Mask image with static threshold in matlab -

I have to infuse an image with a static threshold of 10% of the intensity in matlab. I get the intensity to use the mean2 (image) and it gives a meaning which is one of the 15.10 diagram, thus I mean the threshold 1.51 . im2bw (image, level) takes the threshold between 0 and 1. How to uninterite my image in matlab in this case?

You can binaroarize the image with a simple logical statement. For perfection, I have also added the threshold fixation.

  threshold = means (image (:)); Binarymask = image & gt; 0.1 * threshold;