How to use OpenCV to capture live video feed from multiple cameras?

Question

I am using Opencv 3 and python 3.6 for my project work. I want to set up multiple cameras at a time to see video feed from all of them at once. I want to do facial recognition using it. But there is no good way to do this. Here is one link which I followed but nothing happens: Reading from two cameras in OpenCV at once

I have tried this blog post as well but it only can capture one image at a time from video and cannot show the live video. https://www.pyimagesearch.com/2016/01/18/multiple-cameras-with-the-raspberry-pi-and-opencv/

Previously people have done this with C++ but with python it seems difficult to me.

You seem to be following correct sample code on how to achieve this. If you paste your code here, perhaps we can help debug it. — Shawn Mathew, Feb 19 '18 at 16:27
are you sure about it? Well i am not changing a bit in a code. I am just copying it to see how it works or not — Urvish, Feb 19 '18 at 16:51
Paste your code here and perhaps we can help debug if you're still stuck on the problem — Shawn Mathew, Feb 19 '18 at 20:19

score 1 · Answer 1 · edited Oct 17 '19 at 08:10

1

the below code works and i've tested it, so if u're using two cameras 1 a webcam and another is a usb cam then, (adjust videocapture numbers if both are usb cam)

import cv2


cap1 = cv2.VideoCapture(0)
cap2 = cv2.VideoCapture(1)

while 1:

  ret1, img1 = cap1.read()
  ret2, img2 = cap2.read()

  if ret1 and ret2:

      cv2.imshow('img1',img1)
      cv2.imshow('img2',img2)

      k = cv2.waitKey(100) 
      if k == 27: #press Esc to exit
         break

cap1.release()
cap2.release()
cv2.destroyAllWindows()

edited Oct 17 '19 at 08:10

bharatk

4,202
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answered Feb 15 '18 at 21:43

Ahmed

89
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what If we have more than 10 webcams. any solution using looping ?? or any predefined method or library ?? – M. D. P Oct 03 '18 at 04:59
I dont know how you are gonna add 10 webcams in one pc anyways just add cap3 = cv2.VideoCapture(3) and keep adding ..although i should tell you that the program would run very slowly the more you webcams you add – Ahmed Oct 04 '18 at 14:33

score 0 · Answer 2 · answered Jul 20 '18 at 03:28

0

my experience with R_Pi & 2 cams showed the limitation was the GPU on the R_Pi. I used setup to allocate more GPU memory to 512Mb. It would slow down with more than 10 fps with 2 cams. Also, the USB ports restricted the video stream.

answered Jul 20 '18 at 03:28

spincraft

1

score 0 · Answer 3 · answered Mar 02 '19 at 01:06

One solution is to put each camera on it's own usb controller. I did this using a 4 channel PCIe card. The card must have a separate controller for each port. I'm just finishing a project where I snap images from 4 ELP usb cameras, combine the images into one, and write it to disk. I spent days trying to make it work. I found examples for two cameras that worked with my laptop camera and an external camera but not two external cameras. The internal camera is on a different usb controller than the external ports...

How to use OpenCV to capture live video feed from multiple cameras?

3 Answers3