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Thesis (PDF) - Signal & Image Processing Lab

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iv CONTENTS<br />

3 Implementation of BTVT 37<br />

3.1 Topographic Distance Tree definition . . . . . . . . . . . . . . . . . . 37<br />

3.2 Topographic Distance Tree implementation . . . . . . . . . . . . . . . 38<br />

3.3 Implementation of the BTV Transform . . . . . . . . . . . . . . . . . 40<br />

4 The “trench” problem and the proposed solutions 44<br />

4.1 Filtering using an adaptive structuring element . . . . . . . . . . . . 48<br />

4.2 Filtering using multiple minimal paths . . . . . . . . . . . . . . . . . 53<br />

4.3 Filtering using a combined method . . . . . . . . . . . . . . . . . . . 55<br />

4.4 Results Comparison . . . . . . . . . . . . . . . . . . . . . . . . . . . 55<br />

4.4.1 Comparison of different methods for avoiding trenches . . . . 55<br />

4.4.2 Filtering of AS images versus traditional morphological filtering 55<br />

5 Tree Semilattices 62<br />

5.1 The Complete Inf-Semilattice of Tree Representations . . . . . . . . . 63<br />

5.2 <strong>Image</strong> <strong>Processing</strong> on Tree Semilattices . . . . . . . . . . . . . . . . . 69<br />

5.2.1 Proposed Approach . . . . . . . . . . . . . . . . . . . . . . . . 69<br />

5.2.2 Examples and Particular Cases . . . . . . . . . . . . . . . . . 71<br />

5.3 Semilattice of <strong>Image</strong>s . . . . . . . . . . . . . . . . . . . . . . . . . . . 72<br />

5.3.1 Structure Induction . . . . . . . . . . . . . . . . . . . . . . . . 72<br />

5.4 Summary and discussion . . . . . . . . . . . . . . . . . . . . . . . . . 73<br />

6 Extrema-Watershed Tree example 75<br />

6.1 Extrema watershed tree description . . . . . . . . . . . . . . . . . . . 76<br />

6.2 Morphological operations on the extrema-watershed tree . . . . . . 78<br />

6.2.1 Erosion and opening . . . . . . . . . . . . . . . . . . . . . . . 78<br />

6.2.2 Opening by reconstruction . . . . . . . . . . . . . . . . . . . 87<br />

6.3 Study of EWT properties . . . . . . . . . . . . . . . . . . . . . . . . 89<br />

6.3.1 Implicit segmentation . . . . . . . . . . . . . . . . . . . . . . 89<br />

6.3.2 Comparison to the Shape Tree . . . . . . . . . . . . . . . . . 92<br />

6.3.3 Filtering using Extrema watershed tree versus traditional mor-<br />

phological filtering . . . . . . . . . . . . . . . . . . . . . . . . 94<br />

6.4 Application examples . . . . . . . . . . . . . . . . . . . . . . . . . . 99<br />

6.4.1 Pre-processing for car license plate number recognition . . . 99

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