A Quantitative Analysis on the Subjective Effects of TV Pictures Impaired by Multiple Ghosts

Abstract

A method for quantifying subjective quality of TV pictures impaired by multiple ghosts is discussed by proposing a typical model for the assessment of ghost image problems in TV reception. Equivalent Perceived DC Ratio has been proposed and considered as the first step to obtain quantitative relations between subjective quality evaluation and such physical factors as r.f. signal/r.f. ghost level ratio (D/U), r.f. phase (φ), delay time (τ), number of ghosts (n), and variety of pictures.
Subjective tests have been made on the effect of single ghost and of a few types of multiple ghosts on still color pictures. It is clear that the effect due to D/U and φ can be expressed in terms of Equivalent S/I defined as the signal to positive ghost level ratio to which the subjective effects are equivalent. Multiple ghosts with the same polarity and close delay time with each other can be subjectively converted into a single ghost by the power sum law with delay-time-weighting.