High-Speed Solid State Camera Systems
for Digital Photogrammetry
Hans-Gerd Maas
Institute of Geodesy and Photogrammetry, Swiss Federal Institute of Technology
ETH - Hoenggerberg, CH - 8093 Zurich
Abstract:
For many applications in machine vision, digital photogrammetry and scientific research image sequences of rapidly moving
objects have to be acquired with high temporal resolution. If the standard video rate (30 frames/sec NTSC resp. 25 frames/sec
CCIR) is not sufficient, high-speed solid state cameras may be considered offering frame rates of up to 15,000 frames per sec-
ond. As the processing or data reduction of their images will usually not be possible in real time, appropriate analog or digital
image sequence storage devices have to be discussed.
One of the most important features of a high-speed solid state camera system is the data rate. While the systems with the high-
est data rates still come with analog storage on video tape, systems with digital storage on RAM or realtime disks are prefera-
ble from the aspects of accuracy and data handling. This overview will present some high-speed solid state camera systems
with data rates ranging from 8 MB/sec up to 175 MB/sec, frame rates of 100 to 15,000 images per second, sensor sizes of 64
x 64 to 756 x 287 pixels, digital and analogue data storage including an own scheme with cascaded standard cameras, com-
pare their technical data and discuss their applicability and restrictions.
Introduction
Using the term "high-speed" in combination with solid
state sensor technology one first has to define what is meant
by high-speed. A misunderstanding often to be found in the
literature as well as in manufacturer brochures is the use of
the word high-speed camera for CCD cameras with ultra-
short shutter times. Such cameras - often equipped with
image intensifiers - offer exposure times down to a few
nanoseconds and are suitable for freezing extremely fast
motions, but they usually work with the standard video sig-
nal (which means that they deliver 50 video fields per sec-
ond in the European CCIR norm or 60 video fields per
second in the US NTSC norm, as in all electronically shut-
tered cameras with interlaced output the integration times
of the two video fields do not overlap) and are not suited for
events which require high imaging rates. In this publication
the term high-speed camera is used for solid state cameras
which offer imaging rates of more than 100 images per sec-
ond.
If image sequences with high imaging rates cannot be proc-
essed in realtime (where realtime is defined by the imaging
rate) or have to be played back in a slow motion mode, suit-
able image sequence storage devices have to be designed.
In general one can distinguish systems with analog image
transmission and storage (usually on videotape) and digital
systems (usually with RAM or realtime disk storage).
While analog systems (Miquel, 1987) offer the highest data
rates and storage capacities, digital systems offer some
important advantages like direct random computer access
to data and better data quality especially to users who are
interested in any kind of digital image processing.
Film based systems do still offer the highest imaging rates
(one million images per second and more - Johnson, 1990)
or higher resolution at imaging rates comparable to those of
solid state sensor systems, but they are not considered in
this publication duc to the time consuming off-line process
of developing and digitizing film (Godding, 1990).
To achieve high imaging rates with solid state sensors some
rather different ways can be chosen:
Faster sensor readout (which is generally limited by the
manageable data transmission frequencies).
* Higher temporal resolution at cost of spatial resolution
(i.e. higher imaging rate but less pixels at constant data
rates).
* Selective readout (often by skipping of a certain number
of lines).
* More than one readout port per sensor.
» Multi-sensor systems.
There is no standard around in the high-speed world, so
