scholarly journals Glacier surface motion computation from digital image sequences

2000 ◽  
Vol 38 (2) ◽  
pp. 1064-1072 ◽  
Author(s):  
A.N. Evans
Keyword(s):  
Digital Image ◽  
Image Sequences ◽  
Glacier Surface ◽  
Surface Motion ◽  
Motion Computation

scholarly journals The determination of high-resolution spatio-temporal glacier motion fields from time-lapse sequences

2017 ◽  
Vol 5 (4) ◽  
pp. 861-879 ◽  
Author(s):  
Ellen Schwalbe ◽  
Hans-Gerd Maas
Keyword(s):  
High Resolution ◽  
Vector Fields ◽  
Motion Vector ◽  
Image Sequence ◽  
Image Sequences ◽  
Glacier Surface ◽  
Sequence Processing ◽  
Image Sequence Processing ◽  
Matching Techniques

Abstract. This paper presents a comprehensive method for the determination of glacier surface motion vector fields at high spatial and temporal resolution. These vector fields can be derived from monocular terrestrial camera image sequences and are a valuable data source for glaciological analysis of the motion behaviour of glaciers. The measurement concepts for the acquisition of image sequences are presented, and an automated monoscopic image sequence processing chain is developed. Motion vector fields can be derived with high precision by applying automatic subpixel-accuracy image matching techniques on grey value patterns in the image sequences. Well-established matching techniques have been adapted to the special characteristics of the glacier data in order to achieve high reliability in automatic image sequence processing, including the handling of moving shadows as well as motion effects induced by small instabilities in the camera set-up. Suitable geo-referencing techniques were developed to transform image measurements into a reference coordinate system.The result of monoscopic image sequence analysis is a dense raster of glacier surface point trajectories for each image sequence. Each translation vector component in these trajectories can be determined with an accuracy of a few centimetres for points at a distance of several kilometres from the camera. Extensive practical validation experiments have shown that motion vector and trajectory fields derived from monocular image sequences can be used for the determination of high-resolution velocity fields of glaciers, including the analysis of tidal effects on glacier movement, the investigation of a glacier's motion behaviour during calving events, the determination of the position and migration of the grounding line and the detection of subglacial channels during glacier lake outburst floods.

scholarly journals Glacier Surface Motion Estimation from SAR Intensity Images Based on Subpixel Gradient Correlation

Sensors ◽  
2020 ◽  
Vol 20 (16) ◽  
pp. 4396
Author(s):  
Li Fang ◽  
Zhen Ye ◽  
Shu Su ◽  
Jian Kang ◽  
Xiaohua Tong
Keyword(s):  
Motion Estimation ◽  
Estimation Method ◽  
Correlation Method ◽  
Image Correlation ◽  
Matching Method ◽  
Glacier Surface ◽  
Surface Motion ◽  
Alpine Regions ◽  
Intensity Images ◽  
Comparative Results

With the current extensive availability of synthetic-aperture radar (SAR) datasets with high temporal (e.g., a repeat cycle of a few or a dozen days) and spatial resolution (e.g., in the order of ∼1 m), radar remote sensing possesses an increasing potential for the monitoring of glacier surface motion thanks to the nearly weather and time-independent advantages. This paper proposes a robust subpixel frequency-based image correlation method for dense matching and integrates the improved matching into a workflow of glacier surface motion estimation using SAR intensity images with specific pre-processing and post-processing steps. The proposed matching method combines complex edge maps and local upsampling in the frequency domain for subpixel intensity tracking, which ensure the accuracy and robustness of glacier surface motion estimation. Experiments were carried out with TerraSAR-X and Sentinel-1 images covering two glacier areas in pole and alpine regions. The results of the monitoring and investigation of glacier motion validate the feasibility and reliability of the presented motion estimation method based on subpixel gradient correlation. The comparative results using both simulated and real SAR data indicate that the proposed matching method outperforms commonly used correlation-based matching methods in terms of matching accuracy and the ability to obtain correct matches.

Measurement of the rennet clotting time of milk by digital image sequences (2D+t) processing

2013 ◽  
Vol 114 (2) ◽  
pp. 235-241 ◽  
Author(s):  
Gamraïkréo Djaowé ◽  
Laurent Bitjoka ◽  
Ousman Boukar ◽  
David Gabriel Libouga ◽  
Beldo Waldogo
Keyword(s):  
Digital Image ◽  
Image Sequences ◽  
Clotting Time

scholarly journals DIGITAL IMAGE ANALYSIS OF BURNING DROPLETS IN THE PRESENCE OF BACKLIGHT DIFFRACTION AND SOOT

2019 ◽  
Vol 38 (1) ◽  
pp. 53 ◽  
Author(s):  
Ramya Bhaskar ◽  
Benjamin Shaw
Keyword(s):  
Image Analysis ◽  
Digital Image ◽  
Digital Image Analysis ◽  
Detection Method ◽  
Soot Formation ◽  
Space Station ◽  
Image Sequences ◽  
Synthetic Image ◽  
International Space ◽  
Fuel Droplets

Approaches for analyzing digital images of moving and burning fuel droplets, with the goal of accurately measuring droplet edge coordinates, are discussed. Strategies for locating droplet edges in the presence of obscuration from soot and also backlight diffraction at the droplet edge are described. An outlier detection method is employed to identify outliers in droplet edge coordinates, and the resulting data can have significantly smaller standard deviations in droplet diameters if outliers are rejected, especially for droplets that exhibit significant soot formation. The approaches described herein are applied to images from droplet combustion experiments performed on the International Space Station as well as to synthetic image sequences that were generated to enable the accuracy of the algorithms to be assessed.

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