Evaluation of a Metric Camera System Tailored for High Precision Uav Applications

Abstract

ABSTRACT:In this paper we present the further evaluation of DLR's modular airborne camera system MACS-Micro for small unmanned aerial vehicle (UAV). The main focus is on standardized calibration procedures and on photogrammetric workflows. The current prototype consists of an industrial grade frame imaging camera with 12 megapixel resolutions and a compact GNSS/IMU solution which are operated by an embedded computing unit (CPU). The camera was calibrated once pre-flight and several times post-flight over a period of 5 month using a three dimensional test field. The verification of the radiometric quality of the acquired images has been done under controlled static conditions and kinematic conditions testing different demosaicing methods. The validation of MACSMicro is done by comparing a traditional photogrammetric evaluation with the workflows of Agisoft Photoscan and Pix4D Mapper. The analyses are based on an aerial survey of an urban environment using precise ground control points and acquired GNSS observations. Aerial triangulations with different configuratrions of ground control points (GCP's) had been calculated, comparing the results of using a camera self-calibration and introducing fixed interior orientation parameters for Agisoft and Pix4D. The results are promising concerning the metric characteristics of the used camera and achieved accuracies in this test case. Further aspects have to be evaluated by further expanded test scenarios.

Benchmarking the Optical Resolving Power of Uav Based Camera Systems

“…The influence of different demosaicing methods regarding resolving power of a camera system suited for UAV applications has been pointed out in (Kraft et al, 2016a). Figure 5 shows the parameter σ of the PSF (see section 3) for a Ricoh GXR MountA12 with Zeiss Biogon 21/2.8 lens as a representative of the bridge camera family.…”

“…This effect is often described as vignetting and is caused by the lens system itself and by the integrated aperture. The vignetting can be measured and corrected as an image processing step whilst determine the Photo Response Non-Uniformity (PRNU) (Kraft et al, 2016a). After the light rays passed the lens system they hit the sensor surface.…”

“…The larger the effective area the more photons contribute to the signal assuming identical time frames and therefore increase the signal. The electronic ambient noise can be determined pixel by pixel as part of the Dark Signal Non-Uniformity (DSNU) (Kraft et al, 2016a).…”

Review article: the use of remotely piloted aircraft systems (RPASs) for natural hazards monitoring and management

“…Point clouds can very often be converted into digital surface models (DSMs), and digital terrain models (DTMs) can be extracted by removing the off-ground regions (mainly buildings and trees). In real applications, many parameters can influence the final resolution of DSM/DTM and orthophotos such as real GSD (ground sample distance) (Nocerino et al, 2013) interior and exterior orientation parameters (Kraft et al, 2016), overlapping images, flight strip configuration and used SfM (Structure-from-Motion) software (Nex et al, 2015).…”

Towards Standardized Evaluation of Image Quality for Airborne Camera Systems

“…To support this, a real UAV-based data set from DLRs MACS Micro camera system (Kraft et al, 2016) was acquired over a photogrammetric test site. A bundle block adjustment was calculated for all 632 images in cross-flight configuration (overlap: 80% in flight direction, 60% across flight direction).…”