Detecting a feature in a Medical Image

I have a DICOM image. This image has a three markers which are very small but rectangluar in size. Also they are bright white in color than rest of image in the background ( which is of a bone ).

I want to make an alogorithm to just detect this three small markers. I tried matlab edge detection but does not help.

Could some one suggest some appropaiate filtre for this task ? or some other approach.

Regards

Answer 1

[David Young]

Try thresholding.

binary_image = original_image > threshold;

You choose the value of threshold to be less than the value of the pixels in the white areas.