Systems and methods for improving quality assurance in pathology using automated quality assessment and digital image enhancements on digital slides prior to analysis by the pathologist are provided. The dimensions of the field of view of the optical device are established, indexed by distance, and the dimensions of items in the field of view of the optical device are determined as a percentage of the full field of view of the optical device at the appropriate distance. The choice of one or more of the frequencies, the phase of the pulses, and the recovery period enable cancellation of the ringing signal from the echoes, including the echo from an excitation pulse. In one embodiment of the invention, the reference markings include several lines and textual prompts. Thereby, the control signals create movement or activation of the cursor on the viewing screen such that different conditions in the mouth cavity are associated with specific cursor commands.