Toward a Hand-Held Laser Range Scanner: Integrating Observation-Based Motion Compensation

摘要

Although laser range sensors based on sequential scanning can provide accurate measurements in stable operation, the recovered surface geometry becomes noisy and distorted when sensors are hand-held. To compensate for camera motion, some currently existing prototypes integrate a positioning device. Unfortunately, these may not be accurate and fast enough. To circumvent this problem, a method that can compensate for motion distortion is proposed. The principle consists in using the measured shape geometry as a reference frame in 3-D space. The method is based on the collection of a redundant set of crossing profiles. Each surface profile is measured in a very short period of time such that distortion of the profile is negligible. It is assumed that the perturbation error due to motion, affects inter-profile positioning only. Then, the set of rigid crossing profiles are fitted together by moving them such as to minimize the profile intersection spacings. Experiments show that errors in the geometry can be reduced to the order of magnitude of the sensor error. The method can be integrated in the design of a hand-held sensor or as a complementary post-processing stage for improving measurement accuracy when using a sensor positioning device.