Fast image retrieval in large image collections POEME Neelanjan Bhowmik, Kamel Guissous http ://recherche.ign.fr/labos/matis/ {neelanjan.bhowmik, kamel.guissous}@ign.fr Introduction With the hasty growing of the image contents, it is imperative to develop effectual search processes, such as Content-Based Image Retrieval (CBIR) to access voluminous, complex & unstructured data. Contribution 1i Fusion of Inverted Indices (FII): – An efficient fusion method for image detectors and descriptors, is proposed for image retrieval. – FII, developed on Inverted Multi-Index approach, allows to fuse any number of image detectors and descriptors by integrating their responses to a query in a finer subdivisions. Contribution 2i Visual Saliency: – Visual saliency is incorporated during image retrieval to get more precise information and discard redundant information of query images. – Only the keypoints in the saliency region are considered. Applications: – Query by example image retrieval from large image dataset, specifically for the museum collections. – Image based localization from a large scale streetview repository. .... .... .... .... .... .... .... .... Image Dataset Feature Points Indexing & Similarity Measurement Query Image Feature Extraction **** **** **** Retrieved images similar to query Context Feature Points – CBIR analyzes the contents of the image rather than metadata. – Visual saliency was started as a biologically inspired process for focusing visual attention to certain parts of an image which contain relevant information, thus reducing the complexity of scene analysis. – Distinguished features (i.e. shape, color, texture etc.) are extracted from images to measure the resemblance. – Fusion of detectors and descriptors is a better way to describe image content with more information. Visual Saliency Global Workflow – A novel visual saliency approach, based on the orientations of the segments detected in the image. – Segments are detected using the LSD (Line Segment Detector) algorithm. – Directions of segments (i.e. one, two and multi) in a local window are studied in order to generate the saliency maps for each image, based on the analysis of the distribution of these orientations. – Saliency maps are used to accelerate and improve the performance of query based image retrieval. Image Dataset O F F L I N E Detector Descriptor A S T A G E Descriptor B Codebook generation Training Matrix (TMA) Query Image (Q) Inverted Unique Indices IUIA Training Matrix (TMB) Inverted Unique Indices Codebook (CBA) Codebook (CBB) IUIB Visual Saliency Saliency Image Detector Evaluations Primitives filtred KnnLA Descriptor A Descriptor B QA1 QA2 QAn QB1 QB2 QBn SearchKnn CLA – Image retrieval experiments are conducted based on our FII proposal considering without and with visual saliency information. – Mean average precision (mAP) is presented to measure of quality across the multiple queries by averaging the average precision (images retrieved that are relevant to the query). – Best retrieval results achieved with SIFT, SURF & Shape Context (SC) descriptors fusions with visual saliency information. KnnLB mAP & Average retrieval time with the fusion of different descriptors Reference - all points Randomly selected points Paris_DB† Descriptors mAP Time(s) mAP Time(s) % of points used SIFT 0.498 0.211 SIFT-SURF 0.544 0.419 SIFT-SURF-SC 0.540 0.736 0.480 0.635 88% SURF-SC 0.522 0.408 CLB MultiSequence FLAB Voting mAP & Average retrieval time with the fusion of different descriptors With visual saliency information † Paris_DB Two + Multi (d] ) One + Two + Multi (d] ) Descriptors mAP Time(s) % of Points mAP Time(s) % of Points SIFT-SURF 0.564 0.359 0.546 0.406 88% 98% SIFT-SURF-SC 0.582 0.637 0.583 0.755 SURF-SC 0.561 0.343 0.534 0.383 FqL Retrieved Images Legend = Images = Files = Programs † Public benchmark consisting of 6412 images collected from Flickr by searching for 12 particular Paris landmarks. (d] : Direction) is the number of main directions in local window. = Pre-process Conclusions Project Organization – Project ANR CONTINT "POEME", European Project KET ENIAC "THINGS2DO". – Working at MATIS Lab, IGN/SR & Nicéphore Cité, Chalon-sur-Saône. – Under supervision of Valérie Gouet-Brunet, Head of MATIS Lab, IGN. – Proposed fusion approach has demonstrated its superiority comparing state-of-the-art. – The strategy of fusion brings distinctiveness during nearest neighbor search hence enhance the performance. – The fusion of different image characteristics achieved by visual saliency enhance the content representation. – The use of visual saliency reduces the irrelevant information, thus retrieval computation time reduces with increased accuracy. Journée de la Recherche 2015
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