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We discuss a general framework for recovering edges in piecewise smooth functions with finitely many jump discontinuities, where $[f](x):=f(x+)-f(x-) \neq 0$. Our approach is based on two main aspects--localization using appropriate…

Numerical Analysis · Mathematics 2025-10-20 Anne Gelb , Eitan Tadmor

Microlocal analysis provides deep insight into singularity structures and is often crucial for solving inverse problems, predominately, in imaging sciences. Of particular importance is the analysis of wavefront sets and the correct…

Image and Video Processing · Electrical Eng. & Systems 2019-07-11 Héctor Andrade-Loarca , Gitta Kutyniok , Ozan Öktem , Philipp Petersen

In this paper, we propose a new two-dimensional directional discrete wavelet transform that can decompose an image into 12 multiscale directional edge components. The proposed transform is designed in a fully discrete setting and thus is…

Signal Processing · Electrical Eng. & Systems 2021-12-03 Kensuke Fujinoki , Keita Ashizawa

Wavefront estimation is an essential component of adaptive optics where the goal is to recover the underlying phase from its Fourier magnitude. While this may sound identical to classical phase retrieval, wavefront estimation faces more…

Signal Processing · Electrical Eng. & Systems 2025-04-15 Nicholas Chimitt , Ali Almuallem , Qi Guo , Stanley H. Chan

Image restoration is a class of important tasks that emerges from a wide range of scientific disciplines. It has been noticed that most practical images can be modeled as a composition from a sparse singularity set (edges) where the image…

Functional Analysis · Mathematics 2024-01-08 Bin Dong , Ting Lin , Zuowei Shen , Peichu Xie

In the field of computer vision, the numerical encoding of 3D surfaces is crucial. It is classical to represent surfaces with their Signed Distance Functions (SDFs) or Unsigned Distance Functions (UDFs). For tasks like representation…

Computer Vision and Pattern Recognition · Computer Science 2024-05-07 Virgile Foy , Fabrice Gamboa , Reda Chhaibi

Wavefront sensing is a widely-used non-interferometric, single-shot, and quantitative technique providing the spatial-phase of a beam. The phase is obtained by integrating the measured wavefront gradient. Complex and random wavefields…

Optics · Physics 2021-07-09 Tengfei Wu , Pascal Berto , Marc Guillon

It is known that the continuous wavelet transform of a function $f$ decays very rapidly near the points where $f$ is smooth, while it decays slowly near the irregular points. This property allows one to precisely identify the singular…

Functional Analysis · Mathematics 2007-05-23 Gitta Kutyniok , Demetrio Labate

Sleeve functions are generalizations of the well-established ridge functions that play a major role in the theory of partial differential equation, medical imaging, statistics, and neural networks. Where ridge functions are non-linear,…

Numerical Analysis · Mathematics 2021-09-15 Robert Beinert

Continuous wavefront sensing benefits space observatories in on-orbit optical performance maintenance. To measure the phase of a wavefront, phase retrieval is an attractive technique as it uses multiple point spread function (PSF) images…

Instrumentation and Methods for Astrophysics · Physics 2024-09-17 Hyukmo Kang , Kyle Van Gorkom , Meghdoot Biswas , Daewook Kim , Ewan S. Douglas

In this letter, a new approach to perform edge detection is presented using an all-dielectric CMOS-compatible metasurface. The design is based on guided-mode resonance which provides a high quality factor resonance to make the edge…

Although diffusion models are rising as a powerful solution for blind face restoration, they are criticized for two problems: 1) slow training and inference speed, and 2) failure in preserving identity and recovering fine-grained facial…

Computer Vision and Pattern Recognition · Computer Science 2024-03-20 Yunqi Miao , Jiankang Deng , Jungong Han

In this manuscript we demonstrate a method to reconstruct the wavefront of focused beams from a measured diffraction pattern behind a diffracting mask in real-time. The phase problem is solved by means of a neural network, which is trained…

Image and Video Processing · Electrical Eng. & Systems 2021-04-07 Jonathon White , Sici Wang , Wilhelm Eschen , Jan Rothhardt

Image processing and edge detection are at the core of several newly emerging technologies, such as augmented reality, autonomous driving and more generally object recognition. Image processing is typically performed digitally using…

Change detection in remote sensing imagery plays a vital role in various engineering applications, such as natural disaster monitoring, urban expansion tracking, and infrastructure management. Despite the remarkable progress of deep…

Computer Vision and Pattern Recognition · Computer Science 2025-08-08 Xiaoyang Zhang , Guodong Fan , Guang-Yong Chen , Zhen Hua , Jinjiang Li , Min Gan , C. L. Philip Chen

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

Although a lateral-shear interferometer is robust against optical component vibrations, its interferogram provides information about differential wavefronts rather than the wavefronts themselves, resulting in the loss of specific frequency…

The ocean front has an important impact in many areas, it is meaningful to obtain accurate ocean front positioning, therefore, ocean front detection is a very important task. However, the traditional edge detection algorithm does not detect…

Computer Vision and Pattern Recognition · Computer Science 2019-09-18 Qingyang Li , Guoqiang Zhong , Cui Xie

In this paper, a multi-resolution feature extraction algorithm for face recognition is proposed based on two-dimensional discrete wavelet transform (2D-DWT), which efficiently exploits the local spatial variations in a face image. For the…

Computer Vision and Pattern Recognition · Computer Science 2011-10-10 Hafiz Imtiaz , Shaikh Anowarul Fattah

Contour detection has been a fundamental component in many image segmentation and object detection systems. Most previous work utilizes low-level features such as texture or saliency to detect contours and then use them as cues for a…

Computer Vision and Pattern Recognition · Computer Science 2015-04-24 Gedas Bertasius , Jianbo Shi , Lorenzo Torresani
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