Analysis and correction of the nonuniformity of light field in the high resolution X-ray digital radiography

The nonuniformity of light field in the X-ray digital radiography will cause the sensitivity and resolution of the digital X-ray detection decline. And the causes of the nonuniformity of X-ray image light field are the nonuniformity of the X-ray source intensity, nonuniformity of the double proximity focusing X-ray image intensifier response and nonuniformity of the lens vignetting, CCD dark current and light response. A correction method is proposed based on this analysis, this method obtains correction matrix by experiment and bring forth proper correction parameters to the correction matrix to correct the digital image light field. An correction experiment was done to a step-like aluminum block under the microfocus X-ray source, the outcome indicated that the nonuniformity of the radiographic has been apparently proved and the inspection sensitive and resolution of the image has been proved.