Browsing by Author "Hang, Hsueh-Ming"

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A context adaptive bit-plane coder with maximum-likelihood-based stochastic bit-reshuffling technique for scalable video coding
(2006-08-01)
Peng, Wen-Hsiao
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Chiang, Tihao
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Hang, Hsueh-Ming
;
Lee, Chen-Yi
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電子工程學系及電子研究所
In this paper, we propose a context adaptive bit-plane coding (CABIC) with a stochastic bit reshuffling (SBR) scheme to deliver higher coding efficiency and better subjective quality for fine granular scalable (FGS) video coding. Traditional bit-plane coding in FGS algorithm suffers from poor coding efficiency and subjective quality. To improve coding efficiency, our CABIC constructs context models based on both the energy distribution in a block and the spatial correlations in the adjacent blocks. Moreover, it exploits the context across bit-planes to save side information. To improve subjective quality, our SBR reorders the coefficient bits by their estimated rate-distortion performance. Particularly, we model transform coefficients with Laplacian distributions and incorporate them into the context probability models for content-aware parameter estimation. Moreover, our SBR is implemented with a dynamic priority management that uses a low-complexity dynamic memory organization. Experimental results show that our CABIC improves the PSNR by 0.5 similar to 1.0 dB at medium and high bit rates. While maintaining similar or even higher coding efficiency, our SBR improves the subjective quality.
A digital content protection scheme using MPEG-21 REL with applications to DVB systems
(2006)
Shih, Ying-Tzu
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Chang, Feng-Cheng
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Hang, Hsueh-Ming
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電子工程學系及電子研究所
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Department of Electronics Engineering and Institute of Electronics
In a digital TV system, the Conditional Access (CA) system is essential to protect programs from unauthorized access. However, the encryption technique alone is not sufficient to protect or control the use of contents after decryption. To provide flexible and complete Digital Rights Management (DRM) protection on the Digital Video Broadcasting (DVB) programs, we propose a method that adapts the MPEG-21 REL technology and integrates it into a DVB-T system. By extending the Service Information (SI) section of a DVB stream to include an REL license, the transmitted content can be conveniently consumed and legally protected. Our design is verified by an experimental hardware system. The results show that the proposed method can provide both the conditional access functionality and the usage control of broadcasted contents.
A genetic rhombus pattern search for block motion estimation
(2007)
Tsai, Jang-Jer
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Hang, Hsueh-Ming
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電子工程學系及電子研究所
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Department of Electronics Engineering and Institute of Electronics
Pattern-based block motion estimation (PBME) is one of the most effective yet computational intensive tools in digital video coding standards. Many PBME algorithms have been proposed but few papers have investigated in depth the fundamental characteristics of various PBME algorithms. Why one search algorithm outperforms the others? In this paper, we propose a systematic approach to examine this problem. The minimal numbers of search points achievable by a PBME algorithm form a discrete function in the search area. We analyze this so-called weighting function and suggest an ideal target. Then, we design a genetic rhombus pattern search (GRPS) to match this ideal weighting function. Simulations show that comparing to the other popular search algorithms, GRPS reduces the average search points for more than 20% while it maintains a similar level of coded image PSNR quality.
A rate-distortion analysis on motion prediction efficiency and mode decision for scalable wavelet video coding
(2010-11-01)
Tsai, Chia-Yang
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Hang, Hsueh-Ming
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電子工程學系及電子研究所
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Department of Electronics Engineering and Institute of Electronics
A rate-distortion model for describing the motion prediction efficiency in interframe wavelet video coding is proposed in this paper. Different from the non-scalable video coding, the scalable wavelet video coding needs to operate under multiple bitrate conditions and it has an open-loop structure. The conventional Lagrangian multiplier, which is widely used to solve the rate-distortion optimization problems in video coding, does not fit well into the scalable wavelet structure. In order to find the rate-distortion trade-off due to different bits allocated to motion and textual information, we suggest a motion information gain (MIG) metric to measure the motion prediction efficiency. Based on this metric, a new cost function for mode decision is proposed. Compared with the conventional Lagrangian method, our experiments show that the proposed method is less extraction-bitrate dependent and generally improves both the PSNR performance and the visual quality for the scalability cases. (c) 2010 Elsevier Inc. All rights reserved.
A rate-distortion analysis on motion prediction efficiency and mode decision for scalable wavelet video coding
(2010-11-01)
Tsai, Chia-Yang
;
Hang, Hsueh-Ming
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
A rate-distortion model for describing the motion prediction efficiency in interframe wavelet video coding is proposed in this paper. Different from the non-scalable video coding, the scalable wavelet video coding needs to operate under multiple bitrate conditions and it has an open-loop structure. The conventional Lagrangian multiplier, which is widely used to solve the rate-distortion optimization problems in video coding, does not fit well into the scalable wavelet structure. In order to find the rate-distortion trade-off due to different bits allocated to motion and textual information, we suggest a motion information gain (MIG) metric to measure the motion prediction efficiency. Based on this metric, a new cost function for mode decision is proposed. Compared with the conventional Lagrangian method, our experiments show that the proposed method is less extraction-bitrate dependent and generally improves both the PSNR performance and the visual quality for the scalability cases. (c) 2010 Elsevier Inc. All rights reserved.
A reduced-complexity image coding scheme using decision-directed wavelet-based contourlet transform
(2012-10-01)
Hung, Chao-Hsiung
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Hang, Hsueh-Ming
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電子工程學系及電子研究所
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Department of Electronics Engineering and Institute of Electronics
Recently the wavelet-based contourlet transform (WBCT) is adopted for image coding because it matches better image textures of different orientations. However, its computational complexity is very high. In this paper, we propose three tools to enhance the WBCT coding scheme, in particular, on reducing its computational complexity. First, we propose short-length 2-D filters for directional transform. Second, the directional transform is applied to only a few selected subbands and the selection is done by a mean-shift-based decision procedure. Third, we fine-tune the context tables used by the arithmetic coder in WBCT coding to improve coding efficiency and to reduce computation. Simulations show that, at comparable coded image quality, the proposed scheme saves over 92% computing time of the original WBCT scheme. Comparing to the conventional 2-D wavelet coding schemes, it produces clearly better subjective image quality. (c) 2012 Elsevier Inc. All rights reserved.
A relevance feedback image retrieval scheme using multi-instance and pseudo image concepts
(2006-05-01)
Chang, Feng-Cheng
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Hang, Hsueh-Ming
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電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
Content-based image search has long been considered a difficult task. Making correct conjectures on the user intention (perception) based on the query images is a critical step in the content-based search. One key concept in this paper is how we find the user preferred low-level image characteristics from the multiple positive samples provided by the user. The second key concept is how we generate a set of consistent "pseudo images" when the user does not provide a sufficient number of samples. The notion of image feature stability is thus introduced. The third key concept is how we use negative images as pruning criterion. In realizing the preceding concepts, an image search scheme is developed using the weighted lowlevel image features. At the end, quantitative simulation results are used to show the effectiveness of these concepts.
A study on the meta-data design for long-term digital multimedia preservation
(2008)
Chang, Feng-Cheng
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Chang, Chin-Yuan
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Hang, Hsueh-Ming
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電子工程學系及電子研究所
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Department of Electronics Engineering and Institute of Electronics
Due to the fast growth of multimedia content, the digital preservation emerges as an important technology that prolongs the life of digital objects. For audio-visual contents, we face the obsolescence problem in both supporting hardware/software and data representation formats. Migration strategy is a solution for achieving high-quality archival and easy access. In this paper, we investigate the concepts and structures in the Open Archival Information System (DAIS) and the MPEG-21 Digital Item Adaptation (DIA) specifications. By addressing the issues for a long-term audio-visual preservation system, we propose a combined meta-data scheme to record both the management and technical procedures and parameters. The detailed meta-data that keep the history of evolution versions can be used for subsequent migrations. We also implement a prototype system to realize our design. At the end of this study, we identify additional issues for future improvements.
A switchable DRM structure for embedded device
(2007)
Chang, Feng-Cheng
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Wu, Chiao-Lin
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Hang, Hsueh-Ming
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電子工程學系及電子研究所
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Department of Electronics Engineering and Institute of Electronics
Digital Rights Management (DRM) is a concept for controlling the distribution and consumption of digital media. As embedded multimedia devices are becoming popular, there are strong demands for the light-weight DRM systems that can run smoothly in a resource-limited environment. Due to the variety of embedded devices, an ideal DRM system should be platform independent and inter-operable. These requirements, however, often increase the software complexity, which is undesirable to an embedded device. In this paper, a switchable DRM system is thus proposed. It integrates the concept of downloadable tools and the OMA architecture to provide a balance between flexibility and complexity. We also implement the scheme on an embedded evaluation board to demonstrate its feasibility.
A TRIANGULAR-WARPING BASED VIEW SYNTHESIS SCHEME WITH ENHANCED ARTIFACT REDUCTION FOR FTV
(2011)
Li, Chao-Hsuan
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Tsai, Jang-Jer
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Hang, Hsueh-Ming
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電子工程學系及電子研究所
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Department of Electronics Engineering and Institute of Electronics
View synthesis is one key enabling technology for free-viewpoint television (FTV). It uses multiple image frames and depth maps to generate the intermediate view at nearly any arbitrary viewpoint. In our proposed 2-stage algorithm, we adopt triangular warping with a new feature point extraction scheme for the first texture mapping stage. The new feature point extraction scheme uses the correlation between the image luminance gradients and the depth map. In the second stage, we use the median filtering and the multi-band blending technique to reduce the artifacts on the image object boundaries caused by the discontinuity and the imperfection of depth maps. Experimental results show that our proposed method produces better visual quality in comparison with a latest view synthesis algorithm.
Acceleration and implementation of JPEG2000 encoder on TI DSP platform
(2007)
Liu, Chien-Chih
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Hang, Hsueh-Ming
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電子工程學系及電子研究所
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Department of Electronics Engineering and Institute of Electronics
JPEG2000 provides excellent compression performance and fine granularity scalability but at the cost of high computational complexity. We propose two speed-up techniques and use the TI DSP optimization tools to accelerate the Tier1 module. We eliminate the unnecessary checking cycles by recording the NBC (Need-to-Be-Coded) samples on a list. Furthermore, the sample index is reordered to facilitate fast execution. In the DSP implementation of the proposed methods, we use code acceleration techniques, cache memory allocation, and TI DSP compiler-level optimization tools. Even when the original program is compiled with the same DSP optimization tools and proper cache assignment, our fast algorithm can still reduce the computation by 45%.
Adding selective enhancement in scalable video coding for region-of-interest functionality
(2006)
Peng, Wen-Hsiao
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Chiang, Tihao
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Hang, Hsueh-Ming
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交大名義發表
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National Chiao Tung University
In this paper, we propose a lossless, graceful, and arbitrary-shaped region-of-interest (ROI) functionality for the scalable video coding in MPEG-4 Part 10 Amd. 1. Specifically, we propose a prioritized block coding scheme and a layer remapping technique. Within an enhancement layer, the prioritized block coding reshuffles the transform coefficients for ROI. Moreover, the layer remapping technique prioritizes different ROI among enhancement layers. For graceful and arbitrary-shaped properties, additional syntax are coded at the levels of slice, layer, and macroblock. To minimize overhead, an efficient representation for priority information is proposed. Experimental results show that our schemes can offer the ROI functionality over a wide range of bit rates while maintaining coding efficiency.
Advanced video technologies and applications for H.264/AVC and beyond
(2006)
Yang, Jar-Ferr (Kevin)
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Hang, Hsueh-Ming
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Steinbach, Eckehard
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Sun, Ming-Ting
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電子工程學系及電子研究所
Advances in the scalable amendment of H.264/AVC
(2007-01-01)
Huang, Hsiang-Chun
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Peng, Wen-Hsiao
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Chiang, Tihao
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Hang, Hsueh-Ming
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交大名義發表
To support clients with diverse capabilities, ISO/IEC MPEG and ITU-T form a Joint Video Team (JVT) to develop a scalable video coding (SVC) technology that uses single bitstream to provide multiple spatial, temporal, and quality (SNR) resolutions, thus satisfying low-complexity and low-delay constraints. It is an amendment of the emerging standard H.264/AVC and it provides an H.264/AVC-compatible base layer and a fully scalable enhancement layer, which can be truncated and extracted on-the-fly to obtain a preferred spatio-temporal and quality resolution. An overview of the adopted key technologies in the SVC and a comparison in coding efficiency with H.264/AVC are presented.
An Image Based Overexposed Taillight Detection Method for Frontal Vehicle Detection in Night Vision
(2016)
Chien, Chun-Liang
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Hang, Hsueh-Ming
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Tseng, Din-Chang
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Chen, Yong-Sheng
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交大名義發表
To achieve the goal of frontal vehicle detection in night-driving condition, we propose an effective method to detect the red taillights of vehicles. The challenge is that the taillight images captured with automatic exposure typically are overexposed, which makes red color segmentation often erroneous. Instead of customizing the camera hardware to tackle this problem, we combine morphological and logical operations to extract the overexposed region in taillights, which leads to a much more reliable taillight detection scheme. Then, we develop a robust pairing process that clusters two taillight candidates into a pair that represents a vehicle. Several criteria are considered in the pairing process, including the similarities of area, shape, and height of a pair of lights. In addition, we include the temporal consistency criterion; that is, a pair of taillights should be continually detected for a certain duration of time. An energy function is used to aggregate these criteria together. Our experiments show that both the missing and false detection rates are lower than 1.5%.
An improved presentation method for relevance feedback in a content-based image retrieval system
(2008)
Chang, Feng-Cheng
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Hang, Hsueh-Ming
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電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
Content-based image retrieval (CBIR) has been adopted as a complementary technique to the keyword-based image search. Relevance feedback (RFB) is considered as an effective means to bridge the gap between the designated features and the run-time semantics on a CBIR system. Like many other interactive system, a good user interface, which in RFB is mainly the presentation of the query results, is an important factor that affects the quality of feedbacks. By incorporating the multidimensional scaling (MDS) and the outlier detection techniques, we propose a method of presenting multiple image icons in this paper. It preserves the high-dimensional distance information and shows the selected images at proper 2D locations. Viewing the matched images with distance cues, users are able to give effective and productive feedbacks. We design and implement this presentation system and show some subjective results at the end.
Background Modeling Using Depth Information
(2014)
Liu, Yu-Lun
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Hang, Hsueh-Ming
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電子工程學系及電子研究所
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Department of Electronics Engineering and Institute of Electronics
This paper mainly focuses on creating a global background model of a video sequence using the depth maps together with the RGB pictures. The first key concept is the near objects block the scenes at the back. With the aid of depth information, we can identify the closer moving objects. Secondly, we develop a recursive algorithm that iterates between the depth map and color pictures. Comparing to the existing schemes, our proposed method can produce better quality background images and it improves the background depth map at the same time.
Consistent Picture Quality Control Strategy for Dependent Video Coding
(2009-05-01)
Huang, Kao-Lung
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Hang, Hsueh-Ming
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電子工程學系及電子研究所
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Department of Electronics Engineering and Institute of Electronics
Typically, a video rate control algorithm minimizes the average distortion (denoted as MINAVE) at the cost of large temporal quality variation, especially for videos with high motion and frequent scene changes. To alleviate the negative effect on subjective video quality, another criterion that restricts a small amount of quality variation among adjacent frames is preferred for practical applications. As pointed out by [20], although some existing proposals can produce consistent quality videos, they often fail to fully utilize the available bits to minimize the global total distortion. In this paper, we would like to achieve the triple goal of consistent quality video, minimizing the total distortion, and meeting the bit budget strictly all at the same time on the interframe dependent coding structure. Two approaches are taken to accomplish this goal. In the first algorithm, a trellis-based framework is proposed. One of our contributions is to derive an equivalent condition between the distortion minimization problem and the budget minimization problem. Second, our trellis state (tree node) is defined in terms of distortion, which facilitates the consistent quality control. Third, by adjusting one key parameter in our algorithm, a solution in between the MINAVE and the constant quality criteria can be obtained. The second approach is to combine the Lagrange multipliers method together with the consistent quality control. The PSNR performance is degraded slightly but the computational complexity is significantly reduced. Simulation results show that both our approaches produce a much smaller PSNR variation at a slight average PSNR loss as compared to the MPEG JM rate control. When they are compared to the other consistent quality proposals, only the proposed algorithms can strictly meet the target bit budget requirement (no more, no less) and produce the largest average PSNR at a small PSNR variation.
Decision-directed Adaptive Wavelet Image Coding with Diretional Decomposition
(2009)
Hung, Chao-Hsiung
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Hang, Hsueh-Ming
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電子工程學系及電子研究所
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Department of Electronics Engineering and Institute of Electronics
In this paper, we e propose an adaptive wavelet coding scheme. A decision method is designed to identify whether the LH, HL, and HH wavelet subbands are suitable for directional decomposition. The basic concept behind this decision method is to detect the large impulses in the frequency domain. The transformed data are coded by the bit-plane arithmetic code to achieve scalability. Experimental results show that this adaptive scheme has better results than the 1-D wavelet transform and the original wavelet-based contourlet scheme that applies the directional transform to all the LH, HL and HH subbands.*
Depth Coding using Coded Boundary Patterns
(2012)
Yang, Kai-Hsiang
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Hang, Hsueh-Ming
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電子工程學系及電子研究所
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Department of Electronics Engineering and Institute of Electronics
The depth information plays an essential role in the virtual-view (or free-viewpoint) 3D video systems. In this paper, we propose a new algorithm to code a depth map for the purpose of virtual view synthesis. The idea is to use H. 264/AVC to represent the rough shape (including depth values) of a depth map and then additional information is transmitted to improve the depth values around the object boundaries. The complete encoding and decoding simulation system was built on the H. 264/AVC JM 18.0 platform. In our experiments, three tools can be turned on individually and thus four coding modes are defined and tested. Our data show that these proposed tools offer advantages in either coding efficiency or image quality improvement and some tools work best on simple images while the others work best on complex images. With proper parameter setting, the overall quality of virtual view rendering is noticeably improved.