Calculate optical flow between two pictures

Hi,

I tried to calculate the optical flow between two pictures with the matlab built-in function:

I1 = rgb2gray(imread('Test4.jpg'));
I2 = rgb2gray(imread('Test4e.jpg'));

opticalFlow = vision.OpticalFlow('ReferenceFrameSource', 'Input port')                                                          
step(opticalFlow, I1, I2)

But I get the error:

Error using vision.OpticalFlow/validateInputsImpl (line 846)
Expected input I data type to be floating-point.

I am not sure what this means. I can't see the code of this. Any ideas on what I am doing wrong?

Thanks

Answer 1

[Guillaume]

Your I1 and I2 are of type uint8. Convert them to double:

I1 = im2double(rgb2gray(imread('Test4.jpg')));
I2 = im2double(rgb2gray(imread('Test4e.jpg')));

[Patrick]

Thanks a lot. I actually thought I tried this and it didn't work but it seems like I made another mistake doing this.