The present invention relates to a method for processing a signal obtain, from an in situ reformer tube inspection, that includes X, Y, and intensity data sets for each pixel of a sensor from an image sensor receiving a substantially ring shaped image. The method converts a signal having an X position, a Y position, and an intensity component to a signal having an angle, a radius, and an intensity and filtering out all signal sets that do not have a radius greater than a predetermined radius.