Scanning Digital Camera

Blom can capture images with airborne scanning digital cameras that produce continuous strips of terrain imagery. These types of digital cameras are three-line scanners that generate overlapping forward-, nadir- and backward-pointing strip images that allow the production of 3D stereo-models, DEMs and ortho-images for mapping purposes. Additional linear arrays are incorporated into the scanner focal plane to allow multi-spectral, colour and false colour images to be generated.

Scanning digital camera captures images whose bands are at the same native resolution, so no colorizing technique, such as pan-sharpening, is required. Blom operates with the “Latest Generation” Leica ADS40 scanning digital camera, in which two beam splitter (a tetrachroid prism) are able to generate perfectly co-registered Panchromatic, R,G,B and NIR images, so that colour and infra-red false colour images are derived with the same resolution.

Professionals can get 5 band co-registered imagery to cover all applications in aerial surveying and airborne remote sensing. Another key benefit comes from the possibility of stereo viewing in true color and color infrared with highest resolution images. ADS40 has also increased the sensitivity of its line sensors so that it can yield faster flight speed or improve image quality.

Blom has successfully employed the two Leica ADS40 since 2004 to execute an aerial survey of Italy at an altitude of about 5500 meters above ground level. This has allowed the production of both color and infrared false color image libraries to be completed. These libraries have a ground pixel resolution of 50cm.

Blom CGR has also computed a classified 2x2 meter DSM from the stereopairs of these libraries. The elevation values have been calculated through automatic stereo-correlation process that uses the multiple combinations of stereo pairs for the area covered pairs (backward-nadir, nadir-forward, backward-forward). The elevations have been subsequently classified by the mean of NIR images into 2 basic classes: vegetation and man-made features.