Visual Segmentation without Classification in a Model of the Primary Visual Cortex

Stimuli outside classical receptive fields significantly influence the neurons' activities in primary visual cortex. We propose that such contextual influences are used to segment regions by detecting the breakdown of homogeneity or translation invariance in the input, thus computing global region boundaries using local interactions. This is implemented in a biologically based model of V1, and demonstrated in examples of texture segmentation and figure-ground segregation. By contrast with traditional approaches, segmentation occurs without classification or comparison of features within or between regions and is performed by exactly the same neural circuit responsible for the dual problem of the grouping and enhancement of contours.

Visual Recognition and Categorization on the Basis of Similarities to Multiple Class Prototypes

To recognize a previously seen object, the visual system must overcome the variability in the object's appearance caused by factors such as illumination and pose. Developments in computer vision suggest that it may be possible to counter the influence of these factors, by learning to interpolate between stored views of the target object, taken under representative combinations of viewing conditions. Daily life situations, however, typically require categorization, rather than recognition, of objects. Due to the open-ended character both of natural kinds and of artificial categories, categorization cannot rely on interpolation between stored examples. Nonetheless, knowledge of several representative members, or prototypes, of each of the categories of interest can still provide the necessary computational substrate for the categorization of new instances. The resulting representational scheme based on similarities to prototypes appears to be computationally viable, and is readily mapped onto the mechanisms of biological vision revealed by recent psychophysical and physiological studies.

Visual Speech Synthesis by Morphing Visemes

We present MikeTalk, a text-to-audiovisual speech synthesizer which converts input text into an audiovisual speech stream. MikeTalk is built using visemes, which are a small set of images spanning a large range of mouth shapes. The visemes are acquired from a recorded visual corpus of a human subject which is specifically designed to elicit one instantiation of each viseme. Using optical flow methods, correspondence from every viseme to every other viseme is computed automatically. By morphing along this correspondence, a smooth transition between viseme images may be generated. A complete visual utterance is constructed by concatenating viseme transitions. Finally, phoneme and timing information extracted from a text-to-speech synthesizer is exploited to determine which viseme transitions to use, and the rate at which the morphing process should occur. In this manner, we are able to synchronize the visual speech stream with the audio speech stream, and hence give the impression of a photorealistic talking face.

On the difficulty of feature-based attentional modulations in visual object recognition: A modeling study.

Numerous psychophysical experiments have shown an important role for attentional modulations in vision. Behaviorally, allocation of attention can improve performance in object detection and recognition tasks. At the neural level, attention increases firing rates of neurons in visual cortex whose preferred stimulus is currently attended to. However, it is not yet known how these two phenomena are linked, i.e., how the visual system could be "tuned" in a task-dependent fashion to improve task performance. To answer this question, we performed simulations with the HMAX model of object recognition in cortex [45]. We modulated firing rates of model neurons in accordance with experimental results about effects of feature-based attention on single neurons and measured changes in the model's performance in a variety of object recognition tasks. It turned out that recognition performance could only be improved under very limited circumstances and that attentional influences on the process of object recognition per se tend to display a lack of specificity or raise false alarm rates. These observations lead us to postulate a new role for the observed attention-related neural response modulations.

Geometric Aspects of Visual Object Recognition

This thesis presents there important results in visual object recognition based on shape. (1) A new algorithm (RAST; Recognition by Adaptive Sudivisions of Tranformation space) is presented that has lower average-case complexity than any known recognition algorithm. (2) It is shown, both theoretically and empirically, that representing 3D objects as collections of 2D views (the "View-Based Approximation") is feasible and affects the reliability of 3D recognition systems no more than other commonly made approximations. (3) The problem of recognition in cluttered scenes is considered from a Bayesian perspective; the commonly-used "bounded-error errorsmeasure" is demonstrated to correspond to an independence assumption. It is shown that by modeling the statistical properties of real-scenes better, objects can be recognized more reliably.

Espai creatiu. Poesia visual. Autoretrat

Poesia visual guanyadora del concurs literari organitzat a la Facultat per celebrar la Diada de St. Jordi 2005 amb el lema "Sentir paraules"

Jerome S. Bruner: la construcció narrativa de la identitat en temps de crisi

Resum de l'entrevista realitzada el 30 de juny de 2005 per Moisès Esteban i Guitart al psicòleg nord americà Jerome S. Bruner (Nova York, 1915). Tot plegat un viatge per la història de la psicologia del s. XX i principis del s. XXI

Departament de Psicologia [Ressenya del llibre Adolescents and audio-visual media in five countries, de Ferran Casas, Irene Rizzini, Rose September, Per Egil Mjaavatn i Usha Nayar (coord.)]

Aquest llibre és el producte d'anys de cooperació entre equips de recerca de cinc països diferents, tot ells Key Institutions de la xarxa Childwatch International, en el marc d'un projecte plurinacional sobre adolescents i mitjans

CoDaPack. An Excel and Visual Basic based software of compositional data analysis. Current version and discussion form upcoming versions

In the eighties, John Aitchison (1986) developed a new methodological approach for the statistical analysis of compositional data. This new methodology was implemented in Basic routines grouped under the name CODA and later NEWCODA inMatlab (Aitchison, 1997). After that, several other authors have published extensions to this methodology: Marín-Fernández and others (2000), Barceló-Vidal and others (2001), Pawlowsky-Glahn and Egozcue (2001, 2002) and Egozcue and others (2003). (...)

Ver ordenadamente : el cuadrante visual y su aplicación en los procesos de la percepción visual.

Las fotografías son de Paco Vega y la propia autora

Cultura y tradiciones asturianas en la Educación Plástica y Visual : unidad didáctica La sidra.

Esta unidad didáctica utiliza la sidra como hilo conductor, una bebida típica de la región obtenida de la manzana, elegida por su cercanía al ambiente familiar y social de los alumnos, por dar a conocer un patrimonio cultural y artístico, cercano pero bastante desconocido y por ser tratado al mismo tiempo desde varias áreas: Ciencias Sociales, Música, Ciencias Naturales, Lengua Española, Lengua y Cultura Asturiana, etc...Se seleccionaron los elementos naturales y objetos relacionados con la fabricación de la sidra, así como en algunas de las obras artísticas inspiradas en ella. Sin olvidar su aspecto conceptual, se plantea con un carácter eminentemente práctico, evitando el planteamiento de ejercicios de solución única, procurando que cada actividad propuesta se pueda realizar con mayor o menor grado de dificultad, dependiendo de las características del alumnado. Alternan actividades individuales con otras colectivas. La evaluación se realiza a partir de unos criterios que tratan de medir la propia evaluación de los alumnos. Al final se presenta abundante material de apoyo: que va desde la explicación de los útiles de dibujo, a ejemplos de construcciones geométricas, pasando por la descripción de conceptos visuales, así como de las técnicas y materiales más comunes. Concluye el material con una selección de fotos e ilustraciones que servirán para el desarrollo de la unidad, así como una relación de pintores asturianos relacionados con el tópico.

Gu??a de recursos para la elaboraci??n de la respuesta educativa al alumnado discapacitado visual en el Bachillerato

Resumen basado en la publicaci??n

Rutas literarias : caminos de Leopoldo por Asturias: Regenta, Ingenio y Narrativa. Profesorado.

Resumen basado en la publicación

Rutas literarias : caminos de Leopoldo por Asturias: Regenta, Ingenio y Narrativa. Alumnado.

Resumen basado en la publicación

Rutas literarias : caminos de Leopoldo por Asturias : Regenta, ingenio y narrativa. Cuaderno del profesor.

Resumen basado en el de la publicación