Virtual structured-light coding for three-dimensional shape data compression

In order to reduce the file size of three-dimensional (3D) shape data, we propose two compression algorithms: two-channel phase coding algorithm and three-channel phase coding algorithm. In these two algorithms, 3D shape information is encoded into the color channels of a single 24-bit color image based on virtual structured-light projection system. Tested with a hemisphere of 1 mm diameter used in another virtual structured-light coding algorithm, which was proposed by Nikolaus Karpinsky and Song Zhang in ‘composite phase-shifting algorithm for three-dimensional shape compression’ in 2010, the two-channel phase coding algorithm achieves compression ratio 1:56.6 with reconstruction error of ±4.91×10−4 mm, and the three-channel algorithm gains compression ratio 1:33.8 with reconstruction error of ±0.36×10−4 mm. The theoretical analyses demonstrate that the relative reconstruction errors of our coding algorithms can be reduced to 7.66×10−6 and 2.99×10−8 of the height of the 3D object, respectively. With these theoretical analyses, the virtual structured-light coding algorithms can be used to achieve desired reconstruction qualities with high compression ratios in storing, transmitting, encrypting 3D shapes and constructing 3D face databases.

► Two compression algorithms are proposed for 3D shape data compression.
► Quantitative analysis shows that the reconstruction errors are the same.
► These algorithms can meet the resolution of the common optical measurement.