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You're reading from  Mastering OpenCV 4 with Python

Product typeBook
Published inMar 2019
Reading LevelExpert
PublisherPackt
ISBN-139781789344912
Edition1st Edition
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Alberto Fernández Villán
Alberto Fernández Villán
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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.
Read more about Alberto Fernández Villán

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Custom visualizations of histograms

In order to visualize histograms, we have made use of the plt.plot() function. If we want to visualize a histogram by using only OpenCV capabilities, there is no OpenCV function to draw histograms. In this case, we have to make use of OpenCV primitives (for example, cv2.polylines() and cv2.rectangle(), among others) to create some (basic) functionality for plotting histograms. In the histogram_custom_visualization.py script, we have created the plot_hist() function, which performs this functionality. This function creates a BGR color image, plotting the histogram in it. The code for this function is as follows:

def plot_hist(hist_items, color):
"""Plots the histogram of a image"""

# For visualization purposes we add some offset:
offset_down = 10
offset_up = 10

# This will be used for creating the...
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Mastering OpenCV 4 with Python
Published in: Mar 2019Publisher: PacktISBN-13: 9781789344912

Author (1)

author image
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.
Read more about Alberto Fernández Villán