Importance

Loading Importance Indicators...

Abstract

A test signal for enabling control of picture fidelity in a distribution system for distributing a video signal that has a vertical interval including a number of lines. The test signal comprises plural luminance levels for testing luminance linearity. The luminance levels have a non-linear level relationship with respect to one another. Each luminance level has a predetermined level. The test signal may additionally include a chrominance component for testing differential gain and phase. The chrominance component has a predetermined amplitude and a predetermined phase corresponding to flesh tone. In a method of enabling control of picture fidelity in a distribution system for distributing a video signal, the above test signal is provided at a source stage and is inserted into at least part of a selected line in the vertical interval of the video signal. At a later stage in the distribution system, at least two of the luminance levels in the test signal in the vertical interval of the video signal are measured, each of the at least two measured luminance level are compared with its corresponding predetermined luminance level to provide at least two luminance errors, and luminance linearity in the source stage and/or the later stage is changed to correct the luminance errors. Chrominance gain and phase errors may also be determined, and differential gain and phase changed to correct the chrominance gain and phase errors.

Loading the Abstract Image...

First Claim