Motion, flash, and flicker: A unified spatiotemporal model of perceived edge sharpening

Stephen T. Hammett*, Mark A. Georgeson, Gillian S. Barbieri-Hesse

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Blurred edges appear sharper in motion than when they are stationary. We proposed a model of this motion sharpening that invokes a local, nonlinear contrast transducer function (Hammett et al, 1998 Vision Research 38 2099-2108). Response saturation in the transducer compresses or 'clips' the input spatial waveform, rendering the edges as sharper. To explain the increasing distortion of drifting edges at higher speeds, the degree of nonlinearity must increase with speed or temporal frequency. A dynamic contrast gain control before the transducer can account for both the speed dependence and approximate contrast invariance of motion sharpening (Hammett et al, 2003 Vision Research, in press). We show here that this model also predicts perceived sharpening of briefly flashed and flickering edges, and we show that the model can account fairly well for experimental data from all three modes of presentation (motion, flash, and flicker). At moderate durations and lower temporal frequencies the gain control attenuates the input signal, thus protecting it from later compression by the transducer. The gain control is somewhat sluggish, and so it suffers both a slow onset, and loss of power at high temporal frequencies. Consequently, brief presentations and high temporal frequencies of drift and flicker are less protected from distortion, and show greater perceptual sharpening.

Original languageEnglish
Pages (from-to)1221-1232
Number of pages12
Issue number10
Publication statusPublished - 30 Dec 2003

Bibliographical note

Hammett, Stephen T.; Georgeson, Mark A. and Barbieri-Hesse, Gillian S. (2003). The definitive, peer-reviewed and edited version of this article is published in Perception, 32 (10), pp. 1221-1232, 2003. DOI: 10.1068/p3400.


  • blurred edges
  • motion
  • motion sharpening
  • contrast transducer function
  • dynamic contrast gain control
  • speed
  • contrast invariance


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