DHT Based JPEG Image Compression Using a Novel Energy Quantization Method

DCT based JPEG is an accepted standard for lossy compression of still image. DHT is a real valued transform whose forward and inverse transforms are same except for an inclusion of a scale factor in the inverse transform. In this paper DCT is replaced by DHT to reduce the computational complexity of JPEG. Quantization is mainly responsible for the amount loss in the image quality in the process of lossy compression. Quantisation of the DHT transformed coefficients is quite difficult. A new quantization method is proposed in the present investigation that facilitates speeding up the coding and decoding procedure while preserving image quality. The image quality of the reconstructed image are very good which is verified through extensive simulation. In this paper with the proposed method there is no need of a dequatizer at the decoder side. This would enable reduction of hardware and would make the implementation much simpler.