tracking a point in matlab

To track a point in MATLAB, you can use the built-in functions for image processing and computer vision. Here's an example code for tracking a single point in a video stream:

main.m
% Load the video file
video = VideoReader('sample_video.mp4');

% Initialize the point tracker
pointTracker = vision.PointTracker('MaxBidirectionalError', 2);

% Read the first frame of the video
frame = readFrame(video);

% Select the initial location of the point to be tracked
point = [x, y]; % x and y are the coordinates of the point in the frame
initialize(pointTracker, point, frame);

% Initialize empty arrays to store the path of the tracked point
x_path = [];
y_path = [];

% Loop through the video frames to track the point
while hasFrame(video)
    % Read the next frame
    frame = readFrame(video);

    % Track the point in the current frame
    [point, isFound] = step(pointTracker, frame);

    % If the tracker lost the point, stop the loop
    if ~isFound
        break;
    end

    % Store the tracked point coordinates in the arrays
    x_path = [x_path, point(1)];
    y_path = [y_path, point(2)];

    % Display the tracked point on the current frame
    frame = insertMarker(frame, point, 'Color', 'red', 'Size', 10);

    % Display the current frame with the tracked point and path
    imshow(frame);
    hold on;
    plot(x_path, y_path, 'LineWidth', 2);
    hold off;
end
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In this code, the VideoReader object is used to read the frames of the video. The vision.PointTracker object is then initialized with the maximum bidirectional error set to 2. This controls how much the point can move between frames before it's considered lost by the tracker.

The initial location of the point to track is selected and passed to the initialize method of the pointTracker object. Then, a loop runs over the frames of the video using the hasFrame method of the VideoReader object.

In each iteration of the loop, the step method of the pointTracker object is called with the current frame as input. This updates the position of the tracked point in the frame.

If the tracker loses the point at any time, the loop is stopped using a break statement.

The x and y coordinates of the tracked point are then stored in arrays, and a red marker is inserted at the current point location in the current frame using the insertMarker function. The current frame with the tracked point and path is then displayed using imshow, along with the previous path of the tracked point using the plot function.