Simple 2D A’trous wavelet decomposition using B3 spline in python with SciPy:
_b3spline1d = np.array([1./16, 1./4, 3./8, 1./4, 1./16]) __x = _b3spline1d.reshape(1,-1) _b3spl2d = np.dot(__x.T,__x) def atrous2d(arr, lev, kernel=_b3spl2d, boundary='symm'): "Do 2d a'trous wavelet transform with B3-spline scaling function" approx = signal.convolve2d(arr, kernel, mode='same', boundary=boundary) # approximation w = arr - approx # wavelet details if lev <= 0: return arr if lev == 1: return [w, approx] else: return [w] + atrous1(approx,lev-1, upscale(kernel), boundary)
