Design Gabor Filters for Texture Segmentation
PENNSYLVANIA STATE UNIV UNIVERSITY PARK APPLIED RESEARCH LAB
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Many texture-segmentation schemes use an elaborate bank of filters to decompose a textured image -into a joint spacespatial-frequency representation. While these schemes show promise and some analytical work has been done, the relationship between texture differences and the filter configurations required to discriminate them remains largely known. This thesis examines the issue of designing individual filters. Analysis based on mathematically defined texture models shows that applying a properly configured bandpass filter to a textured image produces distinct output discontinuities at texture boundaries. Depending on the type of texture difference and the filter parameters, these discontinuities form one of four characteristic signatures a step, valley, ridge, or a step change in average local output variation. Accompanying experimental evidence indicates that these signatures are useful for segmenting an image. Initially, a simple 1-D texture model is used to derive the step and valley signatures. Ibis model leads to a simple analytical development providing helpful insight. The 1-D model, however, has certain limitations. For example, the existence of the ridge signature cannot be shown using this model. Consequently, a more general 2-D model is also presented, leading to a more complex but informative analysis.
- Electrical and Electronic Equipment