delete background x ray image

Hi, how can I delete the background of a dicom-image? By now I use this code:

level = graythresh(ImageLowNRUOTATA);
BW = im2bw(ImageLowNRUOTATA,level);
figure (3)
subplot(1,2,1); imshow(BW)

and it returns a binary image (black and white).

bw=uint16(BW);
ImageLowNRUOTATABINARY=uint16(ImageLowNRUOTATA);
C=imsubtract(ImageLowNRUOTATABINARY,bw);

I don't know how subtract the greyscale image (dicom) and the image that i found with the graythresh. Please help me.

Answer 1

[Image Analyst]

Don't use imsubtract, just set the values in the image to zero where your mask is true:

ImageLowNRUOTATABINARY(BW) = 0;

[Laura Fabbri]

Hi, using ImageLowNRUOTATABINARY(BW) = 0; the image becomes all black. I have to delete the background of a dicom chest image and using the 'graytresh' function the image becomes binary (black the chest and white the background, you can see in the photo) but now i don't know how return to a grayscale image without the background.

[edgar avalos]

try:

ImageLowNRUOTATABINARY(imcomplement(BW)) = 0;