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Hands-On Image Processing with Python

You're reading from   Hands-On Image Processing with Python Expert techniques for advanced image analysis and effective interpretation of image data

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Product type Paperback
Published in Nov 2018
Publisher Packt
ISBN-13 9781789343731
Length 492 pages
Edition 1st Edition
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Author (1):
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Sandipan Dey Sandipan Dey
Author Profile Icon Sandipan Dey
Sandipan Dey
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Table of Contents (20) Chapters Close

Title Page
Copyright and Credits
Dedication
About Packt
Contributors
Preface
1. Getting Started with Image Processing 2. Sampling, Fourier Transform, and Convolution FREE CHAPTER 3. Convolution and Frequency Domain Filtering 4. Image Enhancement 5. Image Enhancement Using Derivatives 6. Morphological Image Processing 7. Extracting Image Features and Descriptors 8. Image Segmentation 9. Classical Machine Learning Methods in Image Processing 10. Deep Learning in Image Processing - Image Classification 11. Deep Learning in Image Processing - Object Detection, and more 12. Additional Problems in Image Processing 1. Other Books You May Enjoy Index

Thresholding and Otsu's segmentation


Thresholding refers to a family of algorithms that use a pixel value as a threshold to create a binary image (an image with only black-and-white pixels) from a grayscale image. It provides the simplest way to segment objects from a background in an image. The threshold can be chosen manually (by looking at the histogram of pixel values) or automatically using algorithm. In scikit-image, there are two categories of thresholding algorithm implementations, namely histogram-based (a pixel intensity histogram is used with some assumptions of the properties of this histogram, for example bimodal) and local (only the neighboring pixels are used to process a pixel; it makes these algorithms more computationally expensive).

In this section, we shall only discuss a popular histogram-based thresholding method known as Otsu's method (with the assumption of a bimodal histogram). It computes an optimal threshold value by simultaneously maximizing the inter-class variance...

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