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Snow cover mapped daily at 30 meters resolution using a fusion of multi-temporal MODIS NDSI data and Landsat surface reflectance

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CANADIAN JOURNAL OF REMOTE SENSING 2018年第5期44卷 413-434页

作者： Mityok, Zoltan K. Bolton, Douglas K. Coops, Nicholas C. Berman, Ethan E. Senger, Sue Univ British Columbia Dept Forest Resources Management Integrated Remote Sensing Studio 2424 Main Mall Vancouver BC Canada Windwalker Consulting Serv POB 436 Lillooet BC Canada

Snow fall and melt events are complex meteorological phenomena that help chart the effects of climate change and impact many critical environmental processes including hydrologic and biogeographic systems. Daily snow maps, derived from MODIS imagery, provide managers and researchers with vital snow cover information, but only at spatial scales of 500 m or more. Finer resolution time series maps, however, retain large temporal gaps, particularly during recurrent cloud cover. This paper's authors have developed the novel algorithm MODSAT-NDSI to harness the strengths of both coarse and finer spatial resolution imagery by fusing MODIS and Landsat normalized difference snow index (NDSI) data. Daily 30 m snow cover maps were thus generated for 2000 - 2017 with an overall accuracy of 90%, using 33 validation sites distributed throughout south-central British Columbia. Snow cover trends were analyzed across stratified elevation bands and land cover types, revealing that snow cover persists under lower elevation forests for an average of 23.5 d longer than in adjacent open areas during spring. We conclude that the MODSAT-NDSI approach captures temporal and spatial advantages of freely available snow cover datasets and can be modified to suit a variety of novel investigations relating to snow cover or other spectral indices.

关键词： Snow cover Snow accumulation and ablation Landsat MODIS data fusion algorithm development Time-lapse photography Time series

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Continuity of gamut mapping algorithms

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JOURNAL OF ELECTRONIC IMAGING 2006年第1期15卷 013004.1-013004.1页

作者： Zolliker, Peter Simon, Klaus EMPA Swiss Fed Labs Mat Testing & Res Lab Media Technol CH-8600 Dubendorf Switzerland

The design of a gamut mapping algorithm (GMA) is always a compromise between preserving different competing aspects such as color, contrast, and lightness. A natural requirement of a GMA is that the algorithmic treatment of this competition has to avoid any additional artifacts such as discontinuities or loss of contrast. In this work, several common gamut mapping algorithms are studied from this aspect, resulting in the observation that problems with geometric discontinuities are widespread. For the assessment of the phenomena induced by local mapping properties, an algorithmic test is developed and applied. This new test supports both the quality check of existing as well as the development of new GMAs. (c) 2006 SPIE and IS&T.

关键词： Printing Visualization RGB color model Distance measurement Optical spheres Inkjet technology Photography algorithm development Solids Color reproduction

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ADAPTIVE ESTIMATORS FOR FILTERING NOISY IMAGES

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OPTICAL ENGINEERING 1990年第5期29卷 488-494页

作者： MAHESH, B SONG, WJ PEARLMAN, WA POHANG INST SCI & TECHNOL DEPT ELECT & ELECTR ENGNPOHANG 680SOUTH KOREA

Abstract not available

关键词： Error analysis Image filtering Digital filtering Filtering (signal processing) Visualization Statistical analysis algorithm development Image analysis Image quality Image restoration

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Coherently three-dimensional wavelet-based approach to volumetric image compression

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JOURNAL OF ELECTRONIC IMAGING 1998年第3期7卷 474-485页

作者： Luo, JB Eastman Kodak Co Imaging Res & Adv Dev Rochester NY 14650 USA Univ Missouri Dept Elect Engn Columbia MO 65211 USA

Compression of three-dimensional (3D) or four-dimensional medical image data has now become imperative for clinical picture archiving and communication systems (PACS), telemedicine, and telepresence networks. While lossless compression is often desired, lossy compression techniques are gaining acceptance for medical applications, provided that clinically important information can be preserved in the coding process. We present a coherently three-dimensional method for volumetric image compression using 3D wavelet transform and 3D zerotree coding. First the volumetric image data is decomposed using 3D separable wavelet filterbanks. In this study, we adopt a three-level decomposition to form a 22-band multiresolution pyramid of an octree. Then, to exploit the dependencies among the subband coefficients resulting from 3D wavelet decomposition, a 3D zerotree coding scheme is utilized. To take advantage of the near-Laplacian distributions of the subband coefficients and the efficiency of zerotree coding, a pseudouniform quantization is adopted. The proposed volumetric image compression scheme is applied to two sets of real CT medical data. Significant coding gains have been achieved which demonstrate the effectiveness of the proposed volumetric image compression scheme for medical as well as other applications. (C) 1998 SPIE and IS&T. [S1017-9909(98)02703-2].

关键词： Image compression 3D image processing Quantization Wavelets Image filtering Wavelet transforms algorithm development Lithium Medical imaging Reconstruction algorithms

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Evolution of error diffusion

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JOURNAL OF ELECTRONIC IMAGING 1999年第4期8卷 422-429页

作者： Knox, KT Xerox Corp Digital Imaging Technol Ctr Webster NY 14580 USA

As we approach the new millenium, error diffusion is approaching the 25th anniversary of its invention. Because elf its exceptionally high image quality, it continues to be a popular choice among digital halftoning algorithms. Over the fast 24 years, many attempts have been made to modify and improve the algorithm-to eliminate unwanted textures and to extend if to printing media and color Some of these modifications have been very successful and are in use today. This paper will review the history of the algorithm and ifs modifications. Three watershed events in the development of error diffusion will be described, together with the lessons learned along the way. (C) 1999 SPIE and IS&T.

关键词： Diffusion Error analysis Image enhancement Modulation Spatial frequencies Printing algorithm development Linear filtering Fluctuations and noise Halftones

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Computational approach for edge linking

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JOURNAL OF ELECTRONIC IMAGING 2002年第4期11卷 479-485页

作者： Ghita, O Whelan, PF Dublin City Univ Sch Elect Engn Vis Syst Lab Dublin 9 Ireland

Efficient edge operators such as those based on partial derivatives fail to return continuous edge maps. To address this, a supplementary edge linking step is required to complete initial edge information. In this paper we. propose a fast and efficient algorithm for edge linking using local information around edge terminators. In order to minimize incorrect linking decisions, the direction and the linking path for each edge terminator are established by minimizing a cost function. The particular novelty of this approach lies in the labeling scheme which assigns the directionality of the. edge terminators (endpoints) based only on local knowledge. As a consequence, it relaxes the demand of a priori knowledge and furthermore assures an accurate and efficient search for edge paths in the image. (C) 2002 SPIE and IST.

关键词： Detection and tracking algorithms Edge detection Sensors Image processing Image restoration Image segmentation algorithm development Image analysis Image processing algorithms and systems Image resolution

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Comparative study on morphological skeletonization and fuzzy medial axis transformation

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JOURNAL OF ELECTRONIC IMAGING 2002年第1期11卷 38-49页

作者： Jan, SR Hsueh, YC MingHsin Inst Technol Dept Informat Management Hsinchu 304 Taiwan Natl Chiao Tung Univ Dept Comp & Informat Sci Hsinchu 300 Taiwan

In this paper, we make a comparative study on morphological skeletonization (MSK) and fuzzy medial axis transformation (FMAT), Methods have been proposed to construct convex FMAT from the morphological skeleton points and to translate FMAT to MSK respectively. For the case of translating MSK to convex FMAT the experimental results reveal that the combination of the proposed method and the redundant removal algorithm is very effective. Especially, the combined method is faster than the original method for constructing convex FMAT of smoothed images. (C) 2002 SPIE and IST.

关键词： Fuzzy logic Binary data algorithm development Superposition Computing systems Digital image processing Mathematical morphology Information science Information technology Machine vision

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A Seasonal-Window Ensemble-Based Thresholding Technique Used to Detect Active Fires in Geostationary Remotely Sensed Data

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IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING 2021年第6期59卷 4947-4956页

作者： Engel, Chermelle B. Jones, Simon D. Reinke, Karin RMIT Univ Royal Melbourne Inst Technol Melbourne Vic 3001 Australia

This article introduces a new algorithm to detect active fires in geostationary remotely sensed data. The algorithm calculated dynamic statistical multispectral thresholds based on, and sensitive to, biogeographical region, subseason, and time-of-day. The spectral characteristics of nonfire and noncloud mid-infrared values were found to vary with biogeographical region, subseason, and time-of-day. These differences were exploited to define a new seasonal Biogeographical Region and Individual Geostationary HHMMSS Threshold (BRIGHT) multivariate adaptive threshold geostationary satellite fire anomaly algorithm. The algorithm was demonstrated on 12 months of daytime data acquired from the geostationary satellite system, the Advanced Himawari Imager (on Himawari-8) over Australia (7.69 million km(2)). The resulting hotspots were compared with those from the existing Moderate Resolution Imaging Spectrometer (MODIS) polar-orbiting fire-hotspot algorithm. The intercomparison showed that BRIGHT wildfire hotspots, detected using Himawari-8 and Interim Biogeographic Regionalisation of Australia (IBRA) data, were also detected by MODIS polar-orbiting fire hotspots 88% of the time. While MODIS hotspots were detected by BRIGHT hotspots only 39% of the time;the majority of the undetected MODIS hotspots had low radiative power. BRIGHT provides a new method for the remote sensing of active fires providing reliable observations at spatial and temporal scales useful for fire managers.

关键词： Australia Clouds Cloud computing Fires MODIS Advanced Baseline Imager Advanced Himawari Imager algorithm development clear-sky cloud detection fire anomaly fire detection geostationary Himawari-8

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Robust-to-rotation texture descriptor for image retrieval in wavelets domain

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JOURNAL OF ELECTRONIC IMAGING 2006年第1期15卷 013013.1-013013.1页

作者： Jiang, Jianmin Weng, Ying Guo, Baofeng Feng, Yue Univ Bradford Sch Informat Bradford BD7 1DP W Yorkshire England Chinese Acad Sci Inst Acoust Beijing 100864 Peoples R China Univ Bristol Dept Comp Sci Bristol BS8 1TH Avon England Univ Bradford Dept Elect Imaging & Media Commun Bradford BD7 1DP W Yorkshire England

We describe a texture description algorithm, designed in the wavelets domain, to reduce the dimension of an existing texture-based feature vector and improve on the existing texture description algorithm in terms of both effectiveness and efficiency. We first demonstrate that the estimated texture directions at different wavelet decomposition scales are very similar. Thus, a new texture description with explicit direction representation can be constructed to improve discrimination capability. Second, we propose a subband integration scheme to further improve the texture description and achieve robustness to rotation of texture patterns. Third, a range of successful texture description elements developed in the pixel domain are applied to the LL subband and added to the texture descriptor for further enhancement of the proposed algorithm. Extensive testing, benchmarked by the existing techniques, shows that the proposed algorithm not only reduces the sensitivity of retrieval to image texture rotation, but also improves the retrieval accuracy. c (c) 2006 SPIE and IS&T.

关键词： Image retrieval Wavelets Feature extraction Image compression Databases algorithm development Wavelet transforms Image classification Statistical analysis Content based image retrieval

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A Minimal Sensor Inertial Measurement Unit System Is Replicable and Capable of Estimating Bilateral Lower-Limb Kinematics in a Stationary Bodyweight Squat and a Countermovement Jump

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JOURNAL OF APPLIED BIOMECHANICS 2023年第1期39卷 42-53页

作者： Fain, AuraLea Hindle, Benjamin Andersen, Jordan Nindl, Bradley C. Bird, Matthew B. Fuller, Joel T. Wills, Jodie A. Doyle, Tim L. A. Macquarie Univ Biomech Phys Performance & Exercise BioPPEx Res Gr Sydney NSW Australia Macquarie Univ Fac Med Hlth & Human Sci Sydney NSW Australia Bond Univ Fac Hlth Sci & Med Gold Coast Qld Australia Univ Pittsburgh Warrior Performance Ctr Neuromuscular Res Lab Pittsburgh PA USA Univ Pittsburgh Dept Sports Med Pittsburgh PA USA

This study aimed to validate a 7-sensor inertial measurement unit system against optical motion capture to estimate bilateral lower -limb kinematics. Hip, knee, and ankle sagittal plane peak angles and range of motion (ROM) were compared during bodyweight squats and countermovement jumps in 18 participants. In the bodyweight squats, left peak hip flexion (intraclass correlation coefficient [ICC] = .51), knee extension (ICC = .68) and ankle plantar flexion (ICC = .55), and hip (ICC = .63) and knee (ICC = .52) ROM had moderate agreement, and right knee ROM had good agreement (ICC = .77). Relatively higher agreement was observed in the countermovement jumps compared to the bodyweight squats, moderate to good agreement in right peak knee flexion (ICC = .73), and right (ICC = .75) and left (ICC = .83) knee ROM. Moderate agreement was observed for right ankle plantar flexion (ICC = .63) and ROM (ICC = .51). Moderate agreement (ICC > .50) was observed in all variables in the left limb except hip extension, knee flexion, and dorsiflexion. In general, there was poor agreement for peak flexion angles, and at least moderate agreement for joint ROM. Future work will aim to optimize methodologies to increase usability and confidence in data interpretation by minimizing variance in system-based differences and may also benefit from expanding planes of movement.

关键词： wearables algorithm development joint angles

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