import cv

capture = cv.CaptureFromCAM(0)
img = cv.QueryFrame(capture)
cv.SaveImage("test.JPG", img)

Oi, eu só quero salvar uma foto da minha webcam com OpenCv e Python no meu Ubuntu 10. O OpenCv pode se conectar com a webca

Mas eu recebo este erro:

OpenCV Error: Null pointer (NULL array pointer is passed) in cvGetMat, file /build/buildd/opencv-2.1.0/src/cxcore/cxarray.cpp, line 2376

Traceback (most recent call last):
  File "video.py", line 5, in <module>
    cv.SaveImage("test.JPG", img)
cv.error: NULL array pointer is passed