Nary coded structured light-based range scanners using color invariants

Review and Comparison of High-Dynamic Range Three-Dimensional Shape Measurement Techniques

“…The HDR techniques using polarizing filters are accurate and fast but relatively complex in hardware compared to other techniques. Good results were also obtained by Benveniste andÜnsalan [38], but this technique is easily affected by the colors and complex textures of the object. The gonioplenoptic imaging system developed by Meng et al [52] can measure the specular surfaces in high accuracy.…”

“…By using this color invariant in segmentation, the effects of highlights originating from the ambient light were eliminated in scanning shiny surfaces. Recently, with the development of embedded technology, they [38] designed and implemented a novel structured light range scanner system based on the DSP evaluation module, which extracts range data to reduce the computational burden of the PC.…”

“…For the proposed method by polarization, in their experiment of measuring a planar black/white calibration board, the used polarizers reduced intensity of the whole fringe images resulting in low SNR; thus, it reduces the measurement accuracy. Benefiting from using quaternary color-coded patterns, the algorithm proposed by Benveniste andÜnsalan [38] is the simplest; however, the resolution is limited, so the measurement accuracy is not high. In contrast, the gonio-plenoptic imaging system developed by Meng et al [52] can achieve very high accuracyl however, their system can only measure a small range of surface at a time; thus, it will take a long time to measure the whole surface.…”

“…Binary pattern designed by Benveniste andÜnsalan[38]: (a) a sculpture under the projection of the binary pattern and (b) colorinvariant image.…”

Adaptive Binocular Fringe Dynamic Projection Method for High Dynamic Range Measurement

“…Addressing that it is difficult to improve the dynamic range by hardware for the most camera sensors [6], many experts have carried out a series of approaches to solve the HDR measurement problem. The methods can be divided into several categories: multi-exposure method [12,13,14], light intensity adjustment method [15,16], color invariance method [17,18,19], polarization method [20,21,22], adaptive fringe pattern method [23,24,25,26,27], and others [28,29]. Considering that the dark regions and bright regions of the fringe image require different exposure times, multi-exposure method becomes a way for HDR problem [12,13,14].…”