Browsing by Author "Chen, Ling-Hwei"

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A FAST MULTISPRITE GENERATOR WITH NEAR-OPTIMUM CODING BIT-RATE
(2009-03-01)
Kuo, I-Sheng
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Chen, Ling-Hwei
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資訊工程學系
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Department of Computer Science
Sprite coding, which can increase the coding efficiency of backgrounds greatly, is a novel technology adopted in MPEG-4 object-based coding. Due to the geometric transformation applied to each nonreference frame in the procedure of sprite coding, the generated sprite is distorted and the available view angles relative to the reference frame are restricted. These problems can be resolved by using multiple sprites. An optimal multisprite generator has been proposed by Farin et al., but the optimal method requires high computation in the sprite coding cost. To treat this disadvantage, a fast multisprite partition algorithm is proposed in this paper based on frame translations and scalings. The proposed algorithm divides a video sequence into several subsequences, and a sprite is generated from each subsequence. The experimental results show that the executing speed of the proposed method is increased by 10 to 190 times than the optimal method, with the total size of generated sprites is slightly higher and the qualities of generated sprites are preserved.
A high visual quality sprite generator using intelligent blending without segmentation masks
(2006-12-01)
Kuo, I-Sheng
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Chen, Ling-Hwei
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資訊工程學系
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Department of Computer Science
The sprite generator introduced in MPEG-4 blends frames by averaging, which will make places, that are always occupied by moving objects, look blurred. Thus, providing segmented masks for moving objects is suggested. Several researchers have employed automatic segmentation methods to produce moving object masks. Based on these masks, they used a reliability-based blending strategy to generate sprites. Since perfect segmentation is impossible, some ghost-like shadows will appear in the generated sprite. To treat this problem, in this paper, an intelligent blending strategy without needing segmentation masks is proposed. It is based on the fact that for each point in the generated sprite, the corresponding pixels in most frames belong to background and only few belong to moving objects. A counting schema is provided to make only background points participate in average blending. The experimental result shows that the visual quality of the generated sprite using the proposed blending strategy is close to that using manually segmented masks and is better than that generated by Lu-Gao-Wu method. No ghostlike shadows are produced. Furthermore, a uniform feature point extraction method is proposed to increase the precision of global motion estimation, the effectiveness of this part is presented by showing the comparison results with other existing method.
A Multilayer Steganography Method with High Embedding Efficiency for Palette Images
(2020-07-01)
Wu, Han-Yan
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Chen, Ling-Hwei
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Ching, Yu-Tai
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資訊工程學系
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Department of Computer Science
Embedding efficiency is an important issue in steganography methods. Matrix embedding (1, n, h) steganography was proposed by Crandall to achieve high embedding efficiency for palette images. This paper proposes a steganography method based on multilayer matrix embedding for palette images. First, a parity assignment is provided to increase the image quality. Then, a multilayer matrix embedding (k, 1, n, h) is presented to achieve high embedding efficiency and capacity. Without modifying the color palette, hk secret bits can be embedded into n pixels by changing at most k pixels. Under the same capacity, the embedding efficiency of the proposed method is compared with that of pixel-based steganography methods. The comparison indicates that the proposed method has higher embedding efficiency than pixel-based steganography methods. The experimental results also suggest that the proposed method provides higher image quality than some existing methods under the same embedding efficiency and capacity.
A NEW STEGANOGRAPHY METHOD VIA VARIOUS ANIMATION TIMING EFFECTS IN POWERPOINT FILES
(2009)
Jing, Min-Quan
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Yang, Wen-Chao
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Chen, Ling-Hwei
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資訊工程學系
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Department of Computer Science
In this paper, a new steganography method that hides message via various animation timing effects in a PowerPoint file is proposed. The animation effects are designed for the presenter to emphasis the key points, control the flow or enrich the interesting in presentation. Then the animation timing effect is the speed, time and repeat control part of animation effect. It is worth mentioning that adding animation effects does not change any content of the slides in the PowerPoint file. In contrast to other steganography methods, using various animation effects to hide message not only livens up on-screen presentations, but also keeps the real content of the PowerPoint file intact.
A novel approach for semantic event extraction from sports webcast text
(2014-08-01)
Chen, Chun-Min
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Chen, Ling-Hwei
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資訊工程學系
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Department of Computer Science
Semantic event extraction is helpful for video annotation and retrieval. For sports video, most previous works detect events by video content itself. Some useful external knowledge has been researched recently. In this paper, we proposed an unsupervised approach to extract semantic events from sports webcast text. First, unrelated words in the descriptions of webcast text are filtered out, and then the filtered descriptions are clustered into significant event categories. Finally, the keywords for each event category are extracted. According to our experimental results, the proposed approach actually extracts significant text events, which can be used for further video indexing and summarization. Furthermore, we also provide a hierarchical searching scheme for text event retrieval.
A novel approach for semantic event extraction from sports webcast text
(2014-08-01)
Chen, Chun-Min
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Chen, Ling-Hwei
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資訊工程學系
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Department of Computer Science
Semantic event extraction is helpful for video annotation and retrieval. For sports video, most previous works detect events by video content itself. Some useful external knowledge has been researched recently. In this paper, we proposed an unsupervised approach to extract semantic events from sports webcast text. First, unrelated words in the descriptions of webcast text are filtered out, and then the filtered descriptions are clustered into significant event categories. Finally, the keywords for each event category are extracted. According to our experimental results, the proposed approach actually extracts significant text events, which can be used for further video indexing and summarization. Furthermore, we also provide a hierarchical searching scheme for text event retrieval.
A NOVEL METHOD FOR SHOEPRINTS RECOGNITION AND CLASSIFICATION
(2009)
Jing, Min-Quan
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Ho, Wei-Jong
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Chen, Ling-Hwei
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資訊科學與工程研究所
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Institute of Computer Science and Engineering
In this paper, we present a method for automatically classifying/recognizing the shoeprint images based on the outsole pattern. Shoeprints are distinctive patterns often found at crime scenes that can provide valuable forensic evidence. Directionality is the most obvious feature in these shoeprints. For extracting features corresponding to the directionality, co-occurrence matrices, Fourier transform, and a directional matrix are applied to the shoeprint image. With the stage of principal component transform, the method is invariant to rotation and translation variance. Experimental results demonstrate the performance of the method.
A novel method for slow motion replay detection in broadcast basketball video
(2015-11-01)
Chen, Chun-Min
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Chen, Ling-Hwei
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資訊工程學系
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Department of Computer Science
Slow motion replays are valuable for sports video analysis. Many methods for slow motion replay detection have been proposed, and they are classified into two categories. One assumes that a replay is sandwiched by a pair of visually similar special digital video effects, but the assumption is not always true in basketball videos. The other analyzes replay features to distinguish replay segments from non-replay segments. The results are not satisfactory since some features (e.g. dominant color of sports field) are not applicable for basketball. Most replay detectors focus on soccer videos. In this paper, we propose a novel idea to detect slow motion replays in basketball videos. The existence of scoreboard is referred to filter large amount of non-replay frames, this improves detection accuracy. After scoreboard frame filtering, every consecutive non-scoreboard frame sequence bounded by scoreboard frames are considered as a non-scoreboard segment. Characteristics of replays and non-replays are observed to create features, which can be used to detect replays and prune non-replays from non-scoreboard segments. Experimental results show that the proposed replay detection method is applicable for both kinds of basketball videos with/without TV commercials. As compared with previous researches for basketball videos, our method presents the superior performance.
A novel steganography method via various animation effects in powerpoint files
(2008)
Yang, Wen-Chao
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Chen, Ling-Hwei
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資訊工程學系
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Department of Computer Science
In this paper, a novel steganography method that hides message via various animation effects in a PowerPoint rile is proposed. The animation effects are designed for the presenter to emphasis the key points, control the flow or enrich the interesting in presentation. It is worth mentioning that adding animation effects does not change any content of the slides in the PowerPoint file. In contrast to other steganography methods, using various animation effects to hide message not only livens up on-screen presentations, but also keeps the real content of the PowerPoint rile intact.
A perfect maze based steganographic method
(2010-12-01)
Lee, Hui-Lung
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Lee, Chia-Feng
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Chen, Ling-Hwei
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資訊工程學系
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Department of Computer Science
In steganography, several different types of media have been used as carriers, such as images, audios and video streams, to hide secret data. Nevertheless, various novel media and applications have been developed due to the rapid growth of internet. In this paper, we select maze games as carrier media to conceal secret data. The original idea of embedding data in a maze is proposed by Niwayama et al. Their method has two disadvantages. One is the very small embedding capacity; the other is that the stego maze is not perfect. Here, we propose an improved algorithm for increasing the embedding capacity and preserving the "perfect" property. (C) 2010 Elsevier Inc. All rights reserved.
A REAL-TIME UNUSUAL VOICE DETECTOR BASED ON NURSING AT HOME
(2009)
Jing, Min-Quan
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Wang, Chao-Chun
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Chen, Ling-Hwei
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資訊工程學系
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Department of Computer Science
In this paper, we will propose a method to detect an unusual voice for nursing system. Based on the healthy condition of a person, we define four kinds of unusual voices including cough, groan, wheeze and cry for help. When the person nursed sends out the unusual voices, we judge that his health condition have a doubt, and need someone to pay attention. In order to detect the unusual voices, we extract five features on audio waveform, including the number of segmented parts, duration of waveform, mean of volume, zero crossing rate and correlation. Experimental results show that the detection rate is 94%similar to 97% for these four kinds of unusual voices. In false alarm, there are only 0.08% of wrong rates.
A robust watermarking method for stereo-pair images based on unmatched block bitmap
(2016-03)
Ou, Zhan-He
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Chen, Ling-Hwei
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資訊工程學系
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Department of Computer Science
A stereo-pair image contains two views of a scene called the left image and right image. This paper proposes a novel watermarking method for stereo-pair images. The proposed method is divided into three parts: watermark creation, watermark embedding, and watermark verification. Because the left and right images of a stereo pair appear to be highly similar, a robust watermark is first created based on a feature map that records the positions of the unmatched blocks between these two images. The created watermark is then embedded into the left image by swapping the AC coefficients. A feature map is first extracted from the watermarked stereo-pair image during the verification process. Subsequently, the embedded watermark is extracted from the watermarked left image and converted into an estimated feature map. Ownership is proved when the feature map and the estimated feature map are similar. Experimental results indicate that the proposed method exhibits greater robustness against malicious attacks and produces less distortion than existing methods do.
A steganographic method based on tetris games
(2014-08-20)
Ou, Zhan-He
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Chen, Ling-Hwei
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資訊工程學系
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Department of Computer Science
Although various steganographic methods have been proposed that use distinct cover media, using games to hide data remains a recent development. The study presents a steganographic method based on online Tetris games, in which secret messages are embedded using a generated tetrimino sequence. Each time a person plays an online Tetris game, a new tetrimino sequence should be generated. The proposed method meets this requirement, generating a distinct stegoed tetrimino sequence for each game played. In addition, the study presents a scenario and a simulator for the proposed method. Theoretical proof and experimental results are provided to demonstrate that the proposed method is undetectable. (C) 2013 Elsevier Inc. All rights reserved.
A steganographic method via various animations in PowerPoint files
(2015-02-01)
Yang, Wen-Chao
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Chen, Ling-Hwei
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資訊工程學系
;
Department of Computer Science
In a PowerPoint file, animation effects are used to emphasize objects, timing effects are used to control the presentation time, and slide transition effects are used to highlight particular slides. Thus, using various effects can make the presentation of a PowerPoint file more colorful and attractive. In this paper, we propose a steganographic method to embed message in a PowerPoint file via various effects. In contrast to other steganographic methods, we not only hide message naturally but also keep the content of the cover media intact. Furthermore, the proposed method can resist the format conversion attack. The experiment result demonstrates that the proposed method is undetectable under some visual and statistical attacks.
An efficient algorithm for solving nonograms
(2011-08-01)
Yu, Chiung-Hsueh
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Lee, Hui-Lung
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Chen, Ling-Hwei
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資訊工程學系
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Department of Computer Science
Nonogram is one of logical games popular in Japan and Netherlands. Solving nonogram is a NP-complete problem. There are some related papers proposed. Some use genetic algorithm (GA), but the solution may get stuck in local optima. Some use depth first search (DFS) algorithm, the execution speed is very slow. In this paper, we propose a puzzle solving algorithm to treat these problems. Based on the fact that most of nonograms are compact and contiguous, some logical rules are deduced to paint some cells. Then, we use the chronological backtracking algorithm to solve those undetermined cells and logical rules to improve the search efficiently. Experimental results show that our algorithm can solve nonograms successfully, and the processing speed is significantly faster than that of DFS. Moreover, our method can determine that a nonogram has no solution.
An improved method for hiding data in a maze
(2008-01-01)
Lee, Hui-Lung
;
Lee, Chia-Feng
;
Chen, Ling-Hwei
;
資訊工程學系
;
Department of Computer Science
It is common to use image, audio, video streams as host media in steganography. In this paper, we will select mazes as host media to avoid the problem "robustness" concerned by classic host media. The original idea of embedding data in a maze is proposed by Niwayama et al. Their method has two disadvantages. One is very small embedding capacity; the other is that the embedded maze is not perfect. Here, we present an improved algorithm to increase the embedding capacity. Meanwhile, we can still preserve the property "perfect", that is, we can keep the imperceptible property required in steganography.
An improved method for hiding data in a maze
(2008-01-01)
Lee, Hui-Lung
;
Lee, Chia-Feng
;
Chen, Ling-Hwei
;
交大名義發表
;
National Chiao Tung University
It is common to use image, audio, video streams as host media in steganography. In this paper, we will select mazes as host media to avoid the problem "robustness" concerned by classic host media. The original idea of embedding data in a maze is proposed by Niwayama et al. Their method has two disadvantages. One is very small embedding capacity; the other is that the embedded maze is not perfect. Here, we present an improved algorithm to increase the embedding capacity. Meanwhile, we can still preserve the property "perfect", that is, we can keep the imperceptible property required in steganography.
An interactive flower image recognition system
(2011-05-01)
Hsu, Tzu-Hsiang
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Lee, Chang-Hsing
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Chen, Ling-Hwei
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多媒體工程研究所
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Institute of Multimedia Engineering
In this paper, we present an interactive system for recognizing flower images taken by digital cameras. The proposed system provides an interactive interface allowing each user to draw an appropriate bounding window that contains the interested flower region. Then, a flower boundary tracing method is developed to extract the flower region as accurately as possible. In addition to the color and shape features of the whole flower region, the color and shape features of the pistil/stamen area will also be used to represent the flower characteristics more precisely. Experiments conducted on two distinct databases consisting of 24 species and 102 species have shown that our proposed system outperforms other approaches in terms of the recognition rate.
Image Contrast Enhancement Using Classified Virtual Exposure Image Fusion
(2012-11-01)
Lee, Chang-Hsing
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Chen, Ling-Hwei
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Wang, Wei-Kang
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資訊工程學系
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Department of Computer Science
In our daily life, digital cameras and smart phones have been widely used to take pictures. However, digital cameras and smart phones have a limited dynamic range, which is much lower than that human eyes can perceive. Thus, the photographs taken in high dynamic range scenes often exhibit under-exposure or over-exposure artifacts in shadow or highlight regions. In this study, an image fusion based approach, called classified virtual exposure image fusion (CVEIF), is proposed for image enhancement. First, a function imitating the F-stop concept in photography is designed to generate several virtual images having different intensity. Then, a classified image fusion method, which blends pixels in distinct luminance classes using different fusion functions, is proposed to produce a fused image in which every image region is well exposed. Experimental results on four different kinds of generic images, including a normal image, a low-contrast images, a backlight image, and a dark scene image, have shown that the proposed CVEIF approach produced more pleasingly enhanced images than other methods(1).
Image enhancement approach using the just-noticeable-difference model of the human visual system
(2012-07-01)
Lee, Chang-Hsing
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Lin, Pei-Ying
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Chen, Ling-Hwei
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Wang, Wei-Kang
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多媒體工程研究所
The low-contrast images taken by digital cameras or camera phones are not always satisfactory due to the limitation of the capturing devices or improper illumination/exposure conditions. Conventional image contrast enhancement methods may either fail to produce satisfactory and undistorted images, or they cannot improve every region of interest appropriately, especially faces. In this paper, a histogram equalization (HE) approach exploiting the just-noticeable-difference (JND) model of the human visual system (HVS), denoted by JND-HE, is proposed for generic image contrast enhancement. Further, the proposed JND-HE approach is combined with the exposure correction (EC) method (denoted by JND-HE-EC) for face image enhancement. The proposed JND-HE-EC approach can improve the contrast in face regions and provide proper illumination in the background. Experimental results on both generic images and faces have shown that our proposed approach can produce more pleasing and appealing enhanced images than other methods. (C) 2012 SPIE and IS&T. [DOI: 10.1117/1.JEI.21.3.033007]