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IEEE International Symposium on Signal Processing and Information Technology (ISSPIT)

作者： Turuk, M. P. Dhande, A. P. Kalgaonkar, P. P. Pune Inst Comp Technol Pune Satara Rd Pune 411043 Maharashtra India

ISBN: (纸本)9781479918119

In an e-Health environment medical image protection and authentication are extremely important as medical image and medical data are distributed over electronic network. Research has shown that medical image watermarking is relevant process for enhancing data security and content authentication. Medical image has most sensitive data hence while adding the external data it is important to preserve the perceptual integrity of an image. This Paper presents comparative analysis of interleaving patient information in the form text and electrocardiograph (ECG) signal in medical images, using Discrete Fourier Transform (DFT) and Discrete Cosine Transform (DCT). To provide the security, text data and ECG signal are encrypted before interleaving in the frequency domain. Predicative coding techniques like adaptive delta modulation and differential pulse code modulation are used for ECG signal encryption and compression. The quantitative assessment of the quality of watermarked images is carried out using peak signal to noise ratio (PSNR) and normalized mean square error (NRMSE). The experimental results on different medical image modalities (MRI, MRA, CT) are tabulated, which shows that the DFT based interleaving algorithm is efficient as it preserves imperceptibility better than DCT.

关键词： Medical image watermarking DFT DCT Adaptive delta modulation differential pulse code modulation RSA Encryption

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pulsed Terahertz Time-Domain Communication

Pulsed Terahertz Time-Domain Communication

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IEEE Global Communications Conference (GLOBECOM)

作者： Moshir, Farnoosh Singh, Suresh Portland State Univ Dept Comp Sci Portland OR 97207 USA

ISBN: (纸本)9781479935123

We consider the problem of building a communication channel based on modulation of terahertz pulses. Given the constrained propagation properties of this spectrum, one of our goals is to determine the potential data rates achievable for different environmental conditions. To do this, we first present a detailed channel model based on measurements carried out on a terahertz time-domain system. We next simulate frequency-domain differential quadrature phase shift keying (FD-DQPSK) and Adaptive FD-DQPSK pulse modulation schemes. Finally, we simulate communication for different cities in winter and summer seasons where the primary channel impairment includes humidity. We show that data rates of well over 1 Tbit/s are achievable for all cases for distances of up to three meters. We also examine the error behavior of this transmission channel as a function of humidity and frequency band.

关键词： differential phase shift keying differential pulse code modulation humidity radiocommunication adaptive FD-DQPSK pulse modulation schemes channel impairment channel model communication channel data rates error behavior frequency band frequency-domain differential quadrature phase shift keying pulsed terahertz time-domain communication terahertz time-domain system transmission channel Absorption Bit error rate Cities and towns Frequency modulation Humidity Receivers

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Comparison of Low-Complexity Image Compression Algorithms for Analog Circuit Implementation 14

Comparison of Low-Complexity Image Compression Algorithms fo...

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14th International Workshop on Cellular Nanoscale Networks and their Applications (CNNA)

作者： Oliveira, Fernanda D. V. R. Gomes, Jose Gabriel R. C. Petraglia, Antonio Univ Fed Rio de Janeiro COPPE PEE BR-21941972 Rio De Janeiro RJ Brazil

ISBN: (纸本)9781479960071

CMOS imaging hardware has become a widespread research topic due to its flexibility in allowing focal-plane, pixel-level signal processing. In a number of vision chips, dedicated image processing techniques are carried out in the analog domain to extract relevant information. Analog processing leads to time and power consumption savings, especially if combined with parallel processing, which is conventionally used because of the inherently parallel nature of imaging arrays. We focus on the focal-plane analog implementation of an image compression algorithm, based on differential pulse-code modulation, linear transform, and vector quantization. In a prototype fabricated in a 0.35 mu m CMOS technology, the texture information inside each pixel block in a 32 x 32 array was locally encoded by inner products applied to 4 x 4 pixel neighborhoods followed by vector quantization. In this paper, a new chip implemented in a 0.18 mu m CMOS technology incorporating improvements suggested by the previous prototype experimental evaluation is presented. We highlight a 5 dB increase in image quality, confirmed by numerical simulations, at the expense of modest increase in complexity and bit rate. Cascode current mirrors are used in parts of the circuitry and pixel non-linearity models are made available to the decoder.

关键词： image compression algorithm analog circuits analog domain Vector quantization image processing techniques pixel CMOS technology PARALLEL PROCESSING (COMPUTERS) Electric circuits decoders Power consumption differential pulse code modulation

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ERROR RESILIENCE ENHANCEMENT FOR A ROBUST ADPCM AUDIO CODING SCHEME

ERROR RESILIENCE ENHANCEMENT FOR A ROBUST ADPCM AUDIO CODING...

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IEEE International Conference on Acoustics, Speech and Signal Processing

作者： Gediminas Simkus Martin Holters Udo Zolzer Helmut Schmidt University -- University of the Federal Armed Forces Department of Signal Processing and Communications Holstenhofweg 85 Hamburg Germany

ISBN: (纸本)9781479928941

This work comprises an extension of a backward adaptive quantizer which is employed together with a robust lattice predictor in an ADPCM coding scheme. Predictors of the ADPCM audio coding schemes are often considered as the part most sensitive to transmission errors. Nevertheless, a single transmission error causes a short destabilization of the adaptive quantizer at the decoder side. Therefore, this destabilization boosts the deviation of the prediction filter at the decoder from the encoder side. Desired damping of the quantizer shortens synchronization periods. However, damping leads to degradation of the quantizer's adaptation properties and consequently to a decrease in audio quality. We show that the transmission of the quantizer's envelope to the decoder in short intervals and in combination with envelope error detector reduces the impairment of the reconstructed audio signal in noisy transmissions. An objective audio quality evaluation confirms significant quality improvement at BER higher than 10~(-4) and no quality degradation if an ideal channel is employed.

关键词： quantizer differential pulse code modulation Predictive filter decoders Audio Quality Improvement Transmission errors ideal channel audio signals absorption of shock Resilience Noise

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LOSSLESS COMPRESSION OF MEDICAL IMAGES BASED ON HEVC INTRA CODING

LOSSLESS COMPRESSION OF MEDICAL IMAGES BASED ON HEVC INTRA C...

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IEEE International Conference on Acoustics, Speech and Signal Processing

作者： Victor Sanchez Joan Bartrina-Rapesta Dept. of Computer Science University of Warwick United Kingdom Dept. of Information and Communications Engineering Universitat Autonoma de Barcelona Spain

ISBN: (纸本)9781479928941

The recent introduction of the High Efficiency Video Coding (HEVC) standard provides opportunities to improve medical image compression in picture archiving and communications systems. In this paper, we propose improvements to the HEVC intra coding process for lossless compression of grayscale anatomical medical images, which are characterized by their large amount of edges. Specifically, we propose alternative angular and planar prediction modes that are based on sample-wise differential pulse code modulation (DPCM) with an increased range of directionalities. We also propose an implementation of the DPCM decoding process that maintains the block-wise coding structure of HEVC. Evaluation results on various medical images show that the proposed DPCM modes efficiently predict the large amount of edges in these images achieving bit-rate savings of up to 15%.

关键词： differential pulse code modulation Medical imaging images Picture Archiving and Communication Systems Image compression Data compression lossless compression

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Bit plane modification for improving MSE-near optimal DPCM-based block truncation coding

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DIGITAL SIGNAL PROCESSING 2013年第4期23卷 1171-1180页

作者： Choi, Kang-Sun Korea Univ Technol & Educ Sch Elect Elect & Commun Engn Cheonan 330708 Chungnam South Korea

A hybrid method of block truncation coding (BTC) and differential pulse code modulation (DPCM) offers better visual quality than the standard BTC for small block sizes due to its inherent multitone representation. Recently, a two-level quantizer design method has been proposed to increase the coding performance of the DPCM-BTC framework. However, the design method is near optimal in the sense that its coding performance depends on the initial bit plane patterns. In this paper, we propose a bit plane modification (BPM) algorithm to achieve further performance improvement. The BPM algorithm, inspired by error diffusion, effectively distributes large quantization error at a certain pixel to its neighboring pixels having small quantization errors by changing partial bit patterns. Experimental results show that the proposed algorithm successfully achieves much higher coding performance than various conventional BTC methods. The average PSNR performance of the proposed method is 2.31 dB, 5.15 dB, and 5.15 dB higher than that of BTC, DPCM-BTC, and a recently developed BTC scheme using error diffusion and bilateral filtering, respectively. (C) 2013 Elsevier Inc. All rights

关键词： Quantizer optimization differential pulse code modulation Block truncation coding Error diffusion

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Estimation-Theoretic Approach to Delayed Decoding of Predictively Encoded Video Sequences

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IEEE TRANSACTIONS ON IMAGE PROCESSING 2013年第3期22卷 1175-1185页

作者： Han, Jingning Melkote, Vinay Rose, Kenneth Univ Calif Santa Barbara Dept Elect & Comp Engn Santa Barbara CA 93106 USA

Current video coders employ predictive coding with motion compensation to exploit temporal redundancies in the signal. In particular, blocks along a motion trajectory are modeled as an auto-regressive (AR) process, and it is generally assumed that the prediction errors are temporally independent and approximate the innovations of this process. Thus, zero-delay encoding and decoding is considered efficient. This paper is premised on the largely ignored fact that these prediction errors are, in fact, temporally dependent due to quantization effects in the prediction loop. It presents an estimation-theoretic delayed decoding scheme, which exploits information from future frames to improve the reconstruction quality of the current frame. In contrast to the standard decoder that reproduces every block instantaneously once the corresponding quantization indices of residues are available, the proposed delayed decoder efficiently combines all accessible (including any future) information in an appropriately derived probability density function, to obtain the optimal delayed reconstruction per transform coefficient. Experiments demonstrate significant gains over the standard decoder. Requisite information about the source AR model is estimated in a spatio-temporally adaptive manner from a bit-stream conforming to the H.264/AVC standard, i.e., no side information needs to be sent to the decoder in order to employ the proposed approach, thereby compatibility with the standard syntax and existing encoders is retained.

关键词： Delayed decoding differential pulse code modulation estimation-theoretic prediction motion trajectory predictive coding

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A near-lossless approach for medical image compression using visual quantisation and block-based DPCM

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INTERNATIONAL JOURNAL OF BIOMEDICAL ENGINEERING AND TECHNOLOGY 2013年第1期13卷 17-29页

作者： Cyriac, Marykutty Chellamuthu, C. Jerusalem Coll Engn Dept ECE Chennai 600100 Tamil Nadu India RMK Engn Coll Dept EEE Tiruvallur Dt 601206 Tamil Nadu India

For the efficient transmission of medical image datasets over the internet, compression techniques which offer high compression ratio and less computational cost are required. Since the existing lossless techniques have low compression ratios, the alternative approach is to employ near-lossless methods. The existing near-lossless methods like JPEG-LS are context based and computationally intensive. In this paper, a new approach for near-lossless compression of the medical images is proposed. Pre-processing techniques are applied to the input image to generate a visually quantised image. The visually quantised image is encoded using a low complexity block-based lossless differential pulse code modulation coder, followed by the Huffman entropy encoder. The compression performance is compared with the state-of-the-art technique context-based adaptive lossless image coding, by using the objective analysis parameter peak signal to noise ratio and the image fidelity measurement parameter visual signal to noise ratio. Results show the superiority of the proposed technique in terms of the bit rate and visual quality.

关键词： differential pulse code modulation block-based DPCM near lossless method visual quantisation medical image compression context based adaptive lossless image coding histogram CALIC Huffman coding JPEG-LS predictor image quality visual signal to noise ratio VSNR

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BDC-1: A ROBUST ALGORITHM FOR DISPLAY STREAM COMPRESSION

BDC-1: A ROBUST ALGORITHM FOR DISPLAY STREAM COMPRESSION

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Picture Coding Symposium (PCS)

作者： Walls, Frederick MacInnis, Alexander (Sandy) Broadcom Corp 2451 Miss Coll Blvd Santa Clara CA 95054 USA

ISBN: (纸本)9781479902941

BDC-1 is a low-complexity algorithm to compress digital video in real time in a visually lossless way for transmission over display links. The algorithm is based on DPCM, with a number of improvements. The decoder infers prediction modes and quantization levels based on previously received data. The entropy coding facilitates decoding at 3 pixels per clock at low cost. The decoded image quality is superior to many state-of-the-art low-cost compression schemes, particularly on pathologically difficult and computer-generated content.

关键词： quantization level differential pulse code modulation Entropy coding Digital video Timing devices DECODING Image quality algorithms streams compression

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Improving Inter Prediction in HEVC with Residual DPCM for Lossless Screen Content Coding

Improving Inter Prediction in HEVC with Residual DPCM for Lo...

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Picture Coding Symposium (PCS)

作者： Naccari, Matteo Blasi, Saverio G. Mrak, Marta Izquierdo, Ebroul British Broadcasting Corp R&D 56 Wood Lane London W12 7SB England Queen Mary Univ London London E1 4NS England

ISBN: (纸本)9781479902941

Video content containing computer generated objects is usually denoted as screen content and is becoming popular in applications such as desktop sharing, wireless displays, etc. Screen content images and videos are characterized by high frequency details such as sharp edges and high contrast image areas. On these areas classical lossy encoding tools - spatial transform plus quantization - may significantly compromise their quality and intelligibility. Therefore, lossless coding is used instead and improved coding tools should be specifically devised for screen content. In this context this paper proposes a residual differential pulse code modulation (RDPCM) applied to inter predicted residuals and tested in the context of the HEVC range extension development. The proposed method exploits the spatial correlation present in blocks containing edges or text areas which are poorly predicted by motion compensation. In addition to the baseline inter RDCPM, two improvements to the compression efficiency and the overall throughput are presented and assessed. When compared to HEVC lossless coding as specified in Version 1 of the standard, the proposed algorithm achieves up to 8% average bitrate reduction while not increasing the overall decoding complexity.

关键词： differential pulse code modulation Lossless High efficiency video coding Screen lossless coding lossless compression COMPRESSION EFFICIENCY Videotapes Motion compensation Quantization

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