ABSTRACT
A spectral library is a critical resource for any target detection characterization. Understanding the spectral properties of the target material is essential for designing analysis methods. It is a preliminary step for payload design as well. The USGS and ECOSTRESS are the two main libraries in the public domain. However, more such libraries are required for local studies of urban materials. This is because urban composites show a large variation in the raw materials.
Tarang is one such library of Indian urban materials. It has ~1150 signatures of 105 unique samples of Indian urban materials including pavements, roofs, urban tress, and so on. Tarang is available at https://splibtarang.com" xmlns:xlink="https://www.w3.org/1999/xlink">https://splibtarang.com/index.php. Search and match web services are available for any device communicating using https://protocol" xmlns:xlink="https://www.w3.org/1999/xlink">https://protocol.
Spectral signatures are analysed for diagnostic features, if any, that uniquely identify the target material and so on. In addition to this, choosing bands that are optimal in separating the targe material from others is essential too. Bhattacharyya Distance is used to decide how separable are the two target materials. Larger values of the distance indicate that they are easily separable. Another interesting way to characterize the urban material is by using colour as a discriminator.
This chapter will discuss:
o Importance of spectral resources
o Spectral libraries of urban materials
o International
o Indian
o Availability
o Analysis methods/how to use these resources
o Basic statistics
o Chromatic properties
o Optimal bands
o Analysis of Tarang
o Spectral characteristics of urban materials
o Other notable studies by Herold and Hepner
o Indian urban materials
