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Validation using Warped Images

Given the 70 image sets described above, each with known average misregistration, 79#79, we investigated the relationship between 79#79 and Specificity, Generalisation, and Generalised Overlap, calculating the mean and standard error for each measure over the 10 warp instances for each value of 79#79.

For each misregistered image set, we calculated Specificity and Generalisation, as described in Section [*], using 34#34 = 15 modes of variation for the model and 82#82 = 1000 synthetic images drawn from a Gaussian distribution, as described in Section [*]. This was repeated for values of shuffle radius, 66#66, of 1 (Euclidean distance), 1.5, 2.1 and 3.7, as defined in Section [*], corresponding to circular neighbourhoods contained within 1x1, 3x3, 5x5 and 7x7 pixel patches respectively. We also repeated these experiments with 2.5%, 5.0% and 10% Gaussian intensity noise added to the misregistered images, in order to investigate the sensitivity of the model-based measures to image noise.

Similarly, we calculated Generalised Overlap with volume, equal, inverse volume and complexity weightings, as defined in Section  [*] calculating the mean and standard error for each measure over the 10 warp instances for each value of 79#79.


next up previous
Next: Sensitivity Up: Experimental Validation Previous: Perturbing the Initial Registration
Roy Schestowitz 2007-03-11