The image transmission method of the X-ray television system is to decompose the image into individual pixel points and transmit them point by point.
During the movement of the electron beam from left to right, the process of picking up or transmitting the image brightness signal for image transmission is called the forward process of the line scan; after scanning one field, the electron beam quickly returns to the upper left corner, and the image content is not transmitted during the return period. The process of returning is called the inverse of the field scan.
Since the image is not transmitted during the reverse of the scan, the electron beam must be extinguished during this time. Otherwise, the retrace line returns to the interference image.