Active dictionary models: A framework for non-linear shape modeling

Proyecto de Graduación (Maestría en Ingeniería en Electrónica) Instituto Tecnológico de Costa Rica, Escuela de Ingeniería en Electrónica, 2015.Shape modeling has applications in science and industry fields. The existing algorithms are based on linear methods and on unimodal normal distributions not appropriate to model deformations present in natural signals. This work presents a novel shape model based on dictionary learning which is capable of representing these deformations. First a dictionary is trained through K-SVD and OMP. Then it is used as a model to represent shapes using a sparse weighting vector. The denoising properties of the model are shown for additive noise, but with the limitation that it can also represent invalid shapes. Afterwards, in order to compensate for the dictionary model limitation, a non-linear denoising method is developed based on orthogonal manifold projections. This extension ensures that the output is always a valid shape. Finally the complete iterative algorithm is presented. In this stage, the application o↵ers an initial approximation of the shape to segment. The shape is modeled using the dictionary and projected to the manifold whereby a valid shape is ensured. This process is repeated until an established convergence criteria is met. It is shown how the proposed method is capable of modeling both linear and non-linear deformations with high success

Diseño e implementación de un sistema de transmisión de imágenes de anaglifo sobre dos plataformas embebidas BeagleBoard xM

Proyecto de Graduación (Licenciatura en Ingeniería Electrónica). Instituto Tecnológico de Costa Rica. Escuela de Ingeniería Electrónica, 2010.El presente documento describe el proceso de diseño e implementación sistema de transmisión tiempo real de im agenes en 3D. El m etodo que se utiliza es el de anaglifos basados en el par crom atico rojo y cian. El sistema se implementa sobre dos plataformas embebidas BeagleBoard-xM, operadas por un nucleo GNU/Linux, que permite acceder a los diferentes perif ericos. La captura se realiza con dos m odulos de cámara nectados a los puertos dedicados, en cada plataforma respectivamente. La transmisi on de la imagen de un embebido a otro se consigue mediante el protocolo USB. Para ello es necesario acceder al dispositivo tanto en modo an trion como en modo dispositivo. El despliegue se consigue utilizando la salida DVI disponible. Para el manejo del ujo de video se hace uso de GStreamer. Se implementa un elemento sumidero y otro fuente para el env o y recepci on de datos a trav es del puerto USB respectivamente, y un elemento mezclador para combinar y sincronizar las im agenes. Adem as se programa una aplicaci on que haga uso de estos y otros elementos est andar para lograr el ujo de video deseado. La ejecuci on del algoritmo de anaglifos se realiza en el DSP, o procesador de señales digitales, disponible en el sistema embebido. Se implementan adem as en este procesador las transformadas en el espacio del color de UYVY a RGB y viceversa, requeridas por los anaglifos. Los algoritmos anteriores son optimizados de manera que se logre un paralelismo en la arquitectura del DSP y utilizar la mayor cantidad de m odulos que sea posible por ciclo de reloj. Lo anterior ofrece velocidad de ejecuci on y por tanto un video 3D. ________________________________________________________________________ Abstract: This document describes the design and implementation process of a real-time 3D images transmission system. The used method is the red-cyan chromatic pair Anaglyphs. The system is implemented over two BeagleBoards-xM embedded platforms, operated by a GNU/Linux kernel which enables access to the di_erent pheripherals. Video capture is achieved with two camera modules connected to the proper ports, on each platform respectively. Images transmition from one embedded system to another is made through USB protocol. For instance, USB device must be accessed in host mode and in gadget mode. DVI output port is used as video display. To handle video streaming GStreamer is used. For USB video sending and receiving, sink and src elements are implemented respectively. For image mixing and synchronization a mixer element is programmed. Moreover, an application that makes use of these and other standart elements is implemented to ensure the desired video stream. Anaglyph algorithm execution is done in the DSP or digital signal processor, available in the embedded system. Furthermore, the required colospace transformations from UYVY to RGB and vice versa, are implemented in this same processor. These algorithms are optimized to achieve DSP architecture parallelism and the highest number of modules per clock cycle as possible. This o_ers high execution speed and hence 3D video