The light source contains lamp beads in 5 wavelengths: red, green, blue, white and infra-red, allowing for colour temperature adjustment from 1000-10000K colour temperature (200K interval). The light beads are evenly distributed in 4 zones, each zone can be individually controlled for brightness levels of red, green, blue, white and infra-red, as well as for colour temperature levels, and brightness levels of colour temperature. It can be applied to photometric stereo inspection, producing contrast pictures to highlight local 3D changes in order to extract 3D information about the sample surface; it can also be applied to sample colour difference detection, where a single light source achieves an arbitrary wavelength compound effect, and for subtle colour differences can be discriminated.