Digital near-infrared camera for 3D spatial data capture

Abstract

Low-cost, medium-resolution and hand-held digital cameras with near-infrared (NIR) capability are now readily available. The NIR spectrum (700 to 925 nanometers) is a tiny part of the overall electro-magnetic spectrum. It’s just outside the spectrum seen by the human eye. While it is not possible to see NIR radiation it can be recorded on NIR films or CCDs with special filters. Digital NIR image of vegetations, living things, rocks and man-made objects have a number of positive features over the traditional color or black and white photography. In the past, NIR images were strategically used only because of the expensive and hard-to-find NIR films and high-cost CCDs. However, present CCD cameras require only inexpensive NIR filters to take good NIR images. The paper highlights the current applications and potential of NIR images in photogrammetry. Next, the paper provides discussion on the calibration of digital cameras which could be used for high precision 3D photogrammetric work.