Prediction of binding hot spot residues by using structural and evolutionary parameters

In this work, we present a method for predicting hot spot residues by using a set of structural and evolutionary parameters. Unlike previous studies, we use a set of parameters which do not depend on the structure of the protein in complex, so that the predictor can also be used when the interface region is unknown. Despite the fact that no information concerning proteins in complex is used for prediction, the application of the method to a compiled dataset described in the literature achieved a performance of 60.4%, as measured by F-Measure, corresponding to a recall of 78.1% and a precision of 49.5%. This result is higher than those reported by previous studies using the same data set

Feature-point based matching: a sequential approach based on relaxation labeling and relative orientation

This paper presents a solution for the problem of correspondence and relative orientation (RO) estimation for a pair of images. The solution is obtained by relaxation labeling using multiple metrics applied to image primitives. Besides the use of metrics based on radiometric elements (intensities, gradient, and coefficient of correlation), and on geometry (distance ratios), two additional metrics are considered. One is based on angular relations between primitives and another based on the volume of Matching Parallelepiped (MP) that allows the inclusion of the epipolar geometry constraint directly in the similarity and compatibility computation. The proposed solution was applied to synthetic and real images. The results showed that the use of multiple metrics contribute to the automation of the correspondence process and RO determination, even considering pairs of images subject to convergence, rotation, differences in scale, and presence of repetitive patterns

Automatic visual alignment using planar regional features and stereo vision

This paper addresses the determination of the rigid transformation between camera and object reference frames from a pair of intensity images and a known scene model. Two difficult parts of this problem that deserve particular attention are the matching between image and model features and the matching of image-features between stereo views. We propose the use of planar regions as features, what make both problems simpler. The former is handled by an invariant-based approach, for which a less complex base can be adopted, and the latter, by applying the epipolar constraint for inferior and superior bounds of region coordinates. The presented approach may be useful in many applications where camera-based tracking requires automatic initialization

An Architecture Based on Constraints for Augmented Shared Workspaces

Abstract – Augmented shared workspaces are an instance of augmented reality which move the collaborative work from the desktop to the real workplace, enabling higher interaction level with coworkers and allowing implementation of advanced techniques of human-machine interfaces. In this paper, we advocate the employment of a constraint system as the document model (or program) for the implementation of augmented reality applications. We show that constraint technology is synergistic with augmented reality and collaborative work in many aspects. An architecture model based on agents and constraints is then proposed. Our point of view is supported by the observation of this technology being employed in Computer Graphics and Human-Computer Interaction research and the implementation of typical cases

Toward 3D Reconstruction of Endoscope Images Using Shape from Shading

Abstract – The 3D Reconstruction problem from a single endoscope image of a smooth object is studied in the context of the Shape from Shading methods and considering a single light source at the camera projection center. Based on a curve expansion Shape from Shading algorithm, a spherical projection model for the endoscope camera and a dichromatic model for the surface reflectance, an approach to solve practical problems, namely the endoscope image distortion and the removal of the image specular reflection component, is presented. Results obtained from application of this approach to synthetic and real images are presented