Shading Primitives: Finding Folds and Shallow Grooves
نویسندگان
چکیده
Diffuse interreflections cause effects that make current theories of shape from shading unsatisfactory. We show that distant radiating surfaces produce radiosity effects at low spatial frequencies. This means that, if a shading pattern has a small region of support, unseen surfaces in the environment can only produce effects that vary slowly over the support region. It is therefore relatively easy to construct matching processes for such patterns that are robust to interreflections. We call regions with these patterns “shading primitives.” Folds and grooves on surfaces provide two examples of shading primitives; the shading pattern is relatively independent of surface shape at a fold or a groove, and the pattern is localised. We show that the pattern of shading can be predicted accurately by a simple model, and derive a matching process from this model. Both groove and fold matchers are shown to work well on images of real scenes.
منابع مشابه
Shape Representations from Shading Primitives
Diffuse interreflections mean that surface shading and shape are related in ways that are difficult to untangle; in particular, distant and invisible surfaces may affect the shading field that one sees. The effects of distant surfaces are confined to relatively low spatial frequencies in the shading field, meaning that we can expect signatures, called shading primitives, corresponding to shape ...
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