TABLE OF CONTENTS Laurence J. Thorpe
Jerry C. Whitaker, Editor-in-Chief
The resolution of the displayed picture is the most basic attribute of any video production system. Generally speaking, an HDTV image has approximately twice as much luminance definition horizontally and vertically as the 525-line NTSC system or the 625-line PAL and SECAM systems. The total number of luminance picture elements ( pixels) in the image, therefore, is 4 times as great. The wider aspect ratio of the HDTV system adds even more visual information. The HDTV image is 25 percent wider than the conventional video image for a given image height; the ratio of image width to height in HDTV systems is 16:9, or 1.777. The conventional video image has a 4:3 aspect ratio.
As a result of these attributes, the HDTV image may be viewed more closely than is customary in conventional television systems. Full visual resolution of the detail of conventional television is available when the image is viewed at a distance equal to about 6 or 7 times the height of the display. The HDTV image may be viewed from a distance of about 3 times picture height for the full detail of the scene to be resolved.
Although there is no single, universal definition for HDTV, it is generally accepted to encompass several elements which are described by various consumer, broadcast, and regulatory groups. HDTV offers the potential for approximately twice the horizontal and twice the vertical resolution of current (NTSC) television. When combined...
