English
Related papers

Related papers: On Finding Gray Pixels

200 papers

We present a novel iterative scheme for restoring uneven illumination in grayscale images. Our approach solves, at each global iteration, a nonlinear elliptic equation for an auxiliary field $u$ and then updates the illumination via an…

Analysis of PDEs · Mathematics 2025-06-17 Dragos-Patru Covei

Ghost imaging (GI) forms images from intensity-correlation data collected by a single-pixel detector, decoupling illumination and sensing. Since its quantum-photon origins, the technique has evolved through classical pseudothermal,…

Optics · Physics 2025-12-17 Tong Tian , Sukyoon Oh , Christian Spielmann

This paper discusses the noisy phase retrieval problem: recovering a complex image signal with independent noise from quadratic measurements. Inspired by the dark fringes shown in the measured images of the array detector, a novel phase…

Computer Vision and Pattern Recognition · Computer Science 2022-04-14 Wen-Kai Yu , An-Dong Xiong , Xu-Ri Yao , Guang-Jie Zhai , Qing Zhao

Blind image quality assessment (BIQA) is a task that predicts the perceptual quality of an image without its reference. Research on BIQA attracts growing attention due to the increasing amount of user-generated images and emerging mobile…

Image and Video Processing · Electrical Eng. & Systems 2023-03-24 Zhanxuan Mei , Yun-Cheng Wang , Xingze He , Yong Yan , C. -C. Jay Kuo

Image segmentation is one of the principal approaches of image processing. The choice of the most appropriate Binarization algorithm for each case proved to be a very interesting procedure itself. In this paper, we have done the comparison…

Computer Vision and Pattern Recognition · Computer Science 2011-11-22 Aroop Mukherjee , Soumen Kanrar

Ghost imaging can capture 2D images with a point detector instead of an array sensor. It therefore offers a solution to the challenge of building area format sensors in wavebands where such sensors are difficult and expensive to produce and…

Image and Video Processing · Electrical Eng. & Systems 2022-08-09 Baolei Liu , Fan Wang , Chaohao Chen , Fei Dong , David McGloin

A novel method to convert color/multi-spectral images to gray-level images is introduced to increase the performance of document binarization methods. The method uses the distribution of the pixel data of the input document image in a color…

Computer Vision and Pattern Recognition · Computer Science 2013-06-27 Reza Farrahi Moghaddam , Shaohua Chen , Rachid Hedjam , Mohamed Cheriet

Recent advances in implicit neural representations and differentiable rendering make it possible to simultaneously recover the geometry and materials of an object from multi-view RGB images captured under unknown static illumination.…

Computer Vision and Pattern Recognition · Computer Science 2022-04-15 Yuanqing Zhang , Jiaming Sun , Xingyi He , Huan Fu , Rongfei Jia , Xiaowei Zhou

We present a method to separate a single image captured under two illuminants, with different spectra, into the two images corresponding to the appearance of the scene under each individual illuminant. We do this by training a deep neural…

Computer Vision and Pattern Recognition · Computer Science 2019-04-24 Zhuo Hui , Ayan Chakrabarti , Kalyan Sunkavalli , Aswin C. Sankaranarayanan

Global Illumination (GI) is of utmost importance in the field of photo-realistic rendering. However, its computation has always been very complex, especially diffuse GI. State of the art real-time GI methods have limitations of different…

Graphics · Computer Science 2020-07-30 Jinkai Hu , Milo Yip , G. Elias Alonso , Shihao Gu , Xiangjun Tang , Xiaogang Jin

In this work, we propose a CNN-based approach to estimate the spectral reflectance of a surface and the spectral power distribution of the light from a single RGB image of a V-shaped surface. Interreflections happening in a concave surface…

Computer Vision and Pattern Recognition · Computer Science 2019-01-30 Rada Deeb , Joost Van De Weijer , Damien Muselet , Mathieu Hebert , Alain Tremeau

Casual photography is often performed in uncontrolled lighting that can result in low quality images and degrade the performance of downstream processing. We consider the problem of estimating surface normal and reflectance maps of scenes…

Computer Vision and Pattern Recognition · Computer Science 2020-12-14 Zhihao Xia , Jason Lawrence , Supreeth Achar

Despite recent success of object detectors using deep neural networks, their deployment on safety-critical applications such as self-driving cars remains questionable. This is partly due to the absence of reliable estimation for detectors'…

Computer Vision and Pattern Recognition · Computer Science 2020-06-17 Yongxin Wang , Duminda Wijesekera

In inverse rendering, accurately modeling visibility and indirect radiance for incident light is essential for capturing secondary effects. Due to the absence of a powerful Gaussian ray tracer, previous 3DGS-based methods have either…

Computer Vision and Pattern Recognition · Computer Science 2025-03-25 Chun Gu , Xiaofei Wei , Zixuan Zeng , Yuxuan Yao , Li Zhang

Digital images contain a lot of redundancies, therefore, compression techniques are applied to reduce the image size without loss of reasonable image quality. Same become more prominent in the case of videos which contains image sequences…

Computer Vision and Pattern Recognition · Computer Science 2023-05-17 Nisar Ahmed , Hafiz Muhammad Shahzad Asif , Hassan Khalid

Lighting design and modelling or industrial applications like luminaire planning and commissioning rely heavily on time consuming manual measurements or on physically coherent computational simulations. Regarding the latter,standard…

Computer Vision and Pattern Recognition · Computer Science 2018-12-10 Theodore Tsesmelis , Irtiza Hasan , Marco Cristani , Fabio Galasso , Alessio Del Bue

Shadows are common aspect of images and when left undetected can hinder scene understanding and visual processing. We propose a simple yet effective approach based on reflectance to detect shadows from single image. An image is first…

Computer Vision and Pattern Recognition · Computer Science 2018-07-13 Sri Kalyan Yarlagadda , Fengqing Zhu

Light interreflections occurring in a concave object generate a color gradient which is characteristic of the object's spectral reflectance. In this paper, we use this property in order to estimate the spectral reflectance of matte,…

Computer Vision and Pattern Recognition · Computer Science 2018-07-04 Rada Deeb , Damien Muselet , Mathieu Hebert , Alain Tremeau

Despite recent advances in image enhancement, it remains difficult for existing approaches to adaptively improve the brightness and contrast for both low-light and normal-light images. To solve this problem, we propose a novel 2D histogram…

Computer Vision and Pattern Recognition · Computer Science 2022-09-15 Xiaomeng Wu , Yongqing Sun , Akisato Kimura , Kunio Kashino

Imaging is a sophisticated process combining a plenty of photovoltaic conversions, which lead to some spectral signatures beyond visual perception in the final images. Any manipulation against an original image will destroy these signatures…

Computer Vision and Pattern Recognition · Computer Science 2020-04-10 Zhe Shen , Peng Sun , Yubo Lang , Lei Liu , Silong Peng