Arkady Kopansky

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Motivated by recent results in joint source-channel coding and decoding, we consider the problem of decoding of variable-length codes using soft channel values. We present results of decoding of selected codes using the maximum a posteriori (MAP) decoder and the sequential decoder, and show the performance gains over decoding using hard decisions alone. The(More)
Synchronization patterns aperiodically embedded in data may result from applications such as transmission of framed data and compression of video. In this work a metric for detection of these patterns is derived. It is assumed that the distribution of the synchronization patterns in the symbol stream is known. By taking advantage of this knowledge, improved(More)
The current state-of-the-art video coding standard, H.264, offers substantially better compression performance than II. REDUCED RESOLUTION RESIDUAL CODING earlier video coding standards. However, even with these gains, Reduced Resolution Residual Coding (RRRC) refers to a better compression is still desirable. This paper describes a collection of modes that(More)
Abstract – In this work we consider the problem of locating a known periodically embedded synchronization pattern in random data, which is subject to flat fading and additive white Gaussian noise. We derive the maximum likelihood rule and its high-SNR approximation for the case of noncoherent demodulation and show experimental results for the slow-fading(More)
Correct reception of synchronization patterns aperiodically embedded in random data is vital for robust data transmission. In this letter, we derive general metrics and high-signalto-noise ratio approximations to the metrics for random-length frames transmitted over Rayleigh fading channels. Simulation results are presented for commonly used modulation(More)
A. Kopansky and M.Bystrom Electrical and Computer Engineering Department Drexel University Philadelphia, Pennsylvania 19104 Abstract A new technique for concealing errors in Band P-video object planes of MPEG-4 coded video is proposed. This error recovery scheme is based upon error detection in the decoder through a combination of codeword validity checks(More)
Full motion video (FMV) in unreliable, low-bit rate network channels suffers from quality issues such as jitter and block artifacts. In this paper, we introduce Vision Guided Compression (VGC), as a pre-processing technology that can be coupled with standards-based video coding, to provide FMV at low-bit rates. VGC utilizes computer vision algorithms to(More)
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