[PYTHON] Play with the Raspberry Pi Zero WH camera module Part 1

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In this article, we will set up python and check the operation of the camera module.

-[1. Python initial settings](# 1-python initial settings) -[1.1. Link settings](# 11-Link settings) -[2. Camera Module Connection](# 2-Camera Module Connection) -[2.1. Connection Settings](# 21-Connection Settings) -[2.2. Still image shooting test](# 22-Still image shooting test) -[3. Addition of various python libraries](# 3-Addition of various python libraries) - 3.1. OpenCV -[4. Try using OpenCV](# 4-Try using opencv) -[4.1. Display test](# 41-Display test)

1. python initialization

1.1. Link settings

In the version of Raspberry Pi OS introduced this time, the symbolic link of python was put on python2 (2.7.16), so I will change the link to python3 (3.7.3). As a side note, the Python library on the Raspberry Pi OS seems to be faster with apt-get than with pip.

#Replacing symbolic links
$ cd /usr/bin
$ sudo unlink python
$ sudo ln -s python3 python

2. Camera module connection

2.1. Connection settings

After connecting the camera module cable to the Raspberry Pi main unit, enable the camera from "Settings" → "Raspberry Pi Settings" → "Interface". Then check if the camera module is connected properly.

#Check camera connection
$ vcgencmd get_camera

If "supported = 1 detected = 1" is displayed, the connection is successful.

2.2. Still image shooting test

As a test, I will take a still image.

#By default/home/Save to pi
$ sudo raspistill -o image.jpg

3. Addition of various python libraries

3.1. OpenCV

First, install the libraries that OpenCV depends on.

# libhdf5-xxx version check(This version is 103)
$ sudo apt-cache search libhdf5

#Installation of various libraries
$ sudo apt-get install libhdf5-dev libhdf5-serial-dev libhdf5-103
$ sudo apt-get install libqtgui4 libqtwebkit4 libqt4-test python3-pyqt5
$ sudo apt-get install libatlas-base-dev
$ sudo apt-get install libjasper-dev

Then install OpenCV.

#OpenCV installation
$ sudo pip3 --default-timeout=1000 install opencv-python

If this is left as it is, ʻimport cv2may throw an error, so set the environment variable. Add the following to "~ / .bashrc" and executesource ~ / .bashrc`.

# ~/.Added to bashrc
export LD_PRELOAD=/usr/lib/arm-linux-gnueabihf/libatomic.so.1

4. Try it with OpenCV

4.1. Display test

This code displays the screen captured from the camera in grayscale and ends when the q key is pressed.

capture_test.py

import cv2

def capture():
    # 0 is a camera number.
    cap = cv2.VideoCapture(0)

    print('### Break is \'q\' key.')

    while(cap.isOpened()):
        # 'ret' is a boolean.
        ret, frame = cap.read()

        gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)

        cv2.imshow('frame', gray)

        # Break is 'q' key.
        if cv2.waitKey(1) & 0xff == ord('q'):
            break

    cap.release()
    cv2.destroyAllWindows()

if __name__=='__main__':
    capture()