Abstract 3 Methods for determining best multispectral bands using hyper spectral data

by E. M. Winter, Technical Research Associates, Inc.

Over the years several methods have been used to determining the best bands for a visible near IR multi-spectral sensor. The most popular method, the committee method, places scientists with differing opinions on the phenomena and the sensor mission in one room, and a compromise set is developed. To avoid this, there have been several methods to automate this selection process. We have developed a method to examine hyper spectral data to find the best multi-spectral band set (whether 3, 4, 5 or 6 bands) based on the background, on the premise that, with the target unknown, the band set that best separates the background materials is the best. We start with a hyper spectral data set of a background area without any targets. We then run a program for determining the spectral endmembers. Any endmembers that look like they are due to sensor artifacts or an anomalous point on the ground (junk) are discarded from the list. The resulting hyper spectral endmembers are then input to an exhaustive search program. The goal of the exhaustive search is to find a set of N (say 4) multi-spectral bands that maximizes the spectral angles between all of the endmembers. Thus, at each trial the multi-spectral bands are made by binning the hyper spectral (to four bands in this case) and the spectral angles calculated between endmembers 1 and 2, 1 and 3, 1 and 4, 2 and 3, 2 and 4 etc. The endmembers in each case have been binned to four multi-spectral bands. We save the average of these spectral angle calculations. After examining often millions of combinations, the multi-spectral band set that maximizes the spectral separation is judged to be the best. We have applied this method to the

selection of multi-spectral bands sets for several sensors.

(http://spie.org/Documents/ConferencesExhibitions/DSS07%20abstracts_.pdf)

Abstracts and introductions compared

At first glance, it might seem that the introduction and the abstract are very similar because they both present the research problem and objectives as well as briefly reviewing methodology, main findings and main conclusions.  However, there are important differences between the two:

Introduction

	Should be short, but does not have a word limit;
	Main purpose is to introduce the research by presenting its context or background. Introductions usually go from general to specific, introducing the research problem and how it will be investigated).

Abstract

	Has a maximum word limit;
	Is a summary of the whole research;
	Main purpose is to summarize the research (particularly the objective and the main finding/conclusion), NOT to introduce the research area.

Task 11. Read the introduction and answer the questions:

How does the author characterize the topic of the discussion?

What does the author say about the scientists contributing to the discussion?

Why are physics and molecular biology chosen to represent science as a whole?

Along what lines will the discussion be carried on?