Técnica eficiente para reconocimiento facial global utilizando wavelets y máquinas de vectores de soporte en imágenes 3D

La presente investigación se desarrolla en el marco de los sistemas de reconocimiento facial automático de imágenes, que consisten en procesar las imágenes de caras de personas utilizando métodos estadísticos y matemáticos de extracción de características y de clasificación de imágenes, para conocer si un individuo se encuentra en una determinada clase, y finalmente hallar su identidad. El tratamiento automático de una cara es complicado, debido a que se presenta varios factores que le afectan, como la posición de la cara, la expresión, la edad, la raza, el tipo de iluminación, el ruido, y objetos como lentes, sombrero, barba entre otros. El procesamiento se realiza de forma global, en donde se procesa toda la cara. Se sabe que procesar las imágenes de manera global es más rápido, práctico y fiable que las basadas en rasgos. Además, se conoce que procesar imágenes en tres dimensiones es más real y consistente que en dos dimensiones. El principal objetivo de la tesis que se propuso fue desarrollar una técnica eficiente de reconocimiento facial con rasgos globales, y con imágenes en tres dimensiones. Para ello, se seleccionó los algoritmos más eficientes para extracción de características, filtros de Gabor, y el algoritmo para clasificación, máquina de vectores de soporte (SVM). Este último algoritmo, su eficiencia varía de acuerdo a la función núcleo o kernel, por ello en esta tesis se trabajaron con tres kernel: líneal, gauseano y cúbico. Estos sistemas constan de dos procesos necesarios: 1) Entrenamiento, y 2) Pruebas. Lo que permitió establecer un modelo de reconocimiento facial global para dos y tres dimensiones respectivamente. La técnica fue procesada primero para imágenes 2D, luego para imágenes 3D. Y se utilizó el método de validación cruzada en ambos casos para aprobarlo. Los mejores resultados obtenidos con la técnica alcanzada son 96% de eficiencia con base de datos de imágenes de dos dimensiones; y 98,4% con base de datos de imágenes de tres dimensiones. Finalmente, se hace una comparación de los resultados alcanzados con otros trabajos de investigación similares, obteniéndose mayor eficiencia con este trabajo

Human metrology for person classification and recognition

Human metrological features generally refers to geometric measurements extracted from humans, such as height, chest circumference or foot length. Human metrology provides an important soft biometric that can be used in challenging situations, such as person classification and recognition at a distance, where hard biometric traits such as fingerprints and iris information cannot easily be acquired. In this work, we first study the question of predictability and correlation in human metrology. We show that partial or available measurements can be used to predict other missing measurements. We then investigate the use of human metrology for the prediction of other soft biometrics, viz. gender and weight. The experimental results based on our proposed copula-based model suggest that human body metrology contains enough information for reliable prediction of gender and weight. Also, the proposed copula-based technique is observed to reduce the impact of noise on prediction performance. We then study the question of whether face metrology can be exploited for reliable gender prediction. A new method based solely on metrological information from facial landmarks is developed. The performance of the proposed metrology-based method is compared with that of a state-of-the-art appearance-based method for gender classification. Results on several face databases show that the metrology-based approach resulted in comparable accuracy to that of the appearance-based method. Furthermore, we study the question of person recognition (classification and identification) via whole body metrology. Using CAESAR 1D database as baseline, we simulate intra-class variation with various noise models. The experimental results indicate that given enough number of features, our metrology-based recognition system can have promising performance that is comparable to several recent state-of-the-art recognition systems. We propose a non-parametric feature selection methodology, called adapted k-nearest neighbor estimator, which does not rely on intra-class distribution of the query set. This leads to improved results over other nearest neighbor estimators (as feature selection criteria) for moderate number of features. Finally we quantify the discrimination capability of human metrology, from both individuality and capacity perspectives. Generally, a biometric-based recognition technique relies on an assumption that the given biometric is unique to an individual. However, the validity of this assumption is not yet generally confirmed for most soft biometrics, such as human metrology. In this work, we first develop two schemes that can be used to quantify the individuality of a given soft-biometric system. Then, a Poisson channel model is proposed to analyze the recognition capacity of human metrology. Our study suggests that the performance of such a system depends more on the accuracy of the ground truth or training set

Investigating human-perceptual properties of "shapes" using 3D shapes and 2D fonts

Shapes are generally used to convey meaning. They are used in video games, films and other multimedia, in diverse ways. 3D shapes may be destined for virtual scenes or represent objects to be constructed in the real-world. Fonts add character to an otherwise plain block of text, allowing the writer to make important points more visually prominent or distinct from other text. They can indicate the structure of a document, at a glance. Rather than studying shapes through traditional geometric shape descriptors, we provide alternative methods to describe and analyse shapes, from a lens of human perception. This is done via the concepts of Schelling Points and Image Specificity. Schelling Points are choices people make when they aim to match with what they expect others to choose but cannot communicate with others to determine an answer. We study whole mesh selections in this setting, where Schelling Meshes are the most frequently selected shapes. The key idea behind image Specificity is that different images evoke different descriptions; but ‘Specific’ images yield more consistent descriptions than others. We apply Specificity to 2D fonts. We show that each concept can be learned and predict them for fonts and 3D shapes, respectively, using a depth image-based convolutional neural network. Results are shown for a range of fonts and 3D shapes and we demonstrate that font Specificity and the Schelling meshes concept are useful for visualisation, clustering, and search applications. Overall, we find that each concept represents similarities between their respective type of shape, even when there are discontinuities between the shape geometries themselves. The ‘context’ of these similarities is in some kind of abstract or subjective meaning which is consistent among different people