a comparison of lunar images from clementine and lunar orbiter to search for new surface features or...
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The Lunar Surface: Visualizing Changes
A Comparison of Lunar Images from A Comparison of Lunar Images from Clementine and Lunar Orbiter to Search for Clementine and Lunar Orbiter to Search for
New Surface Features or CratersNew Surface Features or Craters
Chitra Sivanandam, Roger Easton, Zoran NinkovChitra Sivanandam, Roger Easton, Zoran NinkovCenter for Imaging ScienceCenter for Imaging Science
Rochester Institute of TechnologyRochester Institute of Technology
May 8, 1998May 8, 1998
Senior Research: May 8, 1998
Chitra Sivanandam
OutlineOutline
IntroductionIntroduction Proposed ObjectivesProposed Objectives Accomplished Tasks/ResultsAccomplished Tasks/Results AnalysisAnalysis ConclusionConclusion
Senior Research: May 8, 1998
Chitra Sivanandam
IntroductionIntroduction
Lunar Orbiter ImageryLunar Orbiter Imagery Higher Resolution (scan from a contact print)Higher Resolution (scan from a contact print) Better ground resolutionBetter ground resolution Do not have as much information on how the Do not have as much information on how the
image was takenimage was taken exact latitudes and longitudesexact latitudes and longitudes angle of the photographangle of the photograph
Senior Research: May 8, 1998
Chitra Sivanandam
Introduction Introduction cont’dcont’d
Clementine ImageryClementine Imagery Lower resolution, both in ground spot and in Lower resolution, both in ground spot and in
image resolutionimage resolution PDS formatPDS format Have much information on the specifics Have much information on the specifics
pertaining to imagerypertaining to imagery latitudes, longitudes, angle, etc.latitudes, longitudes, angle, etc. limited bandwidth (sensor) compared to sensitivity limited bandwidth (sensor) compared to sensitivity
of filmof film
Senior Research: May 8, 1998
Chitra Sivanandam
Proposed ObjectivesProposed Objectives
Create a tool to use both sets of imagesCreate a tool to use both sets of images Try to account for differences in imagery Try to account for differences in imagery
that do not translate to differences in the that do not translate to differences in the surfacesurface
Look for any differences in the surface that Look for any differences in the surface that may have occurred as a result of timemay have occurred as a result of time
Senior Research: May 8, 1998
Chitra Sivanandam
Accomplished Tasks/ResultsAccomplished Tasks/Results
Created a procedure using NasaView (for Created a procedure using NasaView (for Clementine images), Erdas Imagine, Clementine images), Erdas Imagine, Photoshop and code written in IDLPhotoshop and code written in IDL NasaView - to chose an appropriate section of the NasaView - to chose an appropriate section of the
16bits to use16bits to use Photoshop - convert images to tiff formatPhotoshop - convert images to tiff format Imagine - used the GCP (ground control points) Imagine - used the GCP (ground control points)
editor to create a transform to resample imageseditor to create a transform to resample images IDL - to do the differencingIDL - to do the differencing
Senior Research: May 8, 1998
Chitra Sivanandam
Accomplished Tasks/Results Accomplished Tasks/Results cont’dcont’d
Using IDL, created a tool to do differencing Using IDL, created a tool to do differencing trying to account for various problems with trying to account for various problems with imagery (using test images)imagery (using test images)
Senior Research: May 8, 1998
Chitra Sivanandam
Accomplished Tasks/Results Accomplished Tasks/Results cont’dcont’d
After doing the resampling and After doing the resampling and transformation, applied the code to imagestransformation, applied the code to images
Major differences occurred because the Major differences occurred because the Orbiter image was of a much higher Orbiter image was of a much higher resolution than the Clementine imageresolution than the Clementine image
Chose to use a low pass filterChose to use a low pass filter Invested the use of a Robert’s gradient for Invested the use of a Robert’s gradient for
edge detection prior to differencingedge detection prior to differencing
Senior Research: May 8, 1998
Chitra Sivanandam
Accomplished Tasks/Results Accomplished Tasks/Results cont’dcont’d
Lunar Orbiter image Using a low pass filterLunar Orbiter image Using a low pass filter
Clementine imageClementine image
Senior Research: May 8, 1998
Chitra Sivanandam
Accomplished Tasks/Results Accomplished Tasks/Results cont’dcont’d
Low Pass filterLow Pass filter Gaussian Filter, with a weight of 121Gaussian Filter, with a weight of 121
12321
271172
31117113
271172
12321
Senior Research: May 8, 1998
Chitra Sivanandam
Accomplished Tasks/Results Accomplished Tasks/Results cont’dcont’d
Robert’s GradientRobert’s Gradient
of Orbiter image of low pass imageof Orbiter image of low pass image
Senior Research: May 8, 1998
Chitra Sivanandam
Accomplished Tasks/Results Accomplished Tasks/Results cont’dcont’d
Robert’s Gradient for Clementine imageRobert’s Gradient for Clementine image
Senior Research: May 8, 1998
Chitra Sivanandam
Accomplished Tasks/Results Accomplished Tasks/Results cont’dcont’d
Difference simply Difference simply between imagesbetween images
Difference using the Difference using the low pass imagelow pass image
Senior Research: May 8, 1998
Chitra Sivanandam
Accomplished Tasks/Results Accomplished Tasks/Results cont’dcont’d
Resultant images using the Robert’s gradient / Resultant images using the Robert’s gradient / edge detection before actual differencingedge detection before actual differencing
Senior Research: May 8, 1998
Chitra Sivanandam
AnalysisAnalysis
Smaller, higher frequency differences do Smaller, higher frequency differences do not show up as much when using the low not show up as much when using the low pass filterpass filter
Overall differences due to the histograms of Overall differences due to the histograms of the images are taken care of by doing an the images are taken care of by doing an edge detectionedge detection
Senior Research: May 8, 1998
Chitra Sivanandam
Analysis Analysis cont’dcont’d
What is causing all of the differences?What is causing all of the differences? Most of the features from the difference images Most of the features from the difference images
exist in the Orbiter imageexist in the Orbiter image Most of the difference seems to be due to the Most of the difference seems to be due to the
differences in image resolutiondifferences in image resolution The bulk of the differences is due to the The bulk of the differences is due to the
illumination angle at the time the images were illumination angle at the time the images were takentaken
Senior Research: May 8, 1998
Chitra Sivanandam
ConclusionConclusion
It is possible to create a tool to work with both sets It is possible to create a tool to work with both sets of imageryof imagery
It would be more useful if the images have It would be more useful if the images have something in common (i.e. ground resolution).something in common (i.e. ground resolution).
There were too many differences between the There were too many differences between the imagery.imagery.
Basically, the region immediately near the crater Basically, the region immediately near the crater Aristarchus does not seem to have changed over Aristarchus does not seem to have changed over the last 30 years.the last 30 years.
Senior Research: May 8, 1998
Chitra Sivanandam
THE ENDTHE ENDwww.cis.rit.edu/~cxs2479www.cis.rit.edu/~cxs2479