Comparison of 3D models of an object placed in two different media (air and water) created on the basis of photos obtained with a mobile phone camera

Abstract

Photogrammetry is one of the contactless geodetic techniques that provide reliable information about objects and their surface properties. Traditional photogrammetric methods require specialized equipment, such as metric cameras, which are very expensive and difficult to access, and the processing of the data obtained from them requires a significant investment of time. An alternative to this solution are generally available non-metric cameras, which can replace professional photogrammetric devices. Currently, consumer-grade digital cameras are enjoying the increase of popularity among photogrammeters thanks to the interchangeable lenses, good image sensor quality and the ability to manually set all camera parameters. However, due to the high costs of purchasing and maintaining such equipment, mobile phone digital cameras are increasingly used, the parameters of which are beginning to match many professional digital SLRs. The newest smartphones are also waterproof, so they can have potential applications in underwater photogrammetry.This article presents the possibilities of using mobile phone cameras in close-range photogrammetry and shows the beginning of research on the use of smartphones in underwater photogrammetry. Three-dimensional models of the gear wheel were made on the basis of photos obtained in two media: in the air and underwater. The two point clouds were then compared, obtaining an average distance difference of ±0,3 mm.