Image segmentation by pixel intensity in matlab

Question

I'm trying to segment a part of an image in matlab. I'm using CT images and I would like to segment the teeth that have metal because this metal artifacts compromise the image quality. Can someone give me a help?

1. What I want to segment 2. Original image

Answer 1

As a simple start, you can use a simple threshold that you set manually based on the histogram.

imhist(image)
    threshold = 120
    binaryImage = image>threshold
    imshow(binaryImage)

next find the boundary of the binary image using some function such as bwtraceboundary . Finally, combine the original image and the boundary image to produce the final image.

I think the hardest part would be the threshold.