Spatial Frequency Effective for Increasing Perceived Glossiness by Contrast Enhancement.

Area of Science:

• Visual perception
• Image processing
• Computer vision

Background:

• Luminance edges are potential cues for glossiness perception, especially in low-luminance areas.
• Previous studies showed correlations, not causation, between luminance edges and perceived glossiness.
• The role of spatial frequencies in glossiness perception related to surface micro-roughness is not well understood.

Purpose of the Study:

• To investigate the causal relationship between spatial frequency contrast enhancement and perceived glossiness.
• To determine how different spatial frequencies affect glossiness perception under varying surface roughness conditions.
• To explore the influence of specular component luminance on spatial frequency dependency in glossiness perception.

Main Methods:

• Generated object images with varying surface roughness.
• Enhanced contrast in specific spatial-frequency sub-bands for two conditions: Full (natural specular components) and Dark (specular components in dark regions only).
• Assessed the impact of contrast enhancement on perceived glossiness.

Main Results:

• Sub-band contrast enhancement significantly increased perceived glossiness.
• In the Full condition, the effectiveness of spatial frequencies depended on surface roughness.
• In the Dark condition, a constant middle spatial frequency was effective regardless of surface roughness.

Conclusions:

• The visual system relies on high spatial frequency components for glossiness perception related to specular information.
• The dependency on spatial frequency for glossiness perception shifts based on the luminance of the surface being judged.
• Understanding spatial frequency contributions is key to explaining glossiness perception mechanisms.