Technology application - The photometric stereoscopic technology Four 90-degree quadrant lights are used to project directional shadows in a
stroboscopic manner around the concave and convex features of measured
object. This set of image features is enhanced through various algorithms to
display subtle surface features that are difficult to find or impossible to show
on 2D images.
Application case - Detection of defects in pouch lithium battery
Four-direction original diagram
Photometric stereogram can distinguish between depressions and bulges