METHOD OF AND APPARATUS FOR PROCESSING A RADIATION IMAGE

A method of and apparatus for processing a radiation image in a radiation image recording system in which a stimulable phosphor is stimulated with a scanning stimulating ray and the light emitted from the stimulable phosphor upon stimulation by the stimulating ray is detected by a detector which gives an output to be processed and used for recording a visible image on a recording material. In the processing of the detected output, an operation represented by a formula EQU S'=Sorg+F(X) is conducted at every scanning point, where Sorg is the original image signal detected by the detector, Sus is an unsharp mask signal corresponding to a super-low spatial frequency, X is Sorg-Sus, and F(X) is a monotonically increasing function which satisfies the condition of F'(X.sub.1).gtoreq.F'(X.sub.2).gtoreq.0 for arbitrary values X.sub.1, X.sub.2 of X (.vertline.X.sub.1 .vertline.<.vertline.X.sub.2 .vertline.) and in which there exists at least one certain value X.sub.0 of X which satisfies the condition of F'(X.sub.1)>F'(X.sub.2) when .vertline.X.sub.1 .vertline.<.vertline.X.sub.0 .vertline.<.vertline.X.sub.2 .vertline..