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The ability to subtract foreground contamination from low-frequency observations is crucial to reveal the underlying 21 cm signal. The traditional line-of-sight methods can deal with the removal of diffuse emission and unresolved point…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 Xiao-Chun Mao

In radio astronomy, signals from radio telescopes are transformed into images of observed celestial objects, or sources. However, these images, called dirty images, contain real sources as well as artifacts due to signal sparsity and other…

Instrumentation and Methods for Astrophysics · Physics 2023-08-30 Ruoqi Wang , Zhuoyang Chen , Qiong Luo , Feng Wang

The Zwicky Transient Facility is a time-domain optical survey that has substantially increased our ability to observe and construct massive catalogs of astronomical objects by use of its 47 square degree camera that can observe in multiple…

Instrumentation and Methods for Astrophysics · Physics 2022-01-21 Michael S. Medford , Peter Nugent , Danny Goldstein , Frank J. Masci , Igor Andreoni , Ron Beck , Michael W. Coughlin , Dmitry A. Duev , Ashish A. Mahabal , Reed L. Riddle

Recently, novel quaternion-valued wavelets on the plane were constructed using an optimisation approach. These wavelets are compactly supported, smooth, orthonormal, non-separable and truly quaternionic. However, they have not been tested…

Computer Vision and Pattern Recognition · Computer Science 2024-01-12 Neil D. Dizon , Jeffrey A. Hogan

Radio interferometric imaging has long relied on the CLEAN algorithm, valued for its speed, robustness, and integration with calibration pipelines. However, next-generation facilities such as the ngVLA, SKA, and ALMAs Wideband Sensitivity…

Instrumentation and Methods for Astrophysics · Physics 2025-09-19 Hendrik Müller

In this paper offers a simple and lossless compression method for compression of medical images. Method is based on wavelet decomposition of the medical images followed by the correlation analysis of coefficients. The correlation analyses…

Computer Vision and Pattern Recognition · Computer Science 2010-02-12 S. M. Ramesh , A. Shanmugam

We describe a novel method for removing noise (in wavelet domain) of unknown variance from microarrays. The method is based on a smoothing of the coefficients of the highest subbands. Specifically, we decompose the noisy microarray into…

Signal Processing · Electrical Eng. & Systems 2018-08-01 Mario Mastriani , Alberto. E. Giraldez

View synthesis is usually done by an autoencoder, in which the encoder maps a source view image into a latent content code, and the decoder transforms it into a target view image according to the condition. However, the source contents are…

Computer Vision and Pattern Recognition · Computer Science 2021-03-19 Mingyu Yin , Li Sun , Qingli Li

The constant center frequency to bandwidth ratio (Q-factor) of wavelet transforms provides a very natural representation for audio data. However, invertible wavelet transforms have either required non-uniform decimation -- leading to…

Audio and Speech Processing · Electrical Eng. & Systems 2023-01-20 Nicki Holighaus , Günther Koliander , Clara Hollomey , Friedrich Pillichshammer

Video prediction is a pixel-wise dense prediction task to infer future frames based on past frames. Missing appearance details and motion blur are still two major problems for current predictive models, which lead to image distortion and…

Computer Vision and Pattern Recognition · Computer Science 2020-05-25 Beibei Jin , Yu Hu , Qiankun Tang , Jingyu Niu , Zhiping Shi , Yinhe Han , Xiaowei Li

The bilateral filter is a useful nonlinear filter which without smoothing edges, it does spatial averaging. In the literature, the effectiveness of this method for image denoising is shown. In this paper, an extension of this method is…

Computer Vision and Pattern Recognition · Computer Science 2017-02-07 Seyede Mahya Hazavei , Hamid Reza Shahdoosti

I discuss approaches to optimally remove noise from images. A generalization of Wiener filtering to Non-Gaussian distributions and wavelets is described, as well as an approach to measure the errors in the reconstructed images. We argue…

Astrophysics · Physics 2009-10-31 Ue-Li Pen

The 21 cm radiation of neutral hydrogen provides crucial information for studying the early universe and its evolution. To advance this research, countries have made significant investments in constructing large low-frequency radio…

Instrumentation and Methods for Astrophysics · Physics 2025-08-04 Ming-wei Qin , Rui Tang , Ying-hui Zhou , Chang-jun Lan , Wen-hao Fu , Huan Wang , Bao-lin Hou , Zamri , Jin-song Ping , Wen-jun Yang , Liang Dong

Diffusion models are rising as a powerful solution for high-fidelity image generation, which exceeds GANs in quality in many circumstances. However, their slow training and inference speed is a huge bottleneck, blocking them from being used…

Computer Vision and Pattern Recognition · Computer Science 2023-03-24 Hao Phung , Quan Dao , Anh Tran

Segmentation, a useful/powerful technique in pattern recognition, is the process of identifying object outlines within images. There are a number of efficient algorithms for segmentation in Euclidean space that depend on the variational…

Computer Vision and Pattern Recognition · Computer Science 2019-11-12 Xiaohao Cai , Christopher G. R. Wallis , Jennifer Y. H. Chan , Jason D. McEwen

Image deblurring is a classical computer vision problem that aims to recover a sharp image from a blurred image. To solve this problem, existing methods apply the Encode-Decode architecture to design the complex networks to make a good…

Image and Video Processing · Electrical Eng. & Systems 2021-10-13 Wenbin Zou , Mingchao Jiang , Yunchen Zhang , Liang Chen , Zhiyong Lu , Yi Wu

Calibration of radio interferometric observations becomes increasingly difficult towards lower frequencies. Below ~300 MHz, spatially variant refractions and propagation delays of radio waves traveling through the ionosphere cause phase…

Instrumentation and Methods for Astrophysics · Physics 2015-05-13 H. T. Intema , S. van der Tol , W. D. Cotton , A. S. Cohen , I. M. van Bemmel , H. J. A. Rottgering

Radio astronomy is an indispensable discipline for observing distant celestial objects. Measurements of wave signals from radio telescopes, called visibility, need to be transformed into images for astronomical observations. These dirty…

Computer Vision and Pattern Recognition · Computer Science 2026-01-13 Kai Cheng , Ruoqi Wang , Qiong Luo

Unsupervised image registration commonly adopts U-Net style networks to predict dense displacement fields in the full-resolution spatial domain. For high-resolution volumetric image data, this process is however resource-intensive and…

Computer Vision and Pattern Recognition · Computer Science 2023-07-07 Xi Jia , Joseph Bartlett , Wei Chen , Siyang Song , Tianyang Zhang , Xinxing Cheng , Wenqi Lu , Zhaowen Qiu , Jinming Duan
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