| 摘要 |
PURPOSE:To input a first signal only to a memory element corresponding to a picture element releasing a mask by providing a means for detecting a change of an output from a mask memory read in a reading circuit. CONSTITUTION:An output 12 of a detecting means 40 is reset by a start signal 10 of respective horizontal scanning outputted from a picture address generating circuit 15 to become a binary signal '0', and when a first signal is read from a mask memory 26, it becomes a binary signal 1 by its last transition signal. Then, thereafter, this condition is maintained, and when a second signal is read from the mask memory 26, it becomes a binary signal '0' by its last transition signal. A picture memory 7 has a memory byte equal to the number of picture element of a pick up tube 1 and is constructed so as to store a memory corresponding to an output of an A/D conversion means 3 only when a gate circuit 5 is opened. The pick up tube 1, the picture memory 7 and the mask memory 26 synchronize with a clock signal 17 outputted from a clock circuit 18 to be scanned to an address signal outputted from a picture address generating circuit 15. |
