I am building a scanner component for an iOS app so far I have the result image cropped and in the correct perspective.
Now I need to turn the color image into Black and white "Scanned" document.

I tried to use - "CIPhotoEffectNoir" but it more grayscale then totally black and white. I wish to get a full contrast image with 100% black and 100% white.

How can I achieve that?
Thanks