Image meta search is a type of search engine

Search engine

A search engine is an information retrieval system designed to help find information stored on a computer system. The search results are usually presented in a list and are commonly called hits. Search engines help to minimize the time required to find information and the amount of information...

 specialised on finding pictures, images

Raster graphics

In computer graphics, a raster graphics image, or bitmap, is a data structure representing a generally rectangular grid of pixels, or points of color, viewable via a monitor, paper, or other display medium...

, animation

Animation

Animation is the rapid display of a sequence of images of 2-D or 3-D artwork or model positions in order to create an illusion of movement. The effect is an optical illusion of motion due to the phenomenon of persistence of vision, and can be created and demonstrated in several ways...

s etc. Like the text search, image search is an information retrieval

Information retrieval

Information retrieval is the area of study concerned with searching for documents, for information within documents, and for metadata about documents, as well as that of searching structured storage, relational databases, and the World Wide Web...

 system designed to help to find information on the Internet and it allows the user to look for images etc. using keywords or search phrases and to receive a set of thumbnail images, sorted by relevancy.

Specialized search engines, like in the fields of image search, are among the fastest growing search services on the internet. In 2005 alone the number of image searches increased by 91% (Nielsen/NetRatings 2006-03-31).

The most common search engines today offer image search such as Google

Google Image Search

Google Images is a search service created by Google that allows users to search the Web for image content. The feature was introduced in July 2001. The keywords for the image search are based on the filename of the image, the link text pointing to the image, and text adjacent to the image. When...

, Yahoo or Bing!.

How image search works

A common misunderstanding when it comes to image search is that the technology is based on detecting information in the image itself. But most image search works as other search engine

Search engine

A search engine is an information retrieval system designed to help find information stored on a computer system. The search results are usually presented in a list and are commonly called hits. Search engines help to minimize the time required to find information and the amount of information...

s. The metadata

Metadata

The term metadata is an ambiguous term which is used for two fundamentally different concepts . Although the expression "data about data" is often used, it does not apply to both in the same way. Structural metadata, the design and specification of data structures, cannot be about data, because at...

 of the image is indexed and stored in a large database and when a search query

Web search query

A web search query is a query that a user enters into web search engine to satisfy his or her information needs. Web search queries are distinctive in that they are unstructured and often ambiguous; they vary greatly from standard query languages which are governed by strict syntax rules.- Types...

 is performed the image search engine looks up the index

Inverted index

In computer science, an inverted index is an index data structure storing a mapping from content, such as words or numbers, to its locations in a database file, or in a document or a set of documents...

, and queries are matched with the stored information. The results are presented in order of relevancy. The usefulness of an image search engine depends on the relevance of the results it returns, and the ranking algorithms are one of the keys to becoming a big player.

Some search engines can automatically identify a limited range of visual content, e.g. faces, trees, sky, buildings, flowers, colours etc. This can be used alone, as in content-based image retrieval

Content-based image retrieval

Content-based image retrieval , also known as query by image content and content-based visual information retrieval is the application of computer vision techniques to the image retrieval problem, that is, the problem of searching for digital images in large databases....

, or to augment metadata in an image search.

When performing a search the user receives a set of thumbnail images, sorted by relevancy. Each thumbnail is a link back to the original web site where that image is located. Using an advanced search option the user can typically adjust the search criteria to fit their own needs, choosing to search only images or animations, color or black and white, and setting preferences on image size.

Image search providers

• AltaVista
  AltaVista
  AltaVista is a web search engine owned by Yahoo!. AltaVista was once one of the most popular search engines but its popularity declined with the rise of Google...
  
  
• BuuZo
• Google Image Search
  Google Image Search
  Google Images is a search service created by Google that allows users to search the Web for image content. The feature was introduced in July 2001. The keywords for the image search are based on the filename of the image, the link text pointing to the image, and text adjacent to the image. When...
  
  
• Ditto.com
• Corbis
  Corbis
  Corbis Corporation is an American company, based in Seattle, Washington, that licenses the rights to photographs, footage and other visual media...
  
  
• Imense
  Imense
  Imense Ltd is a UK based company that develops technology for Content-based image retrieval and automatic image annotation.-Imense:The founders of Imense are Dr Christopher Town and Dr David Sinclair...
  
  
• Live Search from Microsoft
  Microsoft
  Microsoft Corporation is an American public multinational corporation headquartered in Redmond, Washington, USA that develops, manufactures, licenses, and supports a wide range of products and services predominantly related to computing through its various product divisions...
  
  
• Picollator
  Picollator
  Picollator - Internet search engine that performs search for web sites and multimedia by visual query or text, or a combination of visual query and text...
  
  
• Picsearch
  Picsearch
  Picsearch is a Swedish company which develops and provides image search services for large websites. The image search services developed and provided by Picsearch power several major Internet companies, such as Lycos. Other Picsearch customers include regional search portals in Germany, Turkey and...
  
  
• Pixsta
  Pixsta
  Pixta Ltd. is a UK-based image and video search company founded in 2006 by Alexander Straub, Dr. Daniel Heesch and David Williams.- Background :...
  
  
• StockPhotoFinder
• TinEye
  TinEye
  TinEye is a reverse image search engine developed and offered by Idée, Inc., a company based in Toronto, Canada, which was founded by Leila Boujnane and Paul Bloore in 1999. The use of the Web application is free of charge for customers. According to the company, TinEye is the first web-based image...
  
   (reverse image search)
• GazoPa
  GazoPa
  GazoPa was an image search engine that used features from an image to search for and identify similar images which closed in 2011.GazoPa began in TechCrunch50 in 2008 before launching into an state of open beta in 2009. GazoPa branched out and released a flower photo community site called 'GazoPa...
  
  (similar image search)