Abstract

Images created from noise filtered to have an approximately 1/f amplitude spectrum were altered by
adding excess energy concentrated at various spatial frequencies. The effects of this manipulation on
judgements of visual discomfort were studied. Visual noise with a 1/f amplitude spectrum (typical of natural
images) was judged more comfortable than any image with a relative increase in contrast energy
within a narrow spatial frequency band. A peak centred on 0.375–1.5 cycles/degree of spatial frequency
was consistently judged as more uncomfortable than a peak at a higher spatial frequency. This finding
was robust to slight differences in eccentricity, and when stimuli were matched for perceived contrast
across spatial frequency. These findings are consistent with the idea that deviation from the statistics
of natural images could cause discomfort because the visual system is optimised to encode images with
the particular statistics typical of natural scenes.