Two image-based search tools are available from Europeana: vieu (European Cultural Heritage Visual Search) and VIRaL (Visual Image Retrieval and Localization).
About vieu:
vieu is a visual image search engine focusing on cultural heritage content. Starting from a random set of images from the available collection, one can invoke a query and get a list of matching images ranked by visual similarity. In the results page, the visual similarity score is dispayed on top of each returned image, along with two basic options. The “details” option shows how the similarity between the image and the query was determined. The “original” option links directly to the source of the original image with all related information. Currently the source of all images is the Europeana portal, where each item is also linked to the content provider. Clicking on each returned image issues a new query.
About VIRaL:
VIRaL is a content-based image search engine. The query is an image, either uploaded, fetched from a given a URL, or chosen from the VIRaL database. Given this single image, it retrieves visually similar images from the database and estimates its location. VIRaL also suggests tags that may be attached to the query image, identifies known landmarks or points of interest, and provides links to relevant Wikipedia articles.
VIRaL also includes two additional functions: VIRaL Explore, which allows browsing of the entire VIRaL image collection on the world map, and VIRaL Routes, which constructs a route on a map showing icons of places visited (after images are processed and grouped with appropriate location information offline). An example of VIRaL Routes is depicted above.