| In the production process of digital image reproduction, the document usually is required a great clarity. Sharpness of image copy is an important indicator to judge the quality and effectiveness of image reproduction. In the procedure of image processing and transmission, due to the interference of various factors, there will always be some detail missing, which lead to the damage of image sharpening and the blurred images in the target profile. Therefore, in actual operation, emphasizing to satisfy our requirements through technical means is particularly important.In practical work, we can only take aimlessly adjustment to the image sharpening depending on experience or feeling, which resulting in failure to emphasize clarity or excessive emphasize. In order to solve this problem, this paper fully analyzes the principle of image sharpening, a variety of factors affected the image sharpening, and the common principle of image sharpening, such as the use of optical effects, electrical effects, and mathematical methods to emphasizes clarity; analyzes the visual effect of several people is how to affect people’s perception of the image clarity, including O’Brien effect, Mach band effect, as well as the significance of human visual modulation transfer function (MTF); made a detailed analysis of the principles and effect of several methods of improving image clarity in PS, such as Unsharp Masking(USM), Smart Sharpen, High Pass, LAB mode L channel sharpening; and contrast of the image applied to different situations in the analysis based on visual characteristics. To be able to fully explain and compare results emphasize clarity, in order to fully express and compare all kinds of effects of sharpening, I make use of MATLAB software for calculation processing with the best resolution for a variety of treatment methods to image sharpening, then finally compare with the theoretical data, demonstrate the practicality in accordance with a standard deviation of clarity emphasized practicality.. |
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