PURPOSE: To extract an irradiation area handily and accurately from a radiation image taken with the reduction of an irradiation field.
CONSTITUTION: After the trimming of an original digital radiation image signal (S1) an image area is divided into small parts (S2). Here, a dispersion value of an image signal contained is calculated from each small area (S3) and columns and lines of the small areas in which the small areas with the dispersion values exceeding a specified value are contained in number larger than a specified number are recognized as candidates specifying the contour of the irradiation field. (S4) Then, the correctness or error in the recognition of the contour is judged depending on whether a representative value of an image signal in a column and line one column (line) outer side of those selected as candidate indicates a value corresponding to an area of stopping the irradiation field. (S5) When the recognition is correct, those inside the candidate column and line are extracted as area of irradiation field. (S6)
ISHII MITSURU
YANAGIDA AKIKO
TSUCHINO HISANORI
| JPS63268077A | 1988-11-04 | |||
| JPH02164352A | 1990-06-25 | |||
| JPS63183434A | 1988-07-28 | |||
| JPH0281278A | 1990-03-22 | |||
| JPH0254267A | 1990-02-23 | |||
| JPS60105081A | 1985-06-10 | |||
| JPH021081A | 1990-01-05 |