English
Related papers

Related papers: Image compression in local helioseismology

200 papers

Linear time-distance helioseismic inversions are carried out for vector flow velocities using travel times measured from two $\sim 100^2\,{\rm Mm^2}\times 20\,{\rm Mm}$ realistic magnetohydrodynamic quiet-Sun simulations of about 20 hr. The…

Solar and Stellar Astrophysics · Physics 2015-06-19 K. DeGrave , J. Jackiewicz , M. Rempel

Due to the increasing requirements for transmission of images in computer, mobile environments, the research in the field of image compression has increased significantly. Image compression plays a crucial role in digital image processing,…

Multimedia · Computer Science 2014-05-26 A. M. Raid , W. M. Khedr , M. A. El-dosuky , Wesam Ahmed

It is of great importance to monitor large solar active regions in the far-side of the Sun for space weather forecast, in particular, to predict their appearance before they rotate into our view from the solar east limb. Local…

Astrophysics · Physics 2009-11-13 Junwei Zhao

The solar atmosphere is extremely dynamic, and many important phenomena develop on small scales that are unresolved in observations with the Helioseismic and Magnetic Imager (HMI) instrument on the Solar Dynamics Observatory (SDO). For…

Solar and Stellar Astrophysics · Physics 2015-08-06 Irina N. Kitiashvili , Sebastien Couvidat , Andreas Lagg

We use a publicly available numerical wave-propagation simulation of Hartlep et al. 2011 to test the ability of helioseismic holography to detect signatures of a compact, fully submerged, 5% sound-speed perturbation placed at a depth of 50…

Solar and Stellar Astrophysics · Physics 2015-06-11 Douglas C. Braun

Lossy image compression has been studied extensively in the context of typical loss functions such as RMSE, MS-SSIM, etc. However, compression at low bitrates generally produces unsatisfying results. Furthermore, the availability of massive…

Image and Video Processing · Electrical Eng. & Systems 2019-06-26 Ashutosh Bhown , Soham Mukherjee , Sean Yang , Shubham Chandak , Irena Fischer-Hwang , Kedar Tatwawadi , Judith Fan , Tsachy Weissman

We derive an algorithm for compression of the currents and varifolds representations of shapes, using ridge leverage score (RLS) sampling, and the theory of Nystrom approximation in Reproducing Kernel Hilbert Spaces. Our method is faster…

Numerical Analysis · Mathematics 2026-03-18 Allen Paul , Neill Campbell , Tony Shardlow

Being able to image active regions on the Sun's far side is useful for modeling the global-scale magnetic field around the Sun, and for predicting the arrival of major active regions that rotate around the limb onto the near side.…

Solar and Stellar Astrophysics · Physics 2020-01-08 Junwei Zhao , Dominick Hing , Ruizhu Chen , Shea Hess Webber

Modern computer vision requires processing large amounts of data, both while training the model and/or during inference, once the model is deployed. Scenarios where images are captured and processed in physically separated locations are…

Computer Vision and Pattern Recognition · Computer Science 2021-03-30 Sudeep Katakol , Basem Elbarashy , Luis Herranz , Joost van de Weijer , Antonio M. Lopez

Deep learning for computer vision depends on lossy image compression: it reduces the storage required for training and test data and lowers transfer costs in deployment. Mainstream datasets and imaging pipelines all rely on standard JPEG…

Computer Vision and Pattern Recognition · Computer Science 2020-03-09 Zhijing Li , Christopher De Sa , Adrian Sampson

Visual Place Recognition (VPR) is the ability of a robotic platform to correctly interpret visual stimuli from its on-board cameras in order to determine whether it is currently located in a previously visited place, despite different…

Computer Vision and Pattern Recognition · Computer Science 2023-03-02 Mihnea-Alexandru Tomita , Bruno Ferrarini , Michael Milford , Klaus McDonald-Maier , Shoaib Ehsan

Monitoring medical data, e.g., Electrocardiogram (ECG) signals, is a common application of Internet of Things (IoT) devices. Compression methods are often applied on the massive amounts of sensor data generated prior to sending it to the…

Signal Processing · Electrical Eng. & Systems 2022-04-05 Eli Brosh , Elad Wasserstein , Anat Bremler-Barr

Deep neural networks have achieved strong performance in image classification tasks due to their ability to learn complex patterns from high-dimensional data. However, their large computational and memory requirements often limit deployment…

Computer Vision and Pattern Recognition · Computer Science 2026-03-06 Sai Shi

Data compression plays a key role in reducing storage and I/O costs. Traditional lossy methods primarily target data on rectilinear grids and cannot leverage the spatial coherence in unstructured mesh data, leading to suboptimal compression…

Estimates of the photospheric magnetic, electric and plasma velocity fields are essential for studying the dynamics of the solar atmosphere, for example through the derivative quantities of Poynting and relative helicity flux and by using…

Solar and Stellar Astrophysics · Physics 2017-12-18 E. Lumme , J. Pomoell , E. K. J. Kilpua

JPEG is still the most widely used image compression algorithm. Most image compression algorithms only consider uncompressed original image, while ignoring a large number of already existing JPEG images. Recently, JPEG recompression…

Computer Vision and Pattern Recognition · Computer Science 2023-12-06 Jianghui Zhang , Yuanyuan Wang , Lina Guo , Jixiang Luo , Tongda Xu , Yan Wang , Zhi Wang , Hongwei Qin

We propose a useful method for mapping large-scale velocity fields in the solar photosphere. It is based on the local correlation tracking algorithm when tracing supergranules in full-disc dopplergrams. The method was developed using…

Astrophysics · Physics 2007-05-23 M. Svanda , M. Klvana , M. Sobotka

Time-distance helioseismology has shown that f-mode travel times contain information about horizontal flows in the Sun. The purpose of this study is to provide a simple interpretation of these travel times. We study the interaction of…

Astrophysics · Physics 2009-06-25 J. Jackiewicz , L. Gizon , A. C. Birch , T. L. Duvall

Presented is a novel way to combine snapshot compressive imaging and lateral shearing interferometry in order to capture the spatio-spectral phase of an ultrashort laser pulse in a single shot. A deep unrolling algorithm is utilised for the…

Applications of satellite data in areas such as weather tracking and modeling, ecosystem monitoring, wildfire detection, and land-cover change are heavily dependent on the trade-offs to spatial, spectral and temporal resolutions of…

Computer Vision and Pattern Recognition · Computer Science 2020-03-03 Thomas Vandal , Ramakrishna Nemani