SCANNER

PROBLEM TO BE SOLVED: To reduce number of components of the scanner or post-processing by providing a means to insert a scaling signal into a video signal prior to the post-processing of the video signal. SOLUTION: An analog insert circuit 7 is arranged in an analog signal branch before an A/D converter 6. Then a scaling signal SKS is inserted in the video signal. The insert circuit 7 and a multiplexer 8 are controlled by a pulse generator 9 so that the scaling signal is written in a test line of the video signal. A horizontal frequency pulse of the video signal is counted to control the pulse generator included in the insert circuit 7. As a result, the video signal is sent from the A/D converter 6 and the scaling signal SKS is sent from the pulse generator 11. Then the scaling signal SKS is processed like a conventional video signal by a post-stage digital signal processor in place of the arithmetic operation of an amplifier.