Nivellieren mit bildunterstützten Totalstationen

Modern Image Assisted Total Stations (IATS) enable to transfer heights with almost the same accuracy as digital levels. This can be achieved by analyzing the telescope camera image of a digital leveling staff instead of a retroreflective prism. For this new method, the evaluation of the images is divided into two main processing steps. First-quite similar as the processing of a digital level-the binary code information is extracted from the pre-processed and correlated with the known reference code pattern. This leads to initial values for the height readings. In the second processing step, the position of the barcode edges are extracted with subpixel accuracy and are matched with the reference code. The final height reading is then calculated by a least square adjustment. With different experiments, the accuracy of this method is determined. The achieved results of the new approach are compared with the measurements to prisms as well as with the results of precise digital levels. The results-standard deviations below 10 μm (1 s) in laboratory experiments-are far better than common methods for height transfers with total stations.