Title of paper

Investigations were carried out for available digital image B,G,R data aiming at the derivation of a colour difference measure for the same scene areas imaged in several overlapping images of a photogrammetric bloc. The images were transformed first into the CIE XYZ tristimulus colour space and then into the approximately uniform CIE L*a*b* colour space using both, the known relative spectral sensitivity curves for each of the colour images and the colour matching functions for the 2o normal CIE observer. Colour differences ∆E for overlapping image areas within a photogrammetric bloc were determined. The results show that the ∆E values within the strip of photographs are relatively small while those to the neighbouring strip are significantly larger as can also be recognized by visual inspection of the images. As the colour transformations require the spectral characteristics of the light source, the effect of a change in illuminating light can be simulated.