Hybrid light coding for fast and high-accuracy shape acquisition

We present a high-accuracy shape acquisition approach that uses a combined Gray code and phase-shifting structured light projection. The Gray code pattern coarsely divides the projected plane into local regions, whereas phase-shifting precisely determines the pixel-accurate index for each point on the plane. The combination of the two codifications greatly decreases the number of patterns as compared to Gray code alone. It also retains high resolution without the required phase unwrapping step in the phase-shifting algorithm, which is time consuming. Most importantly, it works for multiple objects or discontinuous surfaces without using markers, as employed by the phase-shifting method. Experimental results with real objects and human faces indicate the effectiveness of the proposed approach.