METHOD OF CORRECTING MEASUREMENT OF OPTICAL DENSITY FORMED ONTO X-RAY FILM

摘要

PURPOSE: To exclude an adverse influence resulted from the non-linearity of the characteristic curve of the sensitivity of a film. CONSTITUTION: The optical concentration of a picture indicated by an X-ray photograph 6 is detected by a photodetector 8. A signal DO outputted from the photodetector 8 is a timely changing signal as the function of the inspection of the line of an image, and it is digitized by an analog/digital converter 9. A processing operation to be executed to a digital signal outputted by the analog/digital converter 9 is executed by computers 35-37 which process digitized information coded into a binary. In this case, the harmful action of the linear defect of the characteristic curve of the sensitivity of an X-ray photographic film used for the X-ray photograph 6 can be corrected by statistically investigating a picture noise.