| 摘要 |
PURPOSE:To accurately detect a noise in a picture by obtaining the relation of quantity being a difference between signals being photoelectric conversion to the result of picture elements arranged linearly detected from a fluorescent sheet where a radiograph is stored. CONSTITUTION:A picture formed on an accumulation type fluorescent sheet 10 is scanned in the direction of X by a laser beam 12, a stimulated luminous light 15 is subjected to photoelectric conversion 17, subjected to log amplification 20, A/D conversion 21 and the resulting picture signal is inputted to a noise elimination circuit 22. Each difference Di=Fi-Fi-1 (i=2-n) of picture signals F1-Fn of picture elements A1-An in the direction X is obtained. Two differences Dj, Dk having relations of Dj>T1, Dk<-T2 are obtained, where T1, T2 are positive constant and j<k, it is regarded that noise is included if the relation of k<j+u (u is a positive number less than 6) exists and the position of the center picture element of picture elements Aj-Ak-1 is obtained. The processing is applied all to the X direction picture element array. The position of noise is stored in the circuit 22. After the noise is eliminated by a picture processing circuit 23, the picture is reproduced. Thus, the noise due to external ray is eliminated.
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