MATLAB: How to use estimateFlow between two images that are not video frames

Question

I am interested in computing optical flow between images that are not part of a video sequence using the built-in MATLAB function estimateFlow. That is, I would like to compute optical flow between two images in my workspace, Img1 and Img2. How can I do this?

Currently, I am combining the images into an array and running a for loop to obtain the optical flow:

ImgStack(:,:,1) = Img1; % combine the images to a sequence
ImgStack(:,:,2) = Img2;
reset(opticFlow); % clear previous optical flow
opticFlow = opticalFlowLKDoG; % At this point, I don't realy care what method is used
for t = 1:2
    flow = estimateFlow(opticFlow,ImgStack(:,:,t));
end

This procedure is inelegant and quite cumbersome. I am doing this on a large number of images and I would like a more efficient way to do this. It would be nice if I could just do something like flow = estimateFlow(opticFlow,[Img1,Img2]).

Dose anyone know how to do this?

Answer 1

You can use opticalFlow function for this purpose.

img1 = im2double(Img1); % the images should be in double
img2 = im2double(Img2);
opflow = opticalFlow(img1, img2);
h = figure;
movegui(h);
hViewPanel = uipanel(h,'Position',[0 0 1 1],'Title','Plot of Optical Flow Vectors');
hPlot = axes(hViewPanel);
imshow(img1)
hold on
plot(opflow,'DecimationFactor',[5 5],'ScaleFactor',60,'Parent',hPlot);
hold off

For more information, refer to the documentation on opticalFlow

https://www.mathworks.com/help/vision/ref/opticalflowobject.html