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Scene segmentation is a well-known problem in computer vision traditionally tackled by exploiting only the color information from a single scene view. Recent hardware and software developments allow to estimate in real-time scene geometry and open the way for new scene segmentation approaches based on the fusion of both color and depth data. This paper follows this rationale and proposes a novel segmentation scheme where multidimensional vectors are used to jointly represent color and depth data and normalized cuts spectral clustering is applied to them in order to segment the scene. The critical issue of how to balance the two sources of information is solved by an automatic procedure based on an unsupervised metric for the segmentation quality. An extension of the proposed approach based on the exploitation of both images in stereo vision systems is also proposed. Different acquisition setups, like time-of-flight cameras, the Microsoft Kinect device and stereo vision systems have been used for the experimental validation. A comparison of the effectiveness of the different depth imaging systems for segmentation purposes is also presented. Experimental results show how the proposed algorithm outperforms scene segmentation algorithms based on geometry or color data alone and also other approaches that exploit both clues

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Abstract. Depth estimation for dynamic scenes is a challenging and relevant problem in computer vision. Although this problem can be tackled by means of ToF cameras or stereo vision systems, each of the two systems alone has its own limitations. In this paper a framework for the fusion of 3D data produced by a ToF camera and a stereo vision system is proposed. Initially, depth data acquired by the ToF camera are up-sampled to the spatial resolution of the stereo vision images by a novel up-sampling algorithm based on image segmentation and bilateral filtering. In parallel a dense disparity field is obtained by a stereo vision algorithm. Finally, the up-sampled ToF depth data and the disparity field provided by stereo vision are synergically fused by enforcing the local consistency of depth data. The depth information obtained with the proposed framework is characterized by the high resolution of the stereo vision system and by an improved accuracy with respect to the one produced by both subsystems. Experimental results clearly show how the proposed method is able to outperform the compared fusion algorithms.

This paper proposes a method for fusing data acquired by a ToF camera and a stereo pair based on a model for depth measurement by ToF cameras which accounts also for depth discontinuity artifacts due to the mixed pixel effect. Such model is exploited within both a ML and a MAP-MRF frameworks for ToF and stereo data fusion. The proposed MAP-MRF framework is characterized by site-dependent range values, a rather important feature since it can be used both to improve the accuracy and to decrease the computational complexity of standard MAP-MRF approaches. This paper, in order to optimize the site dependent global cost function characteristic of the proposed MAP-MRF approach, also introduces an extension to Loopy Belief Propagation which can be used in other contexts. Experimental data validate the proposed ToF measurements model and the effectiveness of the proposed fusion techniques.