Sinusoidal Pattern Research Articles

Image reconstruction approach for a high space-bandwidth product structured illumination microscopy system

Conventional structured illumination microscopy (SIM) utilizes a sinusoidal excitation pattern of frequency within the detection passband and provides a maximum of twofold resolution enhancement over the diffraction limit. A transmission approach proposed in an earlier publication [J. Phys. D 53, 044006 (2019)JPAPBE0022-372710.1088/1361-6463/ab4e68] to further improve the lateral resolution requires sequential higher frequency illumination patterns. However, the existing reconstruction algorithms fail to deliver appropriate reconstruction when the excitation frequency lies far from the passband boundary. Here, we present a correlation-based SIM reconstruction approach for sequential high-frequency illumination patterns even if the pattern frequency lies far from the passband limit. The scheme can be suitably implemented in a variety of custom-built systems where illumination frequency lies beyond the passband support (e.g., non-linear SIM and plasmonic SIM).

Balance Control Strategies during Perturbed Standing after a Traumatic Brain Injury: Kinematic Analysis.

The objective of the current investigation was to examine the presence, absence or alteration of fundamental postural control strategies in individuals post traumatic brain injury (TBI) in response to base of support perturbations in the anterior-posterior (AP) direction. Four age-matched healthy controls (age: 46.50 ± 5.45 years) and four individuals diagnosed with TBI (age: 48.50 ± 9.47 years, time since injury: 6.02 ± 4.47 years) performed standing on instrumented balance platform with integrated force plates while 3D motion capture data was collected at 60 Hz. The platform was programmed to move in the AP direction, during a sequence of 5 perturbations delivered in a sinusoidal pattern at a frequency of 1 Hz, with decreasing amplitudes of 10, 8, 6, 4, and 2 mm respectively. The sagittal plane peak-to-peak range and root mean square (RMS) of the hip, knee, and ankle joint angles during the 5 seconds of perturbation were computed from optical motion capture data. The TBI group had a higher mean range (5.17 ± 1.91°) about the ankle compared to the HC group (4.17 ± 0.81°) for the 10mm perturbation, but their mean range was smaller than the HCs for the other 4 conditions. About the hip, the TBI group's mean range was larger than the HC's for all conditions. For both groups, the mean range decreased with perturbation amplitude for all conditions. The TBI group showed larger changes in mean range and RMS values as the amplitude of the perturbation changed, while the HC group showed smaller intertrial changes. The results suggest that the TBI group was substantially more reliant on the hip strategy to maintain balance during the perturbations and this reliance was well linked with perturbation amplitude.Clinical Relevance- Existing information regarding changes in postural control strategies in individuals post TBI is limited. The current work demonstrates lower limb kinematic differences between HC and TBI and some preliminary evidence on increased hip movement in the TBI group.

Determination of Optical Parameters on Knee Bending of the Feet Using Fiber Optic

Fiber optics are the right transmission medium to monitor the movement of the human body, one of them is knee activity. Single-mode fiber (SMF) and fiber Bragg grating (FBG) as sensing sensors that can monitor damage to bad conditions of the human joint area so can prevent further damage. The purpose of this study was to design fiber optic-based belts due to macrobending with sinusoidal patterns, determine the relationship of knee benders with average power change (P) of SMF and FBG, measure changes in power loss (L) fiber optics as a function of optical fiber diameter (d) and knee angle (k), and determine the optimum sensitivity (S) of SMF and FBG in detecting knee bending. The results showed that L of 0.0751 dB and S of 0.017442 dB are the largest values produced from the SMF belt with values d of 12 mm and k of 180°. The values L of 2.0177 dB and S of 0.591382 dB are the largest values produced from FBG belts with values d of 8 mm and k of 180°. The results of this study explain that FBG is more effective to use because it has a higher S value than SMF.

3D shape measurement for shiny surface using pixel-wise composed fringe pattern based on multi-intensity matrix projection of neighborhood pixels

Phase shifting profilometry (PSP) has been commonly used in three-dimensional shape measurement. However, image saturation is a challenging problem leading to phase and measurement errors when measuring the shiny surface. We propose a new method using pixel-wise composed fringe pattern based on multi-intensity matrix projection of neighborhood pixels. First, a multi-intensity projection matrix is established and projected onto the object. The optimal intensity (the maximum projection intensity without saturation) for each pixel and the mask of each intensity can be obtained by analyzing the proportion of saturated pixels in the captured matrix region. Then, a set of new fringe pattern images without saturation can be obtained with phase shifted sinusoidal fringe patterns of different intensity levels and the corresponding mask. With PSP, the object can be reconstructed. Compared with existing methods, the proposed method can significantly reduce the number of projection operations and time consumption. The performance of the proposed method is verified by the experiments.

LED source interferometer for microscopic fringe projection profilometry using a Gates’ interferometer configuration

The fringe projection technique is considered one of the most reliable solutions for structured light technology, developed for non-contact three-dimensional (3D) data acquisition. When working with this technique, applying it on a microscopic scale, one often encounters some problems such as the limited depth of field of the projected fringe pattern, typical of the imaging lenses, or the formation of speckle-noise when laser interferometric fringes are projected, which are problems that can cause significant errors on test surfaces whose height exceeds the depth of field, and on which, the other hand, speckle noise affects the resolution of the technique. This paper presents a Gates’ interferometer configuration with a LED source to project a fringe pattern without speckle noise and a very long field depth. We explain how a non-located sinusoidal fringe pattern can be obtained using two-beamsplitter cubes and a LED light source. Moreover, we compare measurements made using the LED and laser concerning a commercial contact profilometer.

S2830 The Presentation of Hepatic Amyloidosis

Introduction: Amyloidosis is a disorder characterized by the abnormal deposition of proteins into bodily tissue. This causes changes to both organ structure and function. Amyloidosis has a wide variety of presentations which makes it a difficult diagnostic encounter. Case Description/Methods: An 81 year old male with history of choledocholithiasis, partial gastrectomy and gastroparesis presents with several months of intermittent nausea with new abnormal liver chemistries. On his initially presentation he reported fatigue, shortness of air, nausea with dry heaving and an unintentional 13lb weight loss. At this time MRCP showed dilatation of the common hepatic duct at 12mm, with hepatic changes concerning for parenchymal disease. He returned one month later with worsening elevations in alkaline phosphatase, bilirubin and creatinine. EGD showed mild chronic gastritis otherwise pathology was unrevealing. He then underwent EUS with ERCP which re-demonstrated dilated CBD, the biliary tree was swept and otherwise unremarkable. Random colon biopsies were without pathologic abnormalities. Due to continuation of symptoms with a fairly unrevealing workup he underwent liver biopsy. His liver biopsy showed diffuse replacement of the hepatic parenchyma with sheets of amorphous, eosinophilic material. Trichrome stain highlighted a predominantly sinusoidal pattern. A Congo red stain demonstrates apple-green birefringence, consistent with amyloid. Discussion: Amyloidosis consist of variable etiologies and manifestations. This case is important as it shows that hepatic amyloidosis typically presents with very non-specific symptoms and when an extensive workup has been unremarkable, amyloid should be considered. When a patient is diagnosed with amyloidosis, clinicians should be suspicious of possible predisposed factors. Amyloid is most commonly a result of an underlying process such as hematologic malignancy, chronic infection or autoimmune disease. Tissue is required for diagnosis. After diagnosis, further workup should include investigating possible underlying conditions and ruling out other organ involvement, particularly cardiac or renal involvement. Prognosis depends on subtype as well as any predisposing processes. Those with GI involvement typically have demonstrated worse outcomes. Treatment ideally includes identifying underlying processes and treating appropriately. However, others may be considered for chemotherapy or stem-cell transplant.

Building a Navigable Fine Texture Design Space.

Friction modulation technology enables the creation of textural effects on flat haptic displays. However, an intuitive and manageably small design space for construction of such haptic textures remains an unfulfilled goal for user interface designers. In this paper, we explore perceptually relevant features of fine texture for use in texture construction and modification. Beginning with simple sinusoidal patterns of friction force that vary in frequency and amplitude, we define irregularity, essentially a variable amount of introduced noise, as a third building block of a texture pattern. We demonstrate using multidimensional scaling that all three parameters are scalable features perceptually distinct from each other. Additionally, participants' verbal descriptions of this 3-dimensional design space provide insight into their intuitive interpretation of the physical parameter changes.

T-type folded SIW-based leaky-wave antennas with wide scanning angle and low cross-polarization

Abstract In this paper, a leaky-wave antenna (LWA) with wide scanning angle and low cross-polarization is proposed based on a T-type folded substrate-integrated waveguide (FSIW). Transverse slots with a sinusoidal distribution pattern are etched on the surface of the FSIW so that transmission lines with slow-wave characteristics can excite and radiate −1 order harmonics. The length of the transverse slot affects the dispersion characteristics of the transmission line, and the sinusoidal modulation period controls the operating range of the LWA. In the frequency range of 8.3–15 GHz, the proposed LWA achieves a wide scanning ranging from backward −42° to forward +68° continuously. The cross-polarization of the beam is also kept at less than −30 dB during this scanning. A prototype is fabricated and measured to confirm the design, and the measured results show an agreement with the simulated one.

A calibrated 3D dual-barrel otoendoscope based on fringe-projection profilometry

An otoendoscopic structured-light system based on fringe-projection profilometry is presented. Two standard rigid otoendoscopes are mounted onto each other and combined with a digital light projector and high-speed camera with respective frame rates of 120 and 210 Hz. Four phase-shifted sinusoidal fringe patterns are projected onto the object’s surface through the imaging channel of one endoscope with a 0° viewing angle, and the fringe patterns reflected by the object are recorded by the camera via the imaging channel of the other endoscope with a 30° viewing angle, resulting in a 3D shape measurement speed of 30 Hz in the current setup. Due to the angle between the projection and imaging axis, the projected patterns appear deformed by the object’s shape to the camera, enabling the reconstruction of its full-field surface height map. Geometric lens distortions in the optics of the projection and imaging channels were calibrated, resulting in a depth measurement precision between 10 and 30 µm and a lateral resolution of 10 to 25 µm. Otoendoscopic profilometry adds an extra dimension of depth to the standard 2D otoendoscopic image and can be used as a noninvasive technique to expand the qualitative depth perception of the physician with quantitative 3D data of the tympanic-membrane surface. Hence, the system holds the potential to provide objective diagnosis of tympanic-membrane and middle-ear disease. In future, the system will be optimized to allow real-time surface-shape visualization and handheld operation for use in a clinical setting.

Non-Uniform Circumferential Expansion of Cylindrical Li-Ion Cells—The Potato Effect

This paper presents the non-uniform change in cell thickness of cylindrical Lithium (Li)-ion cells due to the change of State of Charge (SoC). Using optical measurement methods, with the aid of a laser light band micrometer, the expansion and contraction are determined over a complete charge and discharge cycle. The cell is rotated around its own axis by an angle of α=10° in each step, so that the different positions can be compared with each other over the circumference. The experimental data show that, contrary to the assumption based on the physical properties of electrode growth due to lithium intercalation in the graphite, the cell does not expand uniformly. Depending on the position and orientation of the cell coil, there are different zones of expansion and contraction. In order to confirm the non-uniform expansion around the circumference of the cell in 3D, X-ray computed tomography (CT) scans of the cells are performed at low and at high SoC. Comparison of the high resolution 3D reconstructed volumes clearly visualizes a sinusoidal pattern for non-uniform expansion. From the 3D volume, it can be confirmed that the thickness variation does not vary significantly over the height of the battery cell due to the observed mechanisms. However, a slight decrease in the volume change towards the poles of the battery cells due to the higher stiffness can be monitored.

Passive binary defocusing for large depth 3D measurement based on deep learning.

Phase-shifting profilometry (PSP) based on the binary defocusing technique has been widely used due to its high-speed capability. However, the required adjustment in projector defocus by traditional method is inaccurate, inflexible, and associated with fringe pitch. Instead of manual defocusing adjustment, a passive defocus of the binary patterns based on deep learning is proposed in this paper. Learning the corresponding binary patterns with a specifically designed convolutional neural network, high-quality three-step sinusoidal patterns can be generated. Experimental results demonstrate that the proposed method could reduce phase error by 80%-90% for different fringe pitches without projector defocus and outperform the traditional method by providing more accurate and robust results within a large measuring depth.

An exotic Cretaceous kimberlite linked to metasomatized lithospheric mantle beneath the southwestern margin of the São Francisco Craton, Brazil

We present major and trace element compositions of mineral concentrates comprising garnet xenocrysts, ilmenite, phlogopite, spinel, zircon, and uncommon minerals (titanite, calzirtite, anatase, baddeleyite and pyrochlore) of a newly discovered Late Cretaceous kimberlite (U-Pb zircon age 90.0 ± 1.3 Ma; 2σ) named Osvaldo França 1, located in the Alto Paranaíba Igneous Province (APIP), southeastern Brazil. Pyrope grains are lherzolitic (Lherz-1, Lherz-2 and Lherz-3), harzburgitic (Harz-3) and wehrlitic (Wehr-2). The pyrope xenocrysts cover a wide mantle column in the subcratonic lithosphere (66–143 km; 20–43 kbar) at relatively low temperatures (811–875 °C). The shallowest part of this mantle is represented by Lherz-1 pyropes (20–32 kbar), which have low-Cr (Cr2O3 = 1.74–6.89 wt.%) and fractionated middle to heavy rare earth elements (MREE-HREE) pattern. The deepest samples are represented by Lherz-2, Lherz-3, Harz-3, and Wehr-2 pyropes (36–43 kbar). They contain high-Cr contents (Cr2O3 = 7.36–11.19 wt.%) and are characterized by sinusoidal (Lherz-2 and Wehr-2) and spoon-like (Lherz-3 and Harz-3) REE patterns. According to their REE and trace elements, pyrope xenocrysts have enriched nature (e.g., Ce and Yb vs. Cr2O3), indicating that the cratonic lithosphere has been affected by a silicate melt with subalkaline/tholeiite composition due to their low Zr, Ti and Y concentrations. Besides minerals with typical kimberlitic signatures, such as ilmenite and zircon, the exotic compositions of phlogopite and ulvöspinel suggest an enriched component in the magma source. The formation of rare mineral phases with strong enrichment of light-REE (LREE) and high field strength elements (HFSE) is attributed to the late-stage kimberlitic melt. We propose a tectonic model where a thermal anomaly, represented by the low-velocity seismic anomaly observed in P-wave seismic tomography images, supplied heat to activate the alkaline magmatism from a metasomatized cratonic mantle source during the late-stages of Gondwana fragmentation and consequent South Atlantic Ocean opening. The metasomatism recorded by mineral phases is a product of long-lived recycling of subducted oceanic plates since the Neoproterozoic (Brasiliano Orogeny) or even older collisional events, contributing to the exotic character of the Osvaldo França 1 kimberlite, as well as to the cratonic lithospheric mantle.

Content and Structure of Scientific Values

The purpose of the present research was to identify values relevant to the context of science and test their location in the motivational value circle proposed by Schwartz (1992). Based on the available scientific values literature, creativity, curiosity, skepticism, open-mindedness, rationality, objectivity, communality, integrity, and consistency values were identified as scientific values. Items were generated by the authors to measure their importance. Two studies were conducted to test five hypotheses. In Study 1, with a student sample (N = 624, Mage = 22), results revealed that scientific values were empirically located between Self-Direction and Universalism values, and there was a sinusoidal pattern of correlations between the scientific values and the other value types. In Study 2 (N = 181, Mage = 21.5), scientific values were observed to be positively correlated with the attitudes towards science as measured by semantic differential scales and the need for cognition scores, and negatively correlated with intolerance of uncertainty scores. The present research was the first attempt to integrate scientific values into the circular structure of values. Results were discussed as confirming the hypothesized structure of scientific values, and as providing initial support for the convergent and divergent validity of the scientific values measure. Using convenience samples with a potential self-selection bias, collecting data from Turkish university students, over-representation of women in Study 2, and low reliability coefficients for value type measures other than the scientific values were noted as methodological limitations. Attempts to replicate the results of the present research in cross-cultural studies and to investigate the relationships between the scientific values and personality measures other than the ones used in the present study to extend convergent validity are suggested as future research directions.

Evaluating structured-illumination patterns in optimizing optical-sectioning of HiLo microscopy

HiLo microscopy is a wide-field, optical-sectioning imaging technique, which is based on computational reconstruction from a uniform-illumination image and a structured-illumination (SI) image. Considering different imaging situations, the parameters of SI patterns should be optimized. However, no such discussion has been presented in grid-pattern (such as sinusoidal pattern and checkerboard pattern) based HiLo microscopy. Here, we analyze the dependence of optical-sectioning performance on parameters of SI pattern via both numerical simulations and imaging experiments. We find that both lower frequency and lower duty cycle of the grid-based pattern would introduce higher modulation depth, which would induce less artifacts in final reconstruction. Besides, at given illumination wavelength and objective numerical aperture, the higher the frequency of the grid-based pattern is, the better the axial resolution is, and thus the better the contrast of the optical-sectioning image is. Specially, the axial resolution is optimal when the frequency of pattern is set to half of cut-off frequency. We expect it as a guide of optimizing parameters of SI patterns for optical-sectioning in HiLo microscopy.

End-to-end pattern optimization technology for 3D shape measurement.

The nonlinear errors caused by the gamma effect seriously affect the measurement accuracy of phase-measuring profilometry systems. We present a novel robust end-to-end pattern optimization technology for phase-height mapping. This method generates standard sinusoidal patterns on the reference plane on a camera image instead of on a projection image by optimizing the projection image, which can avoid phase errors due to phase conversion from projector to camera. The pixel set mapping is achieved by chessboard calibration; then the projection image is optimized with the multiscale optimization method and the dislocation optimization method based on proportional integral derivative control. The experiments show that the proposed method can effectively avoid the influence of nonlinear effect and achieve high-quality three-dimensional measurement.

Kinematic gait characteristics of straight line walk in clinically sound dairy cows.

The aim of this study is to describe the kinematic gait characteristics of straight line walk in clinically sound dairy cows using body mounted Inertial Measurement Units (IMUs) at multiple anatomical locations. The temporal parameters used are speed and non-speed normalized stance duration, bipedal and tripedal support durations, maximal protraction and retraction angles of the distal limbs and vertical displacement curves of the upper body. Gait analysis was performed by letting 17 dairy cows walk in a straight line at their own chosen pace while equipped with IMU sensors on tubera sacrale, left and right tuber coxae (LTC and RTC), back, withers, head, neck and all four lower limbs. Data intervals with stride by stride regularity were selected based on video data. For temporal parameters, the median was calculated and 95% confidence intervals (CI) were estimated based on linear mixed model (LMM) analysis, while for limb and vertical displacement curves, the median and most typical curves were calculated. The temporal parameters and distal limb angles showed consistent results with low variance and LMM analysis showed non-overlapping CI for all temporal parameters. The distal limb angle curves showed a larger and steeper retraction angle range for the distal front limbs compared with the hind limbs. The vertical displacement curves of the sacrum, withers, LTC and RTC showed a consistent sinusoidal pattern while the head, back and collar curves were less consistent and showed more variation between and within cows. This kinematic description might allow to objectively differentiate between normal and lame gait in the future and determine the best anatomical location for sensor attachment for lameness detection purposes.

Light field microscopy based on structured light illumination

In this Letter, we present the modeling, design, and characterization of a light sheet-based structured light illumination (SLI) light field microscopy (LFM) system for fast 3D imaging, where a digital micromirror device is employed to rapidly generate designed sinusoidal patterns in the imaging field. Specifically, we sequentially obtain uniformly illuminated and structured light field images, followed by post-processing with a new, to the best of our knowledge, algorithm that combines the deconvolution and HiLo algorithms. This enables fast volumetric imaging with improved optical cross-sectioning capability at a speed of 50 volumes per second over an imaging field of 250×250×80µm3 in the x, y, and z axis, respectively. Mathematical models have been derived to explain the performance enhancement due to suppressed background noises. To verify the results, imaging experiments on fluorescence beads, fern spore, and Drosophila brain samples, have been performed. The results indicate that the light sheet-based SLI-LFM presents a fast 3D imaging solution with substantially improved optical cross-sectioning capability in comparison with a standard light sheet-based LFM. The new light field imaging method may find important applications in the field of biophotonics.

Dynamic factor analysis of seasonal variation in daily physical activity in individuals with heart failure and implanted cardiac devices

BackgroundThe purpose of the present study was to determine the presence and magnitude of seasonal variation in daily physical activity (PA) in those with heart failure (HF). MethodsRetrospective study and dynamic factor analysis (DFA) of Patient Activity data from Medtronic implanted cardioverter defibrillator and cardiac resynchronization devices (ICD/CRTs). ResultsIn a data set of 435 patients, distinct states/trends were identified by DFA including a classic, sinusoidal pattern of seasonal variation and a pattern of decline over the course of 12 months, which were associated with specific clinical characteristics. Overall, model fitting was good. ConclusionsThose with low comorbidities, better NYHA Class, higher BMI, no hospitalization, and male sex demonstrated greater seasonal variation of at least 40 min per day between winter (lowest PA) and spring/summer (highest PA). Those with female sex and hospitalization demonstrated overall downward trajectories of approximately 40 and 80 min, respectively, over the course of the year.

Fast and robust online three-dimensional measurement based on feature correspondence

Online three-dimensional (3D) measurement plays an important role in industry. When phase-shifting profilometry is employed in online 3D measurement, pixel matching is an important step to keep objects at the same coordinate value. However, the correlation operation and marker feature matching algorithms may take a long time, increasing the complexity. So a fast and robust online 3D measurement based on feature correspondence is proposed. In this method, only one frame of the sinusoidal fringe pattern is projected onto the measured object, and image correction technique is employed to rectify pixel size. Then five frames of deformed patterns with equivalent displacement are captured by the camera, and the corresponding modulation patterns are extracted. The oriented fast and rotated brief feature algorithm is used to extract the matching pair of feature points, and the improved grid-based motion statistical feature algorithm can better eliminate the false match to achieve pixel matching. In this way, five frames of deformed patterns with an equivalent shifted-phase can be extracted. Finally, the 3D shape of the measured object is reconstructed by the five-step equivalent phase-shifting algorithm. Experimental results verify the effectiveness and feasibility of the proposed method.

Infrared phase measuring deflectometry by using defocused binary fringe.

Three-dimensional surface information acquisition of specular objects plays an important role in the fields of automobile industry, aerospace, cultural relic protection, intelligent robotics, equipment manufacturing, and so on. Most of the existing specular surface measurement methods are based on focused sinusoidal fringe patterns, so there are certain requirements for the range of the depth of field (DOF) of the camera on the focus position. However, for many specular surfaces with a large gradient, the tested objects may not always be in the DOF of the camera, so sinusoidal fringe patterns are defocused to be vulnerable to the noise. In this Letter, a new infrared phase measuring deflectometry (PMD) based on defocused binary fringe is proposed that combines a binary fringe defocusing technique and direct PMD. The measurement principle and the corresponding system calibration method are described. The feasibility and measurement accuracy of fringe defocus in specular measurement are studied in principle. The experimental results on several specular objects show that the proposed method can effectively measure specular surfaces out of the DOF of the camera.