X-ray image quality evaluation is the key problem of ray detection accuracy.The efficiency and real-time of the traditional subjective assessment method is poor.Also for some objective assessment indexes

such as contrast

definition

and so on

they have a certain limitation because of scatter and noise in the X-ray imaging.So this paper provides the method of X-ray image quality evaluation based on linear constraint with variable energy.First

based on the gray trend between the ray image sequences with variable energy imaging

the concept of the gray gain histogram between sequences is provided.Then based on the linear optimal imaging about imaging detector

evaluate image quality by the linear dispersion.Further

for the failure of dispersion evaluation because of over-exposure

synthesizing the linear dispersion and average contrast

the paper builds a standard of ray image quality evaluation.At last

the experiment proves the feasibility about this new standard.And it can avoid the limitation of the traditional single evaluation index.