Method CalcOpticalFlowFarneback

Namespace

OpenCvSharp

Assembly

OpenCvSharp.dll

CalcOpticalFlowFarneback(InputArray, InputArray, InputOutputArray, double, int, int, int, int, double, OpticalFlowFlags)

Computes a dense optical flow using the Gunnar Farneback's algorithm.

public static void CalcOpticalFlowFarneback(InputArray prev, InputArray next, InputOutputArray flow, double pyrScale, int levels, int winsize, int iterations, int polyN, double polySigma, OpticalFlowFlags flags)

Parameters

prev InputArray

first 8-bit single-channel input image.

next InputArray

second input image of the same size and the same type as prev.

flow InputOutputArray

computed flow image that has the same size as prev and type CV_32FC2.

pyrScale double

parameter, specifying the image scale (<1) to build pyramids for each image; pyrScale=0.5 means a classical pyramid, where each next layer is twice smaller than the previous one.

levels int

number of pyramid layers including the initial image; levels=1 means that no extra layers are created and only the original images are used.

winsize int

averaging window size; larger values increase the algorithm robustness to image noise and give more chances for fast motion detection, but yield more blurred motion field.

iterations int

number of iterations the algorithm does at each pyramid level.

polyN int

size of the pixel neighborhood used to find polynomial expansion in each pixel; larger values mean that the image will be approximated with smoother surfaces, yielding more robust algorithm and more blurred motion field, typically poly_n =5 or 7.

polySigma double

standard deviation of the Gaussian that is used to smooth derivatives used as a basis for the polynomial expansion; for polyN=5, you can set polySigma=1.1, for polyN=7, a good value would be polySigma=1.5.

flags OpticalFlowFlags

operation flags that can be a combination of OPTFLOW_USE_INITIAL_FLOW and/or OPTFLOW_FARNEBACK_GAUSSIAN