| 摘要 |
PROBLEM TO BE SOLVED: To provide a method which decides automatically the contrast and brightness of a radiation image by deciding the minimum and maximum gray levels, defining an area of a gray level that can decide the brightness (WL), preparing a WL calculating rule and deriving a range of gray levels from the WL calculating rule against the contrast. SOLUTION: A series of images and a mathematical model of an object are prepared, and the minimum and maximum gray levels are decided and a range of an effective area is also decided based on a set of parameters of the object and by means of a collector, a detector and a positioning means. Then the parts of a histogram which are lower than the minimum gray level and higher than the maximum gray level respectively are suppressed (limited histogram). A set of rules is applied to the limited histogram to decide a brightness level. Then a contrast is decided from the brightness and also one or plural parameters which are selected by a user or transcendentally decided as necessary. |
