Hierarchical Image Transmission Research Articles

A Study on Power and Bit Assignment of Embedded Multi-Carrier Modulation Schemes for Hierarchical Image Transmission over Digital Subscriber Line

In this letter, we study the problem of designing an efficient power and bit allocation scheme in the context of a hierarchical image transmission system based on an embedded multi-carrier modulation (EMCM) scheme over digital subscriber line. Authors describe a novel algorithm that performs power minimization under bit rate constraint and QoS requirement. It is based on the Hughes-Hartogs algorithm, and successively allocates the bits of the high, then low priority data streams. Simulations that assess the performance of the proposed algorithm are also provided and discussed; they demonstrate the interest of the proposed scheme.

Multiple Hierarchical Image Transmission over Wireless Channels

In this paper, we present a multiple hierarchical image coding and transmission scheme in which both the fragile structure of the set partitioning in hierarchical trees (SPIHT) source coding and unequal bit error sensitivity in the coded bitstreams have been taken into account. Multiple subsampling is applied to split the wavelet coefficients of the source image into multiple subsources so that each subsource is a crude representation of the original image. Therefore, the sequential dependence in the coded bitstream is broken and the error propagation is limited to a single subsource. Each subsource is coded using the SPIHT algorithm to achieve the high source coding performance. Cyclic redundancy code and rate compatible punctured convolutional (RCPC) code have been employed as the channel coding method to offer unequal error protection to the source coded bits. In each substream, all the bits in the same bit-layer are protected with the same channel coding rate. The higher the bit-layer, the more the channel coding protection is provided. Experimental results show that the proposed scheme has an excellent error resilient performance for image transmission over wireless channels with time varying and bursty error characteristics. In particular, the basic image structure is preserved even in highly noisy channels.

Robust mobile image transmission using hierarchical QAM

Abstract This paper proposes a robust hierarchical image transmission system based on the hierarchical quadrature amplitude modulation (QAM) scheme, which gives high-quality image transmission in a band-limited Rayleigh fading channel. Authors examine the selection of Bose–Chaundhuri–Hocquenghem (BCH) error correction codes for two-layer system, and clarified that it is effective to apply forward error correction (FEC) codec to only base significant layer to get higher system performance. By using BCH(63,45,3) code for significant layer, there is about 10 dB improvement of the robustness against channel CNR degradation, with slightly image quality degradation in higher channel CNR region. Authors also analyzed the optimum hierarchical parameter in the Rayleigh fading channel which maximizes the received image quality. Using optimized hierarchical modulation, there is another 2 dB improvement of the robustness against channel CNR degradation.

Still image transmission using unequal error protection coding in mobile radio channel

AbstractWith the advent of multimedia mobile communication, image transmission in the fading channel is becoming more and more important. This paper discusses the highly efficient coding where the image coding and the channel coding are integrated. More precisely, the following hierarchical image transmission is proposed. Assuming Joint Photograph Experts Group (JPEG) progressive image coding, discrete cosine transform (DCT) transform coefficients or the bit planes are divided into groups so that the unequal channel coding rates are assigned according to the effect of the channel error on the image quality. The proposed system is examined and evaluated by a computer simulation. As a result, it is shown that the reconstructed image suffers from less deterioration compared to the case where the channel coding rate is assigned uniformly.