Nuno Gonçalves

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This paper addresses the problem of rigid motion estimation and 3D reconstruction in vision systems where it is possible to recover the incident light ray direction from the image points. Such systems include pinhole cameras and catadioptric cameras. Given two images of the same scene acquired from two different positions, the transformation is estimated by(More)
Estimating the amount and center of distortion from lines in the scene has been addressed in the literature by the socalled “plumb-line” approach. In this paper we propose a new geometric method to estimate not only the distortion parameters but the entire camera calibration (up to an “angular” scale factor) using a minimum of 3 lines. We propose a new(More)
This paper describes a new method to calibrate the intrinsic and extrinsic parameters of a generalized catadioptric camera (central or non-central) if correspondences between incident lines in space and pixels are provided (black box model calibration) in an arbitrary world reference frame. The parameters calibrated are the intrinsic parameters of the(More)
In this paper we present a method for mirror shape recovery and partial calibration for non-central catadioptric systems. This method is based on an existing algorithm for calibration of general vision systems. In addition only two images are required for both mirror shape recovery and partial calibration instead of three as in the original algorithm. On(More)
Stereotypical motor movements are one of the most common and least understood behaviors occurring in individuals with Autism Spectrum Disorder (ASD). To overcome problems with traditional methods for measuring stereotypical motor movements in persons with ASD, the Kinect sensor from Microsoft and gesture recognition algorithms were used to automatically(More)
Stereotypical motor movements are one of the most common and least understood behaviors occurring in individuals with Autism Spectrum Disorder (ASD). The traditional methods for recording the number of occurrences and duration of stereotypies are insufficient and time consuming. Thus the objective of this study is to automatically detect stereotypical motor(More)
In this paper we analyze the problem of motion estimation from a sequence of stereo images. We formulate both the differential and discrete approaches of two methods. The differential approach uses differential optical ¤ow whereas the discrete approaches uses feature correspondences. We use both methods to compute, £rst, the 3D velocity in the Z direction(More)
The tradeoff between error-correcting performance and numerical complexity of LDPC decoding algorithms is a well-known problem. In this paper we depict the unseen errorfloor performance of the Self-Corrected Min-Sum algorithm for long length DVB-S2 codes. We developed a massively parallel simulation using GPUs which allowed a comprehensive BER(More)