Minimization of position uncertainty using 3-D stereo imaging technique for the real-time positioning of a handheld breast tissue anomaly detection probe

There is an associated position uncertainty while determining the position of a handheld diagnostic probe used to detect anomaly present in tissue; this uncertainty is overcome by finding the position and orientation of the diagnostic probe with respect to a reference. A diagnostic probe determines various anatomical parameters but the obtained results are not associated with a position to be compared in time domain. Time domain comparison of anatomical changes helps in pathological findings. For differential comparison, relative position of data collection point with respect to the patient position needs to be the same on different examination days. This paper presents an overview on the work done in overcoming this uncertainty of the position in a hand held probe with respect to the human body. A cost-effective binocular vision system is used to help provide the position information; the method consists of using reference markers and tracking the position and orientation of these reference markers present on the probe. The paper introduces a 3-D stereo imaging technique to determine position of the data collecting point in real time and reconstruct the surface of the patient phantom. The associated error in position determination has been close to 2.5 mm. Yet not clinically tested, this tracking system can be used as a cost effective solution to determine diagnostic hand held probe position information for differential comparison; by installing two to four digital cameras in the examination room.