SIMULTANEOUS ORIENTATION AND CALIBRATION OF IMAGES AND LASER POINT CLOUDS WITH STRAIGHT SEGMENTS

Abstract. This paper presents a method based on the use of straight lines as tie features for simultaneous orientation and calibration of Frame Camera (FC) and Airborne Laser Scanner (ALS) images. For the orientation and calibration of FC images, various methods have been investigated in the past. From those, FC Integrated Sensor Orientation (ISO) has established as the most accurate and robust one. More recently, ISO block adjustment techniques have been successfully applied to ALS orientation and calibration. As of today, for the combined ALS and FC image data sets there are no well-defined procedures as compared to the other two scenarios. Our proposed method essentially reduces to the use of straight line segments as tie features between FC and ALS images. The concept is similar and compatible to the use of tie points in FC ISO and of planar surfaces in ALS ISO thus allowing for the simultaneous orientation and calibration of ALS and FC images that involve, point, line and planar surface tie features. In the paper we describe and derive the two observation equations that relate (1) FC image point measurements to straight lines and (2) distance-parallelism measures between straight lines and planes. The concept and models are validated with a small FC and ALS block with real data. The preliminary results indicate the potential of the approach and confirm its feasibility.