Abstract: In a method of detecting noise in image signals, noise contained in image signals representing a radiation image, which are obtained by exposing a stimulable phosphor sheet carrying the radiation image stored thereon to stimulating rays, and photoelectrically detecting light emitted by the exposed portion of the stimulable phosphor sheet in proportion to the stored radiation energy, is detected. The method comprises the steps of comparing the image signal a at each remark picture element A with values (b1+T1), (b2+T2), . . . , (bn+Tn) obtained by adding predetermined values T1, T2, . . . , Tn respectively to image signals b1, b2, . . . , bn at picture elements B1, B2, . . . , Bn in the vicinity of the remark picture element A, and recognizing that noise is contained in the image signal a in the case where the image signal a attains a value larger than every one of the values (b1+T1), (b2+T2), . . . , (bn+Tn).

Abstract: In a radiation image read-out method wherein preliminary read-out is conducted prior to final read-out for adjusting final read-out conditions and/or image processing conditions for a radiation image stored on a stimulable phosphor sheet, a histogram of preliminary read-out image signals obtained by the preliminary read-out is created. A characteristic value of the preliminary read-out image signals within a region at least outside of a sharp peak region arising near the maximum signal value and/or the minimum signal value in the histogram is calculated. The final read-out conditions and/or the image processing conditions are adjusted based on the characteristic value.