正交函数基

最近做image warping，把image从一个camera warp到另外一个camera。最开始用了homography的方法，不好用；又试了一下使用depth map和camera calibration，但是因为depth map不精确，加上estimated的focal length也不精确，所以这种方法也不行；也试了使用函数warping的方法，使用1, x, x^2, x^3, …函数基，也不行。现在准备试一试正交的函数基。

http://en.wikipedia.org/wiki/Basis_function

Polynomial bases

The collection of quadratic polynomials with real coefficients has {1, t, t²} as a basis. Every quadratic can be written as a1+bt+ct², that is, as a linear combination of the basis functions 1, t, and t². The set {(1/2)(t-1)(t-2), –t(t-2), (1/2)t(t-1)} is another basis for quadratic polynomials, called the Lagrange basis.