Calculate Difference between motion vectors

I have motion vectors from two different blockmatchers.

1) fmvs_x, fmvs_y

matrix size -90 x 160

2) ffmpeg_mvs_x, ffmpeg_mvs_y

matrix size - 92 x 160

so the vector difference would be magnitude of (fmvs_x - ffmpeg_mvs_x ) - (fmvs_y - ffmpeg_mvs_y). But the problem is that both the vectors have different matrix sizes.

Could you please advise how should I scale the size of matrix to get correct result.

[darova]

Can't you just use part of the second matrix?

fmvs_x - ffmpeg_mvs_x(1:85,1:155)

[ImageAnalyst]

if i follow this way then i loose the vectors beyond a certain range

[darova]

Can you attach the data?

[ImageAnalyst]

Please find attched

Answer 1

[darova]

Make matrices the same size with interp2

clc,clear

x = xlsread('motionvectors.xls',1);
y = xlsread('motionvectors.xls',2);
fx = xlsread('motionvectors.xls',3);
fy = xlsread('motionvectors.xls',4);
%%
clc
[m,n] = size(x);                    % size of x data
[fm,fn] = size(fx);                 % size of fx data
[xx,yy] = meshgrid(1:n,1:m);        % interpolation grid of 'x' matrix
xt1 = linspace(1,n,fn);             % interpolation vectors of 'fx' matrix
yt1 = linspace(1,m,fm);
[fxx,fyy] = meshgrid(xt1,yt1);      % interpolation grid of 'fx' matrix
x1 = interp2(fxx,fyy,fx,xx,yy);     % interpolate data
y1 = interp2(fxx,fyy,fy,xx,yy);
h1 = surf(xx,yy,x1,'facecolor','r');
h2 = surface(fxx,fyy+100,fx,'facecolor','b');
set([h1 h2],'edgecolor','none')
legend('interpolated data','original data','location','north')
axis vis3d

x-x1;                               % difference

[ImageAnalyst]

Is there any other simple one rather than using interp2. Something like just scaling the matrix size of 90 x 160 to 92 x 160 using size(92 x 160)

[darova]

No. It's the best solution you can find

[Image Analyst]

You could try imresize() to do a bicubic interpolation of the matrix.