warp_pts.m

function [ warped_pts ] = warp_pts( video_pts, logo_pts, sample_pts)
% warp_pts computes the homography that warps the points inside
% video_pts to those inside logo_pts. It then uses this
% homography to warp the points in sample_pts to points in the logo
% image
% Inputs:
%     video_pts: a 4x2 matrix of (x,y) coordinates of corners in the
%         video frame
%     logo_pts: a 4x2 matrix of (x,y) coordinates of corners in
%         the logo image
%     sample_pts: a nx2 matrix of (x,y) coordinates of points in the video
%         video that need to be warped to corresponding points in the
%         logo image
% Outputs:
%     warped_pts: a nx2 matrix of (x,y) coordinates of points obtained
%         after warping the sample_pts
[ H ] = est_homography(video_pts, logo_pts);
[n,m]=size(sample_pts);
warped_pts=zeros(n,2);
for i=1:n
    result_vector = H * [sample_pts(i,1);sample_pts(i,2);1];
    warped_pts(i,1) = result_vector(1)/result_vector(3);
    warped_pts(i,2) = result_vector(2)/result_vector(3);
end