Finding points of interest in an image

In an image, points of interest are positions where there might be edges, corners, or interesting objects. For example, in a landscape picture, points of interest can be located near a house or a person. Detecting points of interest is useful in image recognition, computer vision, or medical imaging.

In this recipe, we will find points of interest in an image with scikit-image. This will allow us to crop an image around the subject of the picture, even when this subject is not in the center of the image.

Getting ready

Download the Child dataset from the book's GitHub repository at https://github.com/ipython-books/cookbook-data, and extract it into the current directory.

How to do it...

1. Let's import the packages:

   In [1]: import numpy as np
           import matplotlib.pyplot as plt
           import skimage
           import skimage.feature as sf
           %matplotlib inline

2. We create a function to display a colored or grayscale image:

   In [2]: def show(img, cmap=None)...