| 摘要 |
PURPOSE:To suppress the occurrence of gradation jump in a gradation converter which decides the gradation conversion characteristic based on the appearance frequency of the digital image signal. CONSTITUTION:The analog image signal received from a photoelectric transducer 1 is converted into an m-bit digital image signal by an A/D converter 2. A histogram counter 4 counts the appearance frequency of the digital image signal. A gradation conversion characteristic setting means 5 sets the gradation conversion characteristic based on the counting result of the counter 4 and changes this conversion characteristic of a gradation converter means 6 in response to the set gradation conversion characteristic. Then the m-bit digital image signal undergoes the gradation conversion through the means 6 and sent to a printer 7 and a CRT device 8 as an n-bit digital image signal (n<m). |
