Flexible 3D reconstruction method based on phase-matching in multi-sensor system

Laser-speckle-projection-based handheld anthropometric measurement system with synchronous redundancy reduction

Human body measurement is essential in modern rehabilitation medicine, which can be effectively combined with the technology of additive manufacturing. Digital image correlation based on laser speckle projection is a single-shot, accurate, and robust technique for human body measurement. In this paper, we present a handheld anthropometric measurement system based on laser speckle projection. A flexible retroreflective marker target is designed for multi-view data registration. Meanwhile, a synchronous redundancy-reduction algorithm based on a re-projected global disparity map is proposed. Experiment results validate that the proposed system is effective and accurate for different human body part measurements. Comparative experiments show that the proposed redundancy-reduction algorithm has high efficiency and can effectively preserve the features of complex shapes. The comprehensive performance of the algorithm is better than the other two tested methods.

Three-Dimensional Measurement Method of Four-View Stereo Vision Based on Gaussian Process Regression

Multisensor systems can overcome the limitation of measurement range of single-sensor systems, but often require complex calibration and data fusion. In this study, a three-dimensional (3D) measurement method of four-view stereo vision based on Gaussian process (GP) regression is proposed. Two sets of point cloud data of the measured object are obtained by gray-code phase-shifting technique. On the basis of the characteristics of the measured object, specific composite kernel functions are designed to obtain the initial GP model. In view of the difference of noise in each group of point cloud data, the weight idea is introduced to optimize the GP model, which is the data fusion based on Bayesian inference method for point cloud data. The proposed method does not require strict hardware constraints. Simulations for the curve and the high-order surface and experiments of complex 3D objects have been designed to compare the reconstructing accuracy of the proposed method and the traditional methods. The results show that the proposed method is superior to the traditional methods in measurement accuracy and reconstruction effect.

Accurate three dimensional body scanning system based on structured light

Three dimensional (3D) body scanning has been of great interest to many fields, yet it is still a challenge to generate accurate human body models in a convenient manner. In this paper, we present an accurate 3D body scanning system based on structured light technology. A four-step phase shifting combined with Gray-code method is applied to match pixels in camera and projector planes. The calculation of 3D point coordinates are also derived. The main contribution of this paper is twofold. First, an improved registration algorithm is proposed to align point clouds reconstructed from different views. Second, we propose a graph optimization algorithm to further minimize registration errors. Experimental results demonstrate that our system can produce accurate 3D body models conveniently.

Automatic and rapid whole-body 3D shape measurement based on multinode 3D sensing and speckle projection

Automatic and rapid whole-body 3D shape measurement has attracted extensive attention in recent years and been widely used in many fields. Rapid 3D reconstruction, automatic 3D registration, and dedicated system layout are critical factors to enable an excellent 3D measurement system. In this paper, we present an automatic and rapid whole- body 3D measurement system that is based on multinode 3D sensors using speckle projection. A rapid algorithm for searching homologous point pairs is suggested, which takes advantage of the optimized projective rectification and simplified subpixel matching techniques, leading to an improved time efficiency of 3D reconstruction. Meanwhile, a low-cost automatic system with a flexible setup and an improved calibration strategy are proposed, where system parameters of each node sensor can be simultaneously estimated with the assistance of a cubic and a planar target. Furthermore, an automatic range data registration strategy by employing two aided cameras is investigated. Experiment results show that the presented approach can realize automatic whole-body 3D shape measurement with high efficiency and accuracy.