Symposium on Remote Sensing for Resources Development and Environmental Management / Enschede / August 1986
285
A preliminary assessment of an airborne thermal video frame
scanning system for environmental engineering surveys
T.J.M.Kennie & C.D.Dale
University of Surrey, Guildford, UK
G.C.Stove
ERSAC Ltd, Livingston, Scotland, UK
ABSTRACT : Video based camera systems are being used by an increasing number of remote sensing users. These
systems offer several adv-antages in terms of ease of use, speed of operation, portability and cost. Of
particular interest are the thermal video frame scanning (TVFS) systems. These scanners, developed primarily
for military purposes, differ considerably in design from the thermal infrared linescanning instruments
traditionally used for thermal surveys in remote sensing. One specific example, the Barr end Stroud IR18, is
described together with the modifications necessary to mount such a system in a number of light aircraft.
Methods of digitally enhancing and classifying single frames of data are discussed. The paper concludes by
considering the application of suitably processed imagery for environmental engineering projects such as heat
loss monitoring, thermal mapping of roads, geotechnical site investigations and drainage, sewer collapse and
utility duct surveys. Further potential areas of application are also identified.
RESUW: Les utilisateurs de télé-détection utilisent de plus en plus l'appareil photographiaue oui se fonde
sur le video. Ges systems offrent plusieurs advantages - facilité d'usage, vitesse d'operation, portabilité,
et coût. Les systèmes qui se basent sur l'explorateur thermique de cadre video (TVSF) sont d'intérêt
particulier. Le dessin de ces appareils explorateurs qui étaient dévéloppés pour les buts militaires d'abord
différent considérablement des instruments d'exploration thermique et linéaire qu'on emploie d'habitude pour
les levés thermiques dans le télé-détection. On décrit un exemple spécifique, le Barr et Stroud IR 18, et aussi
les modifications nécessaires pour installer un tel système dans quelques avions légers. On discute les
méthodes digitales de rehausser et classifier les cadres uniques de données. Le papier conclut de considérer
l'application des images traités pour les projets de génie de l'environnement, par exemple, la surveillance de
la perte de chaleur, la cartographie thermique de routes, les investigations géotechniques de site et la
surface de captation des eaux, l'effondrement des égouts, et les levés des conduits utilitaires. On identifie
aussi les autres domaines d'application potentiale.
1 INTRODUCTION
An increasing number of users in recent years have
been considering the potential of video based aerial
remote sensing systems. A wide variety of data
acquisition systems are currently available and a
selection of these are reported in section 2,
together with some discusssion of the advantages of
using video as a recording medium.
One of the most exciting developments however, is
in the use of thermal video frame scanners (TVFS)
operated from light aircraft. The design features of
such instruments, with particular reference to the
Barr and Stroud IR18, are discussed in section 3.
This is followed by details relating to the mounting
of such a system in a variety of light aircraft.
The use of digital image processsing techniques to
filter and enhance single frames of thermal date is
presented in section 4. The paper concludes by
reporting some of the current projects for which the
scanner has been used.
2 AIRBORNE VIDEO BASED DATA ACQUISITION SYSTEMS
A summary of previous literature which has reported
on the use of video based data acquisition systems is
given in Table 1. Several advantages can be cited to
demonstrate the benefits of video based systems,
which include system portability, near real time
verification of data capture, rapid turnaround (since
there is no processing stage), low cost of operation
and ease of duplication of data (Meisner and
Lindstrom, 1985). In view of these perceived
advantages a research programme was initiated by the
University of Surrey, in conjunction with the
University of Glasgow, in August 1984 to evaluate the
use of a portable TVFS system for remote sensing
applications. Although low resolution thermal imaging
Table 1 Summery of previous literature
video based date acquisition systems
airborne
Spectral
Region
Author(s)
Application
(0.4-0.70um)
Panchromatic
(0.4-0.7ym)
3 band colour
(0.4-1.lpm)
3 band 'false'
colour
(0.55-l.lym)
4 band
Multispectral
(3-5.6u m,
8-14pm)
Thermal
Infrared
Mussekowski, 1983 Water
assessment
Vlcek, 1983 Forestry
Vlcek and Cheung, 1983 "
Meisner and
Lindstrom, 1985
Everitt Rangeland
and Nixon, 1985 studies
Nixon, Escobar and Vegetation
Menges, 1985 studies
Vlcek and King, 1984 Vegetation
Vlcek, King and Vegetation
Shemilt, 1984 Mapping
Tice end Larsson, 1978 Heat loss
Geraci and
Celtebiano, 1983
Geraci, 1983
Clement, 1985
Amin, 1986
Oil pollutic
Water qualit
Water qualit
Geothermal
Mapping
systems such as the Aga Thermovision have been used
previously (Tice and Larsson, 1978, Geraci, 1983, and
Geraci and Celtebiano, 1983) little attention has
been focussed on the more expensive, but much higher
performance, military forward looking infrared (FLIR)
imaging systems.
