Color Optical Flow

Grayscale optical-flow methods have long been the focus of methods for recovering optical flow. Optical flow recovery from color-images can be implemented using direct methods, i.e. without using computationally costly iterations or search strategies. The quality of recovered optical flow can be assessed and tailored after processing, providing an effective, efficient tool for motion estimation. In this paper, a brief introduction to optical flow is presented, the optical flow constraint equation and its extension to color images is presented. New methods for solving this extended equation are given. Results of applying these methods to two synthetic image sequences are presented

OFCat: An Extensible GUI-Driven Optical Flow Comparison Tool

OFCat is an extensible GUI-driven optical flow computation and analysis tool. The user can add their own image sequences, filtering, differentiating and optical flow techniques. OFCat can process both grayscale and color images. It implements a number of low-pass filtering and differentiating techniques. Many traditional optical flow extraction techniques are available, in addition to some novel color-based methods. Analysis of the recovered flow is performed using groundtruth analysis, image reconstruction and sparsity vs error analysis. Synthetic ground-truth can be created and used to create a test image sequence from a single image

General Purpose Real-Time Object Tracking using Hausdorff Transforms

We describe a real-time computer-vision tracking module capable of using several Hausdorff distance based approaches to localize and match edge models in a scene. The implementation is based on widely supported software and hardware technologies such as Microsoft DirectX/DirectShow, Intel Image Processing and the Open Source Computer Vision libraries

Morphology and Development of Ice Patches in Northwest Territories, Canada

Permanent ice patches in the western Canadian Subarctic have been recently identified as sources of cryogenically preserved artifacts and biological specimens. The formation, composition, and constancy of these ice patches have yet to be studied. As part of the Northwest Territories (NWT) Ice Patch Study, ground-penetrating radar (GPR) and ice coring were used to examine the stratigraphy and internal structure of two ice patches. Results show the patches are composed of a core of distinct offset units, up to several metres thick, covered by a blanket of firn and snow. The interfaces between the units of ice are often demarcated by thin sections of frozen caribou dung and fine sediment. Radiocarbon dates of dung extracted from ice cores have revealed a long history for these perennial patches, up to 4400 years BP. Ice patch growth is discontinuous and occurs intermittently. Extensive time gaps exist between the units of ice, indicating that summers of catastrophic melt can interrupt extended periods of net accumulation. The results of this work not only display the character of ice patch development, but also indicate the significant role that ice patches can play in reconstructing the paleoenvironmental conditions of an area.Récemment, on a déterminé que les névés permanents du subarctique de l’Ouest canadien constituent des sources d’artefacts et de spécimens biologiques préservés cryogéniquement. La formation, la composition et la constance de ces névés n’ont toujours pas été étudiées. Dans le cadre de l’étude des névés des Territoires du Nord-Ouest, on a recouru à des géoradars (GPR) et au carottage de la glace pour examiner la stratigraphie et la structure interne de deux névés. Les résultats indiquent que les névés sont composés d’un noyau d’unités distinctes et décalées, mesurant plusieurs mètres d’épaisseur et recouvertes d’une couverture de vieille neige et de neige. L’interface entre les unités de glace est souvent démarquée par de minces sections de déjections de caribou gelées et de sédiments fins. La datation au radiocarbone des déjections extraites des carottes de glace révèle que ces névés pérennes ont une longue histoire, remontant jusqu’à 4400 ans BP. L’amplification des névés est discontinue et se produit de manière intermittente. Des écarts de temps considérables existent entre les unités de glace, ce qui laisse entendre que des étés de fonte catastrophique peuvent interrompre les périodes prolongées d’accumulation nette. Les résultats de cette étude laissent non seulement entrevoir le caractère de la formation des névés, mais indiquent également le rôle important que les névés peuvent jouer dans la reconstruction des conditions paléoenvironnementales d’une région

Acoustical Boundary Location through Texture Analysis of Multibeam Bathymetric Sonar Data

Texture analysis is performed on multibeam sonar signal returns discriminated angularity by beamforming. A collection of fourteen texture features are computed via co-occurrence matrices and data reduction is then performed using a principal components transformation. Acoustical boundaries (boundaries between regions with homogeneous acoustical properties) are evident from the features. Results indicate that seafloor bottom characteristics can be extracted from these texture features

Computing and Diagnosing Changes in Unit Test Energy Consumption

Many developers have reason to be concerned with with power consumption. For example, mobile app developers want to minimize how much power their applications draw, while still providing useful functionality. However, developers have few tools to get feedback about changes to their application\u27s power consumption behavior as they implement an application and make changes to it over time. We present a tool that, using a team\u27s existing test cases, performs repeated measurements of energy consumption based on instructions executed, objects generated, and blocking latency, generating a distribution of energy use estimates for each test run, recording these distributions in a time series of distributions over time. Then, when these distributions change substantially, we inform the developer of this change, and offer them diagnostic information about the elements of their code potentially responsible for the change and the inputs responsible. Through this information, we believe that developers will be better enabled to relate recent changes in their code to changes in energy consumption, enabling them to better incorporate changes in software energy consumption into their software evolution decisions

Sampling Daphnia's expressed genes: preservation, expansion and invention of crustacean genes with reference to insect genomes

<p>Abstract</p> <p>Background</p> <p>Functional and comparative studies of insect genomes have shed light on the complement of genes, which in part, account for shared morphologies, developmental programs and life-histories. Contrasting the gene inventories of insects to those of the nematodes provides insight into the genomic changes responsible for their diversification. However, nematodes have weak relationships to insects, as each belongs to separate animal phyla. A better outgroup to distinguish lineage specific novelties would include other members of Arthropoda. For example, crustaceans are close allies to the insects (together forming Pancrustacea) and their fascinating aquatic lifestyle provides an important comparison for understanding the genetic basis of adaptations to life on land versus life in water.</p> <p>Results</p> <p>This study reports on the first characterization of cDNA libraries and sequences for the model crustacean <it>Daphnia pulex</it>. We analyzed 1,546 ESTs of which 1,414 represent approximately 787 nuclear genes, by measuring their sequence similarities with insect and nematode proteomes. The provisional annotation of genes is supported by expression data from microarray studies described in companion papers. Loci expected to be shared between crustaceans and insects because of their mutual biological features are identified, including genes for reproduction, regulation and cellular processes. We identify genes that are likely derived within Pancrustacea or lost within the nematodes. Moreover, lineage specific gene family expansions are identified, which suggest certain biological demands associated with their ecological setting. In particular, up to seven distinct ferritin loci are found in <it>Daphnia </it>compared to three in most insects. Finally, a substantial fraction of the sampled gene transcripts shares no sequence similarity with those from other arthropods. Genes functioning during development and reproduction are comparatively well conserved between crustaceans and insects. By contrast, genes that were responsive to environmental conditions (metal stress) and not sex-biased included the greatest proportion of genes with no matches to insect proteomes.</p> <p>Conclusion</p> <p>This study along with associated microarray experiments are the initial steps in a coordinated effort by the <it>Daphnia </it>Genomics Consortium to build the necessary genomic platform needed to discover genes that account for the phenotypic diversity within the genus and to gain new insights into crustacean biology. This effort will soon include the first crustacean genome sequence.</p

Deformation of the Pacific/North America plate boundary at Queen Charlotte Fault : the possible role of rheology

Published 2018. This article is a U.S. Government work and is in the public domain in the USA. The definitive version was published in Journal of Geophysical Research: Solid Earth 123 (2018): 4223-4242, doi:10.1002/2017JB014770.The Pacific/North America (PA/NA) plate boundary between Vancouver Island and Alaska is similar to the PA/NA boundary in California in its kinematic history and the rate and azimuth of current relative motion, yet their deformation styles are distinct. The California plate boundary shows a broad zone of parallel strike slip and thrust faults and folds, whereas the 49‐mm/yr PA/NA relative plate motion in Canada and Alaska is centered on a single, narrow, continuous ~900‐km‐long fault, the Queen Charlotte Fault (QCF). Using gravity analysis, we propose that this plate boundary is centered on the continent/ocean boundary (COB), an unusual location for continental transform faults because plate boundaries typically localize within the continental lithosphere, which is weaker. Because the COB is a boundary between materials of contrasting elastic properties, once a fault is established there, it will probably remain stable. We propose that deformation progressively shifted to the COB in the wake of Yakutat terrane's northward motion along the margin. Minor convergence across the plate boundary is probably accommodated by fault reactivation on Pacific crust and by an eastward dipping QCF. Underthrusting of Pacific slab under Haida Gwaii occurs at convergence angles >14°–15° and may have been responsible for the emergence of the archipelago. The calculated slab entry dip (5°–8°) suggests that the slab probably does not extend into the asthenosphere. The PA/NA plate boundary at the QCF can serve as a structurally simple site to investigate the impact of rheology and composition on crustal deformation and the initiation of slab underthrusting

The TripAnalyser: a wearable system to assess gait and potential tripping

A wearable Arduino system (ESP32s) is described that uses optical time of flight (VL6180X) and inertial measurement unit (SENtral EM7180) sensors to estimate the Minimum Foot Clearance (MFC) of participants during gait. It is envisaged that an affordable wearable device that can acquire kinematic data outside the laboratory over periods of several weeks may find application in falls risk assessment in those with ambulatory disorders including the elderly. A geometric model is presented, and a preliminary trial was conducted with able-bodied subjects to test the correlation and agreement of the device with a Vicon 3D motion capture system, consisting of 12 infrared cameras located at the University of Warwick. The correlation between the device and the gait laboratory data yielded a correlation coefficient of r = 0.88. Agreement was tested using the Bland-Altman plot where the line of equality was within the 95% confidence interval of the mean difference suggesting that the device can be used as an alternative to Vicon for estimating MFC