Research Measurement Method Of The Rolled Ring Surface Temperature Combining CCD With Infrared Thermal Imager

In the process of ring rolling,the accurate measurement of rolling temperature plays an important role in the quality of rolled ring.As an important achievement of the rapid development of modern infrared temperature measurement technology,infrared thermal imager has the advantages of non-contact,rapid response,wide temperature measurement range and high accuracy.However,the accuracy of infrared thermography is easily affected by the rolled ring surface emissivity.Therefore,in order to obtain the real temperature of the rolled ring surface,it is necessary to correct the emissivity of the infrared thermal imager.However,it is found that the rolled ring surface emissivity changes with the temperature during the correction process,which brings difficulties to the accurate measurement of the rolled ring surface temperature.In view of the above problems,this paper combines CCD and infrared thermal imager to construct the rolled ring surface temperature measurement system.Firstly,according to the basic principles of CCD image temperature measurement and infrared thermal imaging,CCD and infrared thermal imager are combined to construct the rolled ring surface temperature measurement system.Based on the measurement system,the measurement formula of the rolled ring surface emissivity is derived by combining the double background radiation method and the trichromatic temperature measurement method to realize the measurement of the rolled ring surface emissivity.Combined with the principle of infrared temperature measurement,the temperature measurement formula after emissivity correction is obtained,and the emissivity correction of infrared thermal imager is realized.Secondly,the main influencing factors about temperature measurement accuracy of the present temperature measurement system are comprehensively analyzed.Aiming at the noise generated in the process of acquisition and transmission of thermal radiation images,this paper uses the nonlocal mean filtering algorithm to search the similar image blocks through the redundant information of the image itself and the information with similar structures.The similar image blocks are weighted and averaged to remove the image noise.Aiming at the non-target region in the thermal radiation image,this paper uses the watershed image segmentation algorithm based on median filtering and region merging to denoise the non-target region.Finally,the calibration experiments,the improvement experiments of the influencing factors of the measurement system,and the temperature measurement experiments of the rolled ring surface are carried out by the temperature measurement system designed in this paper.The feasibility and reliability of the influencing factors improved method of temperature measurement system,the emissivity measurement model and temperature correction model are verified.On this basis,the experimental results are analyzed to obtain the variation law of rolled ring surface emissivity at 300-500 °C.