Image smoothing in Python

Question

I wanted to try to write a simple function to smooth an inputted image. I was trying to do this using the Image and numpy libraries. I was thinking that using a convolution

Answer 1

If you don't want to use scipy, you have three options:

1) you can use the convolution theorem combined with Fourier transforms since numpy has a 2D FFT.

2) you can use a separable kernel and then you can do two 1D convolutions on flattened arrays, one in the x-direction and the other in the y-direction (ravel the transpose), and this will give the same result as the 2D convolution.

3) if you have a small kernel, say, 3x3, it's easy enough just to write out the convolution as multiplications and sums. This sounds like a hassle but it's not so bad.

If you do want to use scipy, you can use ngimage, as tcaswell suggests. scipy also has convolve2d.