Approach for Improving the Integrated Sensor Orientation

Abstract

The direct determination of exterior orientation parameters (EOP) of aerial images via integration of the Inertial Measurement Unit (IMU) and GPS is often used in photogrammetric mapping nowadays. The accuracies of the EOP depend on the accurate parameters related to sensors mounting when the job is performed (offsets of the IMU relative to the projection centre and the angles of boresigth misalignment between the IMU and the photogrammetric coordinate system). In principle, when the EOP values do not achieve the required accuracies for the photogrammetric application, the approach, known as Integrated Sensor Orientation (ISO), is used to refine the direct EOP. ISO approach requires accurate Interior Orientation Parameters (IOP) and standard deviation of the EOP under flight condition. This paper investigates the feasibility of use the in situ camera calibration to obtain these requirements. The camera calibration uses a small sub block of images, extracted from the entire block. A digital Vexcel UltraCam XP camera connected to APPLANIX POS AV TM system was used to get two small blocks of images that were use in this study. The blocks have different flight heights and opposite flight directions. The proposed methodology improved significantly the vertical and horizontal accuracies of the 3D point intersection. Using a minimum set of control points, the horizontal and vertical accuracies achieved nearly one image pixel of resolution on the ground (GSD). The experimental results are shown and discussed.

Developing a Theoretical Assessment Method for an Assisted Direct Georeferencing Approach to Improve Accuracy When Mapping Over Water: The Concept, Potential and Limitations

“…Integrated sensor orientation (ISO) is an established concept in photogrammetry where simultaneous image processing is done by combining the Bundle Adjustment and Direct Georeferencing (Heipke et al, 2002, Ip, 2005, Tanathong and Lee, 2014. Studies have shown that the accuracy that can be achieved from only the DG method is limited by the accuracy of the GNSS, the IMU and calibration errors (Mitishita et al, 2016, Stam, 2010 however with ISO technique, reliable and high accuracy measurements are achievable. Further, ISO can provide an opportunity to use low-cost IMU /GNSS which have less accuracy (Tanathong and Lee, 2014).…”

Lidar and Photogrammetric Datasets Integration Using Sub-Block of Images

“…First, the block configuration should have enough forward and side overlap areas with a minimum number of tie points in these areas (Von Gruber positions); second, accurate IOP values and third, accurate values of EOPs´ standard deviations (Cramer and Stallman, 2001). Mitishita, et al, (2016) proposed an approach to improve the Integrated Sensor Orientation (ISO) using in-situ camera calibration and a small sub-block of images extracted from the main image block. Costa et al, (2018) performed studies to verify the viability of methodology to improve the accuracies of the integration of aerial imagery and Lidar datasets, using Lidar control points (LCPs) in Integrated Sensor Orientation (ISO).…”