| 摘要 |
PURPOSE:To decide the existence of an irradiation diaphragm by comparing the magnitude of the representative value of a picture signal corresponding to the peripheral part of a recording sheet and the magnitude of the representative value of another picture signal corresponding to either the whole or the approximately central part of the recording sheet. CONSTITUTION:The picture signal is obtained by reading a radiation picture from the recording sheet such as a storing type fluorescent substance sheet and a photographic film on which the radiation picture of an object is recorded. Based on this picture signal, a first representative value to represent the value of the picture signal corresponding to either the whole of the peripheral part of the recording sheet (for example, an area 7) or one part of the peripheral part of the recording sheet (for example, an area 7') and a second representative value to represent the value of the picture signal corresponding to either the whole of the recording sheet (the area 7 + an area 8) or the approximately central part of the recording sheet (for example, the area 8) are obtained. Next, the magnitude of the first representative value and the magnitude of the second representative value are compared, and the existence of the irradiation diaphragm can be decided from the compared result. |
