Wie messen wir das subjektive Bildqualitätserleben? 

Angenommen, auf unsererer durch bisektion gefunden subjektiven Skala hat das Bild A den Wert 1, das Bild B den Wert 2 und das Bild B den Wert 5.
Heißt das nun, dass der subjektive Qualitätsunterschied zwischen Bild C und Bild B dreimal so groß ist wie der zwischen Bild B und Bild A?
Das hängt leider doch wieder von Annahmen ab, mit welcher kognitiven Algebra die Testpersonen die Mittelwerte ausgerechnent haben.
category ratings ...
However, the fact that in ITR-Rec. 500 and .... experimental conditions are prescribed in great detail to foster a comparison of results between labs, the strong dependency might be taken as an indicator of how susceptible of a change of circumastances they are
Methods for determining subjective image quality have been standardized for decades, most notably by the International Telecommunication Union (ITU). Here the main recommended methods employ category ratings and are based on a simplistic model of the human judgement process. This model states that an observer segments his subjective quality continuum into several equal steps and then judges and reports to the experimenter into which of these segments a given image falls. Since some statistical fluctuations are to be expected in such an experiment, judgements are repeated and an average termed "mean opinion score" is computed from them.