Siwei Ma

article

Alternating Current‐Driven Oxide Powder Electroluminescent Device Employing Vertically Aligned ZnO Nanowire Array

Siwei Ma, Sirui Tan, Adrian H. Kitai

physica status solidi (RRL) – Rapid Research Letters > 13 > 12 > n/a - n/a

A novel type of AC‐driven oxide powder electroluminescent (EL) device is demonstrated. The device is based on stable heterogeneous junctions between Mn²⁺‐activated zinc germanate (Zn₂GeO₄:Mn) oxide phosphor and a vertically aligned ZnO nanowire array. The ZnO nanowire array is synthesized on an ITO‐coated glass substrate via a hydrothermal growth method. A stable phosphor–nanowire junction is formed...

article

A CuO Nanowire‐Based Alternating Current Oxide Powder Electroluminescent Device with High Stability

Siwei Ma, Zhilin Peng, Adrian H. Kitai

Angewandte Chemie > 130 > 35 > 11437 - 11442

An AC‐driven powder electroluminescent (EL) device has been achieved by constructing a CuO nanowire–Zn₂GeO₄:Mn phosphor heterogeneous junction. The CuO nanowires enhance the local electric field, resulting in electroluminescence of an oxide‐based phosphor in EL devices owing to field injection at the nanowire tips. The CuO nanowire array was synthesized by an in situ thermal oxidation method at 400...

article

A CuO Nanowire‐Based Alternating Current Oxide Powder Electroluminescent Device with High Stability

Siwei Ma, Zhilin Peng, Adrian H. Kitai

Angewandte Chemie International Edition > 57 > 35 > 11267 - 11272

An AC‐driven powder electroluminescent (EL) device has been achieved by constructing a CuO nanowire–Zn₂GeO₄:Mn phosphor heterogeneous junction. The CuO nanowires enhance the local electric field, resulting in electroluminescence of an oxide‐based phosphor in EL devices owing to field injection at the nanowire tips. The CuO nanowire array was synthesized by an in situ thermal oxidation method at 400...

article

Probabilistic Decision Based Block Partitioning for Future Video Coding

Zhao Wang, Shiqi Wang, Jian Zhang, Shanshe Wang, more

IEEE Transactions on Image Processing > 2018 > 27 > 3 > 1475 - 1486

In the latest Joint Video Exploration Team development, the quadtree plus binary tree (QTBT) block partitioning structure has been proposed for future video coding. Compared to the traditional quadtree structure of High Efficiency Video coding (HEVC) standard, QTBT provides more flexible patterns for splitting the blocks, which results in dramatically increased combinations of block partitions and...

article

Reducing Image Compression Artifacts by Structural Sparse Representation and Quantization Constraint Prior

Chen Zhao, Jian Zhang, Siwei Ma, Xiaopeng Fan, more

IEEE Transactions on Circuits and Systems for Video Technology > 2017 > 27 > 10 > 2057 - 2071

The block discrete cosine transform (BDCT) has been widely used in current image and video coding standards, owing to its good energy compaction and decorrelation properties. However, because of independent quantization of DCT coefficients in each block, BDCT usually gives rise to visually annoying blocking compression artifacts, especially at low bit rates. In this paper, to reduce blocking artifacts...

article

Nonlocal Gradient Sparsity Regularization for Image Restoration

Hangfan Liu, Ruiqin Xiong, Xinfeng Zhang, Yongbing Zhang, more

IEEE Transactions on Circuits and Systems for Video Technology > 2017 > 27 > 9 > 1909 - 1921

Total variation (TV) regularization is widely used in image restoration to exploit the local smoothness of image content. Essentially, the TV model assumes a zero-mean Laplacian distribution for the gradient at all pixels. However, real-world images are nonstationary in general, and the zero-mean assumption of pixel gradient might be invalid, especially for regions with strong edges or rich textures...

article

High-Efficiency Image Coding via Near-Optimal Filtering

Xinfeng Zhang, Shiqi Wang, Yabin Zhang, Weisi Lin, more

IEEE Signal Processing Letters > 2017 > 24 > 9 > 1403 - 1407

Wiener filtering, which has been widely used in the field of image restoration, is statistically optimal in the sense of mean square error. The adaptive loop filter in video coding inherits the design of Wiener filters, and has been proved to achieve significant improvement on compression performance by reducing coding artifacts and providing high-quality references for subsequent frames. To further...

article

Hybrid Laplace Distribution-Based Low Complexity Rate-Distortion Optimized Quantization

Jing Cui, Shanshe Wang, Shiqi Wang, Xinfeng Zhang, more

IEEE Transactions on Image Processing > 2017 > 26 > 8 > 3802 - 3816

Rate distortion optimized quantization (RDOQ) is an efficient encoder optimization method that plays an important role in improving the rate-distortion (RD) performance of the high-efficiency video coding (HEVC) codecs. However, the superior performance of RDOQ is achieved at the expense of high computational complexity cost in two stages RD minimization, including the determination of optimal quantized...

chapter

Intelligent analysis oriented surveillance video coding

Lei Zhao, Xiang Zhang, Xinfeng Zhang, Shiqi Wang, more

2017 IEEE International Conference on Multimedia and Expo (ICME) > 37 - 42

2017 IEEE International Conference on Multimedia and Expo (ICME)

The fast growth of surveillance video big data presents great challenges to the video coding technology. Most existing video coding techniques target for visual quality optimization, while the ultimate utility of surveillance videos mainly lies in intelligent analyses, e.g., pedestrian detection and vehicle tracking. In view of this, we aim at proposing an efficient, standard-compatible and simultaneously...

chapter

Image restoration via multi-scale non-local total variation regularization

Jing Mu, Ruiqin Xiong, Xiaopeng Fan, Siwei Ma

2017 IEEE International Conference on Multimedia and Expo (ICME) > 205 - 210

2017 IEEE International Conference on Multimedia and Expo (ICME)

Total-variation (TV) regularization is widely adopted in image restoration problems to exploit the local smoothness of image. However, traditional TV regularization only models the sparsity of image gradient at the original scale. This paper introduces a multi-scale TV regularization method which models the image gradient sparsity at different scales, and constrains the gradient magnitude of different...

chapter

Dynamic backlight scaling considering ambient luminance for mobile energy saving

Wei Sun, Guangtao Zhai, Xiongkuo Min, Yutao Liu, more

2017 IEEE International Conference on Multimedia and Expo (ICME) > 25 - 30

2017 IEEE International Conference on Multimedia and Expo (ICME)

The mobile video playback involves many subsystems of the devices such as computing, rendering and displaying subsystems. Among all subsystems, the displaying subsystem accounts for at least 38% of all consumed power, and it can be up to 68% with the maximum backlight brightness. What is more, lots of people watch videos via mobile devices in various situations, where the ambient luminance condition...

article

Video Compressive Sensing Reconstruction via Reweighted Residual Sparsity

Chen Zhao, Siwei Ma, Jian Zhang, Ruiqin Xiong, more

IEEE Transactions on Circuits and Systems for Video Technology > 2017 > 27 > 6 > 1182 - 1195

The compressive sensing (CS) theory indicates that robust reconstruction of signals can be obtained from far fewer measurements than those required by the Nyquist–Shannon theorem. Thus, CS has great potential in video acquisition and processing, considering that it makes the subsequent complex data compression unnecessary. In this paper, we propose a novel algorithm for effectively reconstructing...

article

Chemical vapor deposition-based growth of aligned ZnO nanowires on polycrystalline Zn₂GeO₄:Mn substrates

Siwei Ma, Adrian H. Kitai

Journal of Materials Science > 2017 > 52 > 16 > 9324-9334

ZnO nanowires have been grown on polycrystalline Zn₂GeO₄:Mn substrates for the first time using a chemical vapor deposition method. Both Zn and ZnO sources were used to supply Zn vapor in the growth process of ZnO nanowires. The Zn₂GeO₄:Mn substrates were prepared using solid-state ceramic synthesis methods, and average grain sizes of ~1 μm were achieved. The nanowires of diameters in the range of...

chapter

An adaptive and low-complexity all-zero block detection for HEVC encoder

Jing Cui, Ruiqin Xiong, Falei Luo, Shanshe Wang, more

2017 IEEE International Symposium on Circuits and Systems (ISCAS) > 1 - 4

2017 IEEE International Symposium on Circuits and Systems (ISCAS)

To improve the detection accuracy of SAD or SATD based threshold and save the time cost of RDO determination, we proposed an All Zero Block (AZB) detection method by adaptively searching the maximum transform coefficient amplitude in low frequency of TU after conventional SATD detection was failed. The experimental results show that our algorithm can achieve around 39% transform and quantization time-saving...

chapter

Fast intra coding unit size decision for HEVC with GPU based keypoint detection

Falei Luo, Shanshe Wang, Siwei Ma, Nan Zhang, more

2017 IEEE International Symposium on Circuits and Systems (ISCAS) > 1 - 4

2017 IEEE International Symposium on Circuits and Systems (ISCAS)

In this paper, a fast intra Coding Unit (CU) size decision framework based on keypoint detection on Graphic Processing Unit (GPU) is proposed. In this framework, firstly the original frames are sent to GPU and then keypoint detection is conducted with numerous threads, which is able to avoid bringing in additional computational complexity even in realtime systems. Then, based on the keypoint distribution,...

chapter

Content Based Fast Intra Coding for AVS2

Junru Li, Falei Luo, Yun Zhou, Shanshe Wang, more

2017 IEEE Third International Conference on Multimedia Big Data (BigMM) > 94 - 97

2017 IEEE Third International Conference on Multimedia Big Data (BigMM)

AVS2 is the new generation of video coding standard developed by the Audio Video Coding Standard Working Group of China. In analogies to HEVC/H.265, a more flexible CU (coding unit), PU (prediction unit) and TU (transform unit) based coding structure is adopted to represent and organize the coding data. For intra coding, AVS2 adopts quad tree based partition coding structure on CU level, and one CU...

chapter

Band-Wise Adaptive Sparsity Regularization for Quantized Compressed Sensing Exploiting Nonlocal Similarity

Jing Mu, Ruiqin Xiong, Xinfeng Zhang, Siwei Ma

2017 Data Compression Conference (DCC) > 452

2017 Data Compression Conference (DCC)

The theory of compressive sensing (CS) has attracted considerable research interests from signal and image processing communities. And in practice, because of the considerations of data storage and transmission, scalar quantization is necessary to be implemented on the CS measurements. In this paper, we propose an adaptive bandwise sparsity regularization to handle the recovery problem of quantized...

chapter

Globally Variance-Constrained Sparse Representation for Rate-Distortion Optimized Image Representation

Xiang Zhang, Siwei Ma, Zhouchen Lin, Jian Zhang, more

2017 Data Compression Conference (DCC) > 380 - 389

2017 Data Compression Conference (DCC)

Sparse representation is efficient to approximately recover signals by a linear composition of a few bases from an over-complete dictionary. However, in the scenario of data compression, its efficiency and popularity are hindered due to the extra overhead for encoding the sparse coefficients. Therefore, how to establish an accurate rate model in sparse coding and dictionary learning becomes meaningful,...

chapter

Wireless Image SoftCast Using Compressive Gradient

Hangfan Liu, Ruiqin Xiong, Xiaopeng Fan, Siwei Ma, more

2017 Data Compression Conference (DCC) > 451

2017 Data Compression Conference (DCC)

Based on observations that the visual quality has strong correlation with image gradients, gradient based image SoftCast (G-Cast) advocates to convey visual information by delivering image gradients. In G-Cast, both horizontal gradients and vertical gradients needs to be transmitted, even if the channel bandwidth is insufficient. This paper propose to send out the random projection measurements of...

chapter

Effective Quadtree Plus Binary Tree Block Partition Decision for Future Video Coding

Zhao Wang, Shiqi Wang, Jian Zhang, Shanshe Wang, more

2017 Data Compression Conference (DCC) > 23 - 32

2017 Data Compression Conference (DCC)

Block partition structure has been recognized as a crucial module in video coding scheme. Recently, a quadtree plus binary tree (QTBT) block partition structure has been proposed in the Joint Video Exploration Team (JVET) development. Compared to the quadtree structure in HEVC, QTBT can achieve better coding performance with hugely increased encoding complexity. Here, we propose an effective QTBT...

INFONA - science communication portal

Search results for: Siwei Ma

Alternating Current‐Driven Oxide Powder Electroluminescent Device Employing Vertically Aligned ZnO Nanowire Array

A CuO Nanowire‐Based Alternating Current Oxide Powder Electroluminescent Device with High Stability

A CuO Nanowire‐Based Alternating Current Oxide Powder Electroluminescent Device with High Stability

Probabilistic Decision Based Block Partitioning for Future Video Coding

Reducing Image Compression Artifacts by Structural Sparse Representation and Quantization Constraint Prior

Nonlocal Gradient Sparsity Regularization for Image Restoration

High-Efficiency Image Coding via Near-Optimal Filtering

Hybrid Laplace Distribution-Based Low Complexity Rate-Distortion Optimized Quantization

Intelligent analysis oriented surveillance video coding

Image restoration via multi-scale non-local total variation regularization

Dynamic backlight scaling considering ambient luminance for mobile energy saving

Video Compressive Sensing Reconstruction via Reweighted Residual Sparsity

Chemical vapor deposition-based growth of aligned ZnO nanowires on polycrystalline Zn₂GeO₄:Mn substrates

An adaptive and low-complexity all-zero block detection for HEVC encoder

Fast intra coding unit size decision for HEVC with GPU based keypoint detection

Content Based Fast Intra Coding for AVS2

Band-Wise Adaptive Sparsity Regularization for Quantized Compressed Sensing Exploiting Nonlocal Similarity

Globally Variance-Constrained Sparse Representation for Rate-Distortion Optimized Image Representation

Wireless Image SoftCast Using Compressive Gradient

Effective Quadtree Plus Binary Tree Block Partition Decision for Future Video Coding

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