| 摘要 |
PURPOSE: To provide the method for automatically adjusting a gradation scale of a digital radiation image. CONSTITUTION: A light (e.g. light in a blue light region) emitted by a storage fluorescent body 10 is detected by a photodetector 34 and converted into a digital image by an A/D converter 36. The digital image is given to an image processor 38, where automatic gradation scale processing and other image processing are applied to the image. That is, a histogram of the digital input image and the accumulated distribution function of the histogram are used to generate final gradation scale conversion by employing an entropy of a sub-section of the histogram. The histogram is divided into a noted area, a low signal foreground area and a high signal background area by using the function above. The gradation scale is formed to be almost a straight line in the noted area by smoothly coupling a nonlinear part at ends of the foreground area and a nonlinear part of the background area. |
