Several scaling methods ale used to quantify the perceptual quality of
television images. One method used is the double-stimulus continuous
quality scale recommended in CCIR Rec. 500-4. In this method a graphic
al scale is divided into five intervals with which quality terms are a
ssociated. The aim of the research discussed in this article was to qu
antify the perceived distances between a number of Dutch-language term
s, including the translated CCIR terms, that are toed to describe the
perceived quality of television images. It is shown that the translate
d CCIR quality terms do not divide the quality scale into intervals of
equal sizes. Also, in view of the large standard deviations of the av
erage positions of the quality terms, if is concluded that a graphical
scale divided into intervals with which quality terms are associated
cannot be used as an interval scale. This implies that numerical proce
ssing of scores (such as averaging) is highly, questionable. A 10-term
ordinal scale is proposed when an indication of the absolute quality
of display systems is needed.