PIxel intensity of specific features

I have a image and I need to measure the pixel intensity of the features against the background. A attached is a reference image.

Not sure what you mean by “against the background” since it appears you have rather severely cropped your image (no way to tell what the background is anymore), but perhaps looking into plotting the intensity would help.

you can see some long features. we need to find their pixel from the base (on which these long features are placed)