Optical Flow_JASOn extraction
error Traceback (most recent call last) in () 84 prevgray = gray 85 ---> 86 cv.imshow('flow', draw_flow(gray, flow)) #its shows the image 87 if show_hsv: 88 cv.imshow('flow HSV', draw_hsv(flow))
error: /home/travis/miniconda/conda-bld/conda_1485299292920/work/opencv-3.2.0/modules/highgui/src/window.cpp:304: error: (-215) size.width>0 && size.height>0 in function imshow
cv.calcOpticalFlowFarneback(prevgray, gray, None, 0.5, 3, 15, 3, 5, 1.2, 0) : http://funvision.blogspot.com/2016/02/opencv-31-tutorial-optical-flow.html
https://docs.opencv.org/2.4/doc/tutorials/imgproc/pyramids/pyramids.html
https://docs.opencv.org/2.4/modules/imgproc/doc/filtering.html?highlight=pyrup#pyrup
ch = cv.waitKey(20) https://codeyarns.com/2015/01/20/how-to-use-opencv-waitkey-in-python/