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2.1 Users Continue with Existing Workflows

To ease the user from film into the all-digital workflows, images were to be as similar to scanned aerial film a possible. The then-established digital processing workflows were to get continued, avoiding add-on training and new photogrammetry software.

2.2 Geometric Accuracy at ±1 μm  

In analogy to film, the geometric accuracy needed to be high and stable over time at ~  ±1 μm. Two considerations were important. First, assembling tiles into a large image needed to rely on overlaps to support a “triangulation” with good redundancy.  Secondly, the individual image tiles needed to be taken with identical perspectives. The so-called “syntopic” imaging system [“syn” = same, “topos” = place] ensured that these conditions were met. The idea is illustrated in Figure 3.

Figure 3:

Illustrating “syntopic” imaging. The individual 4 optical cones “fire” one after the other at intervals in time that correspond with the movement of the camera platform. In a typical aerial mission, a millisecond will represent the airplane’s move forward by ~ 7 cm.

2.3 Superior Radiometry

Digital radiometry can outperform film kamagra 100. At issue is one’s ability to maintain a 72 db signal-to-noise-ratio. This will result in nearly 14 bit of radiometric range and a need to assign to each color channel a 16-bit number. And there is no grain noise.

2.4 Simultaneous Infrared for True and False Color

The film-to-digital transition substitutes the 3 film-colors red-green-blue by 4 digital colors red-green-blue- near infrared. Considerable automated image analysis work is enabled by the additional infrared channel, especially as concerns vegetation.

2.5 Digital Systems at the Film Camera Cost Level

The photogrammetric services industry operated on business plans that include the depreciation of the film camera and the film processing costs, all to be earned via aerial flight projects. Digital cameras already can be expected to become rapidly obsolete along with all things digital. Therefore the depreciation and maintenance of a digital aerial camera must be financed by the savings on film and film processing.

A reliance on software can produce a so-called “software-leverage” to reduce the cost-of-goods in the new UltraCam-technology. Functions previously achieved by precision mechanics and optics must be taken over by software and elaborate calibration techniques [Kröpfl et al., 2004]. This can reduce manufacturing and material costs.