the present invention can be adopted to correct the output value of each pixel body in the uncooled infrared focal plane detector. In addition, the whole technical scheme is only specific to a certain working interval, and in practical application, the working interval can be determined according to the actual working environment temperature.

in the technical scheme provided by the embodiment of the invention, aiming at the uncooled infrared focal plane detector with the same characteristic, only two times of calibration are needed to be carried out on the uncooled infrared focal plane detector to be corrected in two temperature values of a working environment temperature interval to obtain a response rate prediction straight line, and the same temperature point obtains the response rate by using the same response rate error value, so that the nonuniformity of the pixel response rate of the uncooled infrared focal plane detector is accurately corrected. The method not only solves the defects that the working environment of the existing two-point calibration method and the existing extended two-point calibration method is limited and the correction effect is poor, but also solves the problem that the consumption of time and production cost is large due to the fact that a large amount of calibration is needed by a multi-point calibration method, does not limit the working environment temperature of the non-refrigeration infrared focal plane detector, is simple and easy to realize, is beneficial to improving the mass production efficiency of the non-refrigeration infrared focal plane detector, and has strong universality.

Specifically, since the accuracy of each response error value directly determines the accuracy of the response prediction curve, that is, the accuracy of the finally obtained response has a direct influence, in order to improve the accuracy and precision of the correction of the non-uniform response rate of the uncooled infrared focal plane detector, the calculation process for each response error value in the set of response error values may be:

Acquiring the response rate of each pixel of the non-refrigeration infrared focal plane detector calibrated at each preset temperature point, and fitting an actual relation curve of the response rate changing along with the temperature for each pixel according to the temperature value of each calibrated temperature point and the corresponding response rate value;

And for each calibration temperature point of the same detector, calculating the sum of the response rate error values of the pixels at the same calibration temperature point and taking the average value of the sum as the response rate error value of the calibration temperature point detector array.

In order to further improve the accuracy of correcting the non-uniform response rate of the uncooled infrared focal plane detector, based on the above embodiment, the method may further include:

Obtaining response rate error values of a plurality of test uncooled infrared focal plane detectors with the same characteristics as the test uncooled infrared focal plane detector at the same calibration temperature points;

and for each calibration temperature point, calculating the sum of the response rate error values of the non-refrigeration infrared focal plane detectors at the same calibration temperature point, and taking the average value of the sum as the response rate error value of the calibration temperature point.

Specifically, the same batch of uncooled infrared focal plane detectors with the same model are found, and the response rate of part of the uncooled infrared focal plane detectors is calibrated. The specific calibration mode can be that the calibration is performed once every few degrees according to a required working range (for example, 0 to 80 degrees), so as to obtain a plurality of calibrated response rates SiTF (T), wherein T is T₀，T₁，…，T_n. Calculating average response rate value according to the calibrated parameters, and calculating the average response rate value according to the valueAnd synthesizing an actual response rate curve.

Two points of high temperature B and low temperature A are selected, and a linear formula of the response rate (response rate prediction line) is calculated according to the two points. When calculating the calibration straight line of two points, the two points can select two edge points close to all calibration data instead of selecting edge data. And fitting all the calibrated data of which the response rates change along with the temperature into a (response rate, temperature) curve, calculating the response rate difference value of a two-point calibration straight line and the fitted curve at the same temperature point for all the calibrated temperature points, firstly calculating the difference value of the response rate prediction straight line and the fitted actual response rate curve of each uncooled infrared focal plane detector with a single pixel at the same temperature, and then calculating the average of the difference values of all the pixels of the detector to be used as the response rate error value of the detector. And changing a detector with the same characteristics, calculating the response rate difference according to the mode, and paying attention to the fact that temperature calibration needs to be consistent. And repeatedly testing the response rate difference values of the detectors with the same characteristics, and calculating the average value of the response rate difference values.

in order to make the principle and implementation process of the technical solution more obvious to those skilled in the art, the present application also provides a specific example, please refer to fig. 5 and fig. 6, which may specifically include:

calibrating the uncooled infrared focal plane detector by calibration (SiTF (T)_a)，T_a)，(SiTF(T_b)，T_b) Calculating the parameters (S) of the straight line_k[ij](slope, S)_b[ij](intercept)), then T_a-T_bthe response rate prediction straight line of the temperature interval is S_[ij]＝S_k[ij]*T+S_b[ij]。

can be combined with S_k[ij]，S_b[ij]and storing the data into Flash of an uncooled infrared focal plane imaging system, calculating a corresponding response rate value according to the current temperature, and providing the response rate value for the KBC module for use so as to calculate an imaging output value of the uncooled infrared focal plane detector.

All the pre-stored calibration temperature response rate error values Delta S [ n ]](e.g., Δ 1- Δ n in FIG. 1), two points of each pixel are used to calibrate the straight-line coefficients (S)_k[ij]，S_b[ij]) And downloading the data into a flash.

the straight line close to the actual response rate curve can be calculated through the response rate error value and the response rate prediction straight line, and the response rate SiTF at the current temperature is calculated_[ij]. Calculating the value of a response rate correction coefficient K, wherein K is SiTF _ avg/SiTF_[ij]。

and dividing the temperature into a plurality of calculation areas according to the temperature of the test difference. And selecting the temperature subinterval required to be calculated according to the current temperature. For example, referring to FIG. 5, the current temperature T_cAt T₂-T₃And then selecting the applicable a2 area for calculation.

differential temperature T in area a2₂、T₃by the formula S of a straight line for each pixel point_[ij]＝S_k[ij]*T+S_b[ij]then, the response rates at m and n points are calculated, and m ═ m + Δ S2 and n ═ n + Δ S3 are calculated from the differences Δ S2 and Δ S3. Calculating the fitted partial straight line, S 'through m' and n_[ij]＝S_k[ij]`T+S_b[ij]`。

Calculating the response rate Sc of the current temperature Tc_[ij]＝S_k[ij]`Tc+S_b[ij]Calculating the response correction value K_[ij]＝Sc_avg/Sc_[ij]。

In the actual use process, the same response rate error value is used for the group of detectors, only the low-temperature point A and the high-temperature point B which are consistent with the calculated values need to be calibrated each time, then the fitting curve part (actually calculated is a straight line) of each section is calculated according to the difference value, the calculated lines are spliced into a fitting curve, and the more the calibrated temperature is, the more the near the fitting curve is.

From the above, the embodiments of the present invention not only solve the defects of limited working environment and poor correction effect of the existing two-point calibration method and the extended two-point calibration method, but also solve the problem of large time and cost consumption caused by the need of a large number of calibrations by the multi-point calibration method, do not limit the working environment temperature of the uncooled infrared focal plane detector, and are beneficial to improving the mass production efficiency of the uncooled infrared focal plane detector, and have strong universality.

based on the foregoing embodiment, the present application further provides another embodiment, please refer to fig. 7, which may further include:

S405: calculating imaging data of the uncooled infrared focal plane detector by using the following formula to output an infrared image after non-uniformity correction:

Y_[ij]＝K_[ij](X_[ij]-B_[ij])+Bavr；

wherein, the calculation process of each pixel body output value of the uncooled infrared focal plane detector specifically comprises the following steps:

The first working temperature interval is smaller than a first temperature value, the second working temperature interval is larger than the first temperature value and smaller than a second temperature value, the third working temperature interval is larger than the second temperature value and smaller than a third temperature value, and the fourth working temperature interval is larger than the third temperature value; calculating a second slope of a temperature-body output value straight line of a second working temperature interval according to the first body output value, the first temperature value, the second body output value and the second temperature value, and calculating a third slope of a third working temperature interval according to the second body output value, the second temperature value, the third body output value and the third temperature value; and predicting the slopes of the first working temperature interval and the fourth working temperature interval according to the second slope, the third slope and a preset slope adjustment value.

specifically, when the image processing chip begins to map, the algorithm enters the starting stage, and when the map is opened, the shutter Bs value is updated once to obtain a first group (Bs (0), T₀) Current temperature T_cThe corresponding ontology output values are calculated as follows:

B＝B_s(0)+B_k*(T_c-T₀)。

temperature rise after startup, temperature variation value (Tc-T)₀) Is greater than a trigger temperature threshold Tth for triggering shutter update, and the trigger shutter B value is updated to obtain a second group (Bs (1), T₁) The slope of the operating temperature interval can be calculated as:

B_k2＝(Bs(1)-Bs(0))/(T₁–T₀)

the current working temperature is in the working environment temperature interval T₀～T₂Then, the current ontology output value is calculated as follows:

B＝Bs(1)+B_k2(Tc–T₁)。

the current working temperature is in the working environment temperature interval T_-1～T₀then, the current ontology output value is calculated as follows:

B＝Bs(0)+B_k2(Tc–T₀)。

when the temperature is changed continuously, after shutter updating for many times, the Bs ij (original body output value obtained in shutter) generated under three continuous same interval temperatures is obtained, and then the conventional algorithm calculation stage is entered, wherein the conventional algorithm calculation stage comprises two parts 4 of slope Bk value updating and body output value Bc value calculating.

1. Bk value update

When the temperature changes by Δ T (T)_c-T_[n]) Trigger T_th(trigger temperature threshold), the shutter body output value Bs is updated. T is_ththe initial value is generally set to be small, and B is performed relatively quickly when the system is started_kAnd updating, and gradually increasing to a target value.

The output value Bc of the body is updated through the output value Bs of the shutter body, and the temperature T is updated through reading the internal temperature data of the detector.

What needs to be updated by the computation is B_kThe value is obtained.

When the trigger Bs is updated, the Bk before and after (two adjacent working temperature intervals) needs to be updated, for example, the trigger Bs_[n+2](is T)_n+2The body output value at the time) is updated,

Update the previous Bk_[n+1](Bk_[n+1]Is T_n+1-T_n+2Slope of operating temperature interval):

Bk_[n+1]＝(Bs_[n+2]–Bs_[n+1])/(T_[n+2]–T_[n+1])；

then update Bk_[n+2]`(Bk_[n+2]Is T_n+2-T_n+3Slope of operating temperature interval):

Bk_[n+2]`＝Bk_[n+1]+α*(Bk_[n+1]-Bk_[n]) (α is a preset slope adjustment value).

2. outputting and calculating the output value of the uncooled infrared focal plane detector body:

temperature of the probe at T_[n+2]～T_[n+3]or T_[n]～T_[n-1]：

Calculating an ontology output value using the predicted slope value:

B＝Bs_[n+2]+Bk_[n+2]`*(Tc–T_[n+2])

B＝Bs_[n]+BK_[n-1]`*(Tc–T_[n])。

Temperature of the probe at T_[n+2]～T_[n]：

Calculation with Bk and Bs generated

B＝Bs_[n]+BK_[n](Tc–T_[n])。

therefore, the correction method for the output value of each pixel body of the uncooled infrared focal plane detector does not depend on the motion of a scene, does not need to be calibrated, does not limit the working environment temperature of the uncooled infrared focal plane detector, is favorable for improving the mass production efficiency of the uncooled infrared focal plane detector, and has strong universality.

the embodiment of the invention also provides a corresponding implementation device for the non-uniform response rate correction method of the uncooled infrared focal plane detector, so that the method has higher practicability. The following describes a non-uniform response rate correction device for an uncooled infrared focal plane detector provided by an embodiment of the present invention, and the non-uniform response rate correction device for an uncooled infrared focal plane detector described below and the non-uniform response rate correction method for an uncooled infrared focal plane detector described above may be referred to in a corresponding manner.

Referring to fig. 8, fig. 8 is a structural diagram of a non-uniform responsivity correction apparatus for an uncooled infrared focal plane detector according to an embodiment of the present invention, in a specific implementation manner, the apparatus may include:

The calibration module 801 is used for acquiring the response rates of the uncooled infrared focal plane detector calibrated at two preset calibration temperature points and calculating a response rate prediction straight line of the response rate changing along with the temperature;

The response rate prediction curve calculation module 802 is configured to calculate a response rate prediction curve according to the response rate prediction straight line and a response rate error value of each calibration temperature point stored in advance; the response rate error value is a difference value between the response rate predicted by the prediction straight line and the corresponding actual response rate at the same calibration temperature point by using the response rate, and is uniquely corresponding to the characteristic of the uncooled infrared focal plane detector;

the response rate calculating module 803 is configured to calculate, according to the response rate prediction curve, the response rate of the uncooled infrared focal plane detector at the current temperature of the working interval determined by the two target calibration temperature points;

a response rate correction coefficient calculation module 804, configured to calculate a response rate correction coefficient of the current temperature according to the response rate of the current temperature and the average response rate; the average response rate is obtained by summing and averaging the response rates of all pixels of the uncooled infrared focal plane detector at the current temperature.

Optionally, in some embodiments of this embodiment, referring to fig. 9, the apparatus may further include an imaging output value calculating module 805, for example, and the imaging output value calculating module 805 may specifically include:

the calculation submodule is used for calculating the imaging data of the uncooled infrared focal plane detector by using the following formula so as to output the infrared image after the nonuniformity correction:

Y_[ij]＝K_[ij](X_[ij]-B_[ij])+Bavr；

In the formula, X_[ij]Is the original data of each pixel of the uncooled infrared focal plane detector, B_[ij]the output value of each pixel body of the uncooled infrared focal plane detector is represented by Bavr which is the mean value of the output values of the pixel bodies of the uncooled infrared focal plane detector, K_[ij]And the response rate correction coefficient of each pixel, i and j are coordinate values of the pixels.

Optionally, the calculating sub-module may further include a pixel ontology output value correcting unit, which specifically includes:

the information acquisition subunit is used for acquiring a first body output value and a corresponding first temperature value, a second body output value and a corresponding second temperature value, a third body output value and a corresponding third temperature value when a shutter of the uncooled infrared focal plane detector triggers updating at three continuous same-interval temperature points;

The judging subunit is used for judging a working temperature interval in which the current working temperature of the uncooled infrared focal plane detector is positioned, and calculating a body output value of the current working temperature according to a slope corresponding to the working temperature interval;

Optionally, in other embodiments of this embodiment, the response rate correction coefficient calculating module 804 may be a module that calculates a response rate correction coefficient of the current temperature according to the following formula:

K_[ij]＝SiTF_avg/SiTF_[ij]；

In one embodiment, the response prediction curve calculation module 802 may further include a response error value calculation sub-module, and the response error value calculation sub-module may specifically include:

the curve fitting unit is used for acquiring the response rate of the non-refrigeration infrared focal plane detector calibrated at each calibrated temperature point, and fitting an actual relation curve of the response rate changing along with the temperature according to the temperature value of each calibrated temperature point and the corresponding response rate value; testing that the characteristics of the uncooled infrared focal plane detector are the same as those of the uncooled infrared focal plane detector;

the temperature-response rate straight line calculating unit is used for calculating a temperature-response rate straight line positioned in each temperature subinterval according to the response rate values of two nonadjacent calibration temperature points in each temperature subinterval; each temperature subinterval forms a normal working interval of the uncooled infrared focal plane detector;

And the difference value calculating unit is used for respectively calculating the response rate error value of each calibration temperature point according to the actual relation curve and the temperature-response rate straight line of each temperature subinterval.

Optionally, the response rate error value calculation sub-module may also be a module that obtains the response rate of each pixel of the non-refrigeration infrared focal plane detector calibrated at each preset temperature point, and fits an actual relationship curve of the response rate changing with temperature for each pixel according to the temperature value of each calibrated temperature point and the corresponding response rate value.

In addition, the response rate error value calculation submodule can also comprise an average value calculation unit which is used for obtaining the response rate error values of a plurality of test uncooled infrared focal plane detectors with the same characteristics as the test uncooled infrared focal plane detectors at the same calibration temperature points; and for each calibration temperature point of the same uncooled infrared focal plane detector, calculating the sum of the response rate error values of the pixels at the same calibration temperature point and taking the average value of the sum to serve as the response rate error value of the uncooled infrared focal plane detector array of the calibration temperature point.

The functions of the functional modules of the non-uniform response rate correction device of the uncooled infrared focal plane detector in the embodiment of the present invention can be specifically implemented according to the method in the embodiment of the method, and the specific implementation process of the function modules can refer to the related description of the embodiment of the method, which is not described herein again.

the embodiment of the invention also provides non-uniform response rate correction equipment for the uncooled infrared focal plane detector, which specifically comprises the following steps:

A memory for storing a computer program;

A processor for executing a computer program to implement the steps of the non-uniform responsivity correction method of the uncooled infrared focal plane detector according to any of the above embodiments.

The functions of the functional modules of the non-uniform response rate correction device of the uncooled infrared focal plane detector according to the embodiment of the present invention can be specifically implemented according to the method in the embodiment of the method, and the specific implementation process of the function modules can refer to the related description of the embodiment of the method, which is not described herein again.

the embodiment of the invention also provides a computer-readable storage medium, which stores a non-uniform response rate correction program of the uncooled infrared focal plane detector, and the non-uniform response rate correction program of the uncooled infrared focal plane detector is executed by a processor, and the steps of the non-uniform response rate correction method of the uncooled infrared focal plane detector are as described in any one of the embodiments above.

The functions of the functional modules of the computer-readable storage medium according to the embodiment of the present invention may be specifically implemented according to the method in the foregoing method embodiment, and the specific implementation process may refer to the related description of the foregoing method embodiment, which is not described herein again.

The embodiments are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same or similar parts among the embodiments are referred to each other. The device disclosed by the embodiment corresponds to the method disclosed by the embodiment, so that the description is simple, and the relevant points can be referred to the method part for description.

Those of skill would further appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both, and that the various illustrative components and steps have been described above generally in terms of their functionality in order to clearly illustrate this interchangeability of hardware and software. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.

The steps of a method or algorithm described in connection with the embodiments disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in Random Access Memory (RAM), memory, Read Only Memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.

the method, the device, the equipment and the computer readable storage medium for correcting the non-uniform response rate of the uncooled infrared focal plane detector provided by the invention are described in detail above. The principles and embodiments of the present invention are explained herein using specific examples, which are presented only to assist in understanding the method and its core concepts. It should be noted that, for those skilled in the art, it is possible to make various improvements and modifications to the present invention without departing from the principle of the present invention, and those improvements and modifications also fall within the scope of the claims of the present invention.

Claims

1. A non-uniform response rate correction method for an uncooled infrared focal plane detector is characterized by comprising the following steps:

2. The non-uniformity response rate correction method of the uncooled infrared focal plane detector as claimed in claim 1, wherein the calculating the response rate correction coefficient of the current temperature according to the response rate and the average response rate of the current temperature comprises:

K_[ij]＝SiTF_avg/SiTF_[ij]；

3. the method for correcting the non-uniformity response rate of the uncooled infrared focal plane detector as claimed in claim 1, wherein the calculating process of the response rate error value of each calibration temperature point comprises:

4. The method for correcting the non-uniformity response rate of the uncooled infrared focal plane detector as claimed in claim 3, wherein the step of obtaining and testing the response rate of the uncooled infrared focal plane detector calibrated at each calibration temperature point and fitting an actual relation curve of the response rate varying with the temperature according to the temperature value of each calibration temperature point and the corresponding response rate value comprises:

5. The method for correcting the non-uniformity response rate of the uncooled infrared focal plane detector as claimed in claim 4, wherein after the response rate error values of the calibration temperature points are respectively calculated according to the actual relationship curve and the temperature-response rate straight lines of the temperature subintervals, the method further comprises:

6. The non-refrigerated infrared focal plane detector non-uniformity response rate correction method according to any one of claims 1 to 5, further comprising, after calculating the response rate correction coefficient of the current temperature according to the response rate and the average response rate of the current temperature:

Y_[ij]＝K_[ij](X_[ij]-B_[ij])+Bavr；

7. The method for correcting the non-uniformity response rate of the uncooled infrared focal plane detector as claimed in claim 6, wherein the process of calculating the output value of each pixel body of the uncooled infrared focal plane detector comprises:

8. The utility model provides an uncooled infrared focal plane detector inhomogeneous responsivity correcting unit which characterized in that includes:

9. an uncooled infrared focal plane detector non-uniform response rate correcting apparatus, comprising a processor for implementing the steps of the uncooled infrared focal plane detector non-uniform response rate correcting method according to any one of claims 1 to 7 when executing a computer program stored in a memory.

10. A computer-readable storage medium, wherein the computer-readable storage medium has stored thereon a non-refrigerated infrared focal plane detector non-uniformity response rate correction program, and when the non-refrigerated infrared focal plane detector non-uniformity response rate correction program is executed by a processor, the computer-readable storage medium implements the steps of the non-refrigerated infrared focal plane detector non-uniformity response rate correction method according to any one of claims 1 to 7.