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VIEWS: 11 PAGES: 8

									         West Virginia University
College of Engineering and Mineral
             Resources

Lane Department of Computer Science and Electrical Engineering



             EXTENDED PROBLEM STATEMENT

                        September 16, 2008

                     TEAM 9: Stereo GigaPan

                            Adam Brady
                            Dan Brooks
                          Jason Gookins
                           John Sedoski
                           John Trumble
                          Jason Whipkey



            FACULTY MONITOR: Dr. Yenumula Reddy

              FACULTY REVIEWER: Dr. Tim McGraw

   SPONSOR: Randy Sargent, NASA Ames Intelligent Robotics Group

                   ADVISOR: Dr. Tim McGraw




                                                                  0
Table of Contents
Need .............................................................................................................................................................. 2
Objective ....................................................................................................................................................... 2
Background ................................................................................................................................................... 3
Stakeholder Goals ......................................................................................................................................... 3
Marketing Requirements .............................................................................................................................. 4
Objective Tree ............................................................................................................................................... 5
Ranking of Needs .......................................................................................................................................... 6
References .................................................................................................................................................... 7




                                                                                                                                                                   1
Need
NASA is currently looking for cost effective methods of acquiring additional information from
existing technologies. Instead of designing custom hardware to tackle a complex problem it can
often be advantageous to use off-the-shelf components to accomplish the same goal. An example
of this method of development is site survey tools. Using digital cameras you can pick up at your
local electronics store and a specialized pan/tilt unit designed for taking massive panoramas, it is
possible to recreate a surrounding area based on image data alone in the form of either 3D
images or real 3D models. With a pair of cameras it is possible to ascertain detailed depth
information that can then be used for recreating the environment and visualizing it from an
arbitrary viewpoint.

Objective
The objective of our project is to design alternative mounts for a GigaPan[4] unit capable of
acquiring stereo images as well as a methodology and software tools for analysis of these
images. Additionally, the new mounts will need to use a digital trigger in order to synchronize
image capture. Once this is completed, we will work with the resulting stereo images to produce
anaglyphs for rough visualization and detailed point clouds for building 3D models. Point clouds
can then be cleaned up in post-processing and combined with the panoramic image data to build
dynamic 3D meshes that can be inspected from any angle. Possible extensions for this project
include advanced interactive visualization techniques, interfacing with a rover for remote
control, and correlating multiple viewpoints for more accurate models, among other things.




                                                                                                   2
Background
GigaPan is a collaborative project of Google, Carnegie Mellon University and NASA Ames
Intelligent Systems Division's Robotics Group. It is a robotic platform that attaches to a digital
camera and some computer software. The robotic platform allows a user to take a photograph,
autonomously re-aim the camera with great precision, and then take the next photograph. After
taking many photos, the software stitches all the pictures into a gigapixel image.[1]
Anaglyph images are used to provide a stereoscopic 3D effect, when viewed with 2 color glasses
(each lens a chromatically opposite color, usually red and cyan). Images are made up of two
color layers, superimposed, but offset with respect to each other to produce a depth effect.
Usually the main subject is in the center, while the foreground and background are shifted
laterally in opposite directions. The picture contains two differently filtered colored images, one
for each eye. When viewed through the "color coded" "anaglyph glasses", they reveal an
integrated stereoscopic image. The visual cortex of the brain fuses this into perception of a three
dimensional scene or composition.[2]
A point cloud is a set of vertices in a three-dimensional coordinate system. These vertices are
usually defined by X, Y and Z coordinates. Point clouds are most often created by 3D scanners.
These devices measure a large number of points on the surface of an object, and output a point
cloud as a data file. The point cloud represents the visible surface of the object that has been
scanned or digitized.[3]

Stakeholder Goals
The goals of the Stereo GigaPan project are as follows
       Design a mount
       Make a Digital Trigger

       Customize Digital Camera Software for project (if needed)
       Take two cameras and make a stereo image
       From stereo images make an anaglyph
       From anaglyph make a point cloud model
       Combine point cloud and panorama to build 3D scene

       Integrate GigaPan unit on to a rover
       Wirelessly trigger multiple GigaPan units



                                                                                                     3
Marketing Requirements
Although this project focuses more on NASA research than providing a practical product, there
are several features that make this project desirable from a funding standpoint. Firstly, all
hardware consists of (relatively) cheap, off-the-shelf components that are interchangeable and
flexible in their deployment. The stereo mount can accept a wide range of cameras and the
GigaPan unit is agnostic towards the type of hardware mounted on it. The digital trigger works
with any modern Canon Powershot digital camera. The total costs of this project are an order of
magnitude less than purchasing custom stereo pair cameras capable of the same level of zoom as
a consumer-grade digital camera.

Because GigaPan units are being designed for the consumer market, it could be possible to
extend this project into the consumer space. All that would need to be sold would be a special
hardware mount for the GigaPan unit and a free software extension download for working with
the stereo images. All the consumer would need to do is provide the cameras.




                                                                                                 4
Objective Tree

                                      Stereo Gigapan




        Accuracy      Convenience                        Reliability        Adaptable




      Images Stitch   User-Friendly                    Efficient Power     Vary Stereo
        Correctly       Inferface                             Use          Separation




      Depth Values    Off-the-Shelf                                      Multiple Camera
                                                   Durable Hardware
        Correct       Components                                          Compatibility




     Images Exposed                                                      Can Mount on Any
                        Portable                           Cheap
        Correctly                                                             Tripod




                                                                         Suitable for Many
                                                        Replaceable           Different
                                                                          Environments




                                                                                             5
Ranking of Needs
                                Level One Pairwise Comparison Matrix
                 Accuracy           Convenience    Reliability     Adaptable        Total
Accuracy         -                  1              0               1                2
Convenience      -1                 -              -1              -1               -2
Reliability      0                  1              -               1                2
Adaptable        -1                 1              -1              -                -1

                          Level Two Pairwise Comparison Matrix for Accuracy
                      Images Stitch       Depth Values       Images Exposed
                                                                               Total
                      Correctly           Correct            Correctly
Images Stitch
                      -                   1                  -1                0
Correctly
Depth Values
                      -1                  -                  1                 0
Correct
Images Exposed
                      1                   -1                 -                 0
Correctly

                      Level Two Pairwise Comparison Matrix for Convenience
                      User-Friendly       Off-the-Shelf
                                                             Portable          Total
                      Interface           Components
User-Friendly
                      -                   -1                 -1                -2
Interface
Off-the-Shelf
                      1                   -                  1                 2
Components
                                                                               0
Portable              1                   -1                 -




                                                                                            6
                      Level Two Pairwise Comparison Matrix for Reliability
                 Efficient      Durable       Cheap            Replaceable
                                                                             Total
                 Power Use      Hardware      Hardware         Hardware
Efficient
                 -              0               -1            -1             -2
Power Use
Durable
                 0              -               -1            1              0
Hardware
Cheap
                 1              1               -             1              3
Hardware
Replaceable
                 1              -1              -1            -
Hardware                                                                     -1

                      Level Two Pairwise Comparison Matrix for Adaptable
                                Multiple                     Suitable for
                 Vary Stereo                    Can Mount on
                                Camera                       Many         Total
                 Separation                     Any Tripod
                                Compatibility                Environments
Vary Stereo
                 -              1               1             1              3
Separation
Multiple
Camera           -1             -               1             1              2
Compatibility
Can Mount on
             -1                 1               -             -1             -2
Any Tripod
Suitable for
Many         -1                 1               -1            -              -1
Environments


References
    1.   http://en.wikipedia.org/wiki/Gigapan
    2.   http://en.wikipedia.org/wiki/Anaglyph_image
    3.   http://en.wikipedia.org/wiki/Point_cloud
    4.   http://www.gigapan.org




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