Optical method for the positioning of measurement points

When data analysis is based on imaging techniques, a good correlation between measures and their spatial position is needed. To reach this goal, scanning is commonly performed along a rectangular grid (raster scan) and measures are associated with a local Cartesian (planar) reference. Unfortunately this method reveals inadequate in many situations. For example when the scanned object is not planar, or a uniform sampling grid does not reflect the underlying density of details. The proposed method addresses these and other issues thanks to three features: 1) free scan is enabled in 3D space, 2) each measurement is automatically associated with its position in space and 3) all scanning points can be shown on a picture of the scanned object along with a representation of the measured property. The presented method is particularly useful for high frequency hand held GPR and in general for multisensors measurement heads.