Saturday, March 25, 2006

Kepler Motion Blur

Creating an animation of circular orbits, essentially a vector field, appears initially not so difficult. We need not invoke Newton's gravitational force law directly, instead we can use Kepler's law of cubes and squares to calculate orbital periods. One innovation is to incorporate motion blur: instead of plotting points, we plot an arc for the distance traveled between animation frames. In order to make it less bright, we divide the pixel intensity by the arc length. However, gamma correction must performed because of nonlinear scaling of pixel value and brightness. One problem that will be left unsolved is that motion blur will be most significant in inner radii, where the approximation of discrete pixels by arc length is least acurate. A solution which will not be initially pursued, is to perform antialiasing in location in addition to motion blur in time. Because of overlapping pixels, we need pixel brightness summation, with gamma, so the internal, actual intensity is tracked.

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