1 NAC-Slide: Displaying Very Large NAC Images Robert Wagner Mentor: Mark Robinson School of Earth and Space Exploration, ASU 17 April 2010

NAC-Slide Overview Objective was to display the very large LROC Narrow Angle Camera images at full resolution. Initial goal was to display NAC images on the LROC Science Operations Center’s Tile Wall. Developed “NAC-Slide”: Automatically scrolls through LROC NAC images. 2

LROC Narrow Angle Camera Two high-resolution cameras 12-bit grayscale images 5064 pixels per line Usually lines Nominal resolution: 50cm/pixel Footprint:2.5km by 25km With paired images, 5km by 25km footprint 3

The Tile Wall 3x3 grid of high-resolution monitors Total size approximately 7500x6000 pixels Runs on Ubuntu Linux 4 LROC Science Operations Center

Displaying Large Images A standard 1024x768 monitor can only display 0.3% of a NAC image at full resolution. Even the Tile Wall can only display 10% of a NAC image at full resolution. Solution: Scroll vertically down the image. Works on Tile Wall, which can display the full width of a NAC image Not so good for personal computers NAC leftNAC right

NAC-Slide Design Four elements Full-resolution view Overview map Histogram Image information 6

Histogram Shows the distribution of pixel values in the image. Allows science team to easily assess validity of camera settings for the image. Overview Map Shows entire image, and location of the main viewpoint. 8

Information Window Shows location, size, and capture date of image. Lists major nearby features, based on a database of feature names and locations. 9

Implementation Developed in C Command-line driven, with optional parameters Image list, scroll speed, etc. Used X Windows library for interface Cross-platform (Linux, Mac OS) Challenges: Reading NAC image formats Good automated stretch from 12-bit to 8-bit Readable text on huge screens 10

Results and Future Work NAC Slide on the Tile Wall gives the scientists in the control room near-real-time feedback on what the NAC images actually look like. Current goal: Create a NAC image viewer that works well on small monitors, for quickly looking through images at full resolution. Steps across an image, one screen-full at a time First version is mostly complete 11

Questions? NAC image M L