Fig. 5.

The effects of autoscaling and histogram equalization on visualization of formulated ratio images are shown. (a) Standard color photo of an adenoma taken with digital SLR camera. (b) Autoscaled R27 ratio image. (c) Histogram equalized R27 ratio image. (d) An adenoma from a different specimen imaged by digital SLR camera. (e) Autoscaled R7 ratio image. (f) Histogram equalized R7 ratio image. Images (a), (b), and (c) demonstrate that autoscaling of ratio image R27 is more effective than histogram equalization, while (d), (e), and (f) show the benefit of histogram equalization for ratio image R7. Tattoo ink applied prior to excision causes dark color artifacts in images a (immediately left of polyp) and d (bottom center of image).