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

Seam carving


Seam carving is a content-aware image resizing technique where the image is reduced in size by one pixel in height (or width) at a time. A vertical seam in an image is a path of pixels connected from the top to the bottom with one pixel in each row. A horizontal seam is a path of pixels connected from the left to the right with one pixel in each column. Although the underlying algorithm is simple and elegant, it was not discovered until 2007.

 

Now it is now a core feature in Adobe Photoshop and other computer graphics applications. Unlike standard content-agnostic resizing techniques, such as cropping and scaling, seam carving preserves the most interesting features of the image, such as aspect ratio, set of objects present, and so on. Finding and removing a seam involves three parts:

  1. Energy calculation: The first step is to calculate the energy of a pixel, which is a measure of its importance—the higher the energy, the less likely that the pixel will be included as part of a...