Camera

The Follow Along Examples:

Camera <- you are here
SONAR

Follow along: Camera Operation Example

The program launching process along with parameter settings are all simplified and set up on the Jupyter Notebook Environment.

Open the 03_camera.ipynb Jupyter Notebook
Import the necessary python libraries and modules
Follow and Execute the example codes

(The Jetson Board used for these examples are => Jetson Nano)

Open the following jupyter notebook:

03_camera.ipynb
To run the cells within the notebook use Ctrl + Enter

Import the necessary python libraries and modules

import rospy
from sensor_msgs.msg import Image
from cv_bridge import CvBridge, CvBridgeError
import numpy as np
import cv2
import ipywidgets.widgets as widgets

Create zetabot Node
/main_camera/raw Topic Subscribe
Convert Message to jpg format and check with ipywidgets

image_widget = widgets.Image(format='jpeg', width = 640, height=480)
display(image_widget)

bridge = CvBridge()

def rgb8_to_jpeg(value, quality=75):
    return bytes(cv2.imencode('.jpg',value)[1].tostring())

def process_image(msg):
    try:
        cv_img = bridge.imgmsg_to_cv2(msg, "bgr8")
    except CvBridgeError as e:
        print(e)
    else:
        image_widget.value = rgb8_to_jpeg(cv_img)
        rospy.sleep(0.25)

def start_node():
    rospy.init_node('zetabot')
    rospy.Subscriber("/main_camera/raw", Image, process_image)
    rospy.spin()

try:
    start_node()
except rospy.ROSInterruptException as err:
    print(err) #Display camera assembly