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Raspberry Pi Computer Vision Programming

You're reading from   Raspberry Pi Computer Vision Programming Design and implement computer vision applications with Raspberry Pi, OpenCV, and Python 3

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Product type Paperback
Published in Jun 2020
Publisher Packt
ISBN-13 9781800207219
Length 306 pages
Edition 2nd Edition
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Author (1):
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Ashwin Pajankar Ashwin Pajankar
Author Profile Icon Ashwin Pajankar
Ashwin Pajankar
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Table of Contents (15) Chapters Close

Preface 1. Chapter 1: Introduction to Computer Vision and the Raspberry Pi 2. Chapter 2: Preparing the Raspberry Pi for Computer Vision FREE CHAPTER 3. Chapter 3: Introduction to Python Programming 4. Chapter 4: Getting Started with Computer Vision 5. Chapter 5: Basics of Image Processing 6. Chapter 6: Colorspaces, Transformations, and Thresholding 7. Chapter 7: Let's Make Some Noise 8. Chapter 8: High-Pass Filters and Feature Detection 9. Chapter 9: Image Restoration, Segmentation, and Depth Maps 10. Chapter 10: Histograms, Contours, and Morphological Transformations 11. Chapter 11: Real-Life Applications of Computer Vision 12. Chapter 12: Working with Mahotas and Jupyter 13. Chapter 13: Appendix 14. Other Books You May Enjoy

Combining Mahotas and OpenCV

Just like OpenCV, Mahotas uses NumPy arrays to store and process images. We can also combine OpenCV and Mahotas. Let's see an example of this, as follows:

import cv2
import numpy as np
import mahotas as mh
cap = cv2.VideoCapture(0)
while True:
    ret, frame = cap.read()
    frame = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
    T_otsu = mh.otsu(frame)
    output = frame > T_otsu
    output = output.astype(np.uint8) * 255
    cv2.imshow('Output', output)
    if cv2.waitKey(1) == 27:
        break
cv2.destroyAllWindows()
cap.release()

In the preceding program, we converted a live frame into a grayscale version. Then, we applied a Mahotas implementation of Otsu's binarization, which converted the frame from the live video feed into a Boolean binary image. We need to convert this to the np.uint8 type and multiply it by 255 (all of which takes the form of ones in binary 8-bit) so that we can use it with cv2.imshow(). The output is...

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