Workshop I - Laser Scanner Systems for Archeological Surveys - CAA

"This workshop pretends to divulgate information on The State of the Art of the laser scanner technology as far as the software and hardware is concerned when solving the usual problems encountered on arqueological surveys.

To this end, we are limiting ourselves to the description of the features offered by a Laser Scanner system, model IMAGER 5006i, manufacturer by Z+F in Germany as well as the software programs JRC Reconstructor and Cloud Cube.

The problems we will focus on are the following:

• Logistic and portability of the equipment, in the concern that field work sites are not always easy to access
• Need of facing small and big objects with high accuracy

The IMAGER 5006i laser scanner concentrates its power on the following characteristics:

1. Very high speed in data acquisition combined with high resolution on the captured files. This feature makes it valid either for surveys of great targets at very far distances or when we are surveying small pieces at close range.
2. The system is very easy to set up and handle. The equipment can be configured without requiring any external connections. This feature is tremendously appreciated as far as the arqueological field work is concerned. Since the batteries, the data storage unit and the file configuration processor are part of the unit, it is not necessary to connect or use any other external complement to perform the data capture. This feature facilitates the work in scenarios which can be uncomfortable, far from urban areas and often of difficult access.
3. Capacity for data acquisition when working with targets coloured close to black.
4. Merging of images captured using the complementary camera with the scanner acquired data, in a integral and automatic fashion, for each of the scenes involved.

With regard to the software programs, we will discuss them in the same manner as we will discuss the hardware and we will try to demonstrate the tools which are used to solve the most common problems in handling the data acquired with the laser scanner: large files corresponding the huge clouds of points within the Auto Cad environment; how the final products are obtained, including profiles, cross sections, contours and volumes; all of them directly on DXF format or on some other CAD compatible systems.

Finally we will explain the working procedures and proper tools to be used to obtain the final products mentioned above: profiles, volumes, slopes, DTM, surface comparisons, and how to obtain the different results on DXF files or on files which are compatible with other CAD systems, in concrete we will discuss the following characteristics:

• Possibility of registering different files without requiring man-made marks, only using natural marks.
• Work aids to digitize plans, profiles and cross sections in general, starting with the cloud of points; all within the Auto CAD environment.
• Automatic generation of a wire mesh, over flats or curved surfaces by using average cross lines or cross planes.
• Integration of different data capture files in only one using a common reference system .
• Work aids to be used in the generation of a wire mesh.
• Registration of different survey files when the target has been changed in position or location while the scan files were being taken."

source: www.caa2010.org