How to find the angle of bending of a moving worm from a video?

I have video of a worm moving his head and bending. I want to find the bending angle of the worm. How can I do it? I have no idea at all.

[Image Analyst]

Some photos (frames from the movie) would help. Is the worm's head ever over the body so that you have a closed loop? Does the worm's body ever cross itself? Do you have a list of the body's (x,y) coordinates from head to tail, in order?

If you have any more questions, then attach your data and code to read it in with the paperclip icon after you read this:

TUTORIAL: How to ask a question (on Answers) and get a fast answer

Answer 1

[Suraj]

Hello Adarsh,

I understand that you have a video of a worm moving its head and bending, and you would like to find the bending angle of the worm.

I suggest that you provide more details in support of your query to hear a more specific answer. I can however suggest an approach to achieve this using Computer Vision Toolbox on MATLAB.

Here is a step-by-step guide to help you get started:

1. Video Preprocessing: Convert the video frames to grayscale to simplify the analysis and reduce computational complexity. You can use the rgb2gray function in MATLAB to accomplish this.You may refer the following documentation to know more about 'rgb2gray' function: https://www.mathworks.com/help/matlab/ref/rgb2gray.html
2. Object Detection and Tracking: Apply object detection and tracking algorithms to locate and track the worm's body in each frame. You can use the built-in functions in MATLAB's Computer Vision Toolbox, such as vision.ForegroundDetector for background subtraction and vision.BlobAnalysis for blob detection. You can learn more about these functions from the MATLAB's Computer Vision Toolbox documentation: https://www.mathworks.com/help/vision/
3. Skeletonization: Once you have detected and tracked the worm's body, you can perform skeletonization to obtain a simplified representation of the worm's shape. MATLAB provides the bwmorph function that can be used for skeletonization. Here is the documentation for ‘bwmorph’ function: https://www.mathworks.com/help/images/ref/bwmorph.html
4. Bending Angle Calculation: With the skeletonized representation of the worm's shape, you can measure the bending angle at different points along its body. One approach is to calculate the angle between the line segments connecting adjacent points on the skeleton. You can use the atan2d function in MATLAB to calculate the angle. Please refer to the documentation for the same: https://www.mathworks.com/help/matlab/ref/atan2d.html
5. Data Analysis and Visualization: Finally, analyze the bending angles obtained from each frame to extract meaningful information. You can calculate statistics such as the average bending angle, maximum bending angle, or plot the bending angle over time to observe any patterns or changes.

Please note that the specific implementation details may vary depending on the characteristics of your video and the worm's movement. You might need to adapt the above steps to your specific case.

I hope this helps you get started with finding the bending angle of the worm in your video. Good luck with your analysis!

Regards,

Suraj.