Research of Measurement for Digital Image Definition
图像清晰度评价方法研究

Evaluation of definition for gray scale digital image is an important aspect of digital imaging system. Thus, in order to evaluate the definition of a gray scale image accurately and effectively, we present a new approach based on EVA method which, while retaining important features of existing method, overcomes some of their limitation. With curvilinear regression analysis we can prove that the result of the new approach is high correlation with MTF measured by optical instrument, in other words, the new method is sensitive to the change of image definition. When compared with traditional method, the result of analysis can also show that the new method is better than traditional method, such as entropy, to assess gray scale digital image definition. Experiments using hundreds of many kinds of gray scale digital image and the result of this new approach is well accurate to the change of definition of digital image. Form these we can also draw a conclusion that the new approach can be well applied to many kinds of gray scale digital image accurately and effectively.