Motion blur and motion sharpening: temporal smear and local contrast non-linearity

Area of Science:

• Visual perception
• Neuroscience

Background:

• Perceived image sharpness can differ between static and moving patterns.
• Motion can paradoxically enhance or degrade edge sharpness.

Purpose of the Study:

• To investigate the perceived sharpness of moving blurred patterns compared to static ones.
• To resolve the paradox of motion affecting sharpness differently based on blur extent.

Main Methods:

• Comparing perceived sharpness of drifting and static square wave gratings.
• Systematically varying pattern speed, blur extent, and spatial frequencies.
• Developing a quantitative model for motion-induced waveform distortion.

Main Results:

• Motion sharpening occurred for large blurs (> 10 min arc).
• Motion blurring occurred for small blurs (< 10 min arc).
• A model incorporating temporal integration and contrast non-linearity explained the results.

Conclusions:

• Visual perception of sharpness depends on the interplay between motion speed, blur extent, and contrast.
• A dual mechanism involving temporal smearing and local contrast enhancement explains motion-dependent sharpness changes.
• Differential M and P cell recruitment may underlie the observed speed-dependent non-linearity.