| 摘要 |
PURPOSE:To obtain an easy-to-see monitor picture having a stabilized range of density by obtaining the median value of the pre-read picture signal that read out the outline of the stored memory information to a sheet and normalizing the display gray level in response to said median value. CONSTITUTION:The stored memory information on a storage-type fluorescent sheet 103 is read roughly by a pre-reading laser light source 201, a pre-reading photodetector 208, etc. and converted into the pre-reading picture signal Sp via an A/D converter 211. Receiving this signal Sp, a control circuit 314 produces a histogram of the signal Sp and calculates the median value Sm of the signal Sp from said histogram. Then a signal processing circuit 220 normalizes the gray level by the value Sm so that the value Sm is equal to the median value of the display gray level of a monitor means 221. Therefore the gray level is normalized so that the maximum and minimum deflections of the signal Sp if produced can be eliminated. Thus it is possible to obtain an easy-to-see monitor pre-read picture with a stabilized range of density. |
