| 摘要 |
PURPOSE:To avoid the error due to noise, by constituting the detector for changing part for still picture transmission which is for monitor of invasion or transmits the changing part only, with a difference circuit, absolute value circuit, discriminating section discriminating average value and maximum value and a changing detection part. CONSTITUTION:A video signal 1 stored and read out in one screen memory and another input video signal 2 are converted into difference signal 4 by using a difference circuit 3, and this is made to the absolute value signal 6 at the absolute value circuit section 5. Next, this signal 6 is fed to the discriminating section 7 by the average value and the discriminating section 8 by the maximum value respectively and the result of discrimination 9, 10 are input to the change detector 11. With the unit constitution, if either one of the results 9, 10 is changed, it is taken the presence of change and the detected output is delivered as the signal 12. Thus, the detection of the presence of change can be made with fidelity. |
