The terminology is somewhat ambiguous but one can give the 
following short explanations: 
e hue: attribute defining colour, e.g. the dominant wavelength, 
e saturation: colour strength judged in relation to lightness, 
e value: square root of the luminous appearance of reflectance, 
e lightness: goes from black to white along the grey axis, 
e chroma: a measure of the distance from the grey axis on the 
way to a full colour, 
e intensity: similar to lightness, 
e luminance: scale used on the CIE neutral axis. 
6. CONCLUDING REMARKS 
A short review has been given of a number of problems in the 
surround of activities in photogrammetry and remote sensing 
which deserve increased attention. The review has been pre- 
pared in a rather short time as a result of urgent other work 
commitments and can therefore not be as complete as was de- 
sired. 
The review of activities of concern ongoing elsewhere shows 
that the shift in ISPRS activities towards the use of more 
digital images and of space images requires an increase in the 
monitoring of or even active participation irrelevant activities 
outside of ISPRS. As ISPRS has also a tradition in attempting 
a certain degree of standardization through the acceptance of 
recommended procedures but no mechanism to assure their 
up-to-datedness, the author recommends that ISPRS 
224 
e become more actively involved in ISO activities of direct in- 
terest and provide limited financial support to one or several 
liaison officers appointed by the society, 
e look into the ramifications of quality management and 
quality control for its members, 
e seek affiliate status in the CEOS and than actively 
participate in the work of those subgroups dealing with 
subjects of interest to ISPRS members, 
e explore the need to deal with colour order systems. 
These recommendations are based on the author's involvement 
primarily with the activities of ISPRS's TC I. It can be pre- 
sumed that similar experiences regarding the scientific 
surrounding have been made within the context of the other 
Technical Commissions and it may therefore be appropriate to 
look at the problems of standardization from a global society 
point-of-view, for example by forming a respective working 
group under TC VI to possibly co-ordinate activities taking 
place in presumably most of the TC's of ISPRS. 
7. REFERENCES 
The information presented here has been gathered largely from 
unpublished working documents of the CEOS WGCV, from 
various documents of ISO and DIN (German Standards Insti- 
tute) and from as yet unpublished manuscripts prepared for a 
ISPRS WG I/1 workshop held a year ago in Dessau, Germany. 
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B1. Vienna 1996