Fig. 1 shows microdensitometer profiles of the Jade seaway perpendicular
to the dredged navigable water of 20 m depth. For the profiles the origi-
nal HASSELBLAD MK 70 Kodak Ektachrome film was used. The microdensito-
meter was a JOYCE - LOEBL MK III CS with analog recording. The phenomena
shown on the photography are water bodies of different sediment concen-
tration. In the middle of the image and the profiles, relatively deep and
clear water of greenish colour can be interpreted. At both sides brown/
yellow water bodies indicate sedimental plumes, which flow from the tidal
land into the navigable water.
Density
Filter green 0.55 um
Filter red 0.62 pm
Vater body with sediment Water body without sediment Water body with sediment
v
Brown colour Green colour Brown colour
Fig.1: Microdensitometer profiles of the jade seaway in HASSELBLAD MK 70
KODAK EKTACHROME photography
The microdensitometer records this situation best using green filter
(0,55 um) and red filter (0,62 um). This matter of fact has been con-
firmed by multispectral scanner imagery some years later.
The correlation of microdensitometer profiles with in-situ radiometer
profiles from ship leads to many particular problems. Apart from geometric
registration, atmospheric disturbing factors and film properties, the
influence from light fall - off by the camera lens has obviously to
be corrected. In Fig. 1 the light fall - off affects the micro -
densitometer - profiles by superimposing a "catenoid" - shaped curve,
most clearly observed at both ends. Correction of this influence can
be provided only if appropriate compensation procedures for light fall -
off are applied.
3. Design of a LAMBERT-Type Reflector
To determine the transmission properties of the incident light by the
camera lens, a configuration has to be found, where all the other
parameters which influence on the grey values could be neglected. These
are primarily the differnces in reflection by the object per se,. and. the
directions of both incident radiation and lens axis. Therefore a perfect
