Is it possible to change color for the plot function in opticalFlow class?

The plot function in opticalFlow class ( see here ) has three name-value pair arguments. I assumed other regular plot arguments would work too but obviously they don't. I tried to use 'color' unsuccessfully.

I plan to superimpose the plots on images and the current blue color is hardly visible... So my question is: is there any way to change the color of this plot?

Answer 1

[Anand]

Unfortunately, this can't be done directly. You need to find a handle to the underlying quiver plot and modify it. Here's some code to help you:

% Compute and plot optic flow
opflow = opticalFlow(randn(100,100),randn(100,100));
plot(opflow,'DecimationFactor',[10 10],'ScaleFactor',10);

% Find quiver handle
q = findobj(gca,'type','Quiver');

% Change color to red
q.Color = 'r';

[hekimgil]

Thank you Anand. It did work but it slowed things much. Still, this seems to be the only way...

Answer 2

[Oskar Wilhelmsson]

I ran into a similar problem. Using "clf" in the beginning of the video loop will make sure the color is always the same, which is what I think you actually want.

Answer 3

[Adam Danz]

The "Color" name-value-pair appeared in the documentation for the plot function in opticalFlow class starting in R2023a.

https://www.mathworks.com/help/vision/ref/opticalflow.plot.html