Thesis (PDF) - Signal & Image Processing Lab
Thesis (PDF) - Signal & Image Processing Lab
Thesis (PDF) - Signal & Image Processing Lab
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xii LIST OF FIGURES<br />
6.20 A Lena image corrupted by the Salt&Pepper noise. (a) Original <strong>Image</strong><br />
(b) Noisy Lena <strong>Image</strong>. . . . . . . . . . . . . . . . . . . . . . . . . . . 95<br />
6.21 Difference between filtering results of Tree of shapes minus filtering<br />
results of Extrema watershed tree of Noisy Lena <strong>Image</strong>. In both filter-<br />
ing approaches we have used structuring element 2 × 2. (a) Difference<br />
between erosion results of Tree of shapes minus erosion results of Ex-<br />
trema watershed tree (b) Difference between opening results of Tree of<br />
shapes minus opening results of Extrema watershed tree. . . . . . . . 95<br />
6.22 Filtering Noisy Lena <strong>Image</strong> using Extrema watershed tree. (a) Inverse<br />
transform of Extrema watershed tree eroded by structuring element<br />
2×2 (b) Inverse transform of Extrema watershed tree opened by struc-<br />
turing element 2 × 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . 96<br />
6.23 Filtering Noisy Lena <strong>Image</strong> using Tree of shapes. (a) Inverse trans-<br />
form of Tree of shapes eroded by structuring element 2 × 2 (b) Inverse<br />
transform of Tree of shapes opened by structuring element 2 × 2. . . . 96<br />
6.24 Traditional erosion and dilation of a gray scale image. . . . . . . . . . 97<br />
6.25 Traditional opening and closing of a gray scale image. . . . . . . . . . 97<br />
6.26 Traditional pseudo-dual open-close and close-open operators. . . . . . 98<br />
6.27 Median operator compared to the self-dual opening using Extrema<br />
watershed tree. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98<br />
6.28 The structuring element used in opening by reconstruction. . . . . . . 101<br />
6.29 License plate image without noise. . . . . . . . . . . . . . . . . . . . . 102<br />
6.30 License plate image corrupted with noise. . . . . . . . . . . . . . . . . 102<br />
6.31 License plate image in gray scale, as used by the OCR. . . . . . . . . 102<br />
6.32 License plate image filtered by EWT-based opening by reconstruction. 102<br />
6.33 License plate image filtered with an averaging filter. . . . . . . . . . . 103<br />
6.34 License plate image filtered with a median filter. . . . . . . . . . . . . 103<br />
6.35 License plate image filtered with regular opening by reconstruction. . 103<br />
6.36 License plate image filtered with regular self dual opening by recon-<br />
struction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103<br />
6.37 (a) A text image corrupted by Salt&Pepper noise. (b) <strong>Image</strong> restored<br />
by an opening on the watershed tree with 2x2 SE. . . . . . . . . . . . 104