3D model based shading correction for the enhancement of multispectral colour measurement accuracy

Shading effects induced by illumination and local object surface orientation could strongly deteriorate the accuracy of colour imaging. Therefore, a shading correction is needed for high colour fidelity. In this work a 3D model based inverse rendering approach is proposed for a narrowband multispectral 3D colour imaging system with a calibrated extern broadband light source. The colourimetric evaluation with an X-Rite colour checker shows that the proposed method could ensure a mean colour difference value CIEDE2000 ΔE < 3 for the viewing angle range -30° to 30°, while the maximal improvement factor concerning mean ΔE comes to 2.86.