Compensation methods for infrared thermal imager burns

Abstract

This invention provides a method for compensating for burns in infrared thermal imagers. The method includes the following steps: (A1) acquiring the grayscale values ​​B0 and B1 of the burnt area of ​​the infrared thermal imager detector during the two most recent calibrations; (A2) obtaining the current compensated grayscale G at the burnt area, where G is the directly obtained grayscale value at the current burnt area, K is the detector responsivity, Δt is the time difference between the two adjacent calibrations, and t is the time difference between the current and the most recent calibration. This invention has advantages such as accurate temperature measurement.

Description

Technical Field

[0001] This invention relates to infrared thermal imagers, and particularly to a method for compensating for burns caused by infrared thermal imagers. Background Technology

[0002] When an infrared thermal imager faces a high-temperature target for a period of time, it will leave a burn mark on the corresponding image location. This burn mark will slowly recover over time, but it will be more noticeable when facing a uniform scene with a lower temperature.

[0003] The existing solutions mainly include:

[0004] 1. Avoid exposing infrared thermal imagers to high-temperature targets for extended periods or add polarizers to the optical structure to reduce infrared radiation; however, this only prevents burns and does not compensate for burns.

[0005] 2. Compensate for burn marks using an algorithm.

[0006] When an infrared thermal imager faces a high-temperature target for a period of time, it will leave a burn mark at the corresponding imaging location. When facing a uniform surface, the gray level of the burn mark is lower than that of the surrounding normal area. According to experimental results, the burn recovers relatively quickly within 3 minutes after the burn ends. After 3 minutes, the burn recovery slows down over time until it is completely healed. If the temperature during the burn is too high or the burn time is too long, the detector may not be able to recover, forming a permanent burn mark.

[0007] In practical use, it is found that this burn mark can be corrected by using a baffle plate. However, over time, the burn mark will gradually appear in the image and become more and more obvious until the next baffle plate is used, and this cycle repeats. Because the grayscale of the two baffle plates is similar under relatively stable environmental conditions, and the burn mark slowly recovers over time, the difference in grayscale value of the recovered burn mark will increase during imaging, which is reflected in the image as the burn mark appearing and becoming more and more obvious. Summary of the Invention

[0008] To address the shortcomings of the existing technical solutions, this invention provides a method for compensating for infrared thermal imager burns that is accurate, comprehensive, and low-cost.

[0009] The objective of this invention is achieved through the following technical solution:

[0010] A method for compensating for burns caused by infrared thermal imagers, comprising the following steps:

[0011] (A1) Collect the gray values ​​B0 and B1 of the detector burn area of ​​the infrared thermal imager during the most recent two calibrations;

[0012] (A2) Obtain the compensated grayscale of the currently described burn site.

[0013] G is the grayscale directly obtained at the current burn site, K is the detector response rate, Δt is the time difference between the two adjacent corrections, and t is the time difference between the current and the most recent correction.

[0014] To further compensate for the impact of changes in ambient temperature, if the ambient temperature changes during the above compensation process, further compensation is required, in the following manner:

[0015]

[0016] T1 is the temperature of the calibration plate when the gray value B1 is obtained, T0 is the temperature of the calibration plate when the gray value B0 is obtained, and T is the current temperature of the calibration plate.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0018] This invention not only compensates for detector burns, but also provides further compensation when the ambient temperature changes, significantly improving temperature measurement accuracy and minimizing the adverse effects of detector burns. Attached Figure Description

[0019] The disclosure of this invention will become more readily understood with reference to the accompanying drawings. It will be readily understood by those skilled in the art that these drawings are merely illustrative of the technical solutions of this invention and are not intended to limit the scope of protection of this invention. In the drawings:

[0020] Figure 1 This is a flowchart of a method for compensating for burns caused by an infrared thermal imager according to an embodiment of the present invention. Detailed Implementation

[0021] Figure 1 The following description illustrates optional embodiments of the invention to teach those skilled in the art how to implement and reproduce the invention. Some conventional aspects have been simplified or omitted for the purpose of teaching the invention. Those skilled in the art should understand that variations or substitutions derived from these embodiments will be within the scope of the invention. Those skilled in the art should understand that the following features can be combined in various ways to form multiple variations of the invention. Therefore, the invention is not limited to the following optional embodiments, but is defined only by the claims and their equivalents.

[0022] Example:

[0023] Figure 1 A flowchart illustrating the compensation method for infrared thermal imager burns according to an embodiment of the present invention is shown, such as... Figure 1 As shown, the method for compensating for infrared thermal imager burns includes the following steps:

[0024] (A1) Collect the gray values ​​B0 and B1 of the detector burn area of ​​the infrared thermal imager during the most recent two calibrations;

[0025] (A2) Obtain the compensated grayscale of the currently described burn site.

[0026] G is the gray level directly obtained at the current burn site, K is the detector response rate, Δt is the time difference between the two adjacent corrections, and t is the time difference between the current and the most recent correction.

[0027] If the ambient temperature changes during the above compensation process, further compensation is required, in the following manner:

[0028]

[0029] T1 is the temperature of the calibration plate when the gray value B1 is obtained, T0 is the temperature of the calibration plate when the gray value B0 is obtained, and T is the current temperature of the calibration plate.

Claims

1. A method for compensating burn of an infrared thermal imager, the method comprising the following steps: (A1) collecting the gray scale values B0, B1 of the burn of the detector of the infrared thermal imager at the last two calibrations; (A2) obtaining a compensation gray scale of the burn at present ; G is the gray scale value of the burn directly obtained at present, K is the response rate of the detector, Δt is the time difference between the adjacent two calibrations, and t is the time difference between the present and the last calibration.

2. The method of claim 1, wherein the infrared camera is a thermal camera. In the above compensation process, if the ambient temperature changes, the compensated gray scale ; T1 is the temperature of the calibration plate corresponding to the acquisition of the gray scale value B1, T0 is the temperature of the calibration plate corresponding to the acquisition of the gray scale value B0, and T is the temperature of the present calibration plate.

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