Planetary surface photometry and imaging: progress and perspectives.

Spacecraft have visited and returned many thousands of images and spectra of all of the planets, many of their moons, several asteroids, and a few comet nuclei during the golden age of planetary exploration. The signal in each pixel of each image or spectral channel is a measurement of the radiance of scattered sunlight into a specific direction. The information on the structure and composition of the surface that is contained in variation of the radiance with scattering geometry and wavelength, including polarization state, has only just begun to be exploited and is the topic of this review. The uppermost surfaces of these bodies are mainly composed of particles that are continuously generated by impacts of micrometeoroids and larger impactors. Models of light scattering by distributions of sizes and irregular shapes of particles and by closely packed particles within a surface are challenging. These are active topics of research where considerable progress has recently been made. We focus on the surfaces of bodies lacking atmospheres.These surfaces are diverse and their morphologies give evidence of their evolution by impacts and resurfacing by a variety of processes including down slope movement and electrostatic transport of particles, gravitational accumulation of debris, volatile outgassing and migration, and magnetospheric interactions. Sampling of scattering geometries and spatial resolution is constrained by spacecraft trajectories. However, the large number of archived images and spectra demand more quantitative interpretation. The scattering geometry dependence of the radiance is underutilized and promises constraints on the compositions and structure of the surface for materials that lack diagnostic wavelength dependence. The general problem is considered in terms of the lunar regolith for which samples have been returned to Earth.

Reliability and validity of angular measures through the software for postural assessment. Postural Assessment Software

Introducción: El análisis estático fotográfico de la postura con la ayuda de software específico es práctico para estudios a gran escala y facilita el diagnóstico, la planificación y acompañamiento de cualquier tratamiento fisioterapéutico. El objetivo fue determinar tanto test-retest e inter-calificadores fiabilidad y validez de la fotogrametría computerizado con el software de evaluación postural (SAP) en relación con goniometría. Materiales y métodos: Los goniómetros universales se pusieron en una pared del laboratorio, permitiendo la obtención de 4 medidas angulares. Una cámara digital se coloca en un trípode a una altura de 1,47 metros y a una distancia de 3 metros de la pared. Una fotografía fue tomada con los cuatro goniómetros y dos fotos más fueron tomadas cambiando los valores angulares de los goniometros entre cada foto, totalizando doce valores angulares diferentes. Cada fotografía fue analizada por los tres evaluadores utilizando el Software de Evaluación postural. Método de Bland---Altman se utilizó para documentar un acuerdo entre los evaluadores y entre Goniometría y Software de Evaluación postural. Resultados: No hubo diferencias estadísticamente significativas entre los dos métodos de evaluación: goniometría y el software de SAP. La gráfica de Bland-Altman ratificó la fuerte consistencia entre los métodos, con una diferencia media igual a 0,06. El uso de PAS software también mostró ser fiable intra-calificadores (los tres evaluadores no presentaron diferencias significativas entre la primera y la segunda medición) y tener una buena fiabilidad entre evaluadores, sin presentar diferencias estadísticamente significativas entre ellos. Conclusiones: Software de evaluación postural es un método preciso y fiable en comparación con la goniometría (AU)

Introduction. Static posture analysis with the aid of specific software with images is beneficial for large-scale studies and facilitates the diagnosis, planning and follow-up of any physiotherapy treatment. Therefore, this study aimed to determine test–retest and inter-rater reliability and validity of computerized photogrammetry using the Postural Assessment Software (PAS) in relation to goniometry. Materials and methods. Universal Goniometers were placed in a wall of the Lab, making it possible to obtain four angular measures. A digital camera was positioned on a tripod at a height of 147 cm and at a distance of three meters from the wall. A photo was taken with the four goniometers. Two more photos were taken, and the goniometer angles were changed within each photo, obtaining 12 different angular values. Each photograph was analyzed by the three raters using the Postural Assessment Software. Bland–Altman method was used to document the agreement between raters and between Goniometry and Postural Assessment Software. Results. There were no statistical differences between the two evaluation methods: goniometry and PAS software. The Bland–Altman graph supported the strong consistency between methods, with an average difference equal to 0.06. The use of PAS software was also shown to be intra-rater reliable, with the three raters (A, p = 0.17; B, p = 0.31; C, p = 0.17) with no statistical significant differences between the first and the second measurement, and to have good inter-rater reliability with no statistical differences between raters. Conclusions. Postural Assessment Software is an accurate and reliable method when compared to the goniometry (AU)

Coherent detection in optical fiber systems.

The drive for higher performance in optical fiber systems has renewed interest in coherent detection. We review detection methods, including noncoherent, differentially coherent, and coherent detection, as well as a hybrid method. We compare modulation methods encoding information in various degrees of freedom (DOF). Polarization-multiplexed quadrature-amplitude modulation maximizes spectral efficiency and power efficiency, by utilizing all four available DOF, the two field quadratures in the two polarizations. Dual-polarization homodyne or heterodyne downconversion are linear processes that can fully recover the received signal field in these four DOF. When downconverted signals are sampled at the Nyquist rate, compensation of transmission impairments can be performed using digital signal processing (DSP). Linear impairments, including chromatic dispersion and polarization-mode dispersion, can be compensated quasi-exactly using finite impulse response filters. Some nonlinear impairments, such as intra-channel four-wave mixing and nonlinear phase noise, can be compensated partially. Carrier phase recovery can be performed using feedforward methods, even when phase-locked loops may fail due to delay constraints. DSP-based compensation enables a receiver to adapt to time-varying impairments, and facilitates use of advanced forward-error-correction codes. We discuss both single- and multi-carrier system implementations. For a given modulation format, using coherent detection, they offer fundamentally the same spectral efficiency and power efficiency, but may differ in practice, because of different impairments and implementation details. With anticipated advances in analog-to-digital converters and integrated circuit technology, DSP-based coherent receivers at bit rates up to 100 Gbit/s should become practical within the next few years.

Improvement deoxyribo nucleic acid spots classification in polyacrylamide [correction of polyacrilamide] gel images using photometric normalization algorithms.

A comparative study of four enhancement algorithms traditionally used in computer vision for photometric normalization of images affected by illumination changes is presented in this paper. We experimented with the performance of these approaches to reduce the low frequency multiplicative noise that is produced as a result of a non-homogeneity illumination or a non-homogeneity developed chemical process in polyacrylamide gel electrophoresis images for the purpose of automatic classification of deoxyribo nucleic acid (DNA). The algorithms are tested on a database and their results are compared in a system for feature extraction and DNA classification.

Estudio de hemolisinas del sistema ABO por técnica fotométrica simple en niños con ascariasis / Study of hemolysins of the ABO blood group system in children with ascariasis using a simple photometric technique

La heteroinmunización en el sistema ABO, a través de sustancias de origen animal o bacteriano, puede provocar la aparición de hemolisinas de importancia clínica en transfusión o embarazo. El objetivo de este trabajo era estudiar la presencia de hemolisinas ABO en niños con ascariasis utilizando una técnica fotométrica simple. Se trabajó con sueros de 23 niños (19 antes del tratamiento antiparasitario y 4 después). Se determinó el grupo sanguíneo ABO por técnicas convencionales. La técnica fotométrica usada para demostrar la presencia de hemolisinas ABO es una modificación del tiempo hemolítico (tH) 50. El tiempo hemolítico medido tiene significado clínico cuando es inferior a 300 segundos. El 57,89% de los sueros de los niños sin tratamiento presentó hemolisinas ABO, con tiempos hemolíticos comprendidos entre 100 y 210 segundos. Ninguno de los sueros de los niños tratados presentó hemolisinas ABO. Los resultados sugieren que la infección parasitaria puede ser el estímulo externo para la aparición de hemolisinas ABO. La técnica fotométrica usada es simple, rápida y accesible al laboratorio de rutina

Heteroimmunization in the ABO system by animal or bacterial products can provoke the development of hemolysins of clinical importance in transfusions or pregnancy. We proposed to study the presence of ABO hemolysins in children with ascariasis using a simple photometric technique. Serum samples were collected from 23 children (19 prior to and 4 after treatment with antiparasitic agents). The ABO blood group was determined by conventional techniques. The photometric technique employed to demonstrate the presence of ABO hemolysins is a modification of tH 50. A hemolysis time of less than 300 seconds was considered to be clinically significant. We detected ABO hemolysins in 57.89% of the sera of untreated children, with hemolysis times ranging between 100 and 210 seconds. None of the sera from the treated children presented ABO hemolysins. The results suggest that parasitic infection may be the external stimulus that provokes the appearance of ABO hemolysins. The photometric technique employed is simple and rapid, and is available to any routine laboratory

Frederic Ives Medal paper. History and current status of a physiologically based system of photometry and colorimetry.

The CIE chromaticity diagram, which has been in common use for more than 60 years, disguises essential relations among cone excitations that become transparent in a system developed with D. I. A. MacLeod and initially proposed by the author to the CIE in 1979. This proposal led to the formation of a CIE committee to consider an ideal version of the system, to be employed either as a supplement to, or an alternative for, the 1931 "standard observer". After 15 years, the task remains unfinished. The history of debate within the original committee and that of its successor (which is still active today) is briefly reviewed. Among cone fundamentals that might be chosen, a set derived and published by Stockman, MacLeod, and Johnson [J. Opt. Soc. Am. A 10, 2491 (1993)] is favored here, and some of the advantages for displaying visual data in a system based on these fundamentals are illustrated.