Method of image enhancement by raster scanning.

摘要

A method of image enhancement is disclosed in which a raster scan of an original image is made and the electrical signals so generated are processed on line to give an enhanced image.

The adaptive image filtering scheme used gives edge and contrast enhancement. The technique is based on a sliding window, which moves across the image both in vertical and horizontal directions. At each step the center pixel density D<Sub>c</Sub> of this window is transformed to a new value D<Sub>c</Sub>', upon the following mathematical equation<MathDetails id="matha01"><MathText><![CDATA[ <img id="ia01" file="imga0001.tif" wi="29" he="9" img-content="math" img-format="tif" inline="no" /> ]]></MathText></MathDetails>where D represents the mean level of the window. The parameters a and β are identified and adjusted on line.

Since the parameters a and are adaptively adjusted according to the statistics of a given window size, there are no user interactions required. Unlike earlier techniques, high frequency noise components are not uniformly enhanced. The technique is particularly valuable in the treatment of medical radiographic images.