Research On Feature-preserving Image Enhancement Methods

Image enhancement is an important branch of image processing research direction,and its role is to preserve or highlight important features in the original color image through a series of targeted operations to obtain a high-quality resultant image.With the rapid development of computer vision technology and the continuous improvement of people’s requirements for image quality,image enhancement technology involves an increasingly wide range of research contents.At the current stage,color image grayscale technology and underwater image enhancement technology are the research hotspots in the field of image enhancement and have received close attention from many researchers at home and abroad.In this paper,the key issues of feature retention in color image grayscale and underwater image enhancement are investigated on the basis of related research results,and the main results are as follows:(1)In response to the problems of detail loss and lack of contrast and hierarchy in traditional color image grayscale methods,a new method of color image grayscale(referred to as MCVP method)based on visual perceptual contrast and similarity measurement is proposed in the paper.Firstly,a new method of color distance measurement based on visual perception is proposed and visual perceptual contrast is designed based on the visual perceptual characteristics of human eyes with different sensitivity to different wavelengths of light.Second,a new local contrast retention term is designed to better maintain the detail features of the original color image by combining the visual perceptual contrast and similarity measures.In addition,a new global contrast retention term is designed based on the bimodal Gaussian model to allow the resulting image to better maintain the overall hierarchy of the original color image.Finally,a discrete search strategy is used to obtain grayscale results quickly.Extensive experimental results show that the proposed MCVP method has better results in maintaining the image hierarchy and details than the traditional methods,and has better performance in objective evaluation indexes.(2)A new underwater image enhancement method(referred to as RWDC method)is proposed in this paper based on the white balance algorithm of red channel gain and dark channel a priori theory to address the problems of insufficient contrast,blurred details and color distortion in traditional underwater image enhancement methods.Firstly,a red channel gain white balance algorithm is proposed based on the attenuation characteristics of light propagation underwater,which can better color correct the underwater low-quality images by appropriately compensating the red channel pixel values.Second,a histogram equalization algorithm is used to enhance the contrast of the color-corrected image and obtain a preliminary image.Then,the preliminary image is enhanced with the dark channel a priori theory to obtain the final result image.The comparative experimental results show that the proposed RWDC method can improve the contrast and sharpness of underwater images better than the traditional underwater image enhancement methods,and the resultant images have better overall visual effects and objective evaluation indexes such as PSNR.