University of South Wales

Biomedical Engineering and Computing
Research Group

Surface Imaging Tool for Medical Endoscopic Applications

OsteoArthritis is a debilitating disease throughout the developed world, causing significant loss of quality of life to individuals and damaging economies, the imaging system described in this paper has the potential to provide an objective means of measuring and reporting lesion dimensions and providing a machine readable data archive for future study. Existing imaging methodologies have been reviewed and contrasted and despite certain limitations the optical method proposed has the potential to address the issues highlighted to date. The preliminary depth measurement results with an accuracy of 200 μm±6% suggests a potential system for the objective reporting of tissue degradation. It is also envisaged that the bio tribological performance may be inferred from the tissue surface condition as image by the proposed system.

In the proposed system two stereoscopic images are simultaneously captured by the camera system, these images are then processed by the proprietary software to produce the 3D mesh whose measurements are available for analysis.

Surface Imaging Tool for Medical Endoscopic Applications

Figure 1. Prototype of the Surface Imaging Tool for Medical Endoscopic Applications. 1) linear microstage; 2) 40mm rotary stage; 3) main window of the MAVIS software showing stereoscopic images; 4 ) optical bench; 5) adapted Digital SLR camera; 6) reconstructed mesh quality; 7) reconstructed 3D mesh

In order to calibrate the system, i.e. obtain the 3D transformation matrix, it was necessary to image a small target (shown in Fig. 3) at two angles (±3°) relative to the camera optical axis at nine different focal planes, four either side of the principle focal plane.

Flowchart of the calibration procedure

Figure 2. Flowchart of the calibration procedure

Flowchart of the calibration procedure

Figure 3. a) Reticle and b) Target Grid


  1. King P., Kulon J., Plassmann P., Theobald P.,Jones M., Wilcox S., “Design, Calibration and Validation of a Novel Surface Imaging Tool for Medical Endoscopic Applications”. IEEE International Instrumentation and Measurement Technology Conference (I2MTC 2015), pp. 1342-1347, May 2015, Pisa, Italy.10.1109/I2MTC.2015.7151468