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Convolving Gaussian

Python, 49 lines
 ``` 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49``` ```def gauss_kern(size, sizey=None): """ Returns a normalized 2D gauss kernel array for convolutions """ size = int(size) if not sizey: sizey = size else: sizey = int(sizey) #print size, sizey x, y = mgrid[-size:size+1, -sizey:sizey+1] g = exp(-(x**2/float(size)+y**2/float(sizey))) return g / g.sum() def blur_image(im, n, ny=None) : """ blurs the image by convolving with a gaussian kernel of typical size n. The optional keyword argument ny allows for a different size in the y direction. """ g = gauss_kern(n, sizey=ny) improc = signal.convolve(im,g, mode='valid') return(improc) from pylab import figure, show, clf, savefig, cm from scipy import * xmin, xmax, ymin, ymax = -70, 70, -70, 70 extent = xmin, xmax, ymin, ymax X, Y = mgrid[-70:70, -70:70] Z = cos((X**2+Y**2)/200.)+ random.normal(size=X.shape) #Z = cos((X**2+Y**2)/200.) fig1 = figure(1) fig1.clf() ax1a = fig1.add_subplot(131) ax1a.imshow(abs(Z), cmap=cm.jet, alpha=.9, interpolation='bilinear', extent=extent) ax1a.set_title(r'Noisey') P = gauss_kern(3) ax1b = fig1.add_subplot(132) ax1b.imshow(abs(P), cmap=cm.jet, alpha=.9, interpolation='bilinear', extent=extent) ax1b.set_title(r'Convolving Gaussian') U = blur_image(Z, 3) ax1c = fig1.add_subplot(133) ax1c.imshow(abs(U), cmap=cm.jet, alpha=.9, interpolation='bilinear', extent=extent) ax1c.set_title(r'Cleaned') savefig('convolve-gaussian.png') ```
 Created by alexander baker on Tue, 19 May 2009 (MIT)