EEG-Based Assessment of Perceived Quality in Complex Natural Images

Psychophysiological methods gained a lot of interest in recent years as a potential remedy for the inherent flaws of overt psychophysical quality assessment methods. Among the psychophysiological monitoring methods, electroencephalography showed to be a promising choice. Specifically, the steady state visually evoked potential (SSVEP) was shown to provide a reliable neural correlate of perceived visual quality for degraded texture image patches. This paper evaluates the feasibility of the SSVEP-based quality assessment approach for more realistic and practically relevant images. To this end, we collected overt, psychophysical responses and neural, psychophysiological responses of 14 participants to 6 HD images each compressed at 4 distortion levels. The psychophysical part followed the Degradation Category Rating procedure. In the subsequent psychophysiological part, the subjects were presented with distorted and reference images alternating at a fixed rate of $f_{stim}\,=5$ Hz to elicit the SSVEP. We show that the amplitude of the $1 ^{st}$ harmonic of the SSVEP correlates significantly with the psychophysical responses $(\vert \rho \vert = 0.85, p \lt 0.05)$ in a single channel analysis at the Oz electrode.