Research On Thermal Field Pattern Construction And Image Optimization Method For Cylinder Head Inner Wall Image Inspection

Compared with the conventional cylinder head wall inspection method,it can visually detect the thermal fatigue damage information of the cylinder head wall by means of imaging,which greatly improves the efficiency of cylinder head wall thermal fatigue damage detection.However,the reconstruction of the cylinder head inner wall image by the traditional correlation imaging method will have the following problems: the thermal field environment of the cylinder head inner wall and the size of the inner wall,which makes the construction of the thermal field scatter pattern of the cylinder head difficult;the thermal field characteristics of the cylinder head inner wall,the acquired thermal field data has a high redundancy,resulting in a long reconstruction time and poor quality;due to the uneven heating of the cylinder head inner wall It is difficult to detect small cracks in the reconstructed image of the high temperature area of the cylinder head due to uneven heating.In order to solve the above difficulties,this paper carries out the work oriented to the optimization of the correlation imaging method of the cylinder head inner wall,so that it can improve the quality of the reconstructed image of the cylinder head inner wall.The main research work is as follows.(1)Multi-scale image fusion research: firstly,the reconstruction process of cylinder head inner wall images is introduced,and the problems that are prone to occur in the reconstructed images of the inner wall are analyzed;secondly,the effect of reconstructing images at different scales is studied,and the concept of multi-scale image fusion is introduced to obtain different scales of cylinder head inner wall images by setting different scattering sizes of the cylinder head inner wall thermal field,and setting different weight fusion coefficients to improve the quality of the inner wall images;finally,the effectiveness of the proposed method in reducing the amount of measurement data and improving the quality of the reconstructed cylinder head inner wall images is verified through experiments.(2)Research on the construction of thermal field pattern of cylinder head inner wall: firstly,we analyzed the characteristics of the thermal field distribution pattern of cylinder head inner wall,and analyzed the advantages and disadvantages of the traditional interpolation method;secondly,we introduced the fan ring interpolation method into the construction of thermal field scatter pattern of cylinder head inner wall,and then using fan ring interpolation to realize the construction of thermal field scatter pattern of cylinder inner wall;finally,we verified that the method can solve the problem of Finally,it is verified that the method can solve the problem of mosaic effect when constructing the thermal field scatter pattern by traditional interpolation method,which makes it difficult to detect thermal fatigue damage,and also improves the quality of the reconstructed image of the cylinder head inner wall.(3)Research on the difference of total external wall thermal energy value: firstly,we analyzed the thermal environment of the cylinder head inner wall thermal field,analyzed the problem that it is not easy to detect the small cracks in the high temperature area when the cylinder head inner wall reconstructed image,secondly,we analyzed the mechanism of correlation imaging reconstructed cylinder head inner wall image,and proposed a method of cylinder head thermal fatigue detection based on the difference of data,by setting up another group of experimental reference objects under the same working condition,and then comparing the target and reference objects to obtain the difference of external wall thermal energy value.After comparing the total thermal energy value of the external wall of the target and the reference object,the difference data of the total thermal energy value of the external wall is obtained,and then reconstructed with the thermal field scatter pattern of the internal wall to obtain the image information of the thermal fatigue damage area;finally,it is verified through experiments that the method can detect the small crack area in the high temperature region of the cylinder head internal wall,and it is effective in reducing the sampling rate and highlighting the thermal fatigue damage area.The results are obvious.