CSELT technical reports 

Abstract: Experimental methods have been developed particularly for the subjeelive evaluation of picture telephone systems. The viewing conditions deviate to some extent from earlier recommendations, and the experimental procedures comprise some new features. The methods have been validaled in a test with participation from laboratories in five countries. The results obtained from different laboratorles are generally in good agree­ ment. Results obtained by different methods within a Iabaratory are very similar. The tests prove that alternative experimental methods can be applied for the subjeelive assessment of picture quality with the same result. 1. Introduetion Within the framework of the COST 211 project, a special Subjective Tests Subgroup was created, with the task to develop, describe and use methods by which to evaluate solutions for picture coding proposed within the project. The activities of the subgroup have mainly comprised: a) preparatien of a document descrihing recommended methods for the subjective assessment of visual tele­ phone picture quality; b) performance of an international validatien test in order to prove that the recommended experimental methods lead to consistent and valid results if ap­ plied in different laboratories. This paper presents the results achieved by the sub­ group.