A Permanent Test Field for Digital Photogrammetric Systems

Abstract

Comprehensive field-testing and calibration of digital photogrammetric systems are essential to characterize their performance, to improve them, and to be able to use them for optimal results. The radiometric, spectral, spatial, and geometric properties of digital systems require calibration and testing. The Finnish Geodetic Institute has maintained a permanent test field for geometric, radiometric, and spatial resolution calibration and testing of high-resolution airborne and satellite imaging systems in Sjökulla since 1994. The special features of this test field are permanent resolution and reflectance targets made of gravel. The Sjökulla test field with some supplementary targets is a prototype for a future photogrammetric field calibration site. This article describes the Sjökulla test field and its construction and spectral properties. It goes on to discuss targets and methods for system testing and calibration, and highlights the calibration and testing of digital photogrammetric systems.

Digital Airborne Photogrammetry—A New Tool for Quantitative Remote Sensing?—A State-of-the-Art Review On Radiometric Aspects of Digital Photogrammetric Images

“…Self-calibration is a concept commonly used with geometry [43,44] but can be generalized to concern radiometry as well; it means the determination or improvement of system calibration using the actual mapping data. A photogrammetric test field with permanent and temporal radiometric and spatial resolution reference targets in Sjökulla, Finland [50]. Photo by the National Land Survey, Finland.…”

“…In Finland, comprehensive campaigns with various systems have been carried out at the Sjökulla test field [1,2,13,50]. Institut Cartogràphic Catalonia (ICC) has performed comprehensive campaigns with DMC at the Banyoles test field [38,51,52].…”

Analysis of Properties of Reflectance Reference Targets for Permanent Radiometric Test Sites of High Resolution Airborne Imaging Systems

“…In Europe, the idea of a European-wide test site network for geometry and radiometry has been established [8], but currently only individual test site concepts are available [10][11][12]. Existing permanent test sites for the radiometric calibration of airborne systems are the Sjökulla test site of the Finnish Geodetic Institute (FGI) in Finland (Section 3.1) [12] and the Stennis Space Center (SSC) test site in the US [3,4].…”

“…At the Sjökulla test site, the permanent reflectance and spatial resolution targets are constructed out of gravel and have a reflectance range of 0.05-0.50 as well ( Figure 2) [12,23]. The CEOS satellite test sites are bright, large Earth surfaces: sand deserts, dry lakebeds and Antarctica Ice targets [18].…”

“…For example, the mature (60 year old) concrete surfaces at the military airfield on Thorney Island in England have shown that reflectance factors have varied by a factor of two during the year, and are highly influenced by biological materials growing over surfaces and their interactions with moisture [26]. At Sjökulla, the gravel targets have shown many advantages, including durability, low maintenance efforts, natural cleaning of the surface by rain, and a fast drying process, but also significant temporal changes [12,23,27].…”