accessing picamera via python

[jan-willem]

Hi!
Since Monday I've got a tinker board. I'm using opencv (version 3.3.1) and want to use the picamera v2 but I can't access it. I used the tinker board CSI-camera wiki as reference.
I can accessing it via the terminal

Code:

gst-launch-1.0 v4l2src ! videoconvert ! autovideosink

command
What command should I use if I want to get the camera image via cv2.VideoCapture () ?

Thanks in advance!!

Jan-Willem

[Mikerr]

As at https://tinkerboarding.co.uk/wiki/index....CSI-camera

Code:

cap = cv2.VideoCapture("v4l2src ! video/x-raw,format=NV12,width=640,height=480 ! videoconvert ! appsink")

while cap.isOpened():
   ret, frame = cap.read()

[jan-willem]

Thank you, both

Code:

while cap.isOpened():

and

Code:

while True

won't give access to the camera. I put a

Code:

print('frame', frame)

in the loop to see what information comes through. In the first case noting happens at all and in the second case the print gives 'none'

Jan-Willem

[jan-willem]

Anyone?

This is my python code:

Code:

import cv2
import sys
import os
import time

cap = cv2.VideoCapture("v4l2src ! video/x-raw,format=NV12,width=640,height=480 ! videoconvert ! appsink")
cv2.setNumThreads(4)

time.sleep(1.0)

while cap.isOpened:
    ret, webcam = cap.read()
    
    cv2.imshow('webcam',webcam)

    
    if cv2.waitKey(1) & 0xFF == ord('q'):
        break

cap.release()
cv2.destroyAllWindows

and this is the traceback I get:

Code:

Traceback (most recent call last):
  File "/home/linaro/Desktop/2.py", line 14, in <module>
    cv2.imshow('webcam',webcam)
cv2.error: /home/linaro/opencv-3.3.1/modules/highgui/src/window.cpp:331: error: (-215) size.width>0 && size.height>0 in function imshow