True-orthophotographs are now being widely used in some areas, proving already as very valuable documents even replacing maps
being more complete, reliable and objective. But they are still hard to produce with enough quality for other uses and scales, such
as in architecture and conservation. Most works in these fields are just approximate ortho-rectifications by single or multiple
planes [1]. Some academic attempts to reach quality “true” orthophotos were made recently [2] [9] using a combination of laser
scanner and images, but are still costly solutions lacking from the flexibility needed for field work.
In this paper, a new practical technique and software to produce these architectural orthophotographs is presented, departing just
from conventional digital photographs with no need for metric cameras or laser scanner, and for small projects, not even for
topographical surveying. It is also intended to be easy to use for non-photogrammetrists, dramatically reducing the working time
usually spent in other photogrammetry applications.
This method requires very intensive calculations through a dedicated software development using GPU (Graphic Processing Unit),
making easier and faster the production of high quality true-orthophotographs. The prototype was already tested producing some
orthophotographs in a commercial environment and is being now developed as a compact software application making very easy to
widely produce quality architectural orthoimages, that we feel can become a standard in heritage documentation soon.