Compressed Digital Video:Accelerating the Video Communications Revolution

Video is used across a range of applicaticos,from low data-rate mdeo telephony to digitalbroadcast high deftnuzontelevision. Since all applications in thts range require that digually represent-ed sequece of images be reduced in let-rtue for efficient transmision or strage, all applications can uli-lize the same core compression technology. CLI has spent nearl two decades advancing the quality andapplication of digitof video technolegy and continues to rvaluaie meny video compression techniques in-cluding fractof coding, mavelets, subband coding, the discreie cisine transform (DCT), and vectorquantization. CLI currently has concluded that the discrete cosine transform (DCT) combined with mo-tion compensation provides the best pictrue quality for a wide range of video applicarions. In face, theDCT is the technology used by telecommunicationscomputer, and consumer video standards such as H.261 ,JPEG ,adn MPEG. This paper reviews these and other digital video compression iechnologies andthen discusses how CLI applies them to dtfferent video applications. Even within standardsbased mar-kets such as that for MPEG video ditribution syuerns, different products are differentiated easily bydifferences between their proprietary methods for preprocessing ,coding mode selection, postprocessing,etc.

Digital single-operator video cholangioscopy improves endoscopic management in patients with primary sclerosing cholangitis-a retrospective observational study

BACKGROUND Patients with primary sclerosing cholangitis(PSC)are at a high risk of developing cholestatic liver disease and biliary cancer,and endoscopy is crucial for the complex management of these patients.AIM To clarify the utility of recently introduced digital single-operator video cholangioscopy(SOVC)for the endoscopic management of PSC patients.METHODS In this observational study,all patients with a history of PSC and in whom digital SOVC(using the SpyGlass DS System)was performed between 2015 and 2019 were included and retrospectively analysed.Examinations were performed at a tertiary referral centre in Germany.In total,46 SOVCs performed in 38 patients with a history of PSC were identified.The primary endpoint was the evaluation of dominant biliary strictures using digital SOVC,and the secondary endpoints were the performance of selective guidewire passage across biliary strictures and the diagnosis and treatment of biliary stone disease in PSC patients.RESULTS The 22 of 38 patients had a dominant biliary stricture(57.9%).In 4 of these 22 patients,a cholangiocellular carcinoma was diagnosed within the stricture(18.2%).Diagnostic evaluation of dominant biliary strictures using optical signs showed a sensitivity of 75%and a specificity of 94.4%to detect malignant strictures,whereas SOVC-guided biopsies to gain tissue for histopathological analysis showed a sensitivity of 50%and a specificity of 100%.In 13%of examinations,SOVC was helpful for guidewire passage across biliary strictures that could not be passed by conventional methods(technical success rate 100%).Biliary stone disease was observed in 17.4%of examinations;of these,in 37.5%of examinations,biliary stones could only be visualized by SOVC and not by standard fluoroscopy.Biliary stone treatment was successful in all cases(100%);25%required SOVC-assisted electrohydraulic lithotripsy.Complications,such as postinterventional cholangitis and pancreatitis,occurred in 13%of examinations;however,no procedure-associated mortality occurred.CONCLUSION Digital SOVC is effective and safe for the endoscopic management of PSC patients and may be regularly considered an additive tool for the complex endoscopic management of these patients.

Multiresolution Video Watermarking Algorithm Exploiting the Block-Based Motion Estimation

This paper presents a novel technique for embedding a digital watermark into video frames based on motion vectors and discrete wavelet transform (DWT). In the proposed scheme, the binary image watermark is divided into blocks and each watermark block is embedded several times in each selected video frame at different locations. The block-based motion estimation algorithm is used to select the video frame blocks having the greatest motion vectors magnitude. The DWT is applied to the selected frame blocks, and then, the watermark block is hidden into these blocks by modifying the coefficients of the Horizontal sub-bands (HL). Adding the watermark at different locations in the same video frame makes the scheme more robust against different types of attacks. The method was tested on different types of videos. The average peak signal to noise ratio (PSNR) and the normalized correlation (NC) are used to measure the performance of the proposed method. Experimental results show that the proposed algorithm does not affect the visual quality of video frames and the scheme is robust against a variety of attacks.

Peak-to-Average Power Ratio Performance Analysis for Orthogonal Chirp Division Multiplexing Multicarrier Systems Based on Discrete Fractional Cosine Transform

In doubly selective fading channels, the orthogonal frequency division multiplexing (OFDM) multicarrier system may fail. Chirp like basis (fractional Fourier transform-fractional cosine transform) may be used instead of complex exponential basis in this case to improve the system performance. However, in multicarrier transmission, the high peak to average power ratio (PAPR) of the transmitted signal is one of the difficult problems that face both the chirp and the exponential basis. In this paper, an evaluation for the PAPR performance of a multicarrier system based on the fractional cosine transform (FrCT) is introduced and then compared with DFrFT and FFT. Moreover, applying the SLAM technique over these systems is provided to understand the behaviour of these systems when applying SLAM. Simulations verify that this system obtains a better PAPR performance. Moreover, further PAPR reduction can be gained using the well-known PAPR reduction methods. Moreover, applying SLAM technique improves the performance of (dB) by 4 dB to 5 dB and all systems become as competitive to each other when SLAM is applied. Finally, BER performance comparison among OFDM, Discrete Cosine Transform MCM (DCT- MCM), Discrete Hartley Transform MCM (DHT-MCM), DFrFT-OCDM and DFrCT- OCDM MCM systems was done by means of simulation over 100,000 multicarrier blocks for each one and showed that our proposed scenario gave the best performance.

The Formal Specifications for Protocols of Decoders

This paper presents a formal approach, FSPD (Formal Specifications for Protocols of Decoders), to specify decoder communication protocols. Based on axiomatic, FSPD is a precise language with which programmers could use only one suitable driver to handle various types of decoders. FSPD is helpful for programmers to get high adaptability and reusability of decoder-driver software. Key words formalization - digital video security system - protocol of decoders CLC number TP 311 Biography: YUAN Meng-ting(1976-), Ph.D candidate, research direction: software engineering, formal method.

PERFORMANCE ANALYSIS AND SIMULATION OF VARIOUS BURST TIME PLAN GENERATION METHODS IN BROADBAND SATELLITE MULTIMEDIA SYSTEM

The Burst Time Plan(BTP) generation is the key for resource allocation in Broadband Satellite Multimedia(BSM) system.The main purpose of this paper is to minimize the system response time to users' request caused by BTP generation as well as maintain the Quality of Service(QoS) and improve the channel utilization efficiency.Traditionally the BTP is generated periodically in order to simplify the implementation of the resource allocation algorithm.Based on the analysis we find that Periodical BTP Generation(P-BTPG) method cannot guarantee the delay performance,channel utilization efficiency and QoS simultaneously,especially when the capacity requests arrived randomly.The Optimized BTP Generation(O-BTPG) method is given based on the optimal scheduling period and scheduling latency without considering the signaling overhead.Finally,a novel Asynchronous BTP Generation(A-BTPG) method is proposed which is invoked according to users' requests.A BSM system application scenario is simulated.Simulation results show that A-BTPG is a trade-off between the performance and signaling overhead which can improve the system performance insensitive to the traffic pattern.This method can be used in the ATM onboard switching satellite system and further more can be expended to Digital Video Broadcasting-Return Channel Satellite(DVB-RCS) system or IP onboard routing BSM system in the future.

Computational approaches for fast generation of digital 3D video holograms(Invited Paper)

Several approaches for fast generation of digital holograms of a three-dimensional （3D） object have been discussed. Among them, the novel look-up table （N-LUT） method is analyzed to dramatically reduce the number of pre-calculated fringe patterns required for computation of digital holograms of a 3D object by employing a new concept of principal fringe patterns, so that problems of computational complexity and huge memory size of the conventional ray-tracing and look-up table methods have been considerably alleviated. Meanwhile, as the 3D video images have a lot of temporally or spatially redundant data in their inter- and intra-frames, computation time of the 3D video holograms could be also reduced just by removing these redundant data. Thus, a couple of computational methods for generation of 3D video holograms by combined use of the N-LUT method and data compression algorithms are also presented and discussed. Some experimental results finally reveal that by using this approach a great reduction of computation time of 3D video holograms could be achieved.