International Journal of Computer Applications |
Foundation of Computer Science (FCS), NY, USA |
Volume 81 - Number 15 |
Year of Publication: 2013 |
Authors: Dhananjay Patel, Alina Menoth Jose, Nigel Mascarenhas, Steape Stany Monis |
10.5120/14200-2418 |
Dhananjay Patel, Alina Menoth Jose, Nigel Mascarenhas, Steape Stany Monis . JPEG Image Compression using DCT and DHT and Comparison of Both Techniques based on Mean Square Error and Peak Signal to Noise Ratio. International Journal of Computer Applications. 81, 15 ( November 2013), 23-27. DOI=10.5120/14200-2418
DCT based JPEG compression is a widely used standard for lossy image compression. DCT concentrates energy into lower order coefficients. It removes redundancy between neighbouring pixels which leads to uncorrelated transform coefficients which can be encoded independently. There is high computational complexity in DCT. DHT is a real valued transform whose forward and inverse transforms are same except for a an inclusion of a scale factor in the inverse transform. DHT reduces the computational complexity of JPEG compared to DCT. DHT doesn't require a dequantizer at the decoder, since a new quantization technique known as energy quantization is used. It speeds up the encoding procedure, reduces hardware as well as makes the implementation simpler. The quality of the reconstructed image is very good which is verified using MATLAB i. e. the PSNR is improved and the MSE is reduced.