| 摘要 |
PROBLEM TO BE SOLVED: To stably and accurately extract a feature amount in the case of gradation-converting the lung area of an X-ray image by using a density feature amount. SOLUTION: In the case of gradation-converting the lung area, based on the fact that stable gradation characteristics are obtained at the time of using a maximum value inside the lung area as the density feature amount, the-feature amount is extracted. An image conversion circuit 113a binary-converts a pixel value equal to or more than a threshold in an irradiation area image including the lung area to 0 and the pixel value smaller than the threshold to 1 and a connection verification circuit 113b verifies the connection component of the converted binary images and extracts a hole area. A pixel value change circuit 113c calculates the size of the extracted hole area, and when a ratio to the entire image exceeds a fixed ratio, decides the threshold as the feature amount. |
