Laser scanning

  

With traditional surveying, land surveyors go out in the field and do measurements on one the forehand defined objects. FLI-MAP works differently. By using our helicopter based corridor mapping system, a continuous scan of the entire corridor is made. The 150 kHz laser, scans at a rate of 150 times per second, resulting in almost 150,000 points per second and 10-175 per square meter on the ground depending on flight altitude and flight speed. Each scan record contains timing, laser range, data verification/error detection information as well as intensity information, which can be used for feature extraction and filtering

This ' point cloud' contains the geographic data of everything in the corridor. After the survey flight, FLI-MAP uses this data to extract the information that is requested on that moment, e.g. topographic data of power line conductors and structures, height models, shapes and positions of water embankments, distances between overhead lines and buildings. Basically, anything in the corridor can be mapped and analyzed. In a later stage, there may be a need for other information of the corridor. The data can be used and reused for innumerable applications. Cross and longitudinal profiles can be extracted on any location. With traditional survey techniques a new survey expedition would be obliged.

Besides laser data the FLI-MAP Corridor Mapping method captures high resolution, forward and downward looking photo and video data of the corridor to be surveyed. This material gives an actual view of the complete project area.

The downward looking high resolution photo images can be geo-referenced and corrected for lens distortion in order to create true-ortho photo mosaics. These mosaics add visual detail to asset management and GIS applications.

The video imagery can be provided as MPEG4 files. Alternatively, a small software package ‘DV Controller’ can be supplied to integrate the imagery in third party CAD or GIS packages such as ESRI’s ArcView.

The integrated line scan camera in the system captures the RGB-values of the surveyed corridor, enabling a real “as is” 3D-visualization of the surveyed area and therefore results in an easy interpretation of the terrain situation in that area.