Book Image

Hands-On Image Processing with Python

By : Sandipan Dey
Book Image

Hands-On Image Processing with Python

By: Sandipan Dey

Overview of this book

Image processing plays an important role in our daily lives with various applications such as in social media (face detection), medical imaging (X-ray, CT-scan), security (fingerprint recognition) to robotics & space. This book will touch the core of image processing, from concepts to code using Python. The book will start from the classical image processing techniques and explore the evolution of image processing algorithms up to the recent advances in image processing or computer vision with deep learning. We will learn how to use image processing libraries such as PIL, scikit-mage, and scipy ndimage in Python. This book will enable us to write code snippets in Python 3 and quickly implement complex image processing algorithms such as image enhancement, filtering, segmentation, object detection, and classification. We will be able to use machine learning models using the scikit-learn library and later explore deep CNN, such as VGG-19 with Keras, and we will also use an end-to-end deep learning model called YOLO for object detection. We will also cover a few advanced problems, such as image inpainting, gradient blending, variational denoising, seam carving, quilting, and morphing. By the end of this book, we will have learned to implement various algorithms for efficient image processing.
Table of Contents (20 chapters)
Title Page
Copyright and Credits
Dedication
About Packt
Contributors
Preface
Index

Chapter 3. Convolution and Frequency Domain Filtering

In this chapter, we will continue with 2D convolution and understand how convolution can be done faster in the frequency domain (with basic concepts of the convolution theorem). We will see the basic differences between correlation and convolution with an example on an image. We will also describe an example from SciPy that will show how to find the location of specific patterns in an image with a template image using cross-correlation. Finally, we will describe a few filtering techniques (that can be implemented with convolution using kernels, such as box-kernel or Gaussian kernel) in the frequency domain, such as  high-pass, low-pass, band-pass, and band-stop filters, and how to implement them with Python libraries by using examples. We shall demonstrate with examples how some filters can be used for image denoising (for example, the band-reject or notch filters to remove periodic noise from an image, or the inverse or Wiener filters...