Project
| # | Title | Team Members | TA | Documents | Sponsor |
|---|---|---|---|---|---|
| 11 | Reflectance Transformation Imaging Dome Honorable Mention |
Alexander Calmas Hadrian Doromal John Ducham |
Evan Widloski | design_document1.pdf final_paper1.pdf photo1.JPG photo2.jpg presentation1.pptx proposal1.pdf video |
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| # Reflectance Transformation Imaging Dome ## Problem The Spurlock Museum of World Cultures uses RTI photography to preserve digital records of physical artifacts so that they can be studied in psudeo-3D. This is accomplished using "the dome", an array of LED lights and a camera which photographs the artifact multiple times under different lighting conditions. The dome has begun to show its age in a few ways: - The dome's frame is bulky and the components are loose on the exterior, making transport difficult - Several of the LEDs used for photography are unreliable - The software used to control the camera shutter no longer works with current versions of Windows, meaning the photography process must be done manually - The Arduino governing the dome has had reliability issues due to age Additionally, our sponsor is interested in a more portable RTI solution that can photograph larger artifacts and is lightweight, allowing for perpendicular setup (for example when photographing an object in a wall-mounted display). ## Solution We propose a collapsible umbrella-like dome that covers an area around 1.25 meters in diameter when fully expanded. The frame will be composed of durable plastic or thin aluminum rods to save weight, with three rows of lights mounted on the interior of the dome. An opening at the top of the frame will allow the system to be mounted on the camera tripod provided by our sponsor. Finally, a control board mounted on the side of the frame will control the lights and camera, allowing for automatic and manual imaging. ## Subsystems ### Physical dome and lighting requirements RTI Photography requires a hemispherical set of lighting samples that cover a range of inclination angles from 15 to 65 degrees above the horizon. It is also necessary that each light be approximately equidistant from the center of the subject. The physical dome will consist of 48 LED lights arranged as such. There are no sensing requirements, but some care should be taken to ensure that the lights are bright enough to capture usable images. Lighting requirements vary based on ambient light and the location of the subject, but our sponsor has assured us that modern LEDs are more than sufficient- its is more important that the lighting be consistent to avoid creating extra post-processing work. In order to avoid complications created by ambient light, the exterior of the dome may be covered in a neutral colored canvas to block external light sources. ### Control board The device used to control the lights and camera must interface with the camera software in order to change lighting at the right times. Additionally, it must be possible for a human to switch individual lights on and off as needed. The control system must also connect to a computer and transfer the raw image files so that they may be stitched together using Photoshop or another image editing program. A program called RTI Builder is used to accomplish this. ### Software The existing software tools used to generate finished RTI images are cumbersome to use and in some cases do not work on modern operating systems. We would like to provide software tools (likely lightweight scripts) to automate as much of the capture process as possible. ## Criteria for Success The main goal of this project is to create a portable RTI capture dome. This means that the final product should be light enough to be carried by a single person (so less than 40 lbs as a rough estimate) and survive transport by car. More specifically, the lights, control box, and wiring should be contained within an exterior frame so they will not be dislodged by movement, and a collapsible frame will allow for easier transportation. Questions were raised regarding acceptable resolution and model quality in our original project thread. For RTI imaging to be successful, the main requirements are as follows: - All photos must be taken from the same position without moving the subject - All light sources must be equally distant from the subject Our frame design will accomplish both of these things. In terms of resolution, higher is better, but the setup for imaging is separate from the camera used to take photos. Our sponsor is providing us with a Canon EOS Mark III camera that shoots at sufficiently high resolution to generate quality raw files. ## Our Team John Ducham [ducham2] Alexander Calmas [acalmas2] Hadrian Doromal [hadrian2] |
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