I want to measure the number of rotations of an object in a video.

If you have 4 objects, can you measure the number of rotations for each object?

No related algorithm was found.

Answer 1

[Suraj Kumar]

Hello @병연 임,

To measure the number of rotations of objects in a video using MATLAB, you can refer to the following steps:

1. Load the video into MATLAB using the VideoReader class and convert the video frames to grayscale to simplify processing, if color is not important for rotation detection.

2. Then you can use tracking algorithms like `vision.PointTracker` or `vision.ForegroundDetector` to track the objects across frames.

3. Extract features from each object that can help in determining rotation and calculate the orientation of the features in each frame.

4. Track changes in orientation over time to determine when a full rotation has occurred. This might involve calculating the angle between feature vectors in consecutive frames.

5. Implement the logic to count rotations i.e. count a rotation each time the orientation angle completes a 360-degree cycle.

You can refer to the attached code snippet for a better understanding:

videoReader = VideoReader(videoFile);
% Initialize a video player for visualization
videoPlayer = vision.VideoPlayer;
% Loop through each frame
while hasFrame(videoReader)
    frame = readFrame(videoReader);
    grayFrame = rgb2gray(frame);
    % Display the frame
    step(videoPlayer, frame);
end
release(videoPlayer);

To know more about VideoReader in MATLAB, please refer to the following link:

https://www.mathworks.com/help/matlab/ref/videoreader.html

Hope this solves your query!