Patent Document ID: 5454053
Application ID: 08229217
Patent Status: 1

Claim One:
1. A method for compressing a dynamic range of an image, comprising the steps of: applying an original image signal Sorg which represents an original image of an object to an image processing means; calculating a contrast of the original image signal Sorg by using the image processing means; calculating the value of an unsharp mask signal Sus corresponding to each of picture elements in an original image by averaging the values of image signal components of the original image signal Sorg representing the original image, which image signal components represent the picture elements belonging to a predetermined region surrounding each of the picture elements, by using the image processing means; determining a range of image density of the original image to which a function f.sub.1 (Sus) is to be applied in accordance with the level of contrast of the original image signal Sorg, by using the image processing means; determining a value of the function f.sub.1 (Sus), the value of which decreases monotonously as the value of the unsharp mask signal Sus increases, in accordance with the level of the contrast of the original image signal Sorg, by using the image signal processing means; processing the original image signal Sorg with the formula EQU Sproc=Sorg+f.sub.1 (Sus) whereby the values of a processed image signal Sproc representing an image having a narrower dynamic range than the original image is generated, said processing being performed by the image signal processing means; applying the processed image signal Sproc to an image reproducing means; reproducing a visible image in accordance with the processed image signal Sproc, using said image reproducing means.