A learned sparseness and IGMRF-based regularization framework for dense disparity estimation using unsupervised feature learning

Abstract

In this work, we propose a new approach for dense disparity estimation in a global energy minimization framework. We propose to use a feature matching cost which is defined using the learned hierarchical features of given left and right stereo images and we combine it with the pixel-based intensity matching cost in our energy function. Hierarchical features are learned using the deep deconvolutional network which is trained in an unsupervised way using a database consisting of large number of stereo images. In order to perform the regularization, we propose to use the inhomogeneous Gaussian Markov random field (IGMRF) and sparsity priors in our energy function. A sparse autoencoder-based approach is proposed for learning and inferring the sparse representation of disparities. The IGMRF prior captures the smoothness as well as preserves sharp discontinuities while the sparsity prior captures the sparseness in the disparity map. Finally, an iterative two-phase algorithm is proposed to estimate the dense disparity map where in phase one, sparse representation of disparities are inferred from the trained sparse autoencoder, and IGMRF parameters are computed, keeping the disparity map fixed and in phase two, the disparity map is refined by minimizing the energy function using graph cuts, with other parameters fixed. Experimental results on the Middlebury stereo benchmarks demonstrate the effectiveness of the proposed approach.