The Application Research On Image Algorithm Of Terahertz Nondestructive Testing

Terahertz nondestructive testing technology has made great progress in detecting metals,ceramics,composite materials,organisms,and etc.However,compared with other traditional methods,the imaging technology is not mature enough to meet the requirements of industrial application.Therefore,it is of great significance to study its imaging methods and improve the quality of its image to promote and develop terahertz nondestructive testing.The research in this paper is aimed at the terahertz imaging system,based on this,the main work is improving the quality of images obtained by the system,then,designing the production application of terahertz image processing methods.Combining with the practical engineering experience and the demands of the product application,several works following are finished from the theory of algorithms and terahertz technology:The principle of terahertz research and detection.Several THz radiation ways are introduced,the photoconductive antenna,the semiconductor surface electric field,Dembet effect light induced and etc.At the same time,we also introduce the detection principle of terahertz frequency modulated continuous wave.Through the mathematical formula derivation,we can understand the characteristics of it more clearly,and use its principle to manufacture an imaging probe.Explaining the origin and nature of the image of THz.To explain how to interpret optical data from the imaging system to the images that allow us to analyze and process directly,the method is to form a 255 grayscale 3D matrix by mapping and splicing data,each layer of a matrix represents images of different depths.Secondly,the main properties of the images are presented in the image,which represent the different reflection properties of the objects that are detected in terahertz waves.The design of the terahertz NDT visualization system.Based on the application of terahertz nondestructive testing,we use the MATLAB GUI as a tool,integrating the all kinds of image algorithms and other functions to a visual software platform.Through analyzing a sample of the heat shield detection,we proved the practicability of the software platform and functions.Using the continuous wavelet transform to process THz image.Terahertz images collected has the problem of low signal noise ratio(SNR),using the continuous wavelet transform can effectively handle terahertz three-dimensional images and image quality and contrast can get obvious improved.The effect of using different wavelet basis function is also different,the effect of using Mexican hat wavelet basis function on the image processing is best.The full text is about the application of terahertz imaging technology,which contains the terahertz detection method,the generation of terahertz nondestructive detection images,the systematic integration of image algorithm,using the continuous wavelet transform to process images.The whole article is the summary of the work in my master period,I hope it will play a bit role in the industrialized application of terahertz technology.