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Reflectance Map:

Photometric Stereo

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Componente especular:

Componente Difuso:

Um modelo de iluminação (Phong)

Componente ambiente:

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viewer-centered coordinate system

change in z can be shown (using Taylor series expansion) to be:

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We can write the first small step in vector form as (δx, 0, p δx)T

The unit surface normal is:

the unit view vector ˆv from the object to the lens is (0, 0, 1)T

the angle θe between the surface normal and the direction to the lens:

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The Reflectance Map

The reflectance map makes explicit the relationship between surface orientation and brightness.

a source of radiance E illuminating a Lambertian surface

The scene radiance is:

θiis the angle between the surface normal and the direction toward the source

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Photometric Stereo

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Recovering Albedo

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Needle Diagram

11.8 Recovering Depth from a Needle Diagram

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Since both p and q are available, we actually have more information than we really need.

This suggests that we use a least-squares method to find the surface that best fits the imperfect

estimate of the surface gradient

We can, for example, choose z(x, y) so as to minimize the error

We have to minimize na integral of the formWe have to minimize na integral of the form

We have to minimize anintegral of the form

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A good estimator of the second derivative of z, for example, is