En este trabajo se presenta la interfaz gráfica de usuario y se explica el modelo de detección de líneas diseñado en Python para la misma. Luego de los resultados de la calibración del instrumento electrónico se procedió a crear la interfaz gráfica de usuario en python en base al prototipo de la GUI construida en Matlab para lo cual se tuvo que escribir el algoritmo de detección en el mismo lenguaje. El instrumento electrónico está construido con un autocolimador analógico comercial, Nikon 6D, y una interfaz visual ad hoc.

En este trabajo se presenta un método para procesar imágenes para optimizar la calibración de microscopios ópticos Lext Olympus con plantillas. El algoritmo propuesto ya funciona en las escalas de los autocolimadores Nikon, que son similares a las presentes en las plantillas de calibración de estos microscopios. El algoritmo fue adaptado para medir estas plantillas y así optimizar la calibración. .

En este trabajo se estudian los resultados de la calibración de un autocolimador electrónico desarrollado en el Centro de Investigación y transferencia en Metrología -CEMETRO- de UTN FRC. El instrumento está construido en base a un autocolimador analógico comercial, Nikon 6D, y una interfaz visual ad hoc. La calibración fue realizada en el Laboratorio Nacional de Ángulo de Argentina, INTI Córdoba, con trazabilidad internacional al patrón de referencia, el autocolimador Trioptics TA300. El análisis de los resultados de la calibración permite obtener un modelo metrológico más preciso del autocolimador electrónico. Además, define pautas para optimizar las prestaciones del instrumento mediante ajustes de diseño de la interfaz visual electrónica conectada al autocolimador óptico Nikon 6D.

In this study, we present the sub-pixel Hough Transform, which is used to detect line positions at sub-pixel level. A comparison with the conventional Hough Transform was performed. As a result, we obtained an increase in detection resolution.

La trazabilidad en mediciones superficiales de micro y nanoestructuras es condición ineludible para garantizar la calidad en proyectos de innovación, investigación y desarrollo en el espectro disciplinar que abarca las ciencias químicas, biológicas, de materiales, siendo además un requisito para mediciones de rugosidad en la industria. La confiabilidad metrológica (ISO 10012) presupone el uso de instrumentos calibrados, patrones trazables, procedimientos de medición validados y balances de incertidumbre. Estos requerimientos no son habituales en microscopía y representa una debilidad a subsanar. En este trabajo se presentan los resultados de la intercomparación de mediciones de textura superficial en patrones 2D y 3D con cuatro tipos de instrumentos: Rugosímetro, Microscopio Confocal, Microscopio de Fuerza Atómica y Microscopio Electrónico de Barrido. Las evaluaciones de conformidad (ISO 17043) mediante la comparación de los errores normalizados (En), que ponderan los efectos sistemáticos y sus incertidumbres, convalidan el uso de los microscopios como instrumentos metrológicos.

In this paper, we present a methodology which identifies and characterizes the sources of uncertainty associated with the operation of an electronic autocollimator. It was developed based on a commercial autocollimator-Nikon 6B model-with the addition of a visual interface and its respective image processing software. The visual interface allows the optical instrument's performance to be surpassed, thus increasing the resolution and accuracy with respect to the original equipment. The development allows for an improvement in the measurement capacity of the laboratories when calibrating electronic levels, reference planes, and angular patterns, among others. On the other hand, fundamental information is provided for the new instrument's last stage of design through a detailed evaluation of the measurement system's mathematical model. This allows us to determine the relative impact of each uncertainty component in order to identify those of greater weight and minimize them by correction.

In this paper we present an electronic interface developed for the commercial visual analogue autocollimator -Nikon 6B/6D model- that allows the original instrument to be digitized to improve accuracy and increase resolution. The electronic interface consists of a high-definition Basler camera, a positioning device and an integrated computer with a software for the digital processing of images. The algorithm of the developed software includes two main routines: one for scale calibration and another for determining the position of the measuring cross. Both routines work at the sub-pixel level, allowing for a marked improvement in the accuracy of the new autocollimator + interface instrument (A&I). On the other hand, the resolution obtained with A&I is 40 times better than that registered by the original optical system.

In this article we present a new method for measuring the misalignment distortion caused by the lenses of the system used as a visual interface for a Nikon 6B autocollimator. This interface is used for making angle measurements using image processing techniques. This research paper studies the interaction between the optical systems of the interface's camera and the autocollimator. With the proposed method it is possible to quantify tolerances for the assembly process of the camera with the autocollimator. Furthermore, it is possible to quantify the contribution of the camera's misalignment induced by the environment (thermal gradients, for example) to the uncertainty in the autocollimator's scale calibration.

Purpose.: The vertebrate inner retina has a subset of intrinsically photosensitive retinal ganglion cells (ipRGCs) that express the nonvisual photopigment melanopsin. The intrinsically photosensitive retinal ganglion cells send light information from the environment to the brain to control, among other parameters, the amount of energy entering the eyes through the pupillary light reflex (PLR). A daily variation in the PLR in both mice and humans has recently been shown, indicating circadian control of this response. In a previous work involving the sensitivity spectra for the PLR, we showed that blind chickens (GUCY1*) display the highest sensitivity to light of 480 nm. The aim of the present study was to evaluate the potential circadian control of PLRs in blind birds under scotopic conditions. Methods.: Circadian PLR was performed on GUCY1* chickens with lights of different wavelengths (white or blue light of 475 nm) under scotopic conditions. Results.: We found a significant daily variation in the PLRs of chickens exposed to white or blue light of 475 nm, with increased sensitivity at circadian time 6 during the subjective day. Conclusions.: Our observations clearly point to circadian control of PLRs even in blindness, strongly indicating that both the entry of light into the eyes and its quality are differentially regulated during the day in diurnal animals.

In this paper the development of the Sub-pixel gray-scale Hough transform as a method of detecting the positions of lines is presented. The algorithm is part of an electronic interface created for the Nikon 6B/6D autocollimator. This interface allows for an increase in final resolution of measurements and a reduction of the vignetting and distortion effects produced by this optical instrument's lenses. The electronic interface consists of a Basler ACE HD camera and its positioning devices, and a computer with a sub-pixel digital image processing package.

In this paper, we present an electronic interface created for the Nikon 6B/6D visual autocollimator that allows for an increase in the final resolution of measurements and a reduction in the vignetting and distortion effects produced by this optical instrument's lenses. The electronic interface consists of a Basler ACE high-definition camera and its positioning devices and a computer with a subpixel digital image processing package. The latter includes two main procedures: one for scale calibration and the other for determining the position of crosshair lines. Both procedures work at subpixel level. The feasibility of the measurement method was verified. The resolution obtained for the measurement of angular displacements is about 0.019 s of arc, 25 times better than the one registered by the original visual system. Its overall performance was compared against an electronic level with internationally traceable certification.

The goal of this paper is to describe the potential of a basic visual interfase applied to a Nikon 6B/6D autocollimator in order to replace human operator within a "laboratory grade" measurement. The implemented optical interface consists of a CMOS sensor-based camera attached to the autocollimator ocular, camera positioning devices and a proprietary digital image processing package, built around Matlab (R) environment, used to analyze the reticle's image to detect both the scale and the measuring cross at sub-pixel level. In a controlled experiment the system performance was compared against an electronic level with internationally traceable certification. Pitch angles were obtained with a resolution three times better than the original of the instrument. This example shows that the value of 0,06 pixels for the uncertainty associated with sub-pixel position of the reticle lines is realistic, allowing to continue working on a robust interface for all angle parameters that can be measured using an autocollimator.

External visual interfaces for high precision measuring devices are based on the segmentation of images of their measuring reticle. In this paper, a method for subpixel straight lines detection is presented and tested on images taken from the reticle of a dark field autocollimator. The method has three steps, the sharpening of the image using a version of the Savitzky-Golay filter for smoothing and differentiation, the construction of a coarse edge image using Sobel filters, and finally, the subpixel edge location determination, by fitting a Gaussian function to orthogonal sections of the coarse edge image.We discuss results of applying the proposed method to images of the reticle of a Nikon 6D autocollimator, using the scale of the device as a benchmark for testing the error in the location of the lines and compare them with Sobel/Hough and Sobel/polynomial fitting. We report that for this type of image-content, Gaussian fitting has smaller uncertainty, when cameras with two different sensors are used.

The objective of this paper is to study the detection algorithms of line centers. These algorithms are used to precise the positions of such lines on the scales of high precision measuring instruments. Based on previous simulation and on the implementation of the algorithms that were simulated in the actual images of the scale and crosshair lines of a Nikon 6D autocollimator, we studied a line segmentation and center detection algorithm built using the Hough transform. We also present the algorithm behaviour when working with noise images.

Resumen: Este documento tiene el objetivo de describir el potencial de una interfaz visual ba'sica en un Autocolimador del tipo Nikon 6B/6D, para reemplazar al operario en una medición de calidad metrológica. La interfaz visual implementada consta de una cámara con sensor CMOS adosada al ocular del autocolimador, partes posicionales, y un sistema de procesamiento digital de imágenes propio, escrito en lenguaje Matlab OR, que analiza la imagen de la ret́ıcula para detectar la escala y la cruz de medición a nivel sub-ṕıxel. Mediante un experimento controlado, realizado con un nivel electrónico trazable internacionalmente, se obtuvieron, con este sistema, ángulos de cabeceo (αy) con una resolución tres veces mejor que la del instrumento sin interfaz. Este ejemplo sugiere que el valor de 0.06 ṕıxeles para la incertidumbre asociada con la posición sub-ṕıxel de las diferentes ĺıneas que conforman la ret́ıcula de medición es realista, y permite seguir trabajando en una interfaz robusta para todos los parámetros angulares posibles de ser medidos por el autocolimador. Abstract: The goal of this paper is to describe the potential of a ba- sic visual interfase applied to a Nikon 6B/6D autocollimator in order to replace human operator within a “laboratory grade” measurement. The implemented optical interface consists of a CMOS sensor-based camera attached to the autocollimator ocu- lar, camera positioning devices and a proprietary digital image processing package, built around Matlab OR environment, used to analyze the reticle's image to detect both the scale and the measuring cross at sub-pixel level. In a controlled experiment the system performance was compared against an electronic le- vel with internationally traceable certification. Pitch angles we- re obtained with a resolution three times better than the original of the instrument. This example shows that the value of 0,06 pixels for the uncertainty associated with sub-pixel position of the reticle lines is realistic, allowing to continue working on a robust interface for all angle parameters that can be measured using an autocollimator. Palabras clave: Autocolimador, sensor CMOS, Interfaz visual, precisión subpixel., Keywords: Autocollimator, CMOS sensor, image processing, subpixel accuracy

The goal of this paper is to describe the potential of a visual interface applied to a Nikon 6B/6D autocollimator in order to replace human operator within a “laboratory grade” measurement. The optical interface implemented consists of a Basler HD camera attached to the autocollimator's eyepiece, camera positioning devices, and a proprietary digital image processing package, built around Matlab environment. The whole system is used to analyze the reticle image to detect both the scale and the measuring crosshair lines at sub-pixel level. The system performance was compared in a controlled experiment against an electronic level with internationally traceable certification. The resolution of the pitch angles obtained was 10 times better than that originally obtained with the instrument. This example shows that the value of 0.02 pixels for the uncertainty associated with sub-pixel position of reticle lines is realistic, allowing for continue working on a robust interface for all angle parameters that can be measured using autocollimators.

A spin decoupling method in nuclear quadrupole resonance spin echo experiment is used to detect the proton magnetic resonance absorption spectrum. The behavior of proton resonance in α phase of polycrystalline p-dichlorobenzene as a function of the intensity of the proton decoupling oscillating field (H2) is measured. Good agreement between the experimental resonance frequency and Shirley’s theory for a non-interacting 1/2 spin system is observed. To our knowledge this is the first time the NMR proton frequency dependence on linear polarized excitation field intensity for H2/Ho as high as 1.8 is measured.

In mammals, photoreceptors located in the inner retina convey photic information to the brain, regulating diverse non-image-forming tasks such as pupillary light reflexes and photic synchronization (entrainment) of daily activity rhythms. In nonmammalian vertebrates, the retina, deep brain photoreceptors, and pineal organ may be photoreceptive. Here we investigated light perception in the absence of functional cone and rod photoreceptors using GUCY1* chickens, birds carrying a null mutation that causes blindness at hatch. They showed light responses in both the pupillary light reflex and the entrainment of feeding rhythms to a 12:12 h light-dark cycle. Light responses persisted even when the extraretinal photoperception was abolished, but they were lost after enucleation; this strongly indicates the essential role played by the inner retina. A sensitivity spectrum study for the pupillary reflex that combined pupil responses to different monochromatic lights of various intensities demonstrated that a single opsin/vitamin A-based photopigment peaking at 484 nm drives photic responses; the best fit (lowest sum of squares, R(2)=0.9622) was attained with an opsin:vitamin A2 template. The results are the first characterization of functional inner retinal photoreceptors participating in the regulation of non-image-forming activities in nonmammalian vertebrates.

Introduction. Chronic daily headache (CDH) is a chronic painful clinical condition that is frequently found in neurological practice. Diagnosis is clinical and the therapeutic approach is complex. Its mechanism of production is still not altogether clear but a genetic component is acknowledged as a predisposing factor. Numerous areas are involved in the generation of primary headaches, including the periaqueductal grey matter (PAGM), which plays a role as a neuromodulator both in headaches and in other chronic painful conditions. Aims. In order to evaluate possible biochemical changes in patients with CDH, magnetic resonance imaging was used to study the spectra produced in the PAGM. Subjects and methods. The spectra in the PAGM were studied in 17 patients with CDH. These were compared with the average spectra in 17 healthy subjects by means of differential spectroscopy. Results. Subjects with CDH show a reduction of over 70% in the level of the metabolite N-acetyl-aspartyl-glutamate (NAAG) in the PAGM. NAAG is a peptide involved in antinociceptive activity. Conclusions. The reduction of NAAG in the PAGM suggests altered neuromodulation of the antinociceptive systems in subjects with CDH. Whether CDH is the cause or the consequence has still to be determined.