Structure: like below picture, the high angle illumination can allow the light reflecting from even surface to come into the CCD camera and lens, and the image is bright, it also can prevent some disorder light reflecting from uneven surface to come into the CCD camera and lens and the image is some dark.
Main application: surface scratch inspection, stamping letters recognition and inspection, foreign part on the surface inspection, edge size measurement, location and so on
Advantage: good image result, detail clear
Disadvantage: It is some hard to get uniform image
LED machine vision light: high angle ring light, bar light, back light as front light, coaxial light, spot light
Bright field, high angle illumination image result of coin
High angle illumination makes background white, what we usual said white illumination, it can show the even surface configure clearly, the surface scratches, slope information can also show clearly. The reflective rate is different as the harsh rate is different of the surface.