Machine Learning Algorithms - Second Edition

Image convolution

Even if we're not building a complete deep learning model, we can test how convolution works with a simple example. The input image we're using is already provided by SciPy:

from scipy.misc import faceimg = face(gray=True)

The original picture is shown as follows:

Sample picture to test the convolution features

We're going to apply a Laplacian filter (that is, it is equivalent to a discrete Laplacian operator), which emphasizes the boundary of each shape:

import numpy as npkernel = np.array(    [[0, 1, 0],     [1, -4, 0],     [0, 1, 0]],      dtype=np.float32)cfilter = np.zeros((3, 3, 1, 1), dtype=np.float32)cfilter[:, :, 0, 0] = kernel ...