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Y. L. Chan - IEEE Xplore Author Profile

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Fingerprint-based indoor positioning systems are being explored to aid in location-based services due to their robustness in non-line-of-sight conditions. Current systems utilize high-dimensional radio frequency (HDRF) fingerprints, such as Wi-Fi channel state information, to achieve higher positioning precision. Since data acquisition is labor-intensive, researchers proposed to enrich the dataset...Show More
Different from natural videos, where artifacts distributed evenly, the artifacts of compressed screen content videos mainly occur in the edge areas. Besides, these videos often exhibit abrupt scene switches, resulting in noticeable distortions in video reconstruction. Existing multiple-frame models using a fixed range of neighbor frames face challenges in effectively enhancing frames during scene ...Show More
Compressed screen content videos often exhibit artifacts in edge areas and suffer from distortions during scene switches, where content abruptly changes between frames. Existing multi-frame models, which use a fixed range of neighbor frames, struggle with these switches. To address this, we propose a novel method that effectively handles scene switches. Our approach utilizes Long-term Feature Extr...Show More
Screen content video (SCV) has drawn much more attention than ever during the COVID-19 period and has evolved from a niche to a mainstream due to the recent proliferation of remote offices, online meetings, shared-screen collaboration, and gaming live streaming. Therefore, quality assessments for screen content media are highly demanded to maintain service quality recently. Although many practical...Show More
Object detection plays a crucial role in scene understanding and has extensive practical applications. In the field of remote sensing object detection, both detection accuracy and robustness are of significant concern. Existing methods heavily rely on sophisticated adversarial training strategies that tend to improve robustness at the expense of accuracy. However, detection robustness is not alway...Show More
Recently, some transfer learning-based methods have been adopted in video quality assessment (VQA) to compensate for the lack of enormous training samples and human annotation labels. But these methods induce a domain gap between source and target domains, resulting in a sub-optimal feature representation that deteriorates the accuracy. This paper proposes the optimized quality feature learning vi...Show More
Nowadays, video quality assessment (VQA) plays a vital role in video-related industries to predict human perceived video quality to maintain the quality of service. Although many deep neural network-based VQA methods have been proposed, the robustness and performance are limited by small scale of available human-label data. Recently, some transfer learning-based methods and pre-trained models in o...Show More
Video quality enhancement methods are of great significance in reducing the artifacts of decoded videos in the High Efficiency Video Coding (HEVC). However, existing methods mainly focus on improving the quality of natural sequences, not for screen content sequences that have drawn more attention than ever due to the demands of remote desktops and online meetings. Different from the natural sequen...Show More
In recent years, the video quality enhancement techniques have made a significant breakthrough, from the traditional methods, such as deblocking filter (DF) and sample additive offset (SAO), to deep learning-based approaches. While screen content coding (SCC) has become an important extension in High Efficiency Video Coding (HEVC), the existing approaches mainly focus on improving the quality of n...Show More
Surveillance cameras, which are often placed in unconstrained environments, can be tampered with due to many environmental and human factors. It results in degraded surveillance videos and affects the subsequent smart applications that make use of the videos in decision-making. Blur anomaly is one of the most typical problems in those videos, which have the target objects in the videos significant...Show More
Super-Resolving (SR) video is more challenging compared with image super-resolution because of the demanding computation time. To enlarge a low-resolution video, the temporal relationship among frames must be fully exploited. We can model video SR as a multi-frame SR problem and use deep learning methods to estimate the spatial and temporal information. This paper proposes a lighter residual netwo...Show More
Face hallucination or super-resolution is a practical application of general image super-resolution which has been recently studied by many researchers. The challenge of good face hallucination comes from a variety of poses, illuminations, facial expressions, and other degradations. In many proposed methods, researchers resolve it by using a generative neural network to reduce the perceptual loss ...Show More
To improve the coding performance of depth maps, 3D-HEVC includes several new depth intra coding tools at the expense of increased complexity due to a flexible quadtree Coding Unit/Prediction Unit (CU/PU) partitioning structure and a huge number of intra mode candidates. Compared to natural images, depth maps contain large plain regions surrounded by sharp edges at the object boundaries. Our obser...Show More
There is a great leap in objective accuracy on image super-resolution, which recently brings a new challenge on image super-resolution with larger up-scaling (e.g. 4×) using pixel based distortion for measurement. This causes over-smooth effect which cannot grasp well the perceptual similarity. The advent of generative adversarial networks makes it possible super-resolve a low-resolution image to ...Show More
Screen content coding (SCC) is an extension to High Efficiency Video Coding (HEVC) used to compress screen content videos. Besides the conventional intra (INTRA) mode, new coding tools, intra block copy (IBC), palette (PLT) modes, and adaptive color-space transform (ACT) are introduced to encode screen content (SC) such as texts and graphics. However, the use of IBC, PLT and ACT increases the enco...Show More
Screen content coding have been supported recently in Versatile Video Coding (VVC) to improve the coding efficiency of screen content videos by adopting new coding modes which are dedicated to screen content video compression. Two new coding modes called Intra Block Copy (IBC) and Palette (PLT) are introduced. However, the flexible quad-tree plus multi-type tree (QTMT) coding structure for coding ...Show More
Screen content coding (SCC) is developed to encode screen content videos, and it is an extension of High Efficiency Video Coding (HEVC). Since screen content videos contain computer-generated content that shows special characteristics, SCC adopts the new Intra Block Copy mode and Palette mode besides the HEVC based Intra mode to improve the coding efficiency. However, the exhaustive mode searching...Show More
Recent advances in display, networking, and computing technologies have resulted in changing industry focus towards 360-degree/omnidirectional images as witnessed by increased interest in virtual reality (VR) and augmented reality (AR). Numerous curves are generated for 360-degree images due to the lens curvature and projection format. However, in High Efficiency Video Coding (HEVC), the conventio...Show More
Benefited from the deep learning, image Super-Resolution has been one of the most developing research fields in computer vision. Depending upon whether using a discriminator or not, a deep convolutional neural network can provide an image with high fidelity or better perceptual quality. Due to the lack of ground truth images in real life, people prefer a photo-realistic image with low fidelity to ...Show More
Screen content coding (SCC) is an extension of high efficiency video coding (HEVC), and it is developed to improve the coding efficiency of screen content videos by adopting two new coding modes: Intra Block Copy (IBC) and Palette (PLT). However, the flexible quadtree-based coding tree unit (CTU) partitioning structure and various mode candidates make the fast algorithms of the SCC extremely chall...Show More
Screen content coding (SCC) is an extension of high efficiency video coding by adopting new coding modes to improve the coding efficiency of SCC at the expense of increased complexity. This paper proposes an online-learning approach for fast mode decision and coding unit (CU) size decision in SCC. To make a fast mode decision, the corner point is first extracted as a unique feature in screen conte...Show More
The screen content coding (SCC) extension of high efficiency video coding (HEVC) improves coding gain for screen content videos by introducing two new coding modes, namely, intra block copy (IBC) and palette (PLT) modes. However, the coding gain is achieved at the increased cost of computational complexity. In this paper, we propose a decision tree-based framework for fast intra mode decision by i...Show More
Deep learning based image Super-Resolution (SR) has shown rapid development due to its ability of big data digestion. Generally, deeper and wider networks can extract richer feature maps and generate SR images with remarkable quality. However, the more complex network we have, the more time consumption is required for practical applications. It is important to have a simplified network for efficie...Show More
This paper reviews the AIM 2019 challenge on extreme image super-resolution, the problem of restoring of rich details in a low resolution image. Compared to previous, this challenge focuses on an extreme upscaling factor, ×16, and employs the novel DIVerse 8K resolution (DIV8K) dataset. This report focuses on the proposed solutions and final results. The challenge had 2 tracks. The goal in Track 1...Show More
The screen content coding (SCC) extension of High Efficiency Video Coding adopts three modes, the conventional intra mode of HEVC, the new intra block copy mode and palette mode, to improve the coding performance of screen content videos. However, the exhaustive search for the optimal mode among the three mode candidates brings significant computational burden to a SCC encoder. This paper proposes...Show More