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OpenCV 4 for Secret Agents

You're reading from   OpenCV 4 for Secret Agents Use OpenCV 4 in secret projects to classify cats, reveal the unseen, and react to rogue drivers

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Product type Paperback
Published in Apr 2019
Publisher Packt
ISBN-13 9781789345360
Length 336 pages
Edition 2nd Edition
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Authors (2):
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Joseph Howse Joseph Howse
Author Profile Icon Joseph Howse
Joseph Howse
Arun Ponnusamy Arun Ponnusamy
Author Profile Icon Arun Ponnusamy
Arun Ponnusamy
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Toc

Table of Contents (16) Chapters Close

Preface 1. Section 1: The Briefing FREE CHAPTER
2. Preparing for the Mission 3. Searching for Luxury Accommodations Worldwide 4. Section 2: The Chase
5. Training a Smart Alarm to Recognize the Villain and His Cat 6. Controlling a Phone App with Your Suave Gestures 7. Equipping Your Car with a Rearview Camera and Hazard Detection 8. Creating a Physics Simulation Based on a Pen and Paper Sketch 9. Section 3: The Big Reveal
10. Seeing a Heartbeat with a Motion-Amplifying Camera 11. Stopping Time and Seeing like a Bee 12. Making WxUtils.py Compatible with Raspberry Pi
13. Learning More about Feature Detection in OpenCV
14. Running with Snakes (or, First Steps with Python)
15. Other Books You May Enjoy

Summary

This chapter has introduced the relationship between computer vision and digital signal processing. We have considered a video feed as a collection of many signals—one for each channel value of each pixel—and we have learned that repetitive motions create wave patterns in some of these signals. We have used the fast Fourier transform and its inverse to create an alternative video stream that only sees certain frequencies of motion. Finally, we have superimposed this filtered video atop the original to amplify the selected frequencies of motion. There, we summarized Eulerian video magnification in 100 words!

Our implementation adapts Eulerian video magnification to real-time by running the FFT repeatedly on a sliding window of recently captured frames, rather than running it once on an entire prerecorded video. We have considered optimizations such as limiting...

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