How to get only horizontal line from canny edge detection?

[PULSE.Wannabe]

Is it possible to take out horizontal line from canny edge detection ? or what other way can I use for scanning horizontal edge ? My project is to detect horizontal line of a bottle with juice inside, and check whether the water level is normal, or less .

 

[altenbach · Accepted solution]

I would just look at the color change along a vertical line. No need to edge detect the entire image.

[altenbach]

• Is the drink always dark?
• Is the cap always white? Do we know exactly where the cap is?
• Is the bottle always in the same position (horizontal, vertical, distance, magnification, etc.)?