OpenCV 4 with Python Blueprints

封面

Title Page

Copyright and Credits

OpenCV 4 with Python Blueprints Second Edition

About Packt

Why subscribe?

Contributors

About the authors

About the reviewer

Packt is searching for authors like you

Preface

Who this book is for

What this book covers

To get the most out of this book

Download the example code files

Code in Action

Download the color images

Conventions used

Get in touch

Reviews

Fun with Filters

Getting started

Planning the app

Creating a black-and-white pencil sketch

Understanding approaches for using dodging and burning techniques

Implementing a Gaussian blur with two-dimensional convolution

Applying pencil sketch transformation

Using an optimized version of a Gaussian blur

Generating a warming and cooling filter

Using color manipulation via curve shifting

Implementing a curve filter using lookup tables

Designing the warming and cooling effect

Cartoonizing an image

Using a bilateral filter for edge-aware smoothing

Detecting and emphasizing prominent edges

Combining colors and outlines to produce a cartoon

Putting it all together

Running the app

Mapping the GUI base class

Understanding the GUI constructor

Learning about a basic GUI layout

Handling video streams

Drafting a custom filter layout

Summary

Attributions

Hand Gesture Recognition Using a Kinect Depth Sensor

Getting started

Planning the app

Setting up the app

Accessing the Kinect 3D sensor

Utilizing OpenNI-compatible sensors

Running the app and main function routine

Tracking hand gestures in real time

Understanding hand region segmentation

Finding the most prominent depth of the image center region

Applying morphological closing for smoothening

Finding connected components in a segmentation mask

Performing hand shape analysis

Determining the contour of the segmented hand region

Finding the convex hull of a contour area

Finding the convexity defects of a convex hull

Performing hand gesture recognition

Distinguishing between different causes of convexity defects

Classifying hand gestures based on the number of extended fingers

Summary

Finding Objects via Feature Matching and Perspective Transforms

Getting started

Listing the tasks performed by the app

Planning the app

Setting up the app

Running the app – the main() function routine

Displaying results

Understanding the process flow

Learning feature extraction

Looking at feature detection

Detecting features in an image with SURF

Obtaining feature descriptors with SURF

Understanding feature matching

Matching features across images with FLANN

Testing the ratio for outlier removal

Visualizing feature matches

Mapping homography estimation

Warping the image

Learning feature tracking

Understanding early outlier detection and rejection

Seeing the algorithm in action

Summary

Attributions

3D Scene Reconstruction Using Structure from Motion

Getting started

Planning the app

Learning about camera calibration

Understanding the pinhole camera model

Estimating the intrinsic camera parameters

Defining the camera calibration GUI

Initializing the algorithm

Collecting image and object points

Finding the camera matrix

Setting up the app

Understanding the main routine function