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.