Pre-landslide topographic reconstruction using a Digital Elevation Model from CaSSIS onboard the Trace Gas Orbiter.

2021 ◽  
Author(s):  
Anthony Guimpier ◽  
Susan Conway ◽  
Maurizio Pajola ◽  
Alice Lucchetti ◽  
Emanuele Simioni ◽  
...  
Keyword(s):  
High Resolution ◽  
Imaging System ◽  
Three Dimensional ◽  
Vertical Resolution ◽  
Topographic Data ◽  
Contour Lines ◽  
Digital Elevation ◽  
Landslide Event ◽  
Imaging Science ◽  
Topographic Reconstruction

<p>Landslides are common features on the surface of Mars. They have morphologies that resemble debris slides, mudflows [1], or giant rock avalanches [e.g., 2] on Earth. They can mobilise large quantities of material up to 10<sup>12</sup> m<sup>3</sup> and spread over areas of up to 10<sup>9</sup> m<sup>2</sup> [e.g., 3].</p><p>The topography before the landslide event occurred is required to both estimate the volume of mobilised material and quantify the distribution and thickness of the deposit. The mass distribution of the deposit can also be used to compare with 3D flow simulations of landslides [e.g. 1, 3]. However, on Mars there are no landslides that have known topographic data before the event occurred, hence we have to rely on topographic reconstruction.</p><p>This type of reconstruction, which we have already carried out using HiRISE (High Resolution Imaging Science Experiment) Digital Elevation Models (DEM) with 1-2 m vertical resolution [e.g., 1], has never been undertaken using DEMs with 4-5 m vertical resolution derived from CaSSIS (Colour and Stereo Surface Imaging System) stereo pairs [4]. CaSSIS uses a 180° camera rotation to capture stereo images of a given site in a single pass. DEMs are then generated using 3DPD (three Dimensional reconstruction of Planetary Data) software [5].</p><p>Our aim is to test whether a landslide reconstruction can be carried out with a CaSSIS DEM. For our purpose we use a 6 km long landslide in Baetis Chaos region, Mars.</p><p>Our reconstruction consists of three main steps: 1) We first calculate contour lines. 2) Reconstructed contour lines are then drawn by connecting contour lines on either side of the boundary taking into account the overall topography outside the landslide. 3) Then, the reconstructed contour lines are converted into points at intervals equal to the spatial resolution of the DEM. These points are then interpolated using a natural neighbour algorithm to calculate a new DEM without the landslide. We were able to estimate that the landslide in Baetis Chaos has a volume of 10<sup>8</sup> m<sup>3</sup> and the deposit has a maximum thickness of 200 m using CaSSIS data.</p><p>Our successful reconstruction using a CaSSIS DEM increases the potential coverage of high-resolution stereo-topographic data beyond those already available with CTX and/or HiRISE. The resolution CaSSIS DEMs fills a gap in the topographic data currently available for studying landslides. Landslides > 15 km long can be studied with MOLA or HRSC data, and landslides < 5 km long can be studied using HiRISE data. Now, landslides and other landforms 5-15 km can be studied using CaSSIS data with equivalent quality to CTX stereo-topography.</p><p>Acknowledgement: CaSSIS is a project of the University of Bern, with instrument hardware development supported by INAF/Astronomical Observatory of Padova (ASI-INAF agreement n.2020-17-HH.0), and the Space Research Center (CBK) in Warsaw.</p><p>References: [1] A. Guimpier et al. (In review) <em>PSS</em>. [2] G. Magnarini et al. (2019) <em>Nature Communications</em>. [3] G.B. Crosta et al. (2018) <em>ESS</em>, 5, 89–119. [4] A. Lucas et al. (2014) <em>Nature Communications</em>. [5] E. Simioni et al. (In press) <em>PSS</em>.</p>

scholarly journals Rapid Single Image-Based DTM Estimation from ExoMars TGO CaSSIS Images Using Generative Adversarial U-Nets

2021 ◽  
Vol 13 (15) ◽  
pp. 2877
Author(s):  
Yu Tao ◽  
Siting Xiong ◽  
Susan J. Conway ◽  
Jan-Peter Muller ◽  
Anthony Guimpier ◽  
...  
Keyword(s):  
High Resolution ◽  
Large Scale ◽  
Imaging System ◽  
Landing Site ◽  
Parameter Tuning ◽  
Processing Parameters ◽  
Input Image ◽  
Large Area ◽  
Laser Altimeter ◽  
Imaging Science

The lack of adequate stereo coverage and where available, lengthy processing time, various artefacts, and unsatisfactory quality and complexity of automating the selection of the best set of processing parameters, have long been big barriers for large-area planetary 3D mapping. In this paper, we propose a deep learning-based solution, called MADNet (Multi-scale generative Adversarial u-net with Dense convolutional and up-projection blocks), that avoids or resolves all of the above issues. We demonstrate the wide applicability of this technique with the ExoMars Trace Gas Orbiter Colour and Stereo Surface Imaging System (CaSSIS) 4.6 m/pixel images on Mars. Only a single input image and a coarse global 3D reference are required, without knowing any camera models or imaging parameters, to produce high-quality and high-resolution full-strip Digital Terrain Models (DTMs) in a few seconds. In this paper, we discuss technical details of the MADNet system and provide detailed comparisons and assessments of the results. The resultant MADNet 8 m/pixel CaSSIS DTMs are qualitatively very similar to the 1 m/pixel HiRISE DTMs. The resultant MADNet CaSSIS DTMs display excellent agreement with nested Mars Reconnaissance Orbiter Context Camera (CTX), Mars Express’s High-Resolution Stereo Camera (HRSC), and Mars Orbiter Laser Altimeter (MOLA) DTMs at large-scale, and meanwhile, show fairly good correlation with the High-Resolution Imaging Science Experiment (HiRISE) DTMs for fine-scale details. In addition, we show how MADNet outperforms traditional photogrammetric methods, both on speed and quality, for other datasets like HRSC, CTX, and HiRISE, without any parameter tuning or re-training of the model. We demonstrate the results for Oxia Planum (the landing site of the European Space Agency’s Rosalind Franklin ExoMars rover 2023) and a couple of sites of high scientific interest.

Viscous Flows Formed The Branched Ridges Of Antoniadi Crater, Mars

2021 ◽  
Author(s):  
Nicolas Mangold ◽  
Livio Tornabene ◽  
Susan Conway ◽  
Anthony Guimpier ◽  
Axel Noblet ◽  
...  
Keyword(s):  
High Resolution ◽  
Imaging System ◽  
Flow Direction ◽  
Viscous Flows ◽  
Engineering Teams ◽  
The North ◽  
Space Agency ◽  
Imaging Science ◽  
Italian Space Agency ◽  
University Of Bern

<p>Antoniadi basin is a 330 km diameter Noachian basin localized in the East of Arabia Terra that contains a network of ridges with a tree-like organization. Branched ridges, such as these can form by a variety of processes including the inversion of fluvial deposits, thus potentially highlighting aqueous processes of interest for understanding Mars’ climate evolution. Here, we test this hypothesis by analyzing in details data from Colour and Stereo Surface Imaging System (CaSSIS), High Resolution Imaging Science Experiment (HiRISE) and High Resolution Stereo Camera (HRSC).</p><p>Branched ridges are up to 10 km long and from 10 to 200 m wide without obvious organization in width. The branched ridges texture is rubbly with the occurrence of blocks up to ~1 m in size and a complete lack of layering. A HiRISE elevation model shows the local slope is of 0.2° toward South, and thus contrary to the apparent network organization (assuming tributary flows). There is no indication of exhumation of these ridges from layers below the current plains surface. Our observations are not consistent with the interpretation of digitate landforms such as inverted channels: (i) The rubbly texture lacking any layering at meter scale is distinct from inverted channels as observed elsewhere on Mars. (ii) Heads of presumed inverted channels display a lobate shape unlike river springs. (iii) There is no increase in width from small branches toward North as expected for channels with increasing discharge rates downstream. (iv) The slope toward South is contrary to the inferred flow direction to the North. The detailed analysis of these branched ridges shows many characteristics difficult to reconcile with inverted channels formed by fluvial channels flowing northward. Subglacial drainages are known to locally flow against topography, but they are rarely dendritic.<strong> </strong>Assuming that deposition occurred along the current slope, thus from North to South, the organization of the network requires a control by distributary channels rather than tributary ones. Distributary channels are possible for fluvial flows, but generally limited to braiding regimes or deltaic deposits, of which no further evidence is observed here. The lobate digitate shapes of the degree 1 branches are actually more in line with deposits of viscous flows, thus as terminal branches. Such an interpretation is consistent with lava or mudflows that formed along the current topography. The next step in this study will be to determine more precisely the rheology of these unusual flows.</p><p><strong>Acknowledgments:</strong> French authors are supported by the CNES. The authors wish to thank the spacecraft and instrument engineering teams. CaSSIS is a project of the University of Bern and funded through the Swiss Space Office via ESA’s PRODEX. The instrument hardware development was also supported by the Italian Space Agency (ASI) (agreement no. I/018/12/0), INAF/Astronomical Observatory of Padova, and the Space Research Center (CBK) in Warsaw. Support from SGF (Budapest), the Univ. of Arizona (Lunar and Planet. Lab.) and NASA are gratefully acknowledged.</p>

High-Resolution Digital Elevation and Bathymetry Model for Tsunami Run-Up and Inundation Simulation in Penang

2019 ◽  
Vol 13 (05n06) ◽  
pp. 1941001
Author(s):  
Su Yean Teh ◽  
Hock Lye Koh ◽  
Yong Hui Lim
Keyword(s):  
High Resolution ◽  
Indian Ocean ◽  
Sea Level ◽  
Interpolation Method ◽  
Topographic Maps ◽  
Seamless Integration ◽  
Topographic Data ◽  
Digital Elevation ◽  
Run Up ◽  
Tsunami Run Up

Many beaches in Penang island were severely inundated by the 26 December 2004 Indian Ocean mega tsunami with 57 deaths recorded. It is anticipated that the next big tsunami will cause even more damages to beaches in Penang. Hence, developing community resilience against the risks of the next tsunami is essential. Resilience entails many interlinked components, beginning with a good understanding of the inundation scenarios critical to community evacuation and resilience preparation. Inundation scenarios are developed from tsunami simulations involving all three phases of tsunami generation, propagation and run-up. Accurate and high-resolution bathymetric–topographic maps are essential for simulations of tsunami wave inundation along beaches. Bathymetric maps contain information on the depths of landforms below sea level while topographic maps reveal the elevation of landforms above sea level. Bathymetric and topographic datasets for Malaysia are, however, currently not integrated and are available separately and in different formats, not suitable for inundation simulations. Bathymetric data are controlled by the National Hydrographic Centre (NHC) of the Royal Malaysian Navy while topographic data are serviced by the Department of Survey and Mapping Malaysia (JUPEM). It is highly desirable to have seamless integration of high-resolution bathymetric and topographic data for tsunami simulations and for other scientific studies. In this paper, we develop a robust method for integrating the NHC bathymetric and JUPEM topographic data into a regularly-spaced grid system essential for tsunami simulation. A primary objective of this paper is to develop the best Digital Elevation and Bathymetry Model (DEBM) for Penang based upon the most suitable and accurate interpolation method for integrating bathymetric and topographic data with minimal interpolation errors. We analyze four commonly used interpolation methods for generating gridded topographic and bathymetric surfaces, namely (i) Kriging, (ii) Multiquadric (MQ), (iii) Thin Plate Spline (TPS) and (iv) Inverse Distance to Power (IDP). The study illustrated that the Kriging interpolation method produces an integrated bathymetric and topographic surface that best approximates the admiralty nautical chart of Penang essential for tsunami run-up and inundation simulations. Tsunami inundation scenarios critical to risk analysis and mitigation could then be developed using this DEBM for various earthquake scenarios, as presented in this paper for the 2004 Indian Ocean Tsunami.

scholarly journals Bag of Geomorphological Words: A Framework for Integrating Terrain Features and Semantics to Support Landform Object Recognition from High-Resolution Digital Elevation Models

2020 ◽  
Vol 9 (11) ◽  
pp. 620
Author(s):  
Xiran Zhou ◽  
Xiao Xie ◽  
Yong Xue ◽  
Bing Xue ◽  
Kai Qin ◽  
...  
Keyword(s):  
Object Recognition ◽  
High Resolution ◽  
Feature Vector ◽  
Dimensional Space ◽  
Digital Elevation Models ◽  
Three Dimensional ◽  
Slope Aspect ◽  
Digital Elevation ◽  
Great Possibility ◽  
High Level

High-resolution digital elevation models (DEMs) and its derivatives (e.g., curvature, slope, aspect) offer a great possibility of representing the details of Earth’s surface in three-dimensional space. Previous research investigations concerning geomorphological variables and region-level features alone cannot precisely characterize the main structure of landforms. However, these geomorphological variables are not sufficient to represent a complex landform object’s whole structure from a high-resolution DEM. Moreover, the amount of the DEM dataset is limited, including the landform object. Considering the challenges above, this paper reports an integrated model called the bag of geomorphological words (BoGW), enabling automatic landform recognition via integrating point and linear geomorphological variables, region-based features (e.g., shape, texture), and high-level landform descriptions. First, BoGW semantically characterizes the composition of geomorphological variables and meaningful parcels of each type of landform. Based on a landform’s semantics, the proposed method then integrates geomorphological variables and region-level features (e.g., shape, texture) to create the feature vector for the landform. Finally, BoGW classifies a region derived from high-resolution DEM into a predefined type of landform by the feature vector. The experimental results on crater and cirque detection indicated that the proposed BoGW could support landform object recognition from high-resolution DEMs.

A System for Computer-based Reconstruction of 3-Dimensional Structures from Serial Tissue Sections: an Application to the Study of Normal and Neoplastic Mammary Gland Biology

2001 ◽  
Vol 7 (S2) ◽  
pp. 964-965
Author(s):  
Rodrigo Fernandez-Gonzalez ◽  
Arthur Jones ◽  
Enrique Garcia-Rodriguez ◽  
Davis Knowles ◽  
Damir Sudar ◽  
...  
Keyword(s):  
Mammary Gland ◽  
High Resolution ◽  
Imaging System ◽  
Contextual Information ◽  
Three Dimensional ◽  
Tissue Level ◽  
Disease Heterogeneity ◽  
Tissue Sections ◽  
Virtual Reconstruction ◽  
Analytical Microscopy

Tissue heterogeneity and three-dimensionality are generally neglected by most traditional analytical microscopy methods in Biology. These often disregard contextual information important for understanding most biological systems. in breast cancer, which is a tissue level disease, heterogeneity and three dimensionality are at the very base of cancer initiation and clonal progression. Thus, a three dimensional quantitative system that allows low resolution virtual reconstruction of the mammary gland from serial sections, followed by high resolution cell-level reconstruction and quantitative analysis of the ductal epithelium emerges as an essential tool in studying the disease. We present here a distributed microscopic imaging system which allows acquiring and registering low magnification (1 pixel = 5 μm) conventional (bright field or fluorescence) images of entire tissue sections; then it allows tracing (in 3D) the ducts of the mammary gland from adjacent sections, to create a 3D virtual reconstruction of the gland; finally it allows revisiting areas of interest for high resolution (1 pixel = 0.5 μm) imaging and automatic analysis. We illustrate the use of the system for the reconstruction of a small volume of breast tissue.

scholarly journals High-resolution Three-dimensional Surface Imaging Microscope Based on Digital Fringe Projection Technique

2020 ◽  
Vol 20 (3) ◽  
pp. 139-144
Author(s):  
Cheng-Yang Liu ◽  
Tzu-Ping Yen ◽  
Chien-Wen Chen
Keyword(s):  
High Resolution ◽  
Imaging System ◽  
Three Dimensional ◽  
Fringe Projection ◽  
Surface Imaging ◽  
Projection Technique ◽  
Digital Fringe Projection ◽  
Absolute Phase ◽  
The Absolute ◽  
Fringe Patterns

AbstractThe three-dimensional (3-D) micro-scale surface imaging system based on the digital fringe projection technique for the assessments of microfiber and metric screw is presented in this paper. The proposed system comprises a digital light processing (DLP) projector, a set of optical lenses, a microscope, and a charge coupled device (CCD). The digital seven-step fringe patterns from the DLP projector pass through a set of optical lenses before being focused on the target surface. A set of optical lenses is designed for adjustment and size coupling of fringe patterns. A high-resolution CCD camera is employed to picture these distorted fringe patterns. The wrapped phase map is calculated by seven-step phase-shifting calculation from these distorted fringe patterns. The unwrapping calculation with quality guided path is introduced to compute the absolute phase values. The dimensional calibration methods are used to acquire the transformation between real 3-D shape and the absolute phase value. The capability of complex surface measurement for our system is demonstrated by using ISO standard screw M1.6. The experimental results for microfiber with 3 μm diameter indicate that the spatial and vertical resolutions can reach about 3 μm in our system. The proposed system provides a fast digital imaging system to examine the surface features with high-resolution for automatic optical inspection industry.

Exhaustive Photon Reassignment™: A Method Offering Enhanced Sensitivity and Quantitative Accuracy for High Resolution Fluorescence Microscopy

1997 ◽  
Vol 3 (S2) ◽  
pp. 379-380
Author(s):  
Jennifer A. Kramer ◽  
Ramkumar K. Moorthy ◽  
William N. Casavan ◽  
David C. Hitrys
Keyword(s):  
High Resolution ◽  
Dynamic Range ◽  
Imaging System ◽  
Three Dimensional ◽  
Short Exposure ◽  
Enhanced Sensitivity ◽  
Quantitative Accuracy ◽  
University Of Massachusetts ◽  
The University ◽  
Contrast Image

Confocal microscopy is a technique that allows researchers to obtain a highly resolved, high-contrast image of a focal plane in a fluorescent specimen by excluding or rejecting light emanating from out-of-focus planes. However, the basic design of confocals results in limitations for many biologists. It is often difficult to avoid photobleaching of specimens, to visualize fine or faintly-labeled structures, or to acquire high-quality images using short exposure times. The photomultiplier tubes used as the amplification detectors in these systems are restricted to a dynamic range of 8 bits (255 intensity levels), produce noise, and are not quantitatively linear detectors.Members of the Biomedical Imaging Group at the University of Massachusetts Medical School in Worcester, MA have spent the last fifteen years developing and perfecting a digital imaging system that helps scientists overcome these problems. Scanalytics is the exclusive worldwide licensee of this patented technology which allows researchers to obtain high-resolution, quantitatively accurate three-dimensional images of fluorescent specimens

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