composition colorée

CONT: Dans les systèmes de télédétection, nous avons vu qu'il est possible de détecter et d'enregistrer des parties du spectre électromagnétique qui ne sont pas décelables à l'oeil nu, comme l'infrarouge par exemple. Pour pouvoir visualiser cette information, on associe aux bandes spectrales du système d'observation des couleurs d'affichage (rouge-vert-bleu), qui ne leur correspondent pas nécessairement. Ce faisant, on crée des compositions colorées [...]

CONT: The image processing consisted in generating intensity images and one coherence image. To facilitate their analysis and interpretation, a coloured composition has been created with the results. This composition is obtained by adding the coherence image in red, the average of both images phase intensities in green and the difference between these phase intensities in blue. As such, a high coherence level (value close to 1) appears in red and indicates a very good phase correlation between the two images, a consequence of the various mechanisms of radar signal scattering and of the lack of change which could affect the target. On the contrary, a weak coherence level (value tending to 0) appears in black and indicates a movement in these zones during the 24 hours interval which separated the two image shots. Lastly, the white spots correspond to areas with a strong radar signal backscattering i.e. with zones of hills or vegetation.