You're reading from Mastering OpenCV 4 with Python

Product typeBook

Published inMar 2019

Reading LevelExpert

PublisherPackt

ISBN-139781789344912

Edition1st Edition

Languages

Python

Tools

OpenCV

Concepts

Computer Vision

Author (1)

Alberto Fernández Villán

Chapter 8

The cv2.findContours() function finds contours in a binary image (for example, the resulting image after a thresholding operation).
The four flags OpenCV provides for compressing contours are as follows:

cv2.CHAIN_APPROX_NONE
cv2.CHAIN_APPROX_SIMPLE
cv2.CHAIN_APPROX_TC89_KCOS
cv2.CHAIN_APPROX_TC89_L1

The cv2.moments() function calculates all of the moments up to the third order of a polygon or rasterized shape.
The moment, m00, gives the area of the contour.
OpenCV provides the cv2.HuMoments() function to calculate the seven Hu moment invariants.
The cv2.approxPolyDP() function returns a contour approximation of the given contour based on the given precision. This function uses the Douglas-Peucker algorithm. The epsilon parameter specifies the precision for establishing the maximum distance between the original curve and its approximation.
The extreme_points() function...

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Mastering OpenCV 4 with Python

Published in: Mar 2019Publisher: PacktISBN-13: 9781789344912

Author (1)

Alberto Fernández Villán

Alberto Fernndez Villn is a software engineer with more than 12 years of experience in developing innovative solutions. In the last couple of years, he has been working in various projects related to monitoring systems for industrial plants, applying both Internet of Things (IoT) and big data technologies. He has a Ph.D. in computer vision (2017), a deep learning certification (2018), and several publications in connection with computer vision and machine learning in journals such as Machine Vision and Applications, IEEE Transactions on Industrial Informatics, Sensors, IEEE Transactions on Industry Applications, IEEE Latin America Transactions, and more. As of 2013, he is a registered and active user (albertofernandez) on the Q&A OpenCV forum.
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