| 摘要 |
<P>PROBLEM TO BE SOLVED: To convert an input image to an image having contrast properly secured throughout the pixel areas in radiographic processing. <P>SOLUTION: Parameters of sigmoid functions are not set to constants but are set so as to obtain smooth functions (for example, sigmoid functions equivalent to a gradation curve), and a double gamma-gradation curve where gentle sigmoid functions are continuously varied to sharp sigmoid functions or sharp sigmoid functions are continuously varied to gentle sigmoid functions is generated, and thus gray-scale transformation being smooth in all pixels is possible, and contrast of the input image is made proper. <P>COPYRIGHT: (C)2004,JPO |
