Charles Toth 
  
In summary, the actuality of integrating a digital camera into LIDAR systems comes from several facts. First, the 
medium-resolution, direct-digital images simultaneously acquired with the LIDAR data can provide the necessary 
visual backdrop for the surveyed project area. Second, the use of imagery introduces the so far missing redundancy to 
the LIDAR data acquisition and thus, even at medium ground resolution, the stereo coverage can contribute 
meaningfully to the surface extraction process, especially for areas with sparse LIDAR spot distributions. Third, these 
systems are already available at an attractive price per performance ratio (the price of a 4K by 4K digital camera system 
is comparable to the price of the onboard GPS/INS system and is certainly much lower than the price of the LIDAR 
system itself). In fact, we strongly believe that the use of such complementary imaging systems will be mandatory for 
any quality LIDAR systems in the future. A further benefit of the simultaneously captured digital imagery is that it 
provides a fallback potential for unexpected situations such as when the direct orientation data is missing or troubled; 
for example, instrument failures, or GPS outages, etc. 
Finally, we would like to emphasize that although the laser scanning data acquisition technology is already considered 
fairly mature yet the data processing and modeling techniques still require significant research and further 
developments. 
ACKNOWLEDGMENTS 
The authors would like to acknowledge the support of EarthData Technologies for providing test flights and valuable 
technical discussions. : 
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