كاربرد و تكنيكهاي فيلتر و نسبت گيري طيفي در شناسايي و تفكيك تپه هاي ماسه اي قديمي (غيرفعال ) و جديد (فعال ) در منطقه طبس

Application of Filter and Band Ratio techniques to identify and separate active (new) and inactive (old) sand dunes (a case study of Tabas).

Active sand dunes particularly barkhans are serious threats for adjacent civilians live, agricultural lands and economic activities. Deployment quality and motion paths of these dunes are main targets in wind erosion studies in deposit regions. These targets need the active and inactive dunes to be identified. Edges and borders are evident characteristics of wind deposits and sand dunes. Inactive (old) dunes are more voluminous and smooth. Furthermore active dunes have distinct feature. Also temperature, humidity and plant cover variation lead to change surface and feature of inactive dunes. These changes canʹt be observed in one band images. Therefore making uses of filters particularly non directional edges enhancement and band ratio techniques are main ideas to process the images of these dunes especially about their activity and displacement. In present research filter and band ratio techniques have been used and consequently, third band in Profile Testing and Spectral Analysis method (in this case study b5 of Landsat ETM+) and ratio of first and second bands (in this case study b62/b4) have been introduced respectively as appropriate band and ratio for these techniques to identify and separate active (new) and inactive (old) sand dunes.