1. Image searching on the Web Qunyan Mao SIMS, UC Berkeley

2. Image on the Web More images on the web Format of image –GIF: CompuServe Graphics Interchange format, a dominant web format –JPEG: support “true color”, ideal for photographs –TIF: large file size, not well suited for web pages

3. Image format –BMP: such as desktop wallpaper image, not supported by any Web browser –PNG: Portable Network Graphics. An image format for the future.

4. Image indexing Two methods used in indexingimages –text-based –content-based

5. Text-based vs content based Text-based : commonly used image indexing and searching method –descriptive text –controlled vocabulary Drawbacks: –have to have descriptor along with the image to make it accessible –consistency: different type of textual data –human intervention

6. Text-based vs.. content based Content-based indexing and searching –goal: provide algorithms that can automatically recognize the important features in an image without human intervention –search by color, shape,spatial relationship

7. Where to start Search engine: –general search engine: AltaVista, Lycos, –image search engine: WebSEEK Specialized image database: –Museum, archive, and library digital image database

8. How search engine work How does a Web search engine identify images and match to your criteria –look for graphic files: HTML tags: and. Example: AltaVista –Look for caption: HTML tag –Look for title of Web page –Employ human intervention to catalog images

9. Search example: Giraffe AltaVista Lycos WebSEEK

10. AltaVista Http://image.altavista.com/cgi-bin/avncgi Text-based indexing: file name and path name (live search demo)

11. Lycos Http://lycospro.lycos.com Text-based indexing: file name, path name and caption( tag) (live search demo)

12. WebSEEK: Http://www.disney.ctr.columbia.edu/webse ek content-based image search engine (live search demo)

13. Specialized image database Museums, archive, and library digital image database –Fine arts museums of San Francisco http://www.thinker.org/imagebase/index-2.html –California heritage collection http://sunsite.berkeley.edu/CalHeritage/collecti on.html –National Museum of America Art

14. Problems in using search engines Search result heavily relies on the how the webmaster name the image file and directory. Even with the content -based search, there are a lot unexpected results

15. Specialized image database More likely use controlled vocabulary to describe the image well organized comparing to the other images on the Web have their own search tools or find aids

16. Before using the image Available for viewing doesn’t mean available for reuse Make sure you have right to use it