IMAGE CAPTURE

As possible, image capture of the 9 x 9 inch aerial tiles and the 20 x 24 inch photomosaic indexes adhered to the standards promulgated by the Cornell Department of Preservation and Conservation (see Digital Imaging for Library and Archives, Kenny and Chapman, 1996).
TIFF masters were the original capture format. Electronic archive masters are uncompressed TIFF files (ITU 6.0) at 100% scale: the current de facto standard for electronic image archives. Aerial tile images were scanned at 615 dpi, 256 greyscale. Because digitized aerial photographs average approximately 29.9 MB, a compressed SID version of 1.3-1.5 MB was created for serving over the Web.
The photomosaic indexes were scanned at 400 dpi. The photomosaic indexes average 40 MB in uncompressed TIFF format and average 2.0 MB in SID format. SID images are served from a dedicated server at the Florida Center for Library Automation.
     

CAPTURE SOFTWARE & HARDWARE

Epson Expression 1640XL-SE and Microtek 9600XL and 9800XL flatbed scanners were used to capture the aerial tiles. For the larger photomosaic indexes, a planetary PhaseOne PowerPhase FX 4x5 inch digital camera back with a 10,500 pixel by 12,600 pixel scanning area and a 24-bit color depth was used. 13 July, 2004ersal scanning system which is no longer manufactured. It includes a three turret mounted lenses & bellows, a camera stand, and automated control system for calibrated imaging. This scanning system has the look and feel of a commercial microfilming camera. A Rodenstock Rodagon 135 mm professional enlarging lens (f/5.6-f/22)) with an AR-1 high aspect ratio filter is used for imaging oversized materials. The image capture area is evenly illuminated by two daylight balanced fluorescent Videssence ICELITE 360 light banks. Indexes were held in place during imaging by a Cobra-Pro vacuum easel powered by 2 Craftsman wet/dry shop vacuums. All of the images were captured by and processed on a Macintosh Apple G4 with dual 1 GHz processors, 1 GB RAM, and a 36GB SCSI hard drive. The Macintosh computer operates OS 10 with OS 9.2 subroutines for compatibility with Phase One imaging software. Final quality control is performed using Adobe Photoshop 7.01. A Windows workstation encodes the TIFF images with LizardTech's MrSid 1.3.1 for the creation of the compressed SID images.
     

AERIAL COLLECTOR SOFTWARE
developed by Mark Sullivan

The management of the 45,000 physical aerial tiles and the subsequent collection and processing of the scanned images was a challenge faced by this project. Several requirements surfaced from the beginning. Each physical aerial tile needed to be tracked from the time it was borrowed from the Map Library to the time it was returned. For each TIFF image created, several key pieces of data needed to be collected and associated with the tile information - the scanner, the time of the scan, and the student who performed the work. Additionally, the tiles would need to go through a quality control process. Every tile needed to have some post-processing for both image enhancement and creation of web-friendly formats. And finally, each image needed to be archived, and the web formats sent offsite to our image server.

Three different software tools were developed to address these needs. The creation of a user-friendly front end allowed each physical tile to be tracked through the entire in-house process. As each physical tile was received, it was checked against a database, and then assigned to a student for scanning. As each image was collected, processed, and archived the status was tracked in the application. Once all the tiles for a flight were complete, the tiles were returned en masse.

The second tool automated image collection from the disparate scanning locations, performed basic image manipulation for quality control, and stored the data in the database. Scanned images were stored in flight folders on individual harddrives. As images were collected, data related to the scanner and flight numbers were also stored in the database. The TIFF header of each image was read to ensure that the correct technical specifications, e.g., dpi, greyscale, were followed during scanning.

The last tool used for processing images performed the image manipulation and prepared web format images on a dedicated computer. The processor performed histogram correction and jpeg creation for each image. Additional jpeg thumbnails were kept for visual quality control on the images. Each of the web formats was automatically sent to the web hosting site and the raw TIFF images packed into CD-size folders for local archiving. Finally, all of this data was stored in the database and the aerial tiles returned to UF's Map & Imagery Library.