Reserach And System Development Of Accurate Thermal Infrared Temperature Measurement Based On Self-calibration And Altering-spectrum Method

As a non-contact temperature measurement method,infrared thermography is developing rapidly in recent years,and it has been widely used in many applications.Especially when COVID-19 was rampant around the world,infrared thermal imaging technology is frequently seen as an efficient temperature screening tool in important places where people gather.The rapid development of thermal infrared technology is inseparable from its many advantages as a new type of temperature measurement.It not only has the characteristics of non-invasive,fast response time and high throughput reading,but also is not disturbed by bright light and can achieve all-weather temperature detection.In addition,as an imaging device,its detection object is not limited to static objects,but can also effectively read the temperature change process of moving objects.At the same time,infrared thermal imaging technology is constantly developing towards a high degree of integration,miniaturization and low cost.In the future,portable thermal imaging cameras based on smart phones will gradually occupy the mainstream.Then,despite all the advantages of infrared thermography,there are still many interference factors that limit its development.Since the principle of thermal infrared temperature measurement relies heavily on the infrared thermal radiation from the target,interference is inevitable in the process of temperature measurement.Among the interference factors,the thermal drift of the infrared detector and the unknown emissivity of the target have a particular impact on the thermal infrared temperature measurement.In order to solve this problem,based on the previous research,this paper focuses on the accurate temperature measurement method of smartphone type thermal imaging camera and the related system development.1)The temperature self-calibration method is used to achieve real-time compensation for the target measurement temperature by adding a constant temperature heat source at the bottom of the infrared lens,effectively eliminating the temperature measurement error caused by the thermal drift of the detector.2)The altering-spectrum method is designed to add a removable infrared bandpass filter in front of the infrared lens,so that the thermal imaging camera can achieve dual-band measurement in the process of target temperature detection,effectively eliminating the effect of unknown target emissivity for thermal infrared temperature measurement.3)Mobile phone software was developed to automate the control of the constructed external calibration system,based on the open Android platform,which allows accurate temperature measurement of the equipment through simple software operation.Under the joint action of self-calibration system and variable spectrum system,the temperature measurement accuracy of thermal imaging camera is improved from the original ±3℃ to ±0.3℃.The purpose of accurate temperature measurement is achieved.And,to further verify the great application potential of the accurate temperature measurement system.4)The biosensor detection platform built around the accurate temperature measurement system,with the help of the new photothermal conversion material(TMBox),successfully converts biological information into temperature signal,and achieves the high accuracy detection of harmful substance chloramphenicol(CAP)in food,and the detection limit is only 0.09ng/m L after data analysis.In this project,we designed a self-calibration system to improve the accuracy of temperature measurement and a variable spectrum system around the cell phone type thermal imaging camera,which effectively eliminates the main influencing factors of thermal infrared temperature measurement and applies this research to the field of biosensor,successfully realizing the high accuracy detection of biomarkers,fully demonstrating the reliability and great application prospects of thermal infrared accurate temperature measurement system.