Métriques perceptuelles pour la compression d'images : éude et comparaison des algorithmes JPEG et JPEG2000.

Authors: Brunet, Dominique
Advisor: Rostand, Jérémie
Abstract: In the present work we describe the image compression algorithms: JPEG and JPEG2000. We then compare them using a perceptual metric. JPEG algorithm decomposes an image with the discrete cosine transform, the transformed map is then quantized and encoded with the Huffman code. Whereas the JPEG2000 algorithm uses wavelet transform to decompose an image in many resolutions. We describe a few properties of wavelets and prove their utility in image compression. The wavelets properties are for instance: orthogonality or biorthogonality, real wavelets, compact support, number of moments, regularity and symmetry. We then briefly show how does JPEG2000 work. After we prove that RMSE error is clearly not the best perceptual metric. So forth we suggest other metrics based on a human vision system model. We describe the SSIM index and suggest it as a tool to evaluate image quality. Finally, using the SSIM metric, we show that JPEG2000 surpasses JPEG.
Document Type: Mémoire de maîtrise
Issue Date: 2007
Open Access Date: 13 April 2018
Permalink: http://hdl.handle.net/20.500.11794/19752
Grantor: Université Laval
Collection:Thèses et mémoires

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