how to delate some sparse pixels in a binary image

Hi everyone,

I have a binary image in which I have to detect or extract some pixels. I searched and I found some documentation that maybe help me like imclose or imfill but my image has very sparse pixels and the part that I should identify has not a regular shape or type. I am so confused about what can I do for that so I wanted to share with you to know your comments.

the orginal image and the image (rill erosion) in that I draw a red border to specify the wanted pixels is attached.

many thanks