September 2008
Interview

Dr.-Ing. Juergen Dold
Senior Vice-President
Business Area Imaging and Scanning
Leica Geosystems AG
Heerbrugg Switzerland
Technology is changing at blinding speed
Q.How do you see your
market in the areas of
LiDAR and airborne imaging?
Images are getting more
affordable. They are now used
in areas where they were not
used earlier because of cost.
For example, oil exploration
companies are using orthophotos
for planning purposes
where they would have
otherwise sent survey teams.
Ground survey would have
taken months of work to get
less information than from
airborne data acquisition.
I do not think LiDAR is replacing
photogrammetry. These
technologies are unique in their
own way. For example, if you
want a fast DTM, LiDAR is the
most cost-effective solution
and yields high resolution products.
LiDAR has opened new
applications in areas of utilities,
road mapping, environmental
impact, biomass determination,
etc. Imaging and LiDAR both
have their respective applications,
and they are even beginning
to merge. In city modelling,
you can use a terrain model
from LiDAR over which you
drape an orthophoto. LiDAR is
a multi-dimensional driver of
applications.
The need for higher resolution
images than those traditionally
acquired from satellites is
fuelling growth for airborne
digital imagery. The race
between Google and Microsoft
to get imagery in the hands of
consumers has also raised
awareness about geospatial
technology. At the same time,
Leica is seeing even faster
growth in our LiDAR business
as many of our customers have
largely switched to LiDAR to
derive terrain models.
How do you view the
trends in data fusion and
packaged datasets?
We create sensors to do both
together. Our airborne LiDAR
data is integrated with our
medium format camera images,
all perfectly georeferenced by
the same inertial plus GNSS
georeference system. No
longer do you have to have a
two-hole aircraft and two sets
of sensor controls, as needed
with a large format camera
(LFC) plus LiDAR. With one
flight, you get georeferenced
image and LiDAR datasets that
can then be fused by software.
Leica also sees great
progress in fusing terrestrial
scanner data
with airborne
LiDAR point
clouds. We have
also fused data
from thermal
sensors, hyperspectral
sensors
and RGB
(colour)
imagery. Leica believes that
leading edge sensor hardware
technology must be combined
with equivalent software/workflow
expertise to create a total
sensor solution. Our BA I&S
software groups, combined
with the talents of ERDAS, are
integral to our industry leading
position in airborne sensor
technology. Our customers
thereby have the flexibility to
push the envelope in traditional
data deliverables, data fusion
and other packaged datasets.
Are photogrammetrists
accepting the new digital
format of data?
Yes and no. Working on digital
data requires changes in a
company's data production
workflow. Larger companies
producing large mapping
projects have already implemented
these more capable
workflows. For companies that
were using film cameras, even
those with film scanners and
digital photogrammetry capabilities,
the heavily modified
processing steps of digital sensor
imagery becomes a
challenge.
For digital sensors,
workflow virtually starts on the
airplane. With the entire industry
now shifting to digital sensors,
use of film cameras will
decrease dramatically and end
within the next few years. Photogrammetrists
are keeping up with the differences in scanned
digital data from film Vs direct
digital data from digital sensors.
The larger challenge to
many photogrammetrists has
been the new photogrammetry
software that makes it easier
for someone without a photogrammetry
background to
competently process imagery.
Q. Was the transition from
analogue to digital
painful?
Leica started 50 years ago
with our RC series of filmbased
cameras. In these 50
years, there have been
progress 'blocks' of 4-5 years
each including developments in
automatic film transport, lenses,
etc. leading finally to the
RC30 - the gold standard of
airborne film cameras.
Leica has always started early.
In some cases, we can say we
started too early and could
have waited longer for industry
to be ready for new technology.
We knew that the most innovative
sensor solution would be
required to fulfill the automation
level required by the mapping
industry. Therefore, Leica
chose the 'pushbroom' line
sensor concept for its large
format airborne imaging sensor.
With this sensor, we provide
the highest quality imagery
for a changing world.
Leica introduced the first
digital camera ten years ago.
Leica has a perfect base for
starting new technologies. We
have optical, mechanical,
software and electronic capabilities
plus associations with
leading academic and scientific
research centres to help us
manage the challenges.
You
can therefore see that there
has already been a ten-year
overlap of analogue and digital
imaging technology with a few
years of film technology left.
The transition has been
straightforward for Leica as a
manufacturer and many of our
larger, innovative customers. It
has been more stressful for
customers with more limited
financial and technology
resources that help support
such a major transition.
There has always been
changing technology and
changing performance. The
demand for imagery has gone
up. Data providers want to fly
more and want multiple
sensors on each flight. And, so
has the pace of sensor
advancements changed. Just
two years ago, we released a
LiDAR system with a 100,000
kHz pulse rate and today we
have the ALS60 LiDAR that
delivers 200,000 kHz. Two
years ago we released the
second generation ADS large
format digital sensor. This
year, we released the third
generation ADS80 that
collects images even faster
and uses the newest flash
memory technology. Technology
is changing at blinding
speed and product cycles are
shorter forcing our customers
to adapt at a similar rate.
What do you do to sensitise
your customers?
This is done largely through
direct contact with customers.
Our people attend conferences
and other similar fora to
understand our customers
and identify the challenges.
We do projects with our
customers and get to know
application and performance
requirements trends. The
customer education and
sensitisation process is very
important to us. Leica
must always balance the
competitiveness of our product
lines with the concerns of
our customers that their investments
sometime seem to
become outmoded too fast!
Leica has to push the technology
forward at a pace the
market can adopt. We want the
market to push strongly and
when it does, our R&D efforts
must be ready with the appropriate,
reliable technology. It is
not just about providing a
sensor, but also about providing
a solution that the market
needs and about providing an
affordable upgrade path to
keep all of our customers at
the leading edge.
Take the example of our ADS
with its pushbroom workflow
for faster processing of raw
data to deliverable images. Our
long term vision is to process
acquired data in real time during
the flight. Sensors must be
smart and processing must be
fast and efficient. That is a
challenge to the industry, and
Leica is ready. We call it
"Imagery for a changing world".
Q. Are we going to go back
to photographic frame?
Today, there are solutions that
claim they are (single) frame,
but in fact they use multiple
frames merged into one virtual
frame. The pushbroom sensor
was designed for satellites
because it is the perfect solution
for efficiently collecting
large area, perfectly co-registered,
multi-spectral data. The
different line sensor workflow
compared to frame workflow
requires straightforward training
to understand the differences
and to benefit from its
superior performance. Ironically,
many people feel the workflow
from film to digital 'frame' sensors
is almost identical, but this
is not the case. The processes
that attempt to correlate the
multiple images from the multiple
camera heads that shift
around from thermal and
mechanical instabilities can be
harder to learn and produce
results inferior to line sensor
workflow.
Our customers find that ADS
line sensor workflow is much
easier and more efficient to
work with. Frame sensors
require up to 90% forward
overlap and up to 50% sidelap
and all the data from the multiple
heads has to be correlated
and mosaicked. A line sensor
requires zero forward overlap
since it has built-in forward,
nadir and rearward arrays that
scan a continuous, infinitely
long strip. There are also other
advantages to central (frame)
Vs parallel (line) perspective
acquired data. It is about
mosaicking and management
of data. If sensors are not
designed to minimise the processing
software workload, the
goal of moving workflow onto
the sensor in flight cannot be
achieved.
Frame sensor technology is still
competitive for smaller formats
such as 39 Megapixel
'medium- format' and below
used on smaller projects and
with LiDAR. However, as the
geospatial industry embraces
the benefits of line sensors
over frame sensors, line
sensors will become the
technology of choice for wide
area mapping, earth resource
and most other large-format
applications.
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