how to remove the remaining part other than triangle any suggestion please

Answer 1

[Matt J]

Maybe use HOUGHLINES to find lines longer than a certain threshold length?

[mani vikas reddy N CS]

thank u so do we need to perform edge before implementing FOGHLINES ....

Answer 2

[saravanakumar D]

Use the function bwareaopen. So we can eliminate the lower pixel images on the file. In your image triangle has the largest pixels.

Example:- output=bwareaopen(image,50);

50 is threshold pixel rate