Detecting information under and from shadow in panchromatic Ikonos images of the city of Sherbrooke
Dong-Chen He Amani Massalabi · 2004
The presence of shadow is increasingly alarming on the images with very high spatial resolution mainly in urban area. After shadow detection, how to give an added value to detected shadow? Some kinds of exploitation are presented: the restitution of information under shadow and the deduction of object height from their shadow. The restitution of surfaces under shadow is based on the analysis of contextual and textural information between the shadow and its neighbouring surfaces not in sun side. Assuming that the same surface texture is independent of shadow. The height of objects is deduced knowing the length of their projected shadow on the ground, the position (azimuth and zenith) of the sun and the sensor at the time of acquisition. These exploitations of shadow were carried out on a panchromatic Ikonos image of Sherbrooke. Results are validated with land use map for surfaces under shadow, and measured height for the building height from shadow.