Research On The Algorithm Of Vascular Image Structure Enhancement Based On Wavelet Transform

In recent years,with the development of medical imaging technology,it has been widely used in medical diagnosis.However,due to the limitation of imaging conditions and the medical image itself,the visual effect of the image is often unsatisfactory,with a series of problems such as low contrast and loss of detail information.Therefore,in order to solve the problems in the above aspects,this thesis proposes two improved algorithms based on anti-sharpening mask through the study of a series of image enhancement algorithms:(1)Research on anti-sharpening mask algorithm based on bilateral filtering improvement.The traditional image enhancement algorithm has low separation precision for the useful information in the image.There are usually two problems in the enhancement of the separated detail information,that is,the enhancement effect is not obvious and the enhancement of the image noise part while amplifying the detail part.How to separate the useful information in the image with high precision and how to process the details effectively after the separation has become an urgent problem to be solved.On the basis of the above problems,we proposed an anti-sharpening mask algorithm based on bilateral filtering,which can separate the high and low frequency parts of the image through bilateral filtering,which can improves the accuracy of the separation.The concept of gain coefficient is continued for the high frequency part obtained by separation,and the image detail part can be enhanced effectively.Experiments show that this algorithm has high application value in the enhancement of some vascular images with simple structures.(2)Research on anti-sharpening mask algorithm based on improved wavelet transform.Bilateral filtering is based on spatial domain to separate high and low frequency images.It is not suitable for images with many points and lines,and some edges will be blurred after processing and stacking the images.Based on the shortcomings of the above algorithms,we propose an anti-sharpening mask algorithm based on wavelet transform.We used wavelet transform based on frequency domain to separate high and low frequencies of images,and the low-frequency parts are processed by Contrast Limited Adaptive Histogram Equalization(CLAHE),and the high-frequency parts are multiplied by the gain coefficient C(C=2).This improved algorithm can enhance the influence of blood vessels with complex line structure effectively.In addition,this research also extends the enhancement algorithm for color image based on the original gray image processing.At present,the advanced surgical navigation equipment has realized the superposition display effect of multiple modes of white light and fluorescence.Therefore,based on the common color space,this thesis also proposed a 3d color image based vascular enhancement algorithm.Finally,the improvement ideas of the above algorithm are determined through the control variable based control experiment,which is realized based on Matlab and its corresponding function packaging library.