Research on suppressing shading from 3D scanned data using a scanned reference model

When a physical object is scanned with an optical 3D scanner in a normal environment, shading is caused by external lighting that effect on the 3D scanned color data. This shading is not easy to separate from original surface color of the model and can make abnormal rendering result when rendered with additional artificial lighting. Therefore, various kind of automatic or manual processing is required to suppressing shading in general. However, the processing requires information of original scanned physical object and lighting environment which is not simple to sense and record. In our research, using white spherical plaster as a reference model, scan in lighting environment as similar as possible then make a model of external lighting environment using the normal vector and brightness information of the reference model to calibrate the color change due to shading. We have scanned experimental data and be applied processing to show feasibility of our method. We found that sphere or hemisphere reference model is effective reference model for process of suppressing shading. It is recommendable to end user application practice and can be included as component of standard or recommendation.