Method and system for processing an image

Abstract

A method of processing an image having a plurality of picture-elements is disclosed. The method comprises: preprocessing the image to selectively enhance contrast of some picture-elements of the image, and employing a companding procedure for the preprocessed image, thereby providing a processed image. The contrast enhancement optionally and preferably features a mapping function having a plateau region for diminishing image data with intensity levels below an intensity threshold, thereby providing a preprocessed image.

What is claimed is: 
     
         1 . A method of processing an image having a plurality of picture-elements, comprising:
 removing isolated objects from the image;   preprocessing the image to diminish image data with intensity levels below an intensity threshold, thereby providing a preprocessed image;   employing a companding procedure for said preprocessed image, thereby providing a processed image; and   outputting said processed image to a computer readable medium or a display device.   
     
     
         2 . The method of  claim 1 , wherein said removal of said isolated objects features a connected components labeling procedure. 
     
     
         3 . The method of  claim 1 , wherein said intensity threshold is an average intensity over all picture-elements of the image having intensity levels within a predetermined intensity range. 
     
     
         4 . The method of  claim 1 , wherein the image is an image of a section of a living body and said intensity threshold is correlated with intensity levels characterizing fatty tissue present in said body section. 
     
     
         5 . The method of  claim 1 , wherein said mapping function comprises a monotonic region for intensity levels above said intensity threshold. 
     
     
         6 . The method of  claim 1 , wherein said companding procedure comprises, for each picture element of said preprocessed image:
 (i) defining a surrounding region of picture elements and a remote region of picture elements;   (ii) calculating at least one adaptation weight; and   (iii) using said at least one adaptation weight and intensity levels of each picture element of said surrounding and said remote regions, for assigning a new intensity level to said picture element, said new intensity level being in a dynamic range which is smaller than the dynamic range of said preprocessed image.   
     
     
         7 . The method of  claim 6 , wherein said adaptation weight describes, at least in part, contrast induction between said surrounding region and said remote region. 
     
     
         8 . The method of  claim 7 , wherein said adaptation weight features a plurality of different resolutions, and wherein said contrast induction is calculated separately for each resolution. 
     
     
         9 . The method of  claim 8 , wherein for each resolution, said contrast induction is calculated as a subtraction between intensity levels integrated over said surrounding region and intensity levels integrated over a central region. 
     
     
         10 . The method of  claim 1 , further comprising employing anisotropic diffusion procedure for reducing noise. 
     
     
         11 . The method of  claim 1 , wherein said image is a mammography image. 
     
     
         12 . The method of  claim 11 , wherein said processed image exhibits Cooper's ligaments. 
     
     
         13 . The method of  claim 11 , further comprising identifying and highlighting Cooper's ligaments in said processed image. 
     
     
         14 . The method of  claim 1 , wherein said image is selected from the group consisting of a CT image, an X-ray image other than a CT image, a gamma image, a PET image, a SPECT image and a thermal image. 
     
     
         15 . Non-transitory computer-readable medium having stored thereon a computer program, wherein said computer program comprising code means that when executed by a data processing system carry out the method according of  claim 1 . 
     
     
         16 . A system for processing an image having a plurality of picture-elements, comprising:
 an electronic input for receiving the image;   a preprocessing unit configured for preprocessing the image to remove isolated objects from the image, and to diminish image data with intensity levels below an intensity threshold; and   a companding unit which compands said preprocessed image.   
     
     
         17 . The system of  claim 16 , further comprising an imaging system for acquiring the image, wherein said input unit receives the image from said imaging system. 
     
     
         18 . The system of  claim 16 , wherein said preprocessing unit is configured for removing isolated objects from the image, prior to said selective contrast enhancement. 
     
     
         19 . The system of  claim 16 , further comprising a noise reduction unit configured for employing anisotropic diffusion procedure. 
     
     
         20 . The system of  claim 16 , wherein said image is a mammography image and wherein the system comprises a functionality for highlighting Cooper's ligaments in said processed image.