Aerial Triangulation

ABSTRACT:
The Cartographic Institute of Catalonia (ICC) has acquired a DMC digital camera and has performed some first investigations
regarding radiometric performance and geometric accuracy potential. In this cooperation with the Institute of Geodesy and
Photogrammetry (IGP), ETH Zurich various aspects are analysed. The investigations make use of recent test flights near Tortosa, a
plane region with varying landcover. For the quantitative analysis of the DMC results, a ground control points and lidar data exist,
which have been simultaneously acquired with the DMC images. The first part of the investigations focusses on geometric sensor
modeling and aerial triangulation. Preliminary results of ICC have shown that when standard additional parameters, like the 12
Ebner parameters, are used in AT, significant systematic errors remain and each of the 4 subimages that form the virtual
panchromatic image has a different pattern of image deformations. In these investigations, we do not perform analysis of additional
parameters in order to model these deformations, as this has been done in another ICC work. The results are analysed using GCPs
established in the above mentioned testfield, using two different bundle adjustment programs.. Another part of our investigations
regarding AT deals with automatic point transfer using a high quality multi-image, multi-primitive matching method developed at
IGP, initially for automatic DSM generation. Different aspects like number, distribution and accuracy of the tie points are analysed,
as well number of rays per tie point. The second part of the paper focuses on automatic DSM generation. Although digital cameras
offer characteristics, like better image quality, that could be used favourably in automated DSM generation, almost all commercial
systems employ matching methods with limitations, like no support of multi-image matching. In these investigations, we briefly
introduce the above mentioned IGP multi-image matching and present the matching results. Initial results with other digital cameras
and images with large forward and side overlap have shown that this matching approach can produce DSMs at least as dense as those
produced by airborne laser scanning and almost as accurate, preserving also very well surface discontinuities. The processing and
DSM control was performed by IGP using lidar data provided by ICC, while ICC made an independent control of the aerial
triangulation using the software programs at ICC.

KEY WORDS: Aerial digital cameras, DMC, Sensor modelling, Triangulation, Digital Surface Models, Accuracy analysis

STARIMAGER is a helicopter-borne high resolution Three-Line Scanner (TLS) imaging system developed by STARLABO Corporation, Tokyo, Japan, jointly with the University of Tokyo and the Institute of Geodesy and Photogrammetry (IGP), ETH Zurich for large scale applications, especially for line-shaped ground object recording (such as roads, rivers, railways), and remote sensing applications. As other airborne and space-borne linear array imaging