EyeSpy as a Zooming Platform

As more and more libraries, museums, and archives are converting their resources into digital formats, the need for delivering high-quality, high-detail images quickly and efficiently over the Internet has increased. East Carolina University’s Joyner Library is using AXS Technologies’ EyeSpy Image Server (www.axstech.com) to address that need along with other issues concerning image delivery for internally created Internet products such as digital exhibits and digital libraries.

Old Technology

Without a product like EyeSpy, repositories tend to rely on solutions that are not well-adapted for serving large quantities of images. The solutions also are either not elegant, or are not full-featured solutions for the end user. Alternative approaches to provide more detailed images include: (1) Implementing a default low-resolution image with a link to a higher-resolution version. This approach often results in a higher-resolution image that is not well adapted for printing or for viewing. That is, it is restricted in its detail in order to fit the lowest common denominator screen or to print on typical end user printers. (2) Creating a set of higher-resolution images that are linked to areas of an image. This approach cannot be batched in production; the manual labor involved means that the solution is not well suited for large quantities of images. (3) Using a browser’s built-in magnification capability. This approach makes digitized materials browser-dependent and d'es not address the issue of speedy delivery to the user of pixel-rich detail.

Figure 1a:
300 dpi TIFF, 176MB, herbarium specimens collected by John Lawson in North Carolina in about 1710: Galactica, Sampson Snakeroot, Blazing Star, Groundnut, and Sunflower. The original specimen page (Horti Sicci 145 folia 45) is housed at The Sloane Herbarium, a part of The Natural History Museum in London. Original paper dimensions: 15.4 in. x 20.8 in. Online in the Eastern North Carolina Digital History Exhibits at http://www.lib.ecu.edu/exhibits/lawson/Naturalist.html.

Figure 1b:
300 dpi JPEG zoomed area shows flowering head of Blazing Star; the Latin taxonomic name is Liatris squarrosa (L.) Michaux. Zoomed to 100 percent of the detail in the original.

Current Needs Compared to EyeSpy Features

The zooming requirement for an academic library includes providing faculty, students, and researchers worldwide with unrestricted access to the details of maps, blueprints, genealogical charts, and other oversize materials, as well as details that may exist in smaller items. These materials may be in map collections, manuscript collections, university archives, the general stacks, or may originate from yet unknown future partner institutions. At East Carolina University (ECU), some externally created digital items have been integrated with locally digitized materials to enhance and give access to related materials from multiple repositories. One example is the botanical specimens collected in North Carolina in the early 1700s and archived at The Natural History Museum in London (see examples in Figures 1a and 1b). Sophisticated zooming technologies open the range of materials that can be efficiently considered for digitization. (see map example in Figures 2a and 2b).

Tiling for Efficient Delivery
In choosing a zooming solution at ECU’s Joyner Library, many features were specified and compared among leading zooming software providers. Customers using the technology from various vendors were interviewed. One concern we share with those customers is to deliver zoomed images quickly so that dial-up or otherwise slow connections will not be a problem. EyeSpy uses tiling to accelerate client delivery and, as a result, reduces network congestion.

EyeSpy’s tile implementation sends only the user-requested pieces of a large image for zoomed viewing from the image server. When an image is made “zoom-ready,” the file is dynamically broken into tiles. When the user clicks on the area to be zoomed, the server instantly sends the minimum number of tiles required to fill the image viewer on the Web page. Each view request transmits a new set of tiles, yet all tiles are served from the same file created upon image ingest, simplifying workflow. Efficient in terms of network and server activity volume, this method of handling view requests also makes the full quality of the original image accessible. The tile feature supports compressed and uncompressed images in over seventy file formats using various algorithms and provides standard JPEG or PNG output to the browser.

End User Needs
Another criterion for the selection of a zooming product is that we do not want users to need any special viewers, players, applets, or plug-ins in order to view the images. EyeSpy images are served in pure HTML and can be viewed in any standard browser. This HTML delivery also supports US ADA Sec. 508 IT accessibility initiatives and includes ALT tags for reference images and reader-friendly tags for points of interest within images. Not restricting our user base is an important concern for the library. Another additional EyeSpy feature is the ability to customize the way the zoomed images are delivered to the user, so that we are not locked into the interface provided by the vendor. For example, we want to be able to control the size of the original image and the area in which zoomed images are displayed. We also want to deliver special printing support that d'es not come with the default packages from the vendor. EyeSpy’s pure HTML delivery means that we can add and customize such features.

Zooming Features

All of the basics available in the marketplace are also found in the EyeSpy software: zoom in, zoom out, pan, and reset to original image. Several viewers are available from the vendor, including Basic, Launchpad (as seen in Figure 1a where a marquee is placed around the zooming reference point on a small view of the full original image), and Magnifying Glass viewer. The layout for each of the viewers can be modified, including customizing and rearranging buttons. Being able to give different internal products their own interfaces and graphics while keeping the core usability the same is very appealing. In addition to viewers and graphics modifications, the image output is customizable. Zooms can be served with the number of pixels you want in a specific exhibit by changing the HTML link. This feature allows us to use 200x200 pixel images in one exhibit and 400x300 pixel images in another.


Another deciding factor in our choice of this zooming solution was that AXS licenses its software per-server CPU and not per-image. Some vendors license by the number of images that can be zoom-enabled. We did not want to face an expensive process each time we decided on another large project. The EyeSpy license gives us the capability to upload as many images as we have room for on the EyeSpy server without any additional costs.

When considering zooming server workflow, we wanted to be sure that it would be easy to enable zooming on images. Zoom-enabling means that the original images are moved into the server’s folder system and the tiling capability is added to the images. EyeSpy offers a batch import tool which can be set to process at a specified time. This scheduling feature allows an entire directory of images to be zoom-enabled in a batch. One anticipated scenario is that a day’s work of scanning can be zoom-enabled overnight.

After installing the EyeSpy server in February, we find that it takes about two minutes per-image to zoom-enable 500MB images (our largest size images currently). This means that the zoom- enabling process for 500 images of about 80MB each (a more typical image size) would occur in less than three hours. EyeSpy efficiently uses available storage by using standard JPEG compression on imported file formats. For example, imported 80MB TIF files to save onto the server at less than 15MB.

At the end of the zoom-enabling process, a report is available on the images imported into the EyeSpy server. The report includes links to the various viewers, which can then be inserted into the relevant Web pages manually or programmatically. Modifications, like pixel dimensions for zoomed images, are made in commands embedded in the URLs in the processing report. We often use PHP scripting for jobs like this.

Figure 2a: 300 dpi TIFF, 252MB, map of soil survey in Beaufort County, North Carolina. Digitized from a copy of the Soil Survey of Beaufort County, North Carolina by W.B. Cobb and others, printed in 1919 by the U.S. Government Printing Office; from the holdings of the North Carolina Collection at ECU’s Joyner Library. Original paper map dimensions: 27.7 inches x 22.3 inches. Online in the North Carolina History and Fiction Digital Library at http://www.lib.ecu.edu/ncc/historyfiction/.

Figure 2b: 300 dpi JPEG zoomed area shows bodies of water, place names, and colors representing various kinds of soil identified in map’s legend. Zoomed to about 90 percent of the detail in the original.

The EyeSpy server runs on Windows, Linux, and Solaris platforms. Initially we were interested in a Unix-based zooming server in coordination with our other Web services, but the department has recently begun to shift to a Windows environment, so we installed the Windows version of EyeSpy.

Installation was a smooth process that took less than one hour after we upgraded the destination server to the Enterprise Edition of Windows Server 2003.

Tips for Other Academic Libraries

Our library took about a year to define our needs and investigate the marketplace. The process helped us find a solution that confidently meets our immediate and medium-term needs. Take time to compare how various vendors’ features fit your organization’s needs. If you want to invest in customization, these comparisons along with evaluations of the lives of the companies are valuable. One recommendation is to have the vendors zoom-enable some of your own images, so that you can evaluate features across vendors with images you know well. This research will help insure that internal development work will have a longer- lasting value.


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