Welcome to DOFBOT-JetsonNANO repository

USB Camera Display

1. Camera Reading

capture=cv.VideoCapture(0)

Parameter meaning:

The parameter in VideoCapture() is 0, which means opening the notebook's built-in camera. If the parameter is a video file path, it opens the video, such as cap = cv2.VideoCapture("../test.avi")

2. Display Camera Video

ret,img = frame.read()

Return value meaning:

ret: ret is a boolean value, used to determine whether a correct frame has been read back

img: image data of each frame

3. Code and Actual Effect Display

Start Docker

After entering the main board desktop, open a terminal and run the following command to start the corresponding Dofbot container:

./Docker_Ros.sh

Then enter the following command in the Docker terminal to start jupyter-lab,

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cd
jupyter-lab --allow-root

Access Jupyter Lab within Docker:

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IP:9999         // Example: 192.168.1.11:9999

Program path: /root/Dofbot/6.AI_Visual/0.Camera Driver Tutorial.ipynb

Main code:

​x
import cv2
import ipywidgets.widgets as widgets
import threading
import time
​
image_widget = widgets.Image(format='jpeg', width=600, height=500)  #Set camera display component
display(image_widget)                                               #Display camera component

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#bgr8 to jpeg format
import enum
import cv2
​
def bgr8_to_jpeg(value, quality=75):
    return bytes(cv2.imencode('.jpg', value)[1])

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image = cv2.VideoCapture(0,cv2.CAP_V4L2)                   #Open camera
ret, frame = image.read()     
image_widget.value = bgr8_to_jpeg(frame)

After running the code blocks, the image captured by the USB camera can be displayed.