Stereo Vision Matching using Characteristics Vectors

Stereo vision is a usual method to obtain depth information from images. The problems encountered when applying the majority of well established algorithms to provide this information are due to the high computational load required. This occurs in both the block matching and graphical cues (such as edges) matching. In this article we address this issue by performing an image analysis which considers each pixel only once, thus enhancing the efficiency of the image processing. Additionally, when matching is carried out over statistical descriptors of the image regions, commonly referred to as characteristic vectors, whose number of these vectors is, by definition, lower than the possible block matching possibilities, the algorithm achieves an improved level of performance. In this paper we present a new algorithm which has been specifically designed to solve the commonly observed problems which arise from other well know techniques. This algorithm was designed using a previous work carried out by the authors in this area to determine the descriptors extraction processes. The complete analysis has been carried out over gray scale images. The results obtained from both real and synthetic images are presented in terms of matching quality and time consumption and compared to other published results. Finally, a discussion is provided on additional features related to the matching process

Ayuda técnica para la autonomía en el desplazamiento

The project developed in this thesis involves the design, implementation and evaluation of a new technical assistance aiming to ease the mobility of people with visual impairments. By using processing and sounds synthesis, the users can hear the sonification protocol (through bone conduction) informing them, after training, about the position and distance of the various obstacles that may be on their way, avoiding eventual accidents. In this project, surveys were conducted with experts in the field of rehabilitation, blindness and techniques of image processing and sound, which defined the user requirements that served as guideline for the design. The thesis consists of three self-contained blocks: (i) image processing, where 4 processing algorithms are proposed for stereo vision, (ii) sonification, which details the proposed sound transformation of visual information, and (iii) a final central chapter on integrating the above and sequentially evaluated in two versions or implementation modes (software and hardware). Both versions have been tested with both sighted and blind participants, obtaining qualitative and quantitative results, which define future improvements to the project. ---------------------------------------------------------------------------------------------------------------------------------------------El proyecto desarrollado en la presente tesis doctoral consiste en el diseño, implementación y evaluación de una nueva ayuda técnica orientada a facilitar la movilidad de personas con discapacidad visual. El sistema propuesto consiste en un procesador de estereovisión y un sintetizador de sonidos, mediante los cuales, las usuarias y los usuarios pueden escuchar un código de sonidos mediante transmisión ósea que les informa, previo entrenamiento, de la posición y distancia de los distintos obstáculos que pueda haber en su camino, evitando accidentes. En dicho proyecto, se han realizado encuestas a expertos en el campo de la rehabilitación, la ceguera y en las técnicas y tecnologías de procesado de imagen y sonido, mediante las cuales se definieron unos requisitos de usuario que sirvieron como guía de propuesta y diseño. La tesis está compuesta de tres grandes bloques autocontenidos: (i) procesado de imagen, donde se proponen 4 algoritmos de procesado de visión estéreo, (ii) sonificación, en el cual se detalla la propuesta de transformación a sonido de la información visual, y (iii) un último capítulo central sobre integración de todo lo anterior en dos versiones evaluadas secuencialmente, una software y otra hardware. Ambas versiones han sido evaluadas con usuarios tanto videntes como invidentes, obteniendo resultados cualitativos y cuantitativos que permiten definir mejoras futuras sobre el proyecto finalmente implementado