# Changes between Version 12 and Version 13 of libpipi/research/filtersTweet

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Timestamp:
Oct 22, 2008, 3:23:35 PM (11 years ago)
Comment:

LaTeX shit

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Unmodified
 v12 The usual way to create a Gaussian kernel is to evaluate a Gaussian function at the center of each cell: k[i][j] = exp(-(i²+j²)/2σ) {{{ #!latex $k_{i,j} = e^{-\dfrac{i^2+j^2}{2\sigma}}$ }}} This usually works well, except when the kernel is thin (σ < 1). It gets worse when using our generalised kernel: k[i][j] = exp(-((i×cosθ-j×sinθ-dx)²+(j×cosθ+i×sinθ-dy)²)/2σ) {{{ #!latex $k_{i,j} = e^{-\dfrac{(i\cos\theta-j\sin\theta-dx)^2+(j\cos\theta+i\sin\theta-dy)^2}{2\sigma}}$ }}} {{{