Photometric Stereo Defect Inspection System

The photometric stereo method can extract a 3D model
based on 2D texture information. These images are
captured by illuminating the object from different directions
while keeping the relative position between the camera and
the object fixed.
The 3D model of the object is primarily derived from the
local gradients of the 3D surface. The local gradient
information of the 3D surface can be further integrated to
obtain a height images.