There are many other kinds of shadowless light sources. As long as the light coming out is diffuse and disorderly, no shadow can be called shadowless light source when shooting objects. In machine vision LED light source, there are dome shadowless light (also called integral light source), plane shadowless light source, ring shadowless light source and four-sided shadowless light source. Shadowless light sources are generally used for surface inspection, OCR character recognition, uneven product inspection, parts existence inspection, visual inspection which requires higher uniformity of field of view lighting, etc.
Dome Shadowless Light Source:
Figure 1 Dome Shadowless Light Source
Figure 2 Planar Shadowless Light Source
What is a shadow light source?
Shadow light source, because of its strong directivity of illumination, when illuminating uneven workpiece, will make the high target projected to the plane of low target to form shadow, so this kind of light source can be classified as shaded light source. The greatest characteristic of shadowy light source is that the light source usually only illuminates from one direction, instead of illuminating the whole workpiece from above, just like the shadowless light source.
Generally speaking, circular light, strip light, spot light, line light, coaxial (parallel) light, surface light and other LED light sources can be classified as shadow light sources.