{"id":1082,"date":"2026-07-15T12:56:58","date_gmt":"2026-07-15T11:56:58","guid":{"rendered":"https:\/\/schools.stem.open.ac.uk\/knowledge-media-institute\/?page_id=1082"},"modified":"2026-07-15T12:56:58","modified_gmt":"2026-07-15T11:56:58","slug":"local-similarity-search-for-content-based-image-retrieval","status":"publish","type":"page","link":"https:\/\/schools.stem.open.ac.uk\/knowledge-media-institute\/local-similarity-search-for-content-based-image-retrieval\/","title":{"rendered":"Local Similarity Search for Content-based Image Retrieval"},"content":{"rendered":"\n<div class=\"wp-block-group is-nowrap is-layout-flex wp-container-core-group-is-layout-8f761849 wp-block-group-is-layout-flex\">\n<figure class=\"wp-block-image\"><img decoding=\"async\" src=\"https:\/\/stadium.open.ac.uk\/stadia\/stadia\/speakerimages\/742.jpg\" alt=\" Peter Howarth\"\/><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">Peter Howarth &#8211; Imperial College London, and KMi, The Open University<br><small>This event took place on Wednesday 29 November 2006 at 11:30<\/small><\/p>\n<\/div>\n\n\n\n<p class=\"wp-block-paragraph\">The goal of content-based image retrieval (CBIR) is to provide the user with a way to browse or retrieve images from large collections based on visual similarity. At the heart of any CBIR system are visual features that have been extracted from images and (dis)similarity functions that are used to quantify the similarity between these features. The combination of these two components will drive the overall performance of a system.<br><br>Two frequently studied research areas in CBIR are maximising retrieval performance using similarity measures and improving the efficiency and speed of search by applying indexing methods. Often these are mutually exclusive. The best performing similarity measures are usually computationally expensive and the optimal indexing approaches can place many restrictions on what features and similarity functions can be used.<br><br>In this talk we investigate how to localise the measurement of similarity. That is, emphasise points that are close to the query in some subspace of the full feature space. We show that this has dual benefits for CBIR, both improving retrieval performance and speeding up the search of high-dimensional features.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><a href=\"http:\/\/stadium.open.ac.uk\/stadia\/preview.php?s=29&amp;whichevent=922\">Watch the webcast replay &gt;&gt;<\/a><\/p>\n\n\n\n<div class=\"wp-block-group\"><div class=\"wp-block-group__inner-container is-layout-constrained wp-block-group-is-layout-constrained\">\n<p class=\"wp-block-paragraph\"><a href=\"https:\/\/schools.stem.open.ac.uk\/knowledge-media-institute\/past-seminars\/\">View all past events<\/a><\/p>\n\n\n\n<div class=\"wp-block-group is-nowrap is-layout-flex wp-container-core-group-is-layout-8f761849 wp-block-group-is-layout-flex\">\n<figure class=\"wp-block-image size-full has-custom-css wp-custom-css-ac9b5317\"><img loading=\"lazy\" decoding=\"async\" width=\"213\" height=\"246\" src=\"https:\/\/schools.stem.open.ac.uk\/knowledge-media-institute\/wp-content\/uploads\/sites\/8\/2026\/07\/image-2.png\" alt=\"Maven of the Month\" class=\"wp-image-537\"\/><\/figure>\n\n\n\n<div class=\"wp-block-group is-vertical is-layout-flex wp-container-core-group-is-layout-4fc3f8e1 wp-block-group-is-layout-flex\">\n<h3 class=\"wp-block-heading\"><a href=\"https:\/\/schools.stem.open.ac.uk\/knowledge-media-institute\/maven-of-the-month\/\">Maven of the Month<\/a><\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">We are also inviting top experts in AI and Knowledge Technologies to discuss major socio-technological topics with an audience that comprises both members of the Knowledge Media Institute, as well as the wider staff at The Open University. Differently from our seminar series, these events follow a Q&amp;A format.<\/p>\n<\/div>\n<\/div>\n<\/div><\/div>\n","protected":false},"excerpt":{"rendered":"<p>Peter Howarth &#8211; Imperial College London, and KMi, The Open UniversityThis event took place on Wednesday 29 November 2006 at 11:30 The goal of content-based image retrieval (CBIR) is to provide the user with a way to browse or retrieve images from large collections based on visual similarity. At the heart of any CBIR system [&hellip;]<\/p>\n","protected":false},"author":13,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"unity_related_person":[],"unity_sdg":[],"unity_research_theme":[],"unity_strategic_priority":[],"unity_enabler":[],"unity_general_category":[],"unity_stem_unit":[],"unity_related_project":[],"unity_related_archived_project":[],"unity_related_event":[],"class_list":["post-1082","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/schools.stem.open.ac.uk\/knowledge-media-institute\/wp-json\/wp\/v2\/pages\/1082","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/schools.stem.open.ac.uk\/knowledge-media-institute\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/schools.stem.open.ac.uk\/knowledge-media-institute\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/schools.stem.open.ac.uk\/knowledge-media-institute\/wp-json\/wp\/v2\/users\/13"}],"replies":[{"embeddable":true,"href":"https:\/\/schools.stem.open.ac.uk\/knowledge-media-institute\/wp-json\/wp\/v2\/comments?post=1082"}],"version-history":[{"count":1,"href":"https:\/\/schools.stem.open.ac.uk\/knowledge-media-institute\/wp-json\/wp\/v2\/pages\/1082\/revisions"}],"predecessor-version":[{"id":1083,"href":"https:\/\/schools.stem.open.ac.uk\/knowledge-media-institute\/wp-json\/wp\/v2\/pages\/1082\/revisions\/1083"}],"wp:attachment":[{"href":"https:\/\/schools.stem.open.ac.uk\/knowledge-media-institute\/wp-json\/wp\/v2\/media?parent=1082"}],"wp:term":[{"taxonomy":"unity_related_person","embeddable":true,"href":"https:\/\/schools.stem.open.ac.uk\/knowledge-media-institute\/wp-json\/wp\/v2\/unity_related_person?post=1082"},{"taxonomy":"unity_sdg","embeddable":true,"href":"https:\/\/schools.stem.open.ac.uk\/knowledge-media-institute\/wp-json\/wp\/v2\/unity_sdg?post=1082"},{"taxonomy":"unity_research_theme","embeddable":true,"href":"https:\/\/schools.stem.open.ac.uk\/knowledge-media-institute\/wp-json\/wp\/v2\/unity_research_theme?post=1082"},{"taxonomy":"unity_strategic_priority","embeddable":true,"href":"https:\/\/schools.stem.open.ac.uk\/knowledge-media-institute\/wp-json\/wp\/v2\/unity_strategic_priority?post=1082"},{"taxonomy":"unity_enabler","embeddable":true,"href":"https:\/\/schools.stem.open.ac.uk\/knowledge-media-institute\/wp-json\/wp\/v2\/unity_enabler?post=1082"},{"taxonomy":"unity_general_category","embeddable":true,"href":"https:\/\/schools.stem.open.ac.uk\/knowledge-media-institute\/wp-json\/wp\/v2\/unity_general_category?post=1082"},{"taxonomy":"unity_stem_unit","embeddable":true,"href":"https:\/\/schools.stem.open.ac.uk\/knowledge-media-institute\/wp-json\/wp\/v2\/unity_stem_unit?post=1082"},{"taxonomy":"unity_related_project","embeddable":true,"href":"https:\/\/schools.stem.open.ac.uk\/knowledge-media-institute\/wp-json\/wp\/v2\/unity_related_project?post=1082"},{"taxonomy":"unity_related_archived_project","embeddable":true,"href":"https:\/\/schools.stem.open.ac.uk\/knowledge-media-institute\/wp-json\/wp\/v2\/unity_related_archived_project?post=1082"},{"taxonomy":"unity_related_event","embeddable":true,"href":"https:\/\/schools.stem.open.ac.uk\/knowledge-media-institute\/wp-json\/wp\/v2\/unity_related_event?post=1082"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}