How can I get the top and bottom envelopes of a signal?

I need a matlab code to get the top and bottom envelopes for each verse (line) in (1340x1800) image. The following figure represents one verse (line) in the image

Answer 1

[Bjorn Gustavsson]

You go to the file exchange and search for envelope. This gave me 157 hits, and should give you the same number of hits, some of them seem to be solving your problem:

FEX-envelope-search

HTH

[Asmaa Ali]

Thank you.

Answer 2

[Star Strider]

If you have R2015b or later, use the envelope function. Otherwise, see the hilbert funciton (linked to at the end of that page).

[Asmaa Ali]

Thank you