Contact angle, Height

Hello Everyone,

Is there anyone can guide me that how to measure the the contact angle and height of drop automatically.

I tried to measure after converting the file into 8bit but till now i did not succes to measure automatically via programing. Manualy i can do.
Your answer will help me alot.

Thanks alot

Just some basic and untested thoughts:

  1. Make a photo with no drop for background
  2. Difference the drop and the background
  3. Binarize with a threshold
  4. Erode + dilate to remove small objects
  5. Segment the binary image
  6. Select the object with larger size
  7. Identify the pixels touching the bounding box
  8. Compute the centroid, semi-axis and the ellipse equation
  9. Compute the intersection of the ellipse and the bottom line of the box
  10. Compute the tangent vector of the ellipse at this point
  11. The angle between the vector and the horizontal plane is the contact angle

Another option, probably more precise, is to directly fit the segmented object in (6) or its border to an ellipse or a higher order polynomial.

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I will also give this plugin a try: