我发现解决方案是必须将cv2.so和cv.py复制到运行virtualenv的目录,然后pip install numpy。为此,我使用了Ubuntu12.04。
virtualenv virtopencv
cd virtopencv
cp /usr/local/lib/python2.7/dist-packages/cv* ./lib/python2.7/site-packages/
./bin/pip install numpy
source bin/activate
python
import cv