During the restoration of a historical building the true-to-scale reconstruction of lost details or destroyed building parts from historical photos can be of great importance. Identical points between the still existing fabric of a building and the historical pictures are chosen and used as photogrammetric points of measurement. With the help of these points single images can be digitally rectified or the projection of curved surfaces is digitally processed. Several existing historic pictures enable a three-dimensional photogrammetric evaluation. On this basis geometrical information can be derived from historical pictures.

For the preparation of the restoration of a work of art, its style-critical or other analysis as well as for the completion documentation of conservation measures photographs and studies based on images are needed. For photography on location the following photograph systems are available in co-operation with our partners:

• large sized specialized cameras, middle sized cameras - also with special filters for photographs in different spectral regions,
• a Infrared-Vidicon Camera System for the IR Reflectography,
• a Ultraviolet-Vidicon Camera System for the UV Reflectography,
• a specialized X-ray System as well
• thermographic photograph systems.

For the preparation of the restoration of a work of art, its style-critical or other analysis as well as for the completion documentation of conservation measures photographs and studies based on images are needed. For photography on location the following photograph systems are available in co-operation with our partners:

• large sized specialized cameras, middle sized cameras - also with special filters for photographs in different spectral regions,
• a Infrared-Vidicon Camera System for the IR Reflectography,
• a Ultraviolet-Vidicon Camera System for the UV Reflectography,
• a specialized X-ray System as well
• thermographic photograph systems.

In accordance with the conserving classification and the priority of the object and the orders given by the local authority of preservation of monuments and historic buildings an appropriate documentation can be offered. This contains the basic photographic documentation with a large sized camera, the stereo images documentation which can be evaluated photogrammetrically at a later date, the deformation-true tacheometric building survey in different degrees of accuracy, digital photomaps in various scales and graphic facade plans up to the stereo-photogrammetric evaluation.

For planning purposes and for the illustration of change during refurbishment projects and the monument reconstruction visualizations are an important decision guidance. Depending on the respective setting of tasks different proceedings can be chosen.

In the simplest case different drafts can be visualized by picture assemblies, overlays and color variants in the rectified photomap.

For the reconstruction of destroyed building parts or entire buildings a visualization in today's environment is advantageous. For this purpose historical pictures can be used, by which the camera position will be photogrammetrically calculated. The historical building view is inserted into a photograph of the current situation taken from the calculated view point.

For complex tasks of visualization it is advisable to produce a 3D photo model. Using existing plan documents, local geodetic measurements and the photogrammetric evaluations the construction of a true-to-scale 3D CAD model takes place. The degree of detailing of the model depends on the task set. The picture information necessary for the photo model is taken over from existing photmaps. If necessary also historical photographs can be used. The further use of a true-to-scale 3D photo model takes place in various ways: as-built documentation, development of information systems, photo-realistic views, round tours and films for presentations. Additionally views of the 3D photo model with selected lines of sight can be computed and inserted into photographs of the current situation. The 3D photo model can show both the historical state, and the current planning state.

Panoramic photographs offer an interesting possibility for the presentation of your objects due to the unexpected view given. With a high resolution vertical line with up to 10.000 sensor elements panoramas with a horizontal picture angle of 360° are taken. The use of different focal lengths and the high picture resolution make photographs of interiors, of architecture up to spacious landscapes possible.

Digital panoramic photographs represent a new form of object documentation. With the software metigo PAN digital photomaps, projection of curved surfaces, ortho image projections as well as pairs of stereo images can be produced. With several camera positions three-dimensional photogrammetric evaluations for graphic plans on the basis from panoramic photographs can take place.

The fokus GmbH Leipzig is developing photogrammetric software for the evaluation of panoramic photographs in co-operation with TU Dresden and the camera manufacturer KST GmbH Pirna (development project, promoted by the SAB Saxonia).

The thermography is a reliable method for the contact-free measurement of surface temperatures. It is used mainly for the location of heat losses, to recognize areas of damage and weakness. Additionally possible fields of application are the search for plastered skeleton framing and covered brickwork structures, the finding of constructional elements of buildings as well as artwork exploration. When using thermal marks the thermal graphic pictures can be rectified digitally and combined to a true-to-scale photomap. By overlaying the thermalgraphic photomaps and a graphic facade plan it is possible to precisely detect the position of non-visible constructional elements.

Digital rectified images represent an economical alternative to graphic plans. The result of the rectification is a true-to-scale photomap, which connects the photographic documentation of the present state with accurate geometrical object information.

For the comprehensive documentation of buildings with several planes the individual facade regions is separately rectified and combined afterwards digitally to a true-to-scale photomap. Digital photomaps permit the simple measuring of quantities and can be used as basis for a graphical evaluation. The photographs are taken with large format cameras (13x18 cm, 4x5 inch, 6x6 cm negative size) in black-and-white, color respectively slide-positive photo material. The photographs are scanned with highly resolution and consequently digitally rectified. The used program metigo 2D works on the basis of the mathematical method of the projective transformation.

To support restorers, in assembling an inventory in museums and collections as well as for documentation purposes digital photomaps in the scales 1:25, 1:10 and larger are provided in high photographic quality and combined into a true-to-scale documentation. Depending on the geometry of the object the production of the photomaps takes place via projective rectification or digital processing and projection of curved surfaces or via digital orthoimage techniques on the basis of measured surface models.

Digitally rectified images are an economical alternative to graphic plans. The result of the rectification is a true-to-scale photomap, which connects the photographic documentation of the present state with accurate geometrical object information.
To support restorers, in assembling an inventory in museums and collections as well as for documentation purposes digital photomaps in the scales 1 : 25, 1 : 10 and larger are provided in high photographic quality and combined into a true-to-scale documentation.

Curved surfaces (e.g. of towers, apses and vaults) can be processed to scale into the plane. Objects with more than one curvature direction or a strong deformation (e.g. cupola, apses) are projected on a middle cylinder. In both cases the geodetic measurement of gage marks, profile lines and further object information takes place on location in addition to the photogrammetric take. The rectified pieces of image are combined afterwards digitally to a true-to-scale photomap, which can be used for documentation purposes or as mapping basis. The digital processing is worked on with the software metigo 3D.

Large sized stereo images form the basis for the evaluation of true-to-scale drawings of facades, walls and ceilings as well as of single objects. With the photogrammetric on site take a fast contactless measurement of geometry and documentation of the present state also very complex objects takes place. The graphic evaluation of the measured photographs takes place at the PC with the software metigo 3D. The stereo-photogrammetric evaluation corresponds to a deformation-true tacheometric survey regarding the accuracy and completeness. This procedure is particularly suitable for the representation of very decoration-rich and structured objects. Curved surfaces can be projected true to scale in the plane. The derivative of cut profiles, e.g. for the addition of geodetically measured sketches, is likewise possible.