Narrow-band video telephone system - displays whole image whilst still allowing high resolution image area and using reduced capacity memory

摘要

The narrow-band video telephone system displays the entire object viewed by the camera on the screen whilst still allowing areas of high resolution. This is achieved by transmitting from the receiver the wanted image area with high detail resolution but reduced movement resolution and the rest of the image with reduced detail resolution and high movement resolution. The receiver (B) has an image area generator (G) that stores the coordinates of the wanted image area (F) and transmits it via a picture channel (a) to the transmitter (A) and simultaneously operates a changeover switch (SZ, S3). The changeover switch passes the incoming picture signals outside the image area via a memory (Sp) to the crt crt. The transmitter has a detector (C) that responds to the transmitted coordinates and operates an adaptation switch (S1) within the wanted area.