SIFT tracking set1

Video: Result of identification for tracking


the objective is to find an object in the foreground place a rectangle around the object and find SIFT keypoints in that rectangle, for the next frames only match those keypoints from the rectangle to the image

images and details from (based on my understanding):
Lowe, David G. “Distinctive Image Features from Scale­ Invariant Keypoints”. International Journal of Computer Vision, 60, 2 (2004)

The STEPS:

1. go through all the video and find SIFT keypoints in each frame
2. from an initial frame, select a moving object or foreground and place a rectangle around it
3. get all the SIFT keypoints in that rectangle
4. match the points from that rectangle to all the other points found in step 1
5. if match is found place a rectangle in succeeding frames

problem: in some frames keypoints dont match,thats the reason why i loose track of the vehicle
its either there arent enough matches or those keypoints are different from the first frame
again i consider the keypoints found only in the first frame and compare to new frames

TO DO: compare points from first frame to the next.if object found get the new SIFT points of that object from the new frame and then compare to succeeding frame.

objective: track using SIFT points without needed to preselect the cars

code:

img = imread([imgDir '\' fileNames(3).name]);
[r c bands] = size(img);
h=figure;
imshow(img);
hold on;

....

title('Click the top left corner of an object to track...');
[x1 y1] = ginput(1);
plot(x1, y1, 'rx');
title(sprintf('Click the bottom right corner (Right click indicates last object)'));
[x2 y2 button] = ginput(1);
objectCount = objectCount+1;
rectangle('Position', [x1 y1 x2-x1 y2-y1], 'LineWidth', 4, 'EdgeColor', colors(mod(objectCount, size(colors,1))+1, :));

.....

% Find the sift features for the object
imwrite(trackingObjects{objectCount}.img, 'tmp.pgm', 'pgm');
[jnk des locs] = sift('tmp.pgm');
trackingObjects{objectCount}.des = des;

....

% Read in the next image
img = imread([imgDir '\' fileNames(ii).name]);

% Show the image
figure(h)
cla;
imshow(img); hold on;

% Look for features in the image for each object we are tracking

.....

% Match the features for this object
clear match;
match = matchFeatures(trackingObjects{jj}.des, des);
clear newLocs
newLocs = locs(match(match>0), :);

% Only proceed if we found at least one match
if ~isempty(newLocs)
print('match ound');
....