Goniometer System Research Articles

Intelligent Precise Goniometric System of Analysis of Spectral Distribution Intensities for Definition of Chemical Composition of Metal-Containing Substances

Intelligent Precise Goniometric System of Analysis of Spectral Distribution Intensities for Definition of Chemical Composition of Metal-Containing Substances

The Translation of Movement From the Equine to Rider With Relevance for Hippotherapy

Although horseback riding is a well-established means of rehabilitation therapy for a variety of human patients, there are few data on the biomechanical relationships between horse and rider during such hippotherapy. We simultaneously tracked the movements of a horse with several different novice riders, under conditions similar to hippotherapy, to evaluate whether horses pass the same motion to different riders while being lead at a walk. Riders were outfitted with a goniometric data collection system that recorded the angles of flexion and extension and lateral bending of the thoracic and lumbar spine, as well as the flexion, extension, abduction, and adduction of each hip. We found consistent rhythmic motion in the horse's hock, shoulder, and knee. There were no significant differences in equine movement across six different riders, supporting the conclusion that horses can be used as a reproducible rehabilitation platform for riders. Moreover, although riders demonstrated different baseline postures, there were no significant differences in their ranges of motion in each joint. These results indicate that a horse can reproducibly influence a population of participants in a hippotherapy situation.

A Novel Approach for Deriving LAI of Salt Marsh Vegetation Using Structure From Motion and Multiangular Spectra

The leaf area index (LAI) is a structural parameter that plays a major role in modeling the exchange of energy, carbon dioxide, water, and other matter between plants and their surrounding environment. Direct means of measuring LAI are time-intensive and laborious, making indirect LAI retrieval methods desirable. In this study, we developed a method for retrieving structural metrics of erectophile plants that relies on open-source structure from motion software. We achieved this using a novel goniometer system to simultaneously retrieve high-resolution digital imagery and bidirectional spectroscopy measurements of Spartina alterniflora in a laboratory environment during both ${{ peak}}$ and ${{ late}}$ growing season. Retrieved LAI metrics correlated well with directional measurements of the Modified Chlorophyll Absorption Ratio Index 2 (MCARI2). Across all planting densities, the magnitude of the MCARI2 exhibited a high degree of variance, which depended on sensor viewing angle. MCARI2 values in the peak growing season were significantly higher. This result suggests that the MCARI2 metric is sensitive to seasonal changes in plant growth and senescence. We observed a high correlation between the $\text{LAI}_{\text{contact}}$ values and the Total MCARI2 metric for the ${{ peak}}$ growth state plantings of $R^2 = 0.9$ , suggesting that summing multiple directional measurements of MCARI2 potentially provides a more accurate assessment of LAI and compensates for observed variance in MCARI2 as a function of sensor orientation. Future work will focus on validating the observed effects across a broader range of plant species.

The method and mathematical support for calibration of a goniometric system based on the accelerometers

The article is devoted to the development of a calibration method for the goniometric system, which includes accelerometers. The complexity of the technological process of mechanical calibration of accelerometers was noted. It is proposed to apply software-algorithmic correction of measurement results. A mathematical model of signals of an accelerometer converter is described, which takes into account the influence of measurement errors. It is noted that in order to find the parameters of the mathematical model of an accelerometer signal, it is necessary to perform calibration. A mathematical model and the principle of calibration of the misalignment angle of the axes of the accelerometer are proposed and described. To evaluate the effectiveness of the proposed calibration method, experimental studies and data processing of the accelerometer were carried. As a result of experimental studies, an estimation of the degree of error compensation of the ADIS 16534 accelerometer measurements was performed with the application of the modified multi-position calibration method and the calibration method proposed by the authors of this article.

Measurement of coordinates of sources of radio emission at high frequencies goniometric and goniometric and range-metering by methods

Coordinates of sources of a radio emission of range of high frequencies using an on-off system azimuth and meridian direction finders are measured by a goniometric method. In the bearing posts active arrays of vertical vibrators and synchronized coherent radio receivers with frequency conversion are used. For minimization of amplitude and phase not identities preliminary calibration of channels of the receiver at frequencies of the taken the bearings signals is executed. By results of measurements average quadratic deviations of coordinates of sources of a radio emission of type of radio stations of meteo-information of airfield networks of the Russian Federation and the neighboring countries, standard frequency stations and time, transmitters of telecode and continuous messages are investigated. The analysis of dependences of achievable accuracy figures of measurements on the space provision of positions of direction finders, lengths of routes and also fluctuations of electro-physical parameters and space distribution of the ionized layers of the atmosphere leading to changes of beam trajectories of distribution and abnormal errors of measurements of the directions of arrival of radio waves to different season and day is carried out. It is shown that in the lower part of range of high frequencies the measurement error of coordinates of sources of a radio emission a goniometric system makes 4.7 %, and in process of approach of frequency to the upper bound of range this indicator increases by 1.2 times. By results of bearing of signals in one point of space and measurements of height of layers of the atmosphere with use of the station of vertical sounding coordinates of sources of a radio emission are determined by a goniometric and range-metering method. Measurements of coordinates of objects by a goniometric and range-metering method can be executed with average quadratic deviation of 11-13 % of range.

Evaluation of PROSAIL inversion for retrieval of chlorophyll, leaf dry matter, leaf angle, and leaf area index of wheat using spectrodirectional measurements

ABSTRACTBidirectional reflectance measurements of wheat crop acquired with field goniometer system were used to evaluate PROSAIL (PROSPECT and SAIL (Scattering by Arbitrary Inclined Leaves)) inversion for retrieval of biophysical parameters. The measurements on wheat involved 54 view angles (6 azimuthal planes ×9 view zenith angles) to cover the hemispheric span up to 60° view zenith acquired at 7–8 days interval during early growth stages to physiological maturity. Parallel observations on crop, soil, and atmosphere were made for input parameters of radiative transfer model PROSAIL. The spectral sensitivity of the model indicated that the reflectance in visible was relatively more important for chlorophyll retrieval and reflectance in near infrared has more importance for retrieval for leaf inclination angle, dry matter and leaf area index. The coupling of spectrodirectional reflectance with the model using simplex algorithm was found successful in precise retrieval of chlorophyll (root mean square error (RMSE) = 15.62 μg cm−2), leaf inclination angle (RMSE = 2.14), and dry matter (RMSE = 0.00053 g cm−2). LAI retrieval was poor (RMSE = 1.05) because of saturation effect at LAI >4. Limited angular sampling close to hotspot region was found sufficient for precise retrieval of chlorophyll (RMSE = 10.50 μg cm−2) and leaf inclination angle (RMSE = 2.14). This signifies the importance of off-nadir observations in biophysical parameters’ retrieval.

Calibration of rotation axes for multi-axis goniometers in macromolecular crystallography.

The installation of multi-axis goniometers such as the ESRF/EMBL miniKappa goniometer system has allowed the increased use of sample reorientation in macromolecular crystallography. Old and newly appearing data collection methods require precision and accuracy in crystal reorientation. The proper use of such multi-axis systems has necessitated the development of rapid and easy to perform methods for establishing and evaluating device calibration. A new diffraction-based method meeting these criteria has been developed for the calibration of the motors responsible for rotational motion. This method takes advantage of crystal symmetry by comparing the orientations of a sample rotated about a given axis and checking that the magnitude of the real rotation fits the calculated angle between these two orientations. Hence, the accuracy and precision of rotational motion can be assessed. This rotation calibration procedure has been performed on several beamlines at the ESRF and other synchrotrons. Some resulting data are presented here for reference.

Development of artificial neural network for determining the components of errors when measuring angles using a goniometric software-hardware complex

We have developed an artificial neural network to determine the components of error in measuring the angles by automated goniometric systems whose change over time is a non-stationary random process. There are known techniques for processing measurement results and normalizing the systematic and random components of measurement errors, they have been applied for many years, they are well justified, maximally formalized, fundamentally different and are governed by respective regulations. However, it is still a rather difficult and labor-intensive procedure to determine exactly which component of an error is present in the measurement results. A given procedure is based on using the Fisher’s dispersion criterion. In order to automate this procedure and improve performance efficiency of performed operations, we have developed an artificial neural network (ANN) and examined its functioning. It was determined that the proposed ANN could be successfully employed instead of known analytical-computational procedure using the Fisher’s dispersion criterion. The application of ANN could significantly reduce labor intensity and improve the efficiency of determining the systematic and random components of measurement errors. This is predetermined by the capability of ANN to perform parallel processing of measurement data in real time. The practical implementation of ANN is based on using the neuro-simulator Neural Analyzer, analytical software Deductor Professional developed by BaseGroupLabs. We trained ANN and tested its functionality on the set of simulation results and actual multiple observations when measuring the plane angle of a 24-facet prism. The ability of ANN to quickly and correctly determine components of measurement errors at the stage of analysis of measurement information makes it possible to subsequently define methods for its further processing in accordance with regulatory requirements. That would improve the accuracy and reliability of measurement results as it could help avoid incorrect and inaccurate calculations when normalizing measurement errors.

Recent Progress of Residual Stress Distribution and Structural Evolution in Materials and Components by Neutron Diffraction Measurement at RSND

Neutron diffraction is an effective and nondestructive method to investigate inner structure and stress distribution inside bulk materials and components. Compared with X-ray diffraction, neutron diffraction allows a relatively high penetration depth and covers a larger gauge volume, enabling it to measure the lattice structure and three-dimensional (3D) distribution of residual stress deep inside thick sample materials. This paper presents the recent development of a Residual Stress Neutron Diffractometer (RSND) at the Key Laboratory for Neutron Physics of the Chinese Academy of Engineering Physics, Institute of Nuclear Physics and Chemistry, Mianyang, China. By integrating multiple instruments such as a loading frame, Kappa goniometer, and coupling system, the RSND was constructed as a suitable platform for various neutron diffraction experiments, including residual stress measurement, in situ observation, and texture analysis. Neutron diffraction measurement can be used to study various materials such as steels, aluminum alloys, and titanium alloys, as well as various components such as turbine discs and welding parts. An evaluation method for both polycrystalline and monocrystalline materials was developed, and this method was found to have the capability of solving an agelong technical challenge in characterizing monocrystalline materials. Furthermore, by introducing a texture and thermomechanical coupling system, it is now possible to make effective in situ observations of the structural evolution in single crystal materials under high-temperature tensile conditions.

A Wearable Detector for Simultaneous Finger Joint Motion Measurement.

This paper presents a wearable and stretchable detector for simultaneous finger joint motion measurement, providing the feasible technical solutions to solve the problems existing in the current devices. The sensor array installed in the detector consists of 14 custom-made bending sensors and an inertial measurement unit with high accuracy. The glove support for a sensor array, which is made of three silicone materials with different elasticity, not only overcomesthedrawbacks of cloth support, but also addresses the compatibility between the stretch substrate and the inelastic sensing components. Besides, two-section electrical connection avoids the problems caused by the external wires in traditional solutions to enhance the durability of glove. The experiment results indicated that the wearable detector offers a good user experience by exerting a small force on fingers. The device also shows a strong durability as it worked properly after tens of thousands of bending. The measurement tests on a single sensor demonstrated that two kinds of sensors are both with high accuracy. Besides, the hand goniometric system has an excellent performance in terms of hand motion detection. The measurement error of the device in subjects with different hand sizes is within a reasonable range. The good properties of the sensory detector allow it to be applied in clinical applications.

A Pilot Study of Augmented Reality Technology Applied to the Acetabular Cup Placement During Total Hip Arthroplasty

BackgroundWe developed an acetabular cup placement device, the AR-HIP system, using augmented reality (AR). The AR-HIP system allows the surgeon to view an acetabular cup image superimposed in the surgical field through a smartphone. The smartphone also shows the placement angle of the acetabular cup. This preliminary study was performed to assess the accuracy of the AR-HIP system for acetabular cup placement during total hip arthroplasty (THA). MethodsWe prospectively measured the placement angles using both a goniometer and AR-HIP system in 56 hips of 54 patients undergoing primary THA. We randomly determined the order of intraoperative measurement using the 2 devices. At 3 months after THA, the placement angle of the acetabular cup was measured on computed tomography images. The primary outcome was the absolute value of the difference between intraoperative and postoperative computed tomography measurements. ResultsThe measurement angle using AR-HIP was significantly more accurate in terms of radiographic anteversion than that using a goniometer (2.7° vs 6.8°, respectively; mean difference 4.1°; 95% confidence interval, 3.0-5.2; P < .0001). There was no statistically significant difference in terms of radiographic inclination (2.1° vs 2.6°; mean difference 0.5°; 95% confidence interval, −1.1 to 0.1; P = .13). ConclusionIn this pilot study, the AR-HIP system provided more accurate information regarding acetabular cup placement angle than the conventional method. Further studies are required to confirm the utility of the AR-HIP system as a navigation tool.

New design for multi-crystal data collection at SSRF

Data collection with microcrystals at synchrotron radiation facilities is challenging because it is difficult to harvest and locate microcrystals. Moreover, microcrystals are sensitive to radiation damage; thus, typically, a complete data set cannot be obtained with a single microcrystal. Herein, we report a new method for data collection with multiple microcrystals having a crystal size ranging from 1 to 30 µm. This method is suitable for not only low-temperature (100 K) data collection but also room-temperature data collection. Thin Kapton membranes were used to capture multiple crystals simultaneously. The microcrystals were visible under an optical microscope and easily located because the membrane was transparent and sufficiently thin. The film was fixed to a bracket that was prepared using a three-dimensional printer. The bracket was fixed on a magnetic base via screwing and employed by the goniometer system for data collection. Multiple data sets of fatty acid-binding protein 4 (FABP4) and lysozyme microcrystals were collected using this novel designed device. Finally, the structures of protein FABP4 and lysozyme were obtained from these data via the molecule replacement method. The data statistics reveal that this method provides a comparable result to traditional methods such as a nylon loop.

A study of PC-based ultrasonic goniometer system of surface properties and characterization of materials

This paper discussed the design and development of a portable PC-based ultrasonic goniometer system that can be used to study material properties using ultrasonic wave. The system utilizes an ultrasonic pulse-receiver card model attached to computer notebook for signal display. A new specific software package (GoNIO) was developed to control the operation of the scanner, displaying the data and analyze characteristics of materials. System testing was carried out using samples with cubic dimension of about 10 mm x 20 mm x 30 mm. This size allows the sample to be fitted into the goniometer specimen holder and immersed in a liquid during measurement. The sample was rotated from incident angle of 0° to 90° during measurement and the amplitude reflected signals were recorded at every one degree of rotation. Immersion transducers were used to generate and receive the ultrasounds that pass through the samples. Longitudinal, shear and Rayleigh wave measurements were performed on the samples to determine the Dynamic Young’s Modulus. Results of measurements are explained and discussed.

The procedure for determining the number of measurements in the normalization of random error of an information­measuring system with elements of artificial intelligence

Features of estimation and normalization of random components of the errors occurring in measurements with the help of goniometric systems were considered. A general procedure has been formulated that makes it possible to soundly determine the necessary and sufficient number of measurement repetitions to ensure accuracy and reliability of the obtained results. The procedure is based on application of mathematical apparatus of the probability theory, mathematical analysis and statistics, as well as the assumption that random errors obey the normal law of distribution of random quantities. Operatioability of the proposed procedure and effectiveness of its use have been experimentally confirmed. In particular, when comparing the obtained results with those in a similar work [7], the time taken to carry out measurements decreased by 1.3 times. That is, the effect of applying the proposed procedure is greater than the measurement costs while a high accuracy of 0.01 and reliability of 0.95 are maintained. The obtained results indicate the possibility of further extensive laboratory and industrial applications

Modeling and intercomparison of field and laboratory hyperspectral goniometer measurements with G-LiHT imagery of the Algodones Dunes

We compare field hyperspectral bidirectional reflectance distribution function (BRDF) measurements acquired by a hyperspectral goniometer system known as the goniometer of the Rochester Institute of Technology (GRIT) during an experiment in the Algodones Dunes system in March 2015 with NASA Goddard’s light detection and ranging, hyperspectral, and thermal imagery of the site acquired during the experiment. We augment our field spectral data collection with laboratory hyperspectral BRDF measurements of samples brought back from the Algodones Dunes site using GRIT and our second-generation goniometer GRIT-two (GRIT-T). In these laboratory experiments, we vary geophysical parameters such as sediment density and grain size distribution of the sediments that would typically impact observed BRDF with the goal of extending the range of applicability of our resulting BRDF spectral libraries. Geotechnical measurements on site confirm the variability of geophysical parameters such as density and grain size distributions within the dune system, and measurements with GRIT and GRIT-T demonstrate the impact on observed spectral variation. By augmenting field spectral libraries with laboratory BRDF, we show that a greater proportion of the dune system is more faithfully represented in the expanded spectral library. Beyond developing appropriate calibration data for airborne and satellite imagery of the Algodones Dunes, laboratory and field studies also support goals to develop reliable retrieval methods for geophysical quantities such as sediment density directly from spectral imagery. We consider approaches based on the Hapke model. Our approaches use the invariance of the observed functional forms of the single scattering phase function, which must be invariant to differences in the illumination geometry. Fill factor is retrieved and correlates with expected direct measurements of sediment density in a laboratory setting.

Changes in reflectance anisotropy of wheat crop during different phenophases

Abstract The canopy structure of wheat changes significantly with growth stages and leads to changes in reflectance anisotropy. Bidirectional reflectance distribution function characterises the reflectance anisotropy of the targets, which can be approximated. Spectrodirectional reflectance measurements on wheat crop were acquired using a field goniometer system. The bidirectional reflectance spectra were acquired at 54 view angles to cover the hemispheric span up to 60° view zenith. The observations were made during early growth stages till maturity of the crop. The anisotropy was not constant for all wavelengths and anisotropic factors clearly revealed spectral dependence, which was more pronounced in near principal plane. In near infrared, wheat canopy expressed less reflectance anisotropy because of higher multiple scattering. The broad hotspot signature was noticeable in reflectance of canopy whenever view and solar angles were close. Distinct changes in bidirectional reflectance distribution function were observed during booting to flowering stages as the canopy achieves more uniformity, height and head emergence. The function clearly reveals bowl shape during heading to early milking growth stages of the crop. Late growth stages show less prominent gap and shadow effects. Anisotropy index revealed that wheat exhibits changes in reflectance anisotropy with phenological development and with spectral bands.

Construction of a model of a continuous light source specified by a fixed set of rays

A physically correct model of a light source specified by a finite set of rays obtained either by processing the measured characteristics of the light source on the Radiant Imaging goniometric system or as a result of the forward stochastic ray tracing in a scene modeling the radiation of a complex light source is constructed. An algorithm for constructing a continuous emitting surface of a light source and its goniometric diagram given a finite set of rays is developed. The model preserves the spectral composition of the source rays in the surface luminance distribution of the radiation light source. An example of the photorealistic rendering of a scene illuminated by a finite set of rays obtained by the computer processing photometric measurement data.

Flexible field goniometer system: the Goniometer for Outdoor Portable Hyperspectral Earth Reflectance

This paper describes a portable hyperspectral goniometer system for measurement of hemispherical conical reflectance factor (HCRF) data for terrestrial applications, especially in the coastal zone. This system, the Goniometer for Portable Hyperspectral Earth Reflectance (GOPHER), consists of a computer-controlled Spectra Vista Corporation HR-1024 full-range spectrometer mounted on a rotating arc and track assembly, allowing complete coverage in zenith and azimuth of a full hemisphere for recording HCRF. The control software allows customized scan patterns to be quickly modified in the field, providing for flexibility in recording HCRF and the opposition effect with varying grid sizes and scan ranges in both azimuth and zenith directions. The spectrometer track can be raised and lowered on a mast to accommodate variations in terrain and land cover. To minimize the effect of variations in illumination during GOPHER scan cycles, a dual-spectrometer approach has been adapted to link records of irradiance recorded by a second spectrometer during the GOPHER HCRF scan cycle. Examples of field data illustrate the utility of the instrument for coastal studies.

ULGS II: A High-Performance Field and Laboratory Spectrogoniometer for Measuring Hyperspectral Bidirectional Reflectance Characteristics

The derivation of the bidirectional reflectance distribution function (BRDF) from Earth surface features provides vital data for improved remote estimation of Earth surface features and properties. The angular component of a reflectance signature represents a valuable source of information that has largely been ignored due to the lack of empirical data. BRDF data products are now readily available from a variety of remote sensing platforms, and these require extensive field validation to ensure data quality and validity. This paper presents a high-performance, low-cost, and computer-controlled goniometer system capable of sampling surface BRDF and demonstrates several example applications. The system introduces a number of technological advances, including real-time reflectance calibration, programmable sampling schemes, zero target interference structure, and ease of portability. Using this instrument, BRDF estimates were gathered from a variety of agricultural crops in field and laboratory settings, with performance gains of four times the speed of current designs. This system can provide very fast acquisition of a BRDF estimate, depending on the desired angular resolution. Initial experiments demonstrate that this new style of hyperspectral goniometer is a significant advance over previous designs, with respect to scan capabilities, angular resolution, calibration, and portability.

Wavelet Analysis of Humans with Osteoarthritis

In this research proposal we want to develop from kinematic data, measures using thewavelets theory to characterize normal and osteoarthritis knee locomotion. The kinematic data of theradio-carpal flexion-extension angles were analyzed using the wavelet transform. The experimentaldata was acquired with a complex goniometer system. The detail energy for the level 5 is an importantfactor to characterize the osteoarthritis patients and normal subjects.