The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. Vol. XXXVII. Part B4. Beijing 2008
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Because the flight planning has now been fully removed to be a
part of the bidder’s job and subsequently a job for the chosen
contractor, KMS instead maintain and deliver a detailed
specification on how planning and project-definitions must be
done.
Before the contractor is allowed to initiate the data-capture, the
production-solutions must be approved by KMS.
4.2 Tender evaluation
The KMS photo campaign tender, is an EU-tender assigned to
certain specific rules regarding publication, evaluation and so
forth. These rules are the same though, for both analogue and
digital image production.
One topic that has shown to have big influence on the process
of tender-evaluation, is the number of bets that is received on a
tender. The number of bets received on a digital photo
campaign is, among other topics, also a question on how many
companies that actually do offer a digital solution. Especially in
the first years this was evident.
If a tender is open for digital production only, it will probably
mean that prices will be high, reflecting that there is only little
competition. On the other hand, if a tender is open to both
analogue and digital production, then one has to seriously
consider the different weights on the evaluation criteria, on both
economy and on quality.
If the economy is weighted to high, it is certain that the
analogue bidder’s are favoured, by not having new investments
to pay, and one might be “stocked” on old technology. But if
quality is weighted to high, it is likely that the price-jump from
an earlier analogue production will be high, even though there
might be analogue and cheaper bets in the tender as well.
By tuning the evaluation criteria’s in the tender, year by year,
one might keep influence on operating the photo campaign, in a
world of changing accessibility to old and new technical
production systems.
Another topic is that the evaluation of the tender has shown to
be more complicated to handle than before. This is basically
because a digital solution differs more compared to both
analogue and also to other digital solutions, than it did before.
When comparing each solution on technology, methodology
and logistics and quality assessments.
4.3 Data capture
The digital data capture, as for the analogue, is produced by the
contractor, including only informative communication to the
customer on quality and progress.
The digital data capture is facilitated by a possibility to do “on
the fly” verification of what is logged on the camera-computer.
Normally this is done solely by the contractor.
Because of the digital camera-technique and optics, it has
shown that even images captured in less good conditions as
“high cloud cover” or “low sun angle”, can actually be used for
mapping, orthoimages etc. with good results. This is also
because image quality can be optimized in the image processing.
This means that data capturing time can be extended to include
both some “cloudy days” and also by more production hours on
both ends of a photo day. On the other hand, because image
extend, in the digital cameras are smaller than in the analogue
cameras, a higher number of flight lines are needed to cover the
same area.
Camera-failures are more “unexpected” and “uncertain” in the
new digital cameras, when it comes to technique and
architecture, as they are still not yet as fully proven and
understood. KMS has not yet conclusions on how often and
how much this affect the data capture campaign.
4.4 Data logistics
Data logistic is in both analogue and digital data collection in
responsibility of the contractor, with only informative
communication with the customer on quality and progress.
The time delay from “when images are taken” until the
customer has a “read-out image for QA”, is shortened
dramatically. This means that the customer now “has a chance
to be”, more involved in the early process of QA-dialog with
the contractor. This might request more work and also some
new capabilities by the costumer. But it is also a tool for
optimizing the data and the forthcoming use of the data.
A matter to be aware of on logistics, is the maximum possible
data amount to be captured in one day. As for the analogue
production one might run out of film, in the digital production
one must be aware of how much disc space are available for
both capturing images for a whole day, and also how much disc
space and time (speed) are available for emptying the camera-
data to a transport media. It is important that this does not delay
the photo campaign. Especially if data has to be captured within
a limited time-period.
4.5 Data processing
Data processing is essential on merging the digital cameras
different single CCD’s into one geometrically correct image.
Software to do this is developed by the camera-producer and is
derived to handle one specific camera type.
While processing the merged image from the different CCDs,
the contractor also set up the radiometric presentation of the
image. This can include direct processing, pan sharpening and
also 12 bit to 8 bit image conversion. The different camera-
types uses different techniques and different user interfaces for
these processes. And therefore reflect an “camera-specific
methodology”. Actually one has to rely completely on the
producers skills and experiences with the software.
Many important aspect of the image presentation are included
in the image-processing. And the processing is often managed
or presented, as a “black box”. Therefore the conclusion in
KMS is, that this is a very important topic, which KMS will
focus on in the future.
Until now experiences are that, in general it is not very easy to
interact with the producers, during this process.
4.6 Data volume
By analogue aerial image campaigns, the images were
traditionally exposed on either colour or black/white film. For