2017-04-17 Rpiで複数のWebカメラを使う http://www.pyimagesearch.com/2016/01/18/multiple-cameras-with-the-raspberry-pi-and-opencv/https://www.raspberrypi.org/forums/viewtopic.php?f=43&t=50142https://raspberrypi.stackexchange.com/questions/33791/multiple-webcams-on-a-single-raspberry-pihttp://a244.hateblo.jp/entry/2016/10/14/053000