Surface inspection system identifies contamination and defects

Paul Boughton

Stemmer Imaging's Trevista surface inspection system features patented ‘shape from shading’ technology. This allows problem-free inspection of a wide range of materials including those that have varying reflections which are otherwise difficult to measure using traditional machine vision methods.

The intrinsic dome-shaped illumination ensures optimum and even illumination of the material’s surface from different directions and also suppresses interfering ambient light.

Key to the performance of the system is the way image data are processed. The patented ‘shape from shading’ technology uses a special algorithm to analyse a series of four sequential images obtained at different angles of illumination to deduce information on the three-dimensional shape of an object from the shading of its surfaces. This allows defects of just a few microns diameter and depth to be detected on a variety of material surfaces. 

The system is supplied complete with structured diffuse illumination, lens, software, PC and a high resolution Genie TS camera from Teledyne DALSA.