Stability analysis of low-cost digital cameras for aerial mapping using different georeferencing techniques

Increasing resolution and lower cost of off-the-shelf digital cameras are giving rise to their use in traditional and new photogrammetric activities such as aerial mapping, transportation and surveillance as well as archaeological, industrial and medical applications. For most, if not all, photogrammetric applications, the interior orientation parameters (IOP) of the camera need to be determined and analysed. The derivation of these parameters is usually achieved through a bundle adjustment with self-calibration procedure. Prior to using a camera in photogrammetric applications, the IOP should be estimated and their stability should be checked. Camera stability has been rarely addressed when dealing with analogue metric cameras since they have been carefully designed and built to assure the utmost stability of their internal characteristics. However the stability of low-cost digital cameras needs to be investigated since these cameras are not built with photogrammetric applications in mind. This paper introduces three quantitative methods for testing camera stability, where the degree of similarity between reconstructed bundles from two sets of IOP is evaluated. Each of these methods limits the position and orientation of the bundles in a different way. Hence, each method is applicable for a specific georeferencing methodology depending on similar constraints imposed by the stability measures and different georeferencing techniques. The paper will test this hypothesis on the basis of reconstruction results obtained from the use of a low-cost digital camera in an aerial mapping project.