Book Image

NumPy: Beginner's Guide

By : Ivan Idris
Book Image

NumPy: Beginner's Guide

By: Ivan Idris

Overview of this book

Table of Contents (21 chapters)
NumPy Beginner's Guide Third Edition
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
NumPy Functions' References
Index

Time for action – manipulating Lena


The scipy.misc module is a utility that loads the image of "Lena". This is the image of Lena Soderberg, traditionally used for image processing examples. We will apply some filters to this image and rotate it. Perform the following steps to do so:

  1. Load the Lena image and display it in a subplot with grayscale colormap:

    image = misc.lena().astype(np.float32)
    plt.subplot(221)
    plt.title("Original Image")
    img = plt.imshow(image, cmap=plt.cm.gray)

    Note that we are dealing with a float32 array.

  2. The median filter scans the image and replaces each item by the median of neighboring data points. Apply a median filter to the image and display it in a second subplot:

    plt.subplot(222)
    plt.title("Median Filter")
    filtered = ndimage.median_filter(image, size=(42,42))
    plt.imshow(filtered, cmap=plt.cm.gray)
  3. Rotate the image and display it in the third subplot:

    plt.subplot(223)
    plt.title("Rotated")
    rotated = ndimage.rotate(image, 90)
    plt.imshow(rotated, cmap=plt.cm.gray)
  4. The Prewitt...