Contextual visual localization: cascaded submap classification, optimized saliency detection, and fast view matching

In this paper, we present a novel coarse-to-fine visual localization approach: contextual visual localization. This approach relies on three elements: (i) a minimal-complexity classifier for performing fast coarse localization (submap classification); (ii) an optimized saliency detector which exploits the visual statistics of the submap; and (iii) a fast view-matching algorithm which filters initial matchings with a structural criterion. The latter algorithm yields fine localization. Our experiments show that these elements have been successfully integrated for solving the global localization problem. Context, that is, the awareness of being in a particular submap, is defined by a supervised classifier tuned for a minimal set of features. Visual context is exploited both for tuning (optimizing) the saliency detection process, and to select potential matching views in the visual database, close enough to the query view.

Análisis de la eficacia de la terapia visual en el tratamiento de la exotropía intermitente mediante videooculografía 3D

Objetivo: Evaluar la eficacia del tratamiento en 3 casos de exotropia intermitente (XT(i)) mediante ejercicios de terapia visual, completando la exploración clínica con Videooculografia-30 y evidenciar la potencial aplicabilidad de esta tecnología para dicho propósito. Métodos: Exponemos los cambios ocurridos tras ejercicios de terapia visual en una mujer de 36 años con XT(i) de -25 dioptrías prismáticas (dp) de lejos y 18 dp de cerca; Un niño de 10 años de edad con 8 dp de XT(i) en posición primaria, asociados a +6 dp de hipotropia izquierda; y un hombre de 63 años con XT(i) de 6 dp en posición primaria asociada a +7 dp de hipertropia derecha. Todos los pacientes presentaron buena agudeza visual corregida en ambos ojos. La inestabilidad de la desviación ocular se evidenció mediante análisis de VOG-30, revelando la presencia de components verticales y torsionales. Se realizaron ejercicios de terapia visual, incluyendo diferentes tipos de ejercicios de vergencias, acomodación y percepción de la diplopía. Resultados: Tras la terapia visual se obtuvieron excelentes rangos de vergencias fusionales y de punto próximo de convergencia («hasta la nariz»). El examen mediante VOG-3D (Sensoro Motoric lnstruments, Teltow, Germany) confirmó la compensación de la desviación con estabilidad del alineamiento ocular. Se observó una significativa mejora después de la terapia en los components verticals y torsionales, lo cuales se hicieron más estables. Los pacientes se mostraron muy satisfechos de los resultados obtenidos. Conclusión: La VOG-3D es una técnica útil para dotamos de un método objetivo de registro de la compensación y estabilidad de la desviación ocular después de realizar ejercicios de terapia visual en casos de XT(i), ofreciéndonos un detallado análisis de la mejoría de los components verticales y torsionales.

Visual function alterations in essential tremor: A case report

Our purpose is to report alterations in contrast sensitivity function (CSF) and in the magno, parvo and koniocellular visual pathways by means of a multichannel perimeter in case of an essential tremor (ET). A complete evaluation of the visual function was performed in a 69-year old patient, including the analysis of the chromatic discrimination by the Fansworth–Munsell 100 hue test, the measurement of the CSF by the CSV-1000E test, and the detection of potential alteration patterns in the magno, parvo and koniocellular visual pathways by means of a multichannel perimeter. Visual acuity and intraocular pressure (IOP) were within the ranges of normality in both eyes. No abnormalities were detected in the fundoscopic examination and in the optical coherence tomography (OCT) exam. The results of the color vision examination were also within the ranges of normality. A significant decrease in the achromatic CSFs for right eye (RE) and left eye (LE) was detected for all spatial frequencies. The statistical global values provided by the multichannel perimeter confirms that there were significant absolute sensitivity losses compared to the normal pattern in RE. In the LE, only a statistically significant decrease in sensitivity was detected for the blue-yellow (BY) channel. The pattern standard deviation (PSD) values obtained in our patient indicated that there were significant localized losses compared to the normality pattern in the achromatic channel of the RE and in the red-green (RG) channel of the LE. Some color vision alterations may be present in ET that cannot be detected with conventional color vision tests, such as the FM 100 Hue.