TOPOGRAPHIC NORMALIZATION OF TM SCENES THROUGH THE USE OF AN ATMOSPHERIC CORRECTION METHOD AND DIGITAL TERRAIN MODELS

The correction for the topographic effect of remotely sensed images ta ken over rugged terrains has been dealt with by various procedures. Th e calculation of some crucial atmospheric parameters is needed to norm alize deterministically the spectral responses of differently oriented slopes. In a previous model, the authors estimated beam transmittance and diffuse light for Tm scenes by using easily attainable informatio n so as to compute surface reflectances. On the basis of this knowledg e and of a Lambeztian assumption, a procedure has been developed which uses digital terrain models to normalize topographically the spectral responses of rugged areas. The procedure was tested in a case study i n Tuscany using TM scenes from three seasons. The results, estimated b oth visually and statistically, show the potential of the method along with some limitations which are critically discussed.