Grid point extraction exploiting point symmetry in a pseudo-random color pattern

This paper addresses the problem of recovering 3D human pose from a single monocular image. In the literature, Bayesian Mixtures of Experts (BME) was successfully used to represent the multimodal image-to-pose distributions. However, the expectation-maximization (EM) algorithm that learns the BME model may converge to a suboptimal local maximum. And the quality of the final solution depends largely on the initial values. In this paper, we propose an efficient initialization method for BME learning. We first partition the training set so that each subset can be well modeled by a single expert and the total regression error is minimized. Then each expert and gate of BME model is initialized on a partition subset. Our initialization method is tested on both a quasi-synthetic dataset and a real dataset (HumanEva). Results show that it greatly reduces the computational cost in training while improves testing accuracy.

[1]  F. MacWilliams,et al.  Pseudo-random sequences and arrays , 1976, Proceedings of the IEEE.

[2]  M. Fiala,et al.  Automatic Grid Finding in Calibration Patterns Using Delaunay Triangulation , 2003 .

[3]  Christopher G. Harris,et al.  A Combined Corner and Edge Detector , 1988, Alvey Vision Conference.

[4]  Joaquim Salvi,et al.  Pattern codification strategies in structured light systems , 2004, Pattern Recognit..

[5]  Cengizhan Ozturk,et al.  Structured Light Using Pseudorandom Codes , 1998, IEEE Trans. Pattern Anal. Mach. Intell..

[6]  S. M. Steve SUSAN - a new approach to low level image processing , 1997 .

[7]  S. Fujimura,et al.  Measurement of the 3-D shape of specular polyhedrons using an M-array coded light source , 1994, Conference Proceedings. 10th Anniversary. IMTC/94. Advanced Technologies in I & M. 1994 IEEE Instrumentation and Measurement Technolgy Conference (Cat. No.94CH3424-9).

[8]  Akira Ishii,et al.  A three-level checkerboard pattern (TCP) projection method for curved surface measurement , 1995, Pattern Recognit..

[9]  André Oosterlinck,et al.  Range Image Acquisition with a Single Binary-Encoded Light Pattern , 1990, IEEE Trans. Pattern Anal. Mach. Intell..

[10]  Ronald Chung,et al.  Accurate Camera-Projector System Calibration by the use of an LCD Panel , 2007, IPCV.

[11]  P. Lachenbruch Statistical Power Analysis for the Behavioral Sciences (2nd ed.) , 1989 .