How to make the grey area completely black, so it's a binary image?

Hi, I have a grayscale tumor image like this:

I want to make the grey area complely dark, something like this:

(This is a mask for another image)

so that the white area remailns white, but the grey area goes dark. Is it possible?

Answer 1

[Tala]

you mean you want to have the whole tumor area white and the rest of the image black? just threshold your image

I=imread('image.bmp');
I2=I>250;
imshowpair(I2,I,'montage')

Answer 2

[DGM]

The mask that was used to create the hole in the image is the binarized image. You shouldn't need to turn the source image into a copy of the mask.

but if you must:

A = imread('https://www.mathworks.com/matlabcentral/answers/uploaded_files/966480/image.bmp');
A(A<255) = 0;
imshow(A)