Optimizing color reproduction of a topometric measurement system for medical applications.

Integration of color information in 3D models acquired with a topometric measurement system opens a wide field of applications in medicine, e.g. prosthetics. To ensure an accurate and reliable color reproduction in a 3D topometric measurement system, different approaches have been evaluated. These techniques focus on the calibration of the CCD camera using color test charts by applying a polynomial regression method as well as numerical methods to compensate an intensity decay of the illumination in 3D datasets which is caused by varying distances and orientations of the measured object with respect to the light source. The methods presented in this contribution have been applied to a topometric measurement system with one-chip color CCD cameras. An enhanced color reproduction of various objects is demonstrated.

Modular optical topometric sensor for 3D acquisition of human body surfaces and long-term monitoring of variations.

Optical topometric 3D sensors such as laser scanners and fringe projection systems allow detailed digital acquisition of human body surfaces. For many medical applications, however, not only the current shape is important, but also its changes, e.g., in the course of surgical treatment. In such cases, time delays of several months between subsequent measurements frequently occur. A modular 3D coordinate measuring system based on the fringe projection technique is presented that allows 3D coordinate acquisition including calibrated color information, as well as the detection and visualization of deviations between subsequent measurements. In addition, parameters describing the symmetry of body structures are determined. The quantitative results of the analysis may be used as a basis for objective documentation of surgical therapy. The system is designed in a modular way, and thus, depending on the object of investigation, two or three cameras with different capabilities in terms of resolution and color reproduction can be utilized to optimize the set-up.