Contrast mapping and evaluation for electronic X-ray images on CRT display monitor

Simple chest X rays on film are the most common type of image in medical diagnosis. However, amongst the various types of medical X-ray images, they require the highest level of display quality due to the fact that the body structures they capture on film have varying degrees of permeability to X rays. Conventional high-definition digital display technology has not always been able to match the quality of such film images. This has been a major impediment against progress toward the complete digitization of simple chest X rays. The intent of this paper is to examine that, when applied to medical diagnosis of chest X rays, super-high-definition (SHD) images (digital images with resolution exceeding that of HDTV) are capable of producing a level of quality of diagnostic accuracy on a par with conventional film images. We will start out by seeking out the overall transmission characteristics of a system that uses digital radiography and a film digitizer to digitize images. We will then derive gray-scale transform characteristics based on the luminance linear method for approximating, as closely as possible on a CRT, film images on a light box that have wide dynamic range and high luminance. Finally, we will present the results of image evaluation experiments using high-definition CRT monitors. These results indicate that conventional film images and those on super-high-definition CRT monitors have nearly the same quality. They will also show that the contrast mapping selected by radiologists and theoretical luminance linear characteristics were almost the same except in low-luminance regions. We will also discuss radiologists' comments on CRT monitors after they participated in the evaluation experiment.