Deep Zoom

Deep Zoom

Microsoft Deep Zoom Logo
Developer(s)	Microsoft
Stable release	0.9.000.5 / October 13, 2008; 3 years ago (2008-10-13)
Operating system	Microsoft Windows(Media)
Type	Multimedia
License	Proprietary
Website	MSDN Overview for Developers

Deep Zoom is a technology developed by Microsoft for efficiently transmitting and viewing images. It allows users to pan around and zoom in a large, high resolution image or a large collection of images. It reduces the time required for initial load by downloading only the region being viewed and/or only at the resolution it is displayed at. Subsequent regions are downloaded as the user pans to (or zooms into them); animations are used to hide any jerkiness in the transition. The libraries are also available in other platforms including Java and Flash.

History

The Deep Zoom file format is very similar to the Google Maps image format where images are broken into tiles and then displayed as required. The tiling typically follows a quadtree pattern of increasing resolution of image (in other words twice the zoom and twice the resolution). The main difference is that with google maps the actual details on the image change from one zoom level to another, with deep zoom images the same image is displayed at each zoom level.

Seadragon Software, formerly Sand Codex, first created the Seadragon technology and its implementation of what is now called Deep Zoom. This technology was then absorbed into the Microsoft Live Labs when Seadragon Software was acquired. Engineers from Seadragon now work with Microsoft to integrate their work into technology such as Silverlight and Photosynth^[1].

Deep Zoom Examples

The most famous implementation of Deep Zoom was probably the first: the memorabilia collection at the Hard Rock website. Conceived and designed by Duncan/Channon and built by Vertigo, it was demonstrated for the first time in March 2008 at the Microsoft MIX convention in Las Vegas.

Another example is the Deep Earth project. It is described by its creators as "a community project focused on creating a rich interactive mapping control using Silverlight2 Deep Zoom. Concentrating on Microsoft Virtual Earth imagery and data the project offers team members the opportunity to learn and share while creating something cool and useful."

A paintings collection project http://galleryzoom.co.uk/ shows 1000 high resolution/sensor images individually indexed. (Using Deep Zoom Composer).

Blaise Aguera y Arcas gave a demonstration of Seadragon and Photosynth at the 2007 TED conference.

In November 2009, 352 Media Group, a Silverlight developer in the Microsoft Silverlight Partner Program, created an example of Deep Zoom using Microsoft Silverlight version 3^[2]. It is online at 352 Media Group's Web site.

A recent example is the Winston Churchill Deep Zoom mosaic, created by Silverlight developers Shoothill, which features as both an online interactive deep zoom and a standalone deep zoom which forms part of the current Churchill exhibit in the Churchill War Rooms in Whitehall.

Earlier this year, Shoothill built the Sumatran Tiger Deep Zoom - the largest seen to date - for worldwide consevation charity Fauna and Flora International, featuring thousands of images of endangered species.

The first example of deepzoom like technology was implemented at The Department of Maori Affairs in New Zealand in 1997. The technology was used to display Maori land ownership.

Deep Zoom Images

The file format used by Deep Zoom (as well as Photosynth and Seadragon Ajax) is XML based. You can specify a single large image (dzi)^[3] or a collection of images (dzc)^[4]. It also allows for "Sparse Images"; where some parts of the image have greater resolution than others, an example of which can be found on the Seadragon Ajax home page; The bike image displayed is a sparse image.^[5] Though used in the proprietary Deep Zoom, the dzi format is open and able to be used by anyone.

Deep Zoom Image(dzi)

A DZI has two parts: a DZI file (with either a .dzi or .xml extension) and a subdirectory of image files. Each folder in the image subdirectory is labeled with its level of resolution. Higher numbers correspond to a higher resolution level^[6]; inside each folder are the image tiles corresponding to that level of resolution.

Deep Zoom Collection(dzc)

A DZC is a collection of some number of DZIs linked and referenced by a DZC file (with either a .dzc or .xml extension). At a high level, a Collection is a number of image thumbnails whose location is kept track of by the .dzc/.xml file, as you zoom into an image, it accesses greater resolutions tiles. A DZC's structure is similar to that of a DZI; the .dzc/.xml file defines the collection and the subdirectory of folders maps to the DZI file structure, each with their set of .dzi/.xml and image tiles. The DZC is used in Microsoft's Pivot, but not in SeaDragon per se.

Sparse Images

Sparse Images (like the bike image above) are a sub-classification of the DZI file type. As in the bike image, a sparse image is normally a number of separate photographs with varying resolution levels that have been placed in a single DZI instead of a DZC. Sparse Images have no different file structure than that of a DZI and differ only in that there is not a single "highest resolution" level for the entire DZI.

iPhone OS development

Sea Dragon App Logo

Microsoft Live Labs has created an application for the App Store called Seadragon Mobile.^[7] It is run over the internet and includes Deep Zoom on the following categories; art, history, maps, photos, Photosynth which anybody can upload to, space and technology & web.

References

1. ^ Jaime Rodriguez: A deepzoom primer ( explained and coded)..
2. ^ "Turning a Blank Wall in to a Microsoft Silverlight Deep Zoom Project - by Web Design Company 352 Media Group". 352media.com. 2009-11-25. http://www.352media.com/Blog/post/2009/11/25/Turning-a-Blank-Wall-in-to-a-Microsoft-Silverlight-Deep-Zoom-Project.aspx. Retrieved 2010-05-29. 
3. ^ File Extension for Deep Zoom Image
4. ^ File Extension For Deep Zoom Collection
5. ^ Deep Zoom File Format Overview
6. ^ "Creating Seadragon Content – File Formats". Seadragon.com. 2009-03-20. http://seadragon.com/developer/creating-content/file-formats/. Retrieved 2010-05-29. 
7. ^ http://www.engadget.com/2008/12/14/microsoft-releases-first-iphone-application-seadragon/ Microsoft releases first iPhone/iPod application, Seadragon

External links

• The Official Microsoft Silverlight Site
• What is DeepZoom and more
• A DeepZoom Primer
• MSDN Overview in Silverlight for Developers
• Download Deep Zoom Composer
• Demo of Photosynth and Seadragon at TED conference