A permanent test field for digital photogrammetric systems

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 Sjokulla since 1994. The special features of this test field are permanent resolution and reflectance targets made of gravel. The Sjokulla test field with some supplementary targets is a prototype for a future photogrammetric field calibration site. This article describes the Sjokulla 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.