Ammar, Moussa Mathieu (2002) Optimisation d'un schéma de codage d'image à base d'une TCD. Application à un codeur JPEG pour l'enregistrement numérique à bas débit. PhD thesis Traitement Signal & Images, ENST - TSI Traitement du Signal et des Images, ENST.
Abstract
In this thesis, we consider the optimization problem of a JPEG Coding/Decoding scheme and the reduction of blocking effects in transform image coding.
First we propose to optimize for minimum distortion the synthesis subband filters using the Wiener filters, then to calculate the optimal quantizer step sizes based on a rate-constrained image-adaptive quantization. A1 is the iterative algorithm that optimizes jointly the quantizer step sizes and the synthesis subband filters.
The blocking effects in transform image coding are assmilated block boundary discontinuities. These discontinuities represent the quantization error within a block that becomes high frequency quantization noises after reconstruction. To reduce the blocking artefacts we propose the algorithm B1 that minimizes the energy of high frequency quantization noises. A visual inspection of some reconstructed images after applying the algorithm B1 has allowed to evaluate the performance of such technique.
| Item Type: | PhD Thesis (PhD) |
|---|
| Thesis Supervisor: | Duhamel, Pierre |
|---|
| Date: | January 2002 |
|---|
| Board of examiners: | Barlaud, Michel and Prost, Rémy and Pesquet, Béatrice and Prado, Jacques |
|---|
| Ecole Doctorale: | ED 130 INFORMATIQUE, TELECOMMUNICATIONS ET ELECTRONIQUE (EDITE) |
|---|
| Discipline: | Traitement Signal & Images |
|---|
| Collection (Fonds): | ENST |
|---|
| Institution: | ENST |
|---|
| Department: | ENST - TSI Traitement du Signal et des Images |
|---|
| Subjects: | 2. Information and Communication Sciences and Technologies |
|---|
| Uncontrolled Keywords: | Tcd, Jpeg, Mmse, Filtres de Wiener, Allocations de bits, Tables de huffman, Effets de blocs |
|---|
Statistiques de consultation
Repository Staff Only: edit this item
