3. 3D Retargeting
Conceptually retargetting to 3D target is just a simple extension of the 2D case. The motion model parameters estimated are applied to the controlling structure of the 3D model instead of a set of 2D points.
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Preprocessing -
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The problem I ran into was that I had no way of embedding or specifying a control stucture in a 3D model. So I hardwired the control struxture to my rudimentary way. I created a cuboid by sampling a line segment at regular points and generating a rectangular slice for each sampling. Now when the line segment is deformed the corresponding slices deform with it, thus deforming the cuboid.
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| The Cuboid - Wireframe |
The Cuboid - Solid |
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Also the affine transformation encodes an arbitrary scale value. I was rendering the 3D scene in OpenGL. So the coordinate setup of my world had to match exactly that of the image from which the affines transforms were extracted else the transformations did not make any sense.
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The Y-axis also had to be inverted because in images the origin is at the top left corner.
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Retargeting -
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The motion from the source was now transferred to the line segment as before and then the 3D object was generated from the line segment for each frame.
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Page last updated on 04 October, 2005.
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© Parag Chaudhuri , 2009
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