Picture Quality Analysis of Digital TV Signals - Digital Video and Audio Broadcasting Technology - page 201

12.1.2 Double Stimulus Continual Quality Scale Method DSCQS
In the Double Stimulus Continual Quality Scale method according to
ITU-R BT.500, a group of test persons compares an edited or processed
video sequence with the original video sequence. The result obtained is a
comparative quality profile of the edited or processed video sequence, i.e.
a picture quality value from 0 (Bad) to 100 (Excellent) versus time.
The DSCQS method always requires a reference signal, on the one
hand, but, on the other hand, the purely objective analysis can then be per-
formed very simply by forming the difference. In practice, however, a ref-
erence signal is frequently no longer provided. Transmission link meas-
urements cannot be performed using this method. There are test
instruments on the market which reproduce this method (Tektronix).
12.1.3 Single Stimulus Continual Quality Evaluation Method
SSCQE
Since the Single Stimulus Continual Quality Evaluation method SSCQE
deliberately dispenses with a reference signal, this method can be used
much more widely in practice. In this method, a group of test persons only
assesses the processed video sequence and issues marks from 0 (Bad) to
100 (Excellent) which also provides a video quality profile versus time.
Fig. 12.3. Objective picture quality analysis using a test instrument [DVQ]
12.2 Objective Picture Quality Analysis
In the following sections, an objective test method for assessing the picture
quality analysis in accordance with the Single Stimulus Continual Quality
Scale Evaluation method is described. A digital picture analyzer operating
in accordance with this method may provide by Fig. 12.3.