Semi-automated Image Segmenting Software for Martian Soil Granulometry

Photoanalytical segmentation of individual soil grains and granulometry in high-resolution surface images are key in understanding sedimentation processes of planetary bodies before samples return to Earth. Here we present a Mathematica-based semi-automated image segmenting software tool that allows fast segmentation and granulometry analysis of Martian (soil) images based on the algorithm of Karunatillake et al. (2013, 2014), with a graphical user interface (GUI) to increase the software accessibility.Our software has been adapted to Martian in-situ observation images including the Mars Hand Lens Imager (MAHLI) and Microscopic Imager (MI), providing segmenting and granulometry measurement through steps below: (1) Image imported: all common raster images are supported, as well as the IMG formatted MAHLI and MI images. While the MI image possesses a constant pixel size of 31 &#956;m/pixel, for MAHLI images with various focal lengths, a focus motor count is required to calculate pixel size. The imported images are processed with gamma correction, contrast adjustment, background sharpen, and are visually decided whether there is a distinct foreground before going to the second step: (2) Image segmented: two independent modules are designed for segmenting the foreground and background with separate parameters, the coarser-grained foreground was masked before the finer-grained background is segmented. The GUI allows dynamic visualization of how the segmenting result changes with each parameter, facilitating the setting of parameters. (3) Granulometry: the grain size is calculated from the focal length and Wentworth classification of detected grains is established, highlighting the dominant class of grain size. The probability density and cumulative distribution of grain size can also be plotted. The granulometry results and parameters used are supported to export.To check the performance of our software, we qualitatively tested our software with 57 MAHLI and MI images with or without foreground, with comparison to region based segmentation method such as BASEGRAIN, edge detection based method such as ENVI Classification tools and Feature Extraction tools, and supervised segmentation methods such as ENVI supervised classification tools and ImageJ Trainable Weka Segmentation tool. Our software shows better results in generating grains with closed boundaries and distinguishing adjacent grains with similar colors, with the fastest speed and less workload. Factors that may influence the accuracy of segmenting include image resolution, camera angle, inter-grain brightness/color contrast and shadow coverage.In future work, a particle morphometry measuring function will be added so that statistics of grain roundness, sphericity, and angularity could be obtained. High-resolution images from the Moon and the asteroids will also be used in software testing to expand the range of its applicability to other planetary bodies. We will also consider its application on terrestrial cases, such as images of terrestrial sediments or petrological thin sections, which will need further improvement of the software concerning the increased compositional and optical complexity of terrestrial grains.&#160;&#160;

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Combining hyperspectral and XRF analyses to reconstruct high-resolution past flood frequency from lake sediments

10.5194/egusphere-egu2020-20333 ◽

2020 ◽

Author(s):

Kévin Jacq ◽

William Rapuc ◽

Anne-Lise Develle ◽

Pierre Sabatier ◽

Bernard Fanget ◽

...

Keyword(s):

Machine Learning ◽

Grain Size ◽

High Resolution ◽

Lake Sediments ◽

Hyperspectral Imaging ◽

Pixel Size ◽

Naked Eye ◽

Hyperspectral Sensors ◽

Xrf Core Scanning ◽

Continuous Sedimentation

Due to global climate changes, an intensification of extreme events such as floods is expected in many regions, affecting an increasing number of people. An assessment of the flood frequencies is then a public concern. For several years now, numerous studies are undertaken on geological paleoclimate records and especially on lake sediments to understand the fluctuations of the flood activities in contrasting climatic contexts and over long time periods. Flood events produce turbidity currents in lake basins that will usually lead to a normal graded detrital layer that differs remarkably from the continuous sedimentation. Currently, in an overwhelming majority of studies, once identified, the layers with the same characteristics (e.g. texture, geochemical composition, grain-size) are usually counted by naked-eye observation. Unfortunately, this method is time-consuming, has a low spatial resolution potential and can lead to accuracy bias and misidentifications. To resolve these shortcomings, high-resolution analytical methods could be proposed, as X-ray computed tomography or hyperspectral imaging. When coupled with algorithms, hyperspectral imaging allows automatic identifications of these events.Here, we propose a new method of flood layer identification and counting, based on the combination of two high-resolution techniques (hyperspectral imaging and high-resolution XRF core scanning). This approach was applied to one sediment core retrieved from the Lake Le Bourget (French Alps) in 2017. We use two hyperspectral sensors from the visible/near-infrared (VNIR, pixel size: 60 &#181;m) and the short wave infrared (SWIR, pixel size: 200 &#181;m) spectral ranges and several machine learning methods (decision tree and random forest, neural networks, and discriminant analysis) to extract instantaneous events sedimentary signal from continuous sedimentation. The study shows that the VNIR sensor is the optimal one to create robust classification models with an artificial neural network (prediction accuracy of 0.99). This first step allows the estimation of a classification map and then the reconstruction of a chronicle of the frequency and the thicknesses of the instantaneous event layers estimated. &#160;High-resolution XRF core scanning (XRF-CS) analyses were performed on the same core with a 200 &#181;m step. Titanium (Ti) and Manganese (Mn) were selected as a high-resolution grain size indicator and a redox-sensitive element that shows abrupt inputs of oxygenated water-related to floods, respectively. Both elements have thus been added to the model in order to refine the chronicle derived from hyperspectral sensors. The combination of both hyperspectral and XRF-CS signal indicator allows to decipher floods from instantaneous deposits (e.g slump). This combined chronicle is in good agreement with the expected frequency obtained from the naked-eye chronicle realized on the same core (r&#178; = 0.8). In this study, we present for the first time, an innovative approach based on machine learning which allows to propose fast automatized flood frequencies chronicles. This work was assessed by traditional deposits observations, but it can be easily applied to very micrometric deposits, undistinguishable to the naked eye. Finally, this model can be implemented with other indicators. It then represents a promising tool not only for flood reconstructions but also for other paleoenvironmental issues.

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The High Resolution Appearance of Biological Substrates

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100063998 ◽

1969 ◽

Vol 27 ◽

pp. 416-417

Author(s):

Glen B. Haydon

Keyword(s):

High Resolution ◽

Phase Image ◽

Biological Structure ◽

Electron Microscopic ◽

Thin Sections ◽

Resolution Electron ◽

Discrete Structures ◽

Large Phase ◽

Biological Substrates ◽

High Resolution Electron Micrographs

High resolution electron microscopic study of negatively stained macromolecules and thin sections of tissue embedded in a variety of media are difficult to interpret because of the superimposed phase image granularity. Although all of the information concerning the biological structure of interest may be present in a defocused electron micrograph, the high contrast of large phase image granules produced by the substrate makes it impossible to distinguish the phase ‘points’ from discrete structures of the same dimensions. Theory predicts the findings; however, it does not allow an appreciation of the actual appearance of the image under various conditions. Therefore, though perhaps trivial, training of the cheapest computer produced by mass labor has been undertaken in order to learn to appreciate the factors which affect the appearance of the background in high resolution electron micrographs.

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The ultrastructure of the double membrane-bound bodies and endoplasmic reticulum in serial sections of wheat spot mosaic-affected wheat plants

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100161023 ◽

1990 ◽

Vol 48 (3) ◽

pp. 694-695

Author(s):

M. H. Chen ◽

C. Hiruki

Keyword(s):

Endoplasmic Reticulum ◽

High Resolution ◽

Membrane Structure ◽

Mosaic Disease ◽

Serial Sections ◽

Thin Sections ◽

Double Membrane ◽

Southern Alberta ◽

Membrane Bound ◽

Scanning Em

Wheat spot mosaic disease was first discovered in southern Alberta, Canada, in 1956. A hitherto unidentified disease-causing agent, transmitted by the eriophyid mite, caused chlorosis, stunting and finally severe necrosis resulting in the death of the affected plants. Double membrane-bound bodies (DMBB), 0.1-0.2 μm in diameter were found to be associated with the disease.Young tissues of leaf and root from 4-wk-old infected wheat plants were fixed, dehydrated, and embedded in Spurr’s resin. Serial sections were collected on slot copper grids and stained. The thin sections were then examined with a Hitachi H-7000 TEM at 75 kV. The membrane structure of the DMBBs was studied by numbering them individually and tracing along the sections to see any physical connection with endoplasmic reticulum (ER) membranes. For high resolution scanning EM, a modification of Tanaka’s method was used. The specimens were examined with a Hitachi Model S-570 SEM in its high resolution mode at 20 kV.

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Towards 1-Ångstrom-resolution STEM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100150812 ◽

1993 ◽

Vol 51 ◽

pp. 996-997

Author(s):

H.S. von Harrach ◽

D.E. Jesson ◽

S.J. Pennycook

Keyword(s):

High Resolution ◽

Field Emission ◽

Phase Contrast ◽

Spherical Aberration ◽

A Priori ◽

Dark Field ◽

Image Resolution ◽

Objective Lens ◽

Annular Dark Field ◽

First Results

Phase contrast TEM has been the leading technique for high resolution imaging of materials for many years, whilst STEM has been the principal method for high-resolution microanalysis. However, it was demonstrated many years ago that low angle dark-field STEM imaging is a priori capable of almost 50% higher point resolution than coherent bright-field imaging (i.e. phase contrast TEM or STEM). This advantage was not exploited until Pennycook developed the high-angle annular dark-field (ADF) technique which can provide an incoherent image showing both high image resolution and atomic number contrast.This paper describes the design and first results of a 300kV field-emission STEM (VG Microscopes HB603U) which has improved ADF STEM image resolution towards the 1 angstrom target. The instrument uses a cold field-emission gun, generating a 300 kV beam of up to 1 μA from an 11-stage accelerator. The beam is focussed on to the specimen by two condensers and a condenser-objective lens with a spherical aberration coefficient of 1.0 mm.

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High-Performance Ultra-Thin Spectrometer Optical Design Based on Coddington’s Equations

Sensors ◽

10.3390/s21020323 ◽

2021 ◽

Vol 21 (2) ◽

pp. 323

Author(s):

Zhiwei Feng ◽

Guo Xia ◽

Rongsheng Lu ◽

Xiaobo Cai ◽

Hao Cui ◽

...

Keyword(s):

High Resolution ◽

Spectral Resolution ◽

High Performance ◽

Optical Design ◽

Pixel Size ◽

Simulation Design ◽

Central Wavelength ◽

Spot Radius ◽

Unique Method ◽

Almost All

A unique method to design a high-throughput and high-resolution ultrathin Czerny–Turner (UTCT) spectrometer is proposed. This paper reveals an infrequent design process of spectrometers based on Coddington’s equations, which will lead us to develop a high-performance spectrometer from scratch. The spectrometer is composed of cylindrical elements except a planar grating. In the simulation design, spot radius is sub-pixel size, which means that almost all of the energy is collected by the detector. The spectral resolution is 0.4 nm at central wavelength and 0.75 nm at edge wavelength when the width of slit is chosen to be 25 μm and the groove density is 900 lines/mm.

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Strain-Rate and Grain‒Size Effects in Ice

Journal of Glaciology ◽

10.1017/s0022143000008844 ◽

1987 ◽

Vol 33 (115) ◽

pp. 274-280 ◽

Cited By ~ 50

Author(s):

David M. Cole

Keyword(s):

Grain Size ◽

Strain Rate ◽

Transition Point ◽

Boundary Migration ◽

Peak Stress ◽

Strain Rates ◽

Thin Sections ◽

Fine Grained ◽

Lower Strain ◽

Polycrystalline Ice

AbstractThis paper presents and discusses the results of constant deformation-rate tests on laboratory-prepared polycrystalline ice. Strain-rates ranged from 10−7to 10−1s−1, grain–size ranged from 1.5 to 5.8 mm, and the test temperature was −5°C.At strain-rates between 10−7and 10−3s−1, the stress-strain-rate relationship followed a power law with an exponent ofn= 4.3 calculated without regard to grain-size. However, a reversal in the grain-size effect was observed: below a transition point near 4 × 10−6s−1the peak stress increased with increasing grain-size, while above the transition point the peak stress decreased with increasing grain-size. This latter trend persisted to the highest strain-rates observed. At strain-rates above 10−3s−1the peak stress became independent of strain-rate.The unusual trends exhibited at the lower strain-rates are attributed to the influence of the grain-size on the balance of the operative deformation mechanisms. Dynamic recrystallization appears to intervene in the case of the finer-grained material and serves to lower the peak stress. At comparable strain-rates, however, the large-grained material still experiences internal micro-fracturing, and thin sections reveal extensive deformation in the grain-boundary regions that is quite unlike the appearance of the strain-induced boundary migration characteristic of the fine-grained material.

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