Search icon
Subscription
0
Cart icon
Close icon
You have no products in your basket yet
Arrow left icon
All Products
Best Sellers
New Releases
Books
Videos
Audiobooks
Learning Hub
Newsletters
Free Learning
Arrow right icon
Learning OpenCV 4 Computer Vision with Python 3 - Third Edition

You're reading from  Learning OpenCV 4 Computer Vision with Python 3 - Third Edition

Product type Book
Published in Feb 2020
Publisher Packt
ISBN-13 9781789531619
Pages 372 pages
Edition 3rd Edition
Languages
Authors (2):
Joseph Howse Joseph Howse
Profile icon Joseph Howse
Joe Minichino Joe Minichino
Profile icon Joe Minichino
View More author details

Table of Contents (13) Chapters

Preface 1. Setting Up OpenCV 2. Handling Files, Cameras, and GUIs 3. Processing Images with OpenCV 4. Depth Estimation and Segmentation 5. Detecting and Recognizing Faces 6. Retrieving Images and Searching Using Image Descriptors 7. Building Custom Object Detectors 8. Tracking Objects 9. Camera Models and Augmented Reality 10. Introduction to Neural Networks with OpenCV 11. Other Book You May Enjoy Appendix A: Bending Color Space with the Curves Filter

Detecting DoG features and extracting SIFT descriptors

The preceding technique, which uses cv2.cornerHarris, is great for detecting corners and has a distinct advantage because corners are corners; they are detected even if the image is rotated. However, if we scale an image to a smaller or larger size, some parts of the image may lose or even gain a corner quality.

For example, take a look at the following corner detections in an image of the F1 Italian Grand Prix track:

Here is the corner detection result with a smaller version of the same image:

You will notice how the corners are a lot more condensed; however, even though we gained some corners, we lost others! In particular, let's examine the Variante Ascari chicane, which looks like a squiggle at the end of the part of the track that runs straight from northwest to southeast. In the larger version of the image, both...

lock icon The rest of the chapter is locked
Register for a free Packt account to unlock a world of extra content!
A free Packt account unlocks extra newsletters, articles, discounted offers, and much more. Start advancing your knowledge today.
Unlock this book and the full library FREE for 7 days
Get unlimited access to 7000+ expert-authored eBooks and videos courses covering every tech area you can think of
Renews at $15.99/month. Cancel anytime}