250 likes | 388 Views
Internet Resources Discovery (IRD). Introduction to MMIR. Contents. Visual Information Retrieval (VIR) Images Video Video Information Retrieval (VIR) Music Information Retrieval (MIR). Visual Information Retrieval. Introduction VIR system VIR information domains Querying video
E N D
Internet Resources Discovery (IRD) Introduction to MMIR T.Sharon
Contents • Visual Information Retrieval (VIR) • Images • Video • Video Information Retrieval (VIR) • Music Information Retrieval (MIR) T.Sharon
Visual Information Retrieval • Introduction • VIR system • VIR information domains • Querying video • Advanced topics T.Sharon
Introduction • What is VIR? • Who needs it? • Questions and problems T.Sharon
What is VIR? Query VIRSystem VIR allows users toquery and retrieve visual information. Queries will be doneaccording to informationcontent. T.Sharon
Who needs VIR? • Libraries • Museums • Scientific Archives • Image Warehouses T.Sharon
Questions and Problems • How can we search visual information? • How can visual and non-visual information can be searched together? • Problems: • visual information is subjectively interpreted. • few representations: images, graphics, video, animations, stereoscopic images. • requires substantial amount of resources. Dog?? T.Sharon
VIR System • Architecture • Query formulation • Match and ranking • Query answer • Refinement (relevance feedback) T.Sharon
Architecture of VIR System T.Sharon
Query Formulation • Query by example: • sketch an example • give an image • Query by giving values to visual features: • % colors • texture • describe textuallybut use visual tools to define values. T.Sharon
Query matching and ranking • Similarity test • Using combination of features, for example: • colors • texture • shape • motion • additional information • Actions in feature space can be: • maximal distance • K nearest neighbors Feature 1 . . . Feature 3 . . . . . . . . . . Feature 2 T.Sharon
Query Answer • Thumbnails: • Images • DC images • Video • built fromselected DC images (key frames) T.Sharon
Query Refinement • Using a result image from previous query. • Launch a new query. • Modifying a result image with an image processing tool to specify an an additional criteria. • Changing relative weights of visual features and get a new ranking to the previous results. T.Sharon
VIR Information Domains • Information domain • Queries at Pixels Level • examples • problems • Implementations • color • color complex • shape T.Sharon
Information Domains • Metadata information • alphanumeric, database scheme • Visual characteristic • contained in the object • achieved by using computational process, usually image processing T.Sharon
Queries at Pixels Level - Examples • Find all objects for which the 100th to 200th pixels are orange (RGB=255,130,0). • Find all the images that have about the same color (certain RGB) in the central region (relative or absolute). • Find all images that are a shifted version of this particular image, in which the maximum allowable shift is D. T.Sharon
Queries at Pixels Level -Problems • Pixel queries are noise sensitive • couple of noise pixels can cause to discard a good image. • Do not work on rotations. • Changes in lightning and imaging conditions effect pixels significantly and bias queries. T.Sharon
Implementations • Pixels location combined with • Database scheme built by humans • Example techniques: • Color • Color complex • Texture • Shape T.Sharon
Color • Method: • Color definition • Hue (color spectrum) • Saturation (gray) • Calculate histograms • Enables queries: • Find all images for which more than 30% is sky blue and more than 25% is grass green • Sort histogram drawers, find 5 most frequent colors, find all other images with these color features • Find all images far from this image only D T.Sharon
Color Complex • Method: Create histograms quad-tree: • Calculate image histogram • Divide image to quarters and calculate histogram for each quarter • Continue recursively till 16x16 squares • Enables queries: • Find images for which: • more than 20% red-orange pixels in the right upper quarter • more than 20% yellow pixels in the left upper quarter • about 30% brown pixels in the bottom half of the picture • Find all images with red patch in the middle and blue patch around. T.Sharon
Shape • Method: • Suppose we have graphics collection (clip arts) • contain pure colors (little hue changes, no saturation) • Divide image to color areas so that each area contains pixels with the same pure color • Calculate features for each area: • color, area, elongation (sqrt(perimeter)/area), centrality (distance of shape centroid to image center) • Enables queries: • Find all images containing white squares in the center • Find all images containing 2 blue circles close to the center T.Sharon
Examples: Existing Systems • SaFe http://disney.ctr.columbia.edu/SaFe/ • Virage http://www.virage.com/virdemo.html • QBIC http://wwwqbic.almaden.ibm.com/ (stamps) download! http://wwwqbic.almaden.ibm.com/cgi-bin/pcd-demo/drawpicker (photos) • MetaSEEK http://mahler.ctr.columbia.edu:8080/cgi-bin/MetaSEEk_cate • WebSEEK • VisualSEEK • MELDEX http://www.nzdl.org/cgi-bin/gw?c=meldex&a=page&p=coltitle T.Sharon
SaFe T.Sharon
QBIC - Histogram Query T.Sharon
QBIC - Color Layout Query T.Sharon