Edge detection and filling

I have an image and im trying to get the edges and filled the spaces, I have been trying with imfill, but the issue is that when i use the function edge, it doesn't detect the sides, any ideas on how to do it? thanks

this is the image

and i need it to be like this

Answer 1

[Image Analyst]

I'd try adaphisteq() to flatten the shading across the image. Then use a global threshold, then call imfill().

[Federico Uribe]

Thank you Analyst, I just try it and I´m getting a better image, really close to what im looking for, however im still mising a little bit on the side and getting some pixels that are nos supposed to be on the image, should I'm using bwareaopen to get rid of them, but at the same time I´m losing some pixels on the side.

Thanks