Philosophical Society of Washington

Minutes of the 2071st Meeting

Speaker: Lee J. Rickard, Naval Research Laboratory
Topic: “Hyperspectral Imaging”

President Lettieri called the 2071st meeting to order at 8:24 p.m. on March 7, 1997. The Recording Secretary read the minutes of the 2070th meeting and they were approved.

The speaker for the 2071st meeting was Lee J. Rickard, from the Naval Research Laboratory. The title of his talk was “Hyperspectral Imaging.”

Over the past 25 years, Landsat-style or multispectral remote sensing has gone from being a research activity to a mainstay of international commerce. It also continues as an important contributor to military preparation for actions in peace and war. This same kind of transition is now beginning with hyperspectral imaging. The technology involved combines every element of a picture with a fully sampled spectrum.

We need remote sensing to make large scale observations of small scale structures. For example, we have detailed ocean temperatures measured by ships. However, they are focused measurements taken in the well traveled shipping lanes. Ocean temperatures from ships are quite sparse for the majority of the ocean surface. Ocean temperatures measured by satellite on the other hand cover all the ocean surface. However, satellite monitoring is expensive. Consider $220 million to put up a satellite and $10 million per year to operate it versus $3 million per year to operate an aircraft.

Remote sensing imaging spectroscopy enhances the measured information we collect. Such analyses of the earth fall into three categories, multispectral, hyperspectral and ultraspectral, depending on how many filters are involved. As an example of hyperspectral imaging, Mr. Rickard described the Landsat D Satellite imaging of a 31,450 mi2 image of the area around Charleston, SC at an altitude of 705 km done in 1989. A seven band sweep ranging from the visible through the infrared was used to show desert, forest, mountains and water. However, it could not show needed details such as the specific kind of trees in the forests. Spectral decomposition and resolution of the images however were used to identify the needed details of the forest.

Extensive research has shown that hyperspectral imaging can contribute to most aspects of earth systems science. Mr. Rickard supported that claim with examples mostly from coastal oceanography, even though his original background is in astronomy. Mr. Rickard discussed the difficulties of making hyperspectral imaging an everyday tool. This imaging involves mostly methods for navigating large volumes of data and finding the truly useful information. Finally, the speaker reflected on aspects of how developing the scientific uses of hyperspectral imaging contrasts, but does not conflict with, the developments of its military uses.

Mr. Rickard then closed his presentation and kindly responded to questions from the audience.

President Lettieri thanked Mr. Rickard for the society and announced the next meeting. He then made the usual parking announcement and adjourned the 2071st meeting to the Social Hour at 9:35 p.m.


Respectfully submitted,
Bill Spargo
Recording Secretary

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