Changes between Version 12 and Version 13 of libpipi/research/filters
 Timestamp:
 Oct 22, 2008, 3:23:35 PM (11 years ago)
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libpipi/research/filters
v12 v13 5 5 The usual way to create a Gaussian kernel is to evaluate a Gaussian function at the center of each cell: 6 6 7 k[i][j] = exp((i²+j²)/2σ) 7 {{{ 8 #!latex 9 $k_{i,j} = e^{\dfrac{i^2+j^2}{2\sigma}}$ 10 }}} 8 11 9 12 This usually works well, except when the kernel is thin (σ < 1). It gets worse when using our generalised kernel: 10 13 11 k[i][j] = exp(((i×cosθj×sinθdx)²+(j×cosθ+i×sinθdy)²)/2σ) 14 {{{ 15 #!latex 16 $k_{i,j} = e^{\dfrac{(i\cos\thetaj\sin\thetadx)^2+(j\cos\theta+i\sin\thetady)^2}{2\sigma}}$ 17 }}} 12 18 13 19 {{{