VRFP: On-the-fly Video Retrieval using Web Images and Fast Fisher Vector Products
This addresses the problem of efficient and accurate video retrieval for users needing quick access to multimedia content, presenting an incremental advance with a novel acceleration technique.
The paper tackles real-time video retrieval from text queries by using web images and a fast Fisher Vector method, achieving state-of-the-art performance with improvements of 3.5%, 1.3%, and 5.2% on TRECVID MED13, MED14, and CCV datasets.
VRFP is a real-time video retrieval framework based on short text input queries, which obtains weakly labeled training images from the web after the query is known. The retrieved web images representing the query and each database video are treated as unordered collections of images, and each collection is represented using a single Fisher Vector built on CNN features. Our experiments show that a Fisher Vector is robust to noise present in web images and compares favorably in terms of accuracy to other standard representations. While a Fisher Vector can be constructed efficiently for a new query, matching against the test set is slow due to its high dimensionality. To perform matching in real-time, we present a lossless algorithm that accelerates the inner product computation between high dimensional Fisher Vectors. We prove that the expected number of multiplications required decreases quadratically with the sparsity of Fisher Vectors. We are not only able to construct and apply query models in real-time, but with the help of a simple re-ranking scheme, we also outperform state-of-the-art automatic retrieval methods by a significant margin on TRECVID MED13 (3.5%), MED14 (1.3%) and CCV datasets (5.2%). We also provide a direct comparison on standard datasets between two different paradigms for automatic video retrieval - zero-shot learning and on-the-fly retrieval.