Imaging Science Research Articles

Geometric processing of TGO CaSSIS observations

The Colour and Stereo Surface Imaging System (CaSSIS) is the scientific imager onboard the European Space Agency/Roscosmos ExoMars Trace Gas Orbiter. CaSSIS has one of the most advanced capabilities for colour imaging of the Martian surface on any spacecraft currently orbiting Mars. Such capability can only be utilized, however, by accurate geometric processing of CaSSIS datasets. Here we describe the dataset processing carried out by the CaSSIS geometry pipeline. This pipeline takes a number of single CaSSIS exposures and applies co-registration and map projection algorithms to produce full CaSSIS image mosaics in single and multiple wavelength bands. This process is described in detail along with the software packages that are implemented. The need for accurate co-registration between the different wavelength channels is shown. A description of the output from the pipeline is also given, with example images being shown to illustrate the result of using different CaSSIS wavelength channel combinations for image reconstruction.

Supervised Optimal Transport

Optimal transport, a theory for optimal allocation of resources, is widely used in various fields such as astrophysics, machine learning, and imaging science. However, many applications impose elementwise constraints on the transport plan which traditional optimal transport cannot enforce. Here we introduce supervised optimal transport (sOT), which formulates a constrained optimal transport problem where couplings between certain elements are prohibited according to specific applications. sOT is proved to be equivalent to an penalized optimization problem, from which efficient algorithms are designed to solve its entropy regularized formulation. We demonstrate the capability of sOT by comparing it to other variants and extensions of traditional optimal transport in the color transfer problem. We also study the barycenter problem in sOT formulation, where we discover and prove a unique reverse and portion selection (control) mechanism. Supervised optimal transport is broadly applicable to applications in which a constrained transport plan is involved and the original unit should be preserved by avoiding normalization.

Searching for the sources of ice block falls at the martian north polar scarps

We searched for the sources of ice block falls at the steep scarps of the martian North Polar Layered Deposits (NPLD). We focused on two study areas at the NPLD, i.e., Scarp 1 (centered at 85.0°N, 151.5°E with a length of ∼20 km) and Scarp 2 (centered at 83.8°N, 235.5°E with a length of ∼12.5 km). Repeat High Resolution Imaging Science Experiment (HiRISE) observations with image scales of up to 0.25 m/pixel were used. Specifically, we identified changes in the shadow patterns at the scarps which attest to block fall activity. An automated change detection method, which searches for the grayscale difference between multi-temporal images, was developed to identify these patches where shadows have changed. The method was evaluated in six areas of Scarp 1 over all detection periods, and achieved an average true positive rate of 97.6% and false discovery rate of 9.4%. The spatio-temporal distribution showed that ice block falls were an active process. Along Scarp 1, about 129 ice block falls occurred per Mars year per km2, mostly at elevations 0–300 m of the 500 m high scarp, where the slope is over 30°. The amount of ice block falls increased with steeper slope angles. Along Scarp 2, about 237 ice block falls occurred per Mars year per km2, resting in the form of smaller blocks and fine particles, or spreading outward in fan-shaped patterns. We compared the detected source areas at Scarp 2 with the fresh ice blocks observed on the underlying Basal Unit (BU) between MY 30 and MY 31 to analyze the dynamic process of ice block falls. Underneath the areas with large numbers of detached ice-fragments, many fresh ice blocks were found on the BU. On the other hand, some regions of Scarp 2 did not show evidence of detached ice-fragments despite fresh ice blocks on the BU areas below. Our comparison proved that both the NPLD and the BU scarps are active source areas of ice block falls. The detections of block fall sources at the NPLD scarps can help to distinguish events from the NPLD and those from the BU and refine the estimates of active polar scarp retreat, which will improve the understanding of the polar cap evolution.

Parallelizable Global Quasi-Conformal Parameterization of Multiply Connected Surfaces via Partial Welding

Conformal and quasi-conformal mappings have widespread applications in imaging science, computer vision and computer graphics, such as surface registration, segmentation, remeshing, and texture map compression. While various conformal and quasi-conformal parameterization methods for simply connected surfaces have been proposed, efficient parameterization methods for multiply connected surfaces are less explored. In this paper, we propose a novel parallelizable algorithm for computing the global conformal and quasi-conformal parameterization of multiply connected surfaces onto a 2D circular domain using variants of the partial welding algorithm and the Koebe's iteration. The main idea is to partition a multiply connected surface into several subdomains and compute the free-boundary conformal or quasi-conformal parameterizations of them respectively, and then apply a variant of the partial welding algorithm to reconstruct the global mapping. We apply the Koebe's iteration together with the geodesic algorithm to the boundary points and welding paths before and after the global welding to transform all the boundaries to circles conformally. After getting all the updated boundary conditions, we obtain the global parameterization of the multiply connected surface by solving the Laplace equation for each subdomain. Using this divide-and-conquer approach, the parameterization of surfaces with very high resolution can be efficiently computed. Experimental results are presented to demonstrate the effectiveness of our proposed algorithms.

Solar-induced chlorophyll fluorescence imaging spectrometer: design, manufacture, and evaluation.

A scientific imaging spectrometer has been presented for the observation of solar-induced chlorophyll fluorescence of vegetation in NIR waveband, which may provide a new method to scale SIF application from leaf to canopy for the research of terrestrial vegetation photosynthesis. The SIF imaging spectrometer accommodates a telescope with a medium spatial resolution (1 mrad) over a field of view of 20°, a high spectral resolution (0.3nm) to measure the fluorescence spectrum within two oxygen absorption bands (O2A and O2B), and a high numerical aperture (0.25) for high SNR. Both of transmission optical systems, with high etendue and dispersive prism-VPH grating (P-G) with high diffraction efficiency, have been utilized for the optical design of imaging spectrometer. The design and prototype present excellent optical performances as demonstrated by the latest simulation and calibration. The in-situ observation proves that the advanced SIF imaging spectrometer could provide precise fluorescence data. The instrument will highlight SIF signal retrieval strategies, techniques for field and airborne and satellite sensing, and applications of these capabilities in evaluation of photosynthesis and stress effects for fluorescence science.

Special Section Guest Editorial: Machine Vision—Systems, Methods, and Applications

The <i>Journal of Electronic Imaging</i> (JEI), copublished bimonthly with the Society for Imaging Science and Technology, publishes peer-reviewed papers that cover research and applications in all areas of electronic imaging science and technology.

Special Section Guest Editorial: Image and Video Manipulation—Challenges and Solutions

The <i>Journal of Electronic Imaging</i> (JEI), copublished bimonthly with the Society for Imaging Science and Technology, publishes peer-reviewed papers that cover research and applications in all areas of electronic imaging science and technology.

Planet Four: A Neural Network’s search for polar spring-time fans on Mars

Dark deposits visible from orbit appear in the Martian south polar region during the springtime. These are thought to form from explosive jets of carbon dioxide gas breaking through the thawing seasonal ice cap, carrying dust and dirt which is then deposited onto the ice as dark ‘blotches’, or blown by the surface winds into streaks or ‘fans’. We investigate machine learning (ML) methods for automatically identifying these seasonal features in High Resolution Imaging Science Experiment (HiRISE) satellite imagery. We designed deep Convolutional Neural Networks (CNNs) that were trained and tested using the catalog generated by Planet Four, an online citizen science project mapping the south polar seasonal deposits. We validated the CNNs by comparing their results with those of ISODATA (Iterative Self-Organizing Data Analysis Technique) clustering and as expected, the CNNs were significantly better at predicting the results found by Planet Four, in both the area of predicted seasonal deposits and in delineating their boundaries. We found neither the CNNs or ISODATA were suited to predicting the source point and directions of seasonal fans, which is a strength of the citizen science approach. The CNNs showed good agreement with Planet Four in cross-validation metrics and detected some seasonal deposits in the HiRISE images missed in the Planet Four catalog; the total area of seasonal deposits predicted by the CNNs was 27% larger than that of the Planet Four catalog, but this aspect varied considerably on a per-image basis.

Chinese Culture and Cognitive Science

In the civilizations of the axial age, Chinese and Western cultures gave birth to different scientific traditions—the image sciences and the natural sciences—within the knowledge frameworks of the union of man and nature and of the subject–object dichotomy respectively. Therefore, there are inevitably insurmountable barriers to explaining the differences between Chinese and Western cultures in terms of a natural science concerned with “things.” However, human nature is universal, and it is possible to make direct comparisons and interpretations of the differences between Chinese and Western cultures in terms of the cognitive sciences dealing with the mind. One important way to compare and interpret Chinese culture and cognitive science is the mutual interpretation of Chinese and Western cultures. In view of this, we have integrated enactive cognition (the frontier of cognitive science) and the free energy principle to propose the predictive mind model of enactive cognition and have used this mutual interpretation to study the two cultures using this model of cognitive science as a truly unified cross-cultural paradigm for cognitive science. First, the theory of enaction embedded in Chinese culture is actually closely related to enactive cognition, the frontier of Western cognitive science. Laozi’s theory of universal enaction (cosmology) shows that Chinese culture has an ancient theory of enaction. He firmly planted in the minds of Chinese people a way of thinking dealing with union of man and nature. Western enactive cognition, as a modern theory, advocates continuity of life and mind and emphasizes that life is both autopoietic and cognitive, which is actually a scientific cognitive expression of the Chinese cultural idea of the harmony of man and nature. This is actually a scientific cognitive expression of Chinese culture’s idea of the harmony of man and nature. Second, the qi in Chinese culture is similar to the free energy in Western cognitive science. In terms of concept definition, qi is a mixture of matter, function and principles (information), while free energy is the synthesis of energy and information. From the point of view of the mode of operation, qi is the contradictory harmony between yin and yang, while free energy is the unity of top-down and bottom-up approaches. In terms of kinetic purpose, the kinetic purpose of qi is the doctrine of benevolence, while the kinetic purpose of free energy has gradually changed from representation of nature to construction of meaning. Through comparison and interpretation, we find that enactive cognition is closely related to Chinese culture on the cognitive science route, in what will be a practical path for the rejuvenation of Chinese culture. In addition, through the association of qi in Chinese culture and free energy in Western cognitive science, Chinese and Western cultures can be expected to be truly connected through cognitive science.

Patterns of martian glacial deformation: Implications for glacio-geology, internal structure, and regional climate

Viscous Flow Features (VFF) are widespread in the martian mid-latitudes and indicative of near-surface ice deposits. Their distribution and morphology hint at the regional history of ice deposition and ablation, as well as changes in surface temperature. Here we interrogate the deformation history of a type of VFF, a Lobate Debris Apron (LDA), located in the eastern Hellas region, from its surface morphology, discussing the implications it poses for its internal structure and regional climate variability. Our observations integrate data from the Colour and Stereo Surface Imaging System (CaSSIS), the SHAllow RADar (SHARAD), the Context Camera (CTX), the High Resolution Imaging Science Experiment (HiRISE), and the Mars Orbiter Laser Altimeter (MOLA). Morphological observations, spectral analysis of characteristic wavelengths, and ice deformation stability analysis place constraints on the dynamics and deformation history of the deposit. We discuss contrasting hypotheses for the origin of the different surface structures, including the possibility of gelifluction in addition to glacial creep. Our results provide a guide to interpret glacial deformation patterns in martian VFFs in the light of internal structure, regional climate history, and underlying topography.

Complementary astrometry of Cassini Imaging Science Subsystem images of Phoebe

Phoebe is the only major satellite of Saturn with a retrograde orbit. The Cassini Imaging Science Subsystem (ISS) took a lot of Phoebe images between 2004 and 2017, but only a selection of them has been reduced. In this paper, we reduced the remaining ISS images of Phoebe. In the reduction, the Gaia EDR3 catalogue was used to provide the reference stars' positions, and the modified moment was used to measure the centre of image stars and Phoebe. Finally, a total of 834 ISS images of Phoebe have been reduced successfully. Compared with the JPL ephemeris SAT375, Phoebe's positions are consistent. The average residuals in the right ascension and declination are 0.08" and $-0.05$", and the standard deviations of the residuals are about 0.2". In terms of residuals in linear units, the means in the right ascension and declination are about 5 km and $-2$ km, respectively; The standard deviations are about 11 km. Compared with the JPL ephemeris SAT427 and IMCCE ephemeris PH20, our measurements show a strong bias and a large dispersion.

Pulmonary Arteriovenous Fistula Leading to Artery of Percheron Infarcts.

HomeStrokeVol. 53, No. 12Pulmonary Arteriovenous Fistula Leading to Artery of Percheron Infarcts No AccessCase ReportRequest AccessFull TextAboutView Full TextView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toNo AccessCase ReportRequest AccessFull TextPulmonary Arteriovenous Fistula Leading to Artery of Percheron Infarcts Naveen Kumar Paramasivan, MD, DM, Jineesh Valakkada, MD, Sapna Erat Sreedharan, MD, DM and P.N. Sylaja, MD, DM Naveen Kumar ParamasivanNaveen Kumar Paramasivan https://orcid.org/0000-0002-2185-4385 Comprehensive Stroke Care Program, Department of Neurology (N.K.P., S.E.S.), Sree Chitra Tirunal Institute for Medical Sciences and Technology, Thiruvananthapuram, Kerala. Search for more papers by this author , Jineesh ValakkadaJineesh Valakkada https://orcid.org/0000-0003-3382-6063 Department of Imaging Sciences and Interventional Radiology (J.V.), Sree Chitra Tirunal Institute for Medical Sciences and Technology, Thiruvananthapuram, Kerala. Search for more papers by this author , Sapna Erat SreedharanSapna Erat Sreedharan https://orcid.org/0000-0003-0633-4899 Comprehensive Stroke Care Program, Department of Neurology (N.K.P., S.E.S.), Sree Chitra Tirunal Institute for Medical Sciences and Technology, Thiruvananthapuram, Kerala. Search for more papers by this author and P.N. SylajaP.N. Sylaja Correspondence to: P.N. Sylaja, Comprehensive Stroke Care Program, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, India 695011. Email E-mail Address: [email protected] https://orcid.org/0000-0003-4896-8275 Search for more papers by this author Originally published20 Sep 2022https://doi.org/10.1161/STROKEAHA.122.040893Stroke. 2022;53:e521–e522"Pulmonary Arteriovenous Fistula Leading to Artery of Percheron Infarcts." Stroke, 53(12), pp. e521–e522FootnotesFor Sources of Funding and Disclosures, see page e522.Correspondence to: P.N. Sylaja, Comprehensive Stroke Care Program, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, India 695011. Email [email protected]com

EINet: camouflaged object detection with pyramid vision transformer (Erratum)

The <i>Journal of Electronic Imaging</i> (JEI), copublished bimonthly with the Society for Imaging Science and Technology, publishes peer-reviewed papers that cover research and applications in all areas of electronic imaging science and technology.

Digital transformation in rock physics: Deep learning and data fusion

Rock physics plays an essential role in geophysical reservoir characterization. It aims to build a bridge between geophysical measurements and in-situ rock and fluid properties. With the advancement of microscopic imaging and computer science, rock physics is transitioning to the digital age. This is referred to as digital rock physics (DRP). DRP provides a nondestructive and efficient way to determine physical rock properties directly from digital images. Over the last decades, it has become a routine tool in reservoir characterization by complementing or replacing expensive and time-consuming laboratory measurements. With the emergence of deep learning, DRP has advanced significantly from image processing to physical simulation. This paper presents an application of deep learning in multiscale fusion of digital rock images. It aims to overcome the trade-off between image resolution and field of view (FoV) by integrating imaging data from multiple sources including (1) 3D microcomputed tomography images at micronscale with a large FoV and (2) 2D scanning electron microscopy images at nanoscale with a small FoV. The reconstructed image integrates information of microstructures at different scales and helps characterize heterogeneous porous rocks more accurately. It is helpful to improve the prediction accuracy of effective rock properties and to have deeper insight into physical processes at pore scale. Data fusion based on deep learning would unlock new pathways for geophysical characterization of porous rocks, with broad implications for various subsurface applications such as groundwater transport, enhanced oil recovery, and geologic carbon sequestration.

The Martian Boulder Automatic Recognition System, MBARS

AbstractBoulder‐sized clasts are common on the surface of Mars, and many are sufficiently large to be resolved by the high resolution imaging science experiment (HiRISE) camera aboard the Mars reconnaissance orbiter. The size, number, and location of boulders on the surface and their spatial distribution can reveal the processes that have operated on the surface, including boulder erosion, burial, impact excavation, and other mechanisms of boulder transport and generation. However, quantitative analysis of statistically significant boulder populations, which could inform these processes, entails prohibitively laborious manual segmentation, granulometry, and morphometry measurements over large areas. Here, we develop, describe, and validate an automated tool to locate and measure boulders on the Martian surface: the Martian Boulder Automatic Recognition System (MBARS). Our open‐source Python‐based toolkit automatically measures boulder diameter and height in HiRISE images enabling rapid and accurate assessments of boulder populations. We compare our algorithm with existing boulder‐counting methods, manual analyses, and objects of known size to verify accuracy and precision. Additionally, we test how MBARS quantitatively characterizes boulders around an impact crater in the Martian northern lowlands. We compare this to previous work on rock excavation during impact cratering using manually counted boulders around lunar craters.

Pre-landslide topographic reconstruction in Baetis Chaos, mars using a CaSSIS Digital Elevation Model

Planview detailed morphological analysis of martian landslides is usually performed using orbital imagery such as from the ConTeXt camera (CTX) at 6 ​m/pix, the Colour and Stereo Surface Imaging System (CaSSIS) at 4.5 ​m/pix or the High-Resolution Imaging Science Experiment (HiRISE) at 0.25–0.5 ​m/pix. However, topographic information is key to fully understand a landslide's formation mechanism and its mobility, by estimating the material volumes mobilised and the spatial distribution of erosion and deposition. Digital Elevation Models (DEM) are required to carry out these analyses; nevertheless, there is currently a gap in landslide-volume studies between those using Mars Orbiter Laser Altimeter (MOLA) dataset at ∼450 ​m/pix or HRSC at 50–200 m/pix and those using HiRISE data at 1–2 m/pix, which is only partially filled by CTX elevation data at ∼20 ​m/pix. The CaSSIS camera on board the ESA/Trace Gas Obiter (TGO) can be used to produce DEMs, but so far, such data have not yet been used to conduct a landslide volume analysis. Here, we use three reconstruction methods (semi-automatic, morphology-based and tilted) on a CaSSIS DEM to estimate the initial topography and hence the volume and the distribution of erosion and deposition of a 6 ​km long landslide in Baetis Chaos. Despite the complex topography of the surrounding area due to the presence of an ejecta deposit beneath the landslide, we were able to estimate the landslide's volume and mass distribution. Using a tilted plane as part of estimating the initial topography produced the best results. We evaluated the success by considering the quantifiable balance between erosion and deposition (given the uncertainties) and more subjectively by considering whether the volume distribution matched with what was expected based on the morphology in images alone. Therefore, we recommend the use of this method for individual landslide studies in complex topography where detailed knowledge of the deposit-thickness distribution is required. The semi-automatic reconstruction method produces satisfactory volume estimates and would be better suited to studies where hundreds of landslides are present. We found that CaSSIS data can be used to successfully conduct such analyses, providing additional DEM coverage to study martian medium-scale landslides or other landforms of similar scale (5–15 ​km) with the notable benefit that it provides single-pass stereo image acquisition. • Digital Elevation Model are needed to estimates landslide's material volumes and distribution in order to fully understand their mobility. • CaSSIS (Colour and Stereo Surface Imaging System) DEM have not yet been used to conduct such landslide analysis. • Three reconstruction on a CaSSIS DEM have been used to estimate the volume and the material distribution of a landslide in Baetis Chaos on Mars. • CaSSIS data can be used to conduct analysis and provide additional coverage to study medium-scale landslides or other landforms (scale 5–15 km).

Multiple convective storms within a single cyclone on Saturn

Here we describe a cyclone at 50∘N in the atmosphere of Saturn that was the source of eight separate convective storms. The storm clouds that appeared bright in scattered sunlight were identified using images from the Cassini Imaging Science Subsystem (ISS) and ground-based telescopes. The Cassini Radio and Plasma Wave Science (RPWS) instrument detected Saturn Electric Discharge (SED) signals from the lightning within the storms, which were correlated to the sudden appearance of bright storm clouds in and surrounding the cyclone. Using the number and flash rate of SEDs we infer the duration and intensity of the storms. Although previous storms have been observed to erupt from within cyclones, the cyclone studied here is unusual in that it survived six storms before being disrupted by the seventh and strongest storm. An eighth storm occurred in the remnant of the disrupted cyclone. We conjecture that the anticyclonic circulation generated by the seventh storm was enough to overwhelm the cyclone’s gradient wind balance.

Special Section Guest Editorial: Biologically Inspired Computer Vision and Image Processing

The <i>Journal of Electronic Imaging</i> (JEI), copublished bimonthly with the Society for Imaging Science and Technology, publishes peer-reviewed papers that cover research and applications in all areas of electronic imaging science and technology.

Transverse aeolian ridges in the landing area of the Tianwen-1 Zhurong rover on Utopia Planitia, Mars

The enigmatic transverse aeolian ridges (TARs), with distinct morphology and albedo, are among the key geological features investigated by China's Tianwen-1 Zhurong rover on southern Utopia Planitia, Mars. Their morphologies and morphometrics are investigated through high-resolution imaging science experiment (HiRISE) orthoimage and Digital Terrain Model (DTM) products. A total of 5089 TARs are identified, with barchan TARs being predominant (97.6%). Morphometric analysis shows these TARs to be small and symmetrical aeolian landforms, with an average crest–ridge lengths of 33.9 ± 20.5 m, profile widths of 9.4 ± 3.8 m, profile heights of 0.4 ± 0.4 m, profile-height-width ratios of 0.04 ± 0.02, and profile symmetry ratios of −0.01 ± 0.13. In-situ observations from the Navigation and Terrain Camera (NaTeCam) show the crests of the TARs to be dark and sharp, while the flanks are interlaced by dark and bright materials. Close-up Multispectral Camera (MSCam) images reveal the TARs to be coated by granules of ∼1.5 mm in diameter. Given the morphometric characteristics and the presence of coating granules, the TARs in the landing area could be categorized as megaripples. Buffered crater counting (BCC) technique-derived absolute model age (AMA) reveals the formation time, or the last active period of the TARs, could be as recent as 1 Ma in the Late Amazonian. The morphometrics and direction of the horns of the barchan TARs suggest the winds for the formation of TARs blew mostly from the north. During the spring-summer transition period (Ls: 50°–93°), the Mars Climate Station (MCS) had recorded local bimodal winds in the landing area, with the speed of the northerly wind in the afternoon being a little stronger than the speed of the southerly wind in the morning. These observations are consistent with the wind fields described in the Mars Climate Database (MCD), which imply the northerly winds during the northern winter season to be responsible for the net sediment transport to the south. Two TARs observed in-situ with secondary NW-SE trending crest-ridges indicate that forked TARs might form given sufficient time (i.e., in the order of millions of years) under modern wind conditions, i.e., the TARs may be currently reworked, if only extremely weakly.

Old data, new tools: leveraging routinely acquired patient data to address current challenges in I–O

Better predicting which patients will respond to checkpoint inhibitors remains a critical challenge for the I–O field. Biomedical engineer and AI expert Anant Madabhushi discusses how combining routine patient data with the power of computational tools can help to address the problem – and why he chose to take an ‘anti-black box’ AI approach.Anant Madabhushi is a Professor of Biomedical Engineering; and on faculty in the Departments of Pathology, Biomedical Informatics, and Radiology and Imaging Sciences at Emory University. He is also a Research Health Scientist at the Atlanta Veterans Administration Medical Center. Dr Madabhushi has authored more than 450 peer-reviewed publications and more than 100 patents issued or pending. He is a, Fellow of the American Institute of Medical and Biological Engineering (AIMBE), and the Institute for Electrical and Electronic Engineers (IEEE) and the National Academy of Inventors (NAI). His work on ‘Smart Imaging Computers for Identifying lung cancer patients who need chemotherapy’ was called out by Prevention Magazine as one of the top 10 medical breakthroughs of 2018. In 2019, Nature hailed him as one of five scientists developing “offbeat and innovative approaches for cancer research”. Dr Madabhushi was named to The Pathologist’s Power List in 2019, 2020, 2021 and 2022.