Subjective tests on visual telecommunications standards

Quality grading tests have been conducted to investigate the subjective effects of various combinations of transmission channel bandwidth, television-line standard and display size. The test pictures used were head-and-shoulders views. 313-line signals transmitted through a channel with 1 MHz bandwidth proved to be more acceptable than 625-line signals transmitted through the same channel. A smaller display of height, equal to 1/8 times the viewing distance, was always preferred to one of height equal to 1/4 times the distance. The results will be of use in determining the parameters for future visual telecommunications systems, not necessarily using the 625-line broadcast t.v. standard.