Method and apparatus for analyzing the appearance features of a surface
US5155558A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 19, 1990 |
| Grant date | Oct 13, 1992 |
| Priority date | — |
| Expiry date | Sep 19, 2010 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2021/1765
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method and apparatus for analyzing the appearance features of a surface with a spatially coherent beam of uniformly distributed collimated polychromatic light that is directed through a beam limiting means (or mask) and onto the surface at an acute angle of incidence. A scanned imaging detector, translatable through a sequence of focal plane positions along the optic axis between the mask and surface, measures the reflectance values associated with the scanned pixel intensities. After standardization, the scan intensity values are Fourier transformed into the spatial frequency domain to obtain an optical transfer function (OTF) and power and amplitude spectra. The visual spatial frequency response characteristic V(f) and standard psychophysical methodology is applied to mathematically determine surface appearance attributes such as orange peel, microwrinkle, cracks and crazes, distinctness of image (DOI), gloss, haze, contrast, luster, fog and texture.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.