Adaptive spectrum-based variable bit truncation of discrete cosine transform (DCT) for energy-efficient wireless multimedia communication

This work presents a new adaptive scheme to reduce the computation energy of the discrete cosine transform (DCT) architecture for image/video coding. The scheme employs the noise masking effect of quantization and the spectral difference of the quantization factors. Spectrum-based variable bit truncation is used to allocate more energy for the computations that affect the low frequency DCT coefficients more. We propose a benchmark driven search mechanism based on energy and distortion weight to find the optimal truncation sets for different quality constraints and quantization tables. They are stored in a look-up table (LUT) for the on-line reconfiguration. Simulation results show that significant energy saving is achieved with negligible quality degradation.