Python OpenCV 3.3 NVIDIA Jetson TX example for built-in camera; L4T 28.1

CannyDetection.py

#!/usr/bin/env python
# MIT License

# Copyright (c) 2017 Jetsonhacks

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import sys
import cv2
import numpy as np

def read_cam():
    # On versions of L4T previous to L4T 28.1, flip-method=2
    # Use the Jetson onboard camera
    cap = cv2.VideoCapture("nvcamerasrc ! video/x-raw(memory:NVMM), width=(int)1280, height=(int)720,format=(string)I420, framerate=(fraction)30/1 ! nvvidconv flip-method=0 ! video/x-raw, format=(string)BGRx ! videoconvert ! video/x-raw, format=(string)BGR ! appsink")
    if cap.isOpened():
        windowName = "CannyDemo"
        cv2.namedWindow(windowName, cv2.WINDOW_NORMAL)
        cv2.resizeWindow(windowName,1280,720)
        cv2.moveWindow(windowName,0,0)
        cv2.setWindowTitle(windowName,"Canny Edge Detection")
        showWindow=3  # Show all stages
        showHelp = True
        font = cv2.FONT_HERSHEY_PLAIN
        helpText="'Esc' to Quit, '1' for Camera Feed, '2' for Canny Detection, '3' for All Stages. '4' to hide help"
        edgeThreshold=40
        showFullScreen = False
        while True:
            if cv2.getWindowProperty(windowName, 0) < 0: # Check to see if the user closed the window
                # This will fail if the user closed the window; Nasties get printed to the console
                break;
            ret_val, frame = cap.read();
            hsv=cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
            blur=cv2.GaussianBlur(hsv,(7,7),1.5)
            edges=cv2.Canny(blur,0,edgeThreshold)
            if showWindow == 3:  # Need to show the 4 stages
                # Composite the 2x2 window
                # Feed from the camera is RGB, the others gray
                # To composite, convert gray images to color. 
                # All images must be of the same type to display in a window
                frameRs=cv2.resize(frame, (640,360))
                hsvRs=cv2.resize(hsv,(640,360))
                vidBuf = np.concatenate((frameRs, cv2.cvtColor(hsvRs,cv2.COLOR_GRAY2BGR)), axis=1)
                blurRs=cv2.resize(blur,(640,360))
                edgesRs=cv2.resize(edges,(640,360))
                vidBuf1 = np.concatenate( (cv2.cvtColor(blurRs,cv2.COLOR_GRAY2BGR),cv2.cvtColor(edgesRs,cv2.COLOR_GRAY2BGR)), axis=1)
                vidBuf = np.concatenate( (vidBuf, vidBuf1), axis=0)

            if showWindow==1: # Show Camera Frame
                displayBuf = frame 
            elif showWindow == 2: # Show Canny Edge Detection
                displayBuf = edges
            elif showWindow == 3: # Show All Stages
                displayBuf = vidBuf

            if showHelp == True:
                cv2.putText(displayBuf, helpText, (11,20), font, 1.0, (32,32,32), 4, cv2.LINE_AA)
                cv2.putText(displayBuf, helpText, (10,20), font, 1.0, (240,240,240), 1, cv2.LINE_AA)
            cv2.imshow(windowName,displayBuf)
            key=cv2.waitKey(10)
            if key == 27: # Check for ESC key
                cv2.destroyAllWindows()
                break ;
            elif key==49: # 1 key, show frame
                cv2.setWindowTitle(windowName,"Camera Feed")
                showWindow=1
            elif key==50: # 2 key, show Canny
                cv2.setWindowTitle(windowName,"Canny Edge Detection")
                showWindow=2
            elif key==51: # 3 key, show Stages
                cv2.setWindowTitle(windowName,"Camera, Gray scale, Gaussian Blur, Canny Edge Detection")
                showWindow=3
            elif key==52: # 4 key, toggle help
                showHelp = not showHelp
            elif key==44: # , lower canny edge threshold
                edgeThreshold=max(0,edgeThreshold-1)
                print 'Canny Edge Threshold Maximum: ',edgeThreshold
            elif key==46: # , raise canny edge threshold
                edgeThreshold=edgeThreshold+1
                print 'Canny Edge Threshold Maximum: ', edgeThreshold
            elif key==74: # Toggle fullscreen; This is the F3 key on this particular keyboard
                # Toggle full screen mode
                if showFullScreen == False : 
                    cv2.setWindowProperty(windowName, cv2.WND_PROP_FULLSCREEN, cv2.WINDOW_FULLSCREEN)
                else:
                    cv2.setWindowProperty(windowName, cv2.WND_PROP_FULLSCREEN, cv2.WINDOW_NORMAL) 
                showFullScreen = not showFullScreen
              
    else:
     print "camera open failed"



if __name__ == '__main__':
    read_cam()

camera open failed

in jetson tx2 ,any thing to do to acirvate the camera on board?

have you solved this problem? Its probably with the version

My guess is that you have to use nvarguscamerasrc, something like:

cv2.VideoCapture("nvarguscamerasrc ! video/x-raw(memory:NVMM), width=(int)1280, height=(int)720, format=(string)NV12, framerate=(fraction)30/1 ! nvvidconv ! video/x-raw,format=(string)BGRx ! videoconvert ! video/x-raw, format=(string)BGR ! appsink")

I have a jetson tx2 and I am getting camera open failed using the original string and also the string in jetsonhacks' post. Any ideas?

My guess is that you have to use nvarguscamerasrc, something like:

cv2.VideoCapture("nvarguscamerasrc ! video/x-raw(memory:NVMM), width=(int)1280, height=(int)720, format=(string)NV12, framerate=(fraction)30/1 ! nvvidconv ! video/x-raw,format=(string)BGRx ! videoconvert ! video/x-raw, format=(string)BGR ! appsink")

Thanks but this didn't work either. This works on the command line:
gst-launch-1.0 nvarguscamerasrc ! 'video/x-raw(memory:NVMM), width=640, height=480, framerate=30/1, format=NV12' ! nvvidconv flip-method=4 ! nvegltransform ! nveglglessink -e

However when I put the same string in the python code it doesn't work. I changed the nveglglessink to appsink. Like this:

cap = cv2.VideoCapture("nvarguscamerasrc ! 'video/x-raw(memory:NVMM), width=640, height=480, framerate=30/1, format=NV12' ! nvvidconv flip-method=4 ! nvegltransform ! appsink")

Did you try:

https://github.com/JetsonHacksNano/CSI-Camera/blob/master/simple_camera.py

I was having the same issue, the link above "simple_camera.py" worked. The one difference I noticed in the gst pipeline was the format. I changed

format=(string)I420
to
format=(string)NV12

and it worked for me.

This is on a Jetsontx2 running jetpack 4.3.