Three-dimensional planar object tracking with sub-pixel accuracy

Subpixel techniques are commonly used to increase the spatial resolution in tracking tasks. Object tracking with targets of known shape permits obtaining information about object position and orientation in the three-dimensional space. A proper selection of the target shape allows us to determine its position inside a plane and its angular and azimuthal orientation under certain limits. Our proposal is demonstrated both numerical and experimentally and provides an increase the accuracy of more than one order of magnitude compared to the nominal resolution of the sensor. The experiment has been performed with a high-speed camera, which simultaneously provides high spatial and temporal resolution, so it may be interesting for some applications where this kind of targets can be attached, such as vibration monitoring and structural analysis.The authors acknowledge the support of the Spanish Ministerio de Economía y Competitividad through the project BIA2011-22704 and the Generalitat Valenciana through the projects GV/2013/009 and PROMETEO/ 2011/021. A. B. Roig acknowledges a grant from Cajamurcia

High-speed video-oculography applied to assess pupil light reflex

Póster presentado en el VII European/ I World Meeting in Visual and Physiological OpticsEye response to light exposure is usually described through the pupillary light reflex, which controls the pupil diameter and allows for testing the sensory and motor functions of the eye. We have arranged an experimental setup and developed a procedure in order to improve the video-oculography experiment through high-speed imaging. The technique has been applied over eleven people distinguishing between consensual and direct pupillary light reflexes and analyzing the eye dominance. We found no significant differences. Moreover, obtained time parameters describing the pupil light reflex agree with those from literature.The authors acknowledge the projects BIA2011-22704, GV/2013/009 and PROMETEO/ 2011/021. A. B. Roig acknowledges a grant from Cajamurcia

A high-resolution binocular video-oculography system: assessment of pupillary light reflex and detection of an early incomplete blink and an upward eye movement

Background: The pupillary light reflex characterizes the direct and consensual response of the eye to the perceived brightness of a stimulus. It has been used as indicator of both neurological and optic nerve pathologies. As with other eye reflexes, this reflex constitutes an almost instantaneous movement and is linked to activation of the same midbrain area. The latency of the pupillary light reflex is around 200 ms, although the literature also indicates that the fastest eye reflexes last 20 ms. Therefore, a system with sufficiently high spatial and temporal resolutions is required for accurate assessment. In this study, we analyzed the pupillary light reflex to determine whether any small discrepancy exists between the direct and consensual responses, and to ascertain whether any other eye reflex occurs before the pupillary light reflex. Methods: We constructed a binocular video-oculography system two high-speed cameras that simultaneously focused on both eyes. This was then employed to assess the direct and consensual responses of each eye using our own algorithm based on Circular Hough Transform to detect and track the pupil. Time parameters describing the pupillary light reflex were obtained from the radius time-variation. Eight healthy subjects (4 women, 4 men, aged 24–45) participated in this experiment. Results: Our system, which has a resolution of 15 microns and 4 ms, obtained time parameters describing the pupillary light reflex that were similar to those reported in previous studies, with no significant differences between direct and consensual reflexes. Moreover, it revealed an incomplete reflex blink and an upward eye movement at around 100 ms that may correspond to Bell’s phenomenon. Conclusions: Direct and consensual pupillary responses do not any significant temporal differences. The system and method described here could prove useful for further assessment of pupillary and blink reflexes. The resolution obtained revealed the existence reported here of an early incomplete blink and an upward eye movement.The authors acknowledge the support of the Spanish Ministerio de Economía y Competitividad through the project BIA2011-22704 and the Generalitat Valenciana through the projects GV/2013/009 and PROMETEO/2011/021. A. B. Roig acknowledges a grant from Cajamurcia

Effective focal length through a microscope

Póster presentado en el VII European/ I World Meeting in Visual and Physiological OpticsThe optical power of a thick spherical lens and its Coddington shape factor are essential magnitudes that characterize its image quality. We propose an experimental procedure and apparatus that allow accurate determination of those magnitudes for any spherical lens from geometrical measurements. It overcomes the drawbacks of other devices that need of the refractive index or may damage the lens surfaces, like spherometers, and provides similar results to commercial lensmeters.The authors acknowledge the projects BIA2011-22704, GV/2013/009 and PROMETEO/ 2011/021. J. Espinosa thanks R. Tomás the provisioning. A. B. Roig acknowledges a grant from Cajamurcia

IV Edición. Colaboración con centros de secundaria para la formación experimental de alumnos de bachillerato

La “Red para la colaboración con centros de secundaria para la formación experimental de alumnos de bachillerato” ha llevado a cabo este año su quinta edición. La línea de actuación prioritaria se mantiene siendo el fomento del intercambio de experiencias en diferentes campos del conocimiento científico dirigidas al alumnado que cursa Bachillerato o estudios de Secundaria. En la edición de este curso hemos recibido en nuestros laboratorios a 233 alumnos procedentes de 11 centros de la provincia de Alicante para la realización de diferentes prácticas. El periodo elegido, como viene siendo habitual han sido los meses de Enero y Febrero, durante el periodo de elaboración de exámenes, no lectivo que tiene la Universidad de Alicante para los alumnos de todas las titulaciones de grado. en las que los alumnos han sido los verdaderos protagonistas. Esto significaría que en las 5 ediciones de nuestra red hemos recibido en nuestros laboratorios en total a 858 alumnos de Bachiller y de de 4º año de educación secundaria obligatoria (ESO). Estudiantes que han realizado bajo nuestra supervisión las prácticas de laboratorio que previamente habían sido ofertadas a sus centros. En todas las ediciones, los resultados obtenidos han sido plenamente satisfactorios tanto para los alumnos como para todos los profesores integrantes de la Red. Pensamos que es tiempo de reunir y reflexionar sobre todo el trabajo realizado

Mesura de l'índex de refracció d'una làmina pla paral·lela de vidre amb el microscopi

En esta pràctica calcularem l'índex de refracció de diverses làmines de vidre, mesurant la seua grossària real i la seua grossària aparent observada a través del microscopi

Mesura de l'índex de refracció d'un prisma

Avaluar la relació entre el angle de incidència de la llum en un prisma y la desviació produïda. Trobar la mínima desviació així com mostrar un mètode precís per la determinació de l'índex de refracció

Association Between Preexisting Versus Newly Identified Atrial Fibrillation and Outcomes of Patients With Acute Pulmonary Embolism

Background Atrial fibrillation (AF) may exist before or occur early in the course of pulmonary embolism (PE). We determined the PE outcomes based on the presence and timing of AF. Methods and Results Using the data from a multicenter PE registry, we identified 3 groups: (1) those with preexisting AF, (2) patients with new AF within 2 days from acute PE (incident AF), and (3) patients without AF. We assessed the 90-day and 1-year risk of mortality and stroke in patients with AF, compared with those without AF (reference group). Among 16 497 patients with PE, 792 had preexisting AF. These patients had increased odds of 90-day all-cause (odds ratio [OR], 2.81; 95% CI, 2.33-3.38) and PE-related mortality (OR, 2.38; 95% CI, 1.37-4.14) and increased 1-year hazard for ischemic stroke (hazard ratio, 5.48; 95% CI, 3.10-9.69) compared with those without AF. After multivariable adjustment, preexisting AF was associated with significantly increased odds of all-cause mortality (OR, 1.91; 95% CI, 1.57-2.32) but not PE-related mortality (OR, 1.50; 95% CI, 0.85-2.66). Among 16 497 patients with PE, 445 developed new incident AF within 2 days of acute PE. Incident AF was associated with increased odds of 90-day all-cause (OR, 2.28; 95% CI, 1.75-2.97) and PE-related (OR, 3.64; 95% CI, 2.01-6.59) mortality but not stroke. Findings were similar in multivariable analyses. Conclusions In patients with acute symptomatic PE, both preexisting AF and incident AF predict adverse clinical outcomes. The type of adverse outcomes may differ depending on the timing of AF onset.info:eu-repo/semantics/publishedVersio

Estudio de correlaciones binoculares de microtrémores y derivas

El ojo humano está en continuo movimiento incluso durante la fijación. Existen tres tipos de movimientos de fijación, microsacádicos, derivas y trémores. Dichos movimientos se han estudiado a lo largo de los años utilizando diferentes métodos, algunos de los cuales precisaban contacto con el ojo. Hemos desarrollado un método no invasivo para el análisis de estos movimientos utilizando secuencias grabadas con cámaras de alta velocidad. Después, usando técnicas sub-píxel realizamos un procesado de imágenes a partir del cual obtenemos los parámetros del ajuste de la pupila a una elipse y que nos sirven para estudiar los movimientos oculares. Con nuestro método se ha comprobado que los dos ojos de un mismo sujeto se mueven de manera similar. Se ha visto también que aparecen frecuencias típicas de los movimientos de fijación.The human eye is constantly moving even when it tries to maintain a fixation point. There are three types of fixational eye movements: microsaccades, drifts and tremors. These movements have been studied over the years using different methods, some of which are in contact with the eye. We have developed a non-invasive method for the analysis of these movements. We have recorded sequences of the eyes using high-speed cameras. Then, we have analyzed the parameters obtained after the adjustment of the pupil to an ellipse using image processing and sub-pxiel techniques. We have found that both eyes of a same subject do similar movement and have observed the typical frequencies of the fixational eye movements.AB.Roig agradece a la Fundación Cajamurcia la Beca de investigación Cajamurcia 201