THE LUNAR SURFACE: Visualizing Changes   Chitra Sivanandam  

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Abstract           This research project attempted to create a method of comparison between the imagery from the Lunar Orbiter program (from the mid 1960's) with that of the Clementine mission (of the mid 1990's).  The premise behind this research is that if any new surface features developed over the course of the past thirty years, they could be found by doing such a digitial comparison.  There are many implication that such research could have on the future.  Being that the moon is currently the most thouroughly studied celestial body, the use of doing such a comparison between databases of imagery would prove to be useful on ly for the moon.  But in the future, such techniques could be applied to a variety of imagery.  In the specific case of the lunar surface, it is important to know of things that develop on the surface (either volcanically or due to an impact) because it is the closest indicator of what may be happening at the earth's outermost layer of atmosphere.  Previously, these large databases had been collected, but not much had been done with the imagery.
 
    This research has been able to create a procedure in which such imagery from the Clementine satellite could be compared to imagery from the Lunar Orbiter program.  This procedure is a bit involved because of the way that both of these databases of imagery are being archived.  The Orbiter images exist as photographic negatives and the Clementine images exist on CDs as written in the PDS (Planetary Data Systems) format.  This procedure is thus easy for the Orbiter imagery, which only needs to be obtained and then scanned.  The Clementine image needs to be obtained and put through four programs: NasaView, Adobe Photoshop, Erdas Imagine, and an IDL (Interactive Data Language) code.  Using the region of the lunar surface around the crater Aristarchus, digital comparisons yielded that there was no evidence that the lunar surface had changed.  It did however prove that the major differences that were seen were due to inherent differences in the images and due to the sun's illumination angle on the crater.  Therefore, it seems logical to conclude that in order to obtain better results (that may translate into actual changes in lunar surface) it may be better to try to minimize the differences in image structure and resolution along with trying to correct for different illumination angles.
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