Study On Temperature Measurement Accuracy Of Infrared Thermal Imager

All physical and chemical reactions are related to temperature in nature.It is very important to measure the temperature in military and modern chemical industry.The infrared temperature measurement does not need to contact with the measured object.So that the infrared temperature measurement range is wide and the application field is more and more.However,for the development of the infrared temperature measurement technology,the accuracy of temperature measurement is difficult to achieve satisfactory degree,the development of infrared temperature measurement method has been limited.Therefore,how to improve the accuracy of the infrared temperature measurement technology is the direction of domestic and foreign scholars have been working hard,but also a very meaningful topic.Aiming at the uncooled infrared thermal imager,based on the existing research results at home and abroad,the influence of internal factors and external environment factors on the infrared thermal imager temperature measurement accuracy is analyzed detail.To improve the accuracy of temperature measurement,the corresponding measures are put forward.Specific contents are as follows:Firstly,the structure of infrared thermal imager,the principle of temperature measurement and the basis of radiation temperature measurement are introduced.In order to solve the problem of the radiation influence on the temperature measurement accuracy of uncooled infrared thermal imager,a method based on voltage compensation is proposed.The relationship between infrared image gray value and blackbody temperature,ambient temperature and the infrared thermal imager temperature change quantity is established according to the infrared data of standard blackbody.A model for reducing its radiation of infrared thermal imager is established.And the model is solved.Secondly,the influence of measuring distance on the accuracy of infrared thermal imager is analyzed from different angles.The principle of the influence of three aspects,such as the instantaneous field of view,the temperature of the measured object and the contrast of the ambient background temperature and the atmospheric transmittance are analyzed.The method to reduce the influence of these three aspects is put forward.And the theoretical formula is obtained.Thirdly,the mature infrared temperature measurement formula is derived.It is concluded that the atmospheric transmittance is an important factor which can not be ignored in infrared thermal imager.According to the composition of the main air in the air,three main factors affecting the atmospheric transmittance are determined.Aiming at the absorption effects of water vapor and carbon dioxide,the scattering effects of atmospheric molecular and aerosol particles,the attenuation of rain and snow weather conditions,the temperature measurement transmission model of sea level is established.The theoretical calculation formula of atmospheric transmittance is obtained.Finally,in order to verify the model and formula established in the above three sections,the experiments are carried out.The correctness and feasibility of the proposed method are proved by experiments.