Control of geometric unsharpness in digital radiography

From the perspective of practical radiographic testing, the main parameters affecting the geometric unsharpness is analyzed. Especially for the widely used digital radiography at present, the control requirements of focal distance under the condition of geometric transillumination is discussed when the detector cannot be placed closely with the object, the accurate calculation formula of the distance between the surface of curved object and the detector is derived, and a guidance for examiners to optimize the testing process is provided.