Difference between revisions of "Main Page"
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In this paper we address the problem of object-class retrieval in large image data sets: given a small set of training examples defining a visual category, the objective is to efficiently retrieve images of the same class from a large database. We propose two contrasting retrieval schemes achieving good accuracy and high efficiency. The first exploits sparse classification models expressed as linear combinations of a small number of features. These sparse models can be efficiently evaluated using inverted file indexing. Furthermore, we introduce a novel ranking procedure that provides a significant speedup over inverted file indexing when the goal is restricted to finding the top-k (i.e., the k highest ranked) images in the data set. We contrast these sparse retrieval models with a second scheme based on approximate ranking using vector quantization. Experimental results show that our algorithms for object-class retrieval can search a 10 million database in just a couple of seconds and produce categorization accuracy comparable to the best known class-recognition systems. | In this paper we address the problem of object-class retrieval in large image data sets: given a small set of training examples defining a visual category, the objective is to efficiently retrieve images of the same class from a large database. We propose two contrasting retrieval schemes achieving good accuracy and high efficiency. The first exploits sparse classification models expressed as linear combinations of a small number of features. These sparse models can be efficiently evaluated using inverted file indexing. Furthermore, we introduce a novel ranking procedure that provides a significant speedup over inverted file indexing when the goal is restricted to finding the top-k (i.e., the k highest ranked) images in the data set. We contrast these sparse retrieval models with a second scheme based on approximate ranking using vector quantization. Experimental results show that our algorithms for object-class retrieval can search a 10 million database in just a couple of seconds and produce categorization accuracy comparable to the best known class-recognition systems. | ||
| + | |||
| + | ===Dog Breed Classification Using Part Localization=== | ||
| + | Speaker: [http://www.cs.umd.edu/~kanazawa/ Angjoo Kanazawa] -- Date: February 7, 2013 | ||
| + | |||
| + | We propose a novel approach to fine-grained image classification in which instances from different classes share common parts but | ||
| + | have wide variation in shape and appearance. We use dog breed identification as a test case to show that extracting corresponding parts improves classification performance. This domain is especially challenging since the appearance of corresponding parts can vary dramatically, e.g., the faces of bulldogs and beagles are very different. To find accurate correspondences, we build exemplar-based geometric and appearance models of dog breeds and their face parts. Part correspondence allows us to extract and compare descriptors in like image locations. Our approach also features a hierarchy of parts (e.g., face and eyes) and breed-specific part localization. We achieve 67% recognition rate on a large real-world dataset including 133 dog breeds and 8,351 images, and experimental results show that accurate part localization significantly increases classification performance compared to state-of-the-art approaches. | ||
==Past Semesters== | ==Past Semesters== | ||
Revision as of 20:40, 1 February 2013
Computer Vision Student Seminars
The Computer Vision Student Seminars at the University of Maryland College Park are a student-run series of talks given by current graduate students for current graduate students.
To receive regular information about the Computer Vision Student Seminars, subscribe to our mailing list or our talks list.
Description[edit]
The purpose of these talks is to:
- Encourage interaction between computer vision students;
- Provide an opportunity for computer vision students to be aware of and possibly get involved in the research their peers are conducting;
- Provide an opportunity for computer vision students to receive feedback on their current research;
- Provide speaking opportunities for computer vision students.
The guidelines for the format are:
- An hour-long weekly meeting, consisting of one 20-40 minute talk followed by discussion and food.
- The talks are meant to be casual and discussion is encouraged.
- Topics may include current research, past research, general topic presentations, paper summaries and critiques, or anything else beneficial to the computer vision graduate student community.
Schedule Spring 2013[edit]
All talks take place Thursdays at 4:30pm in AVW 3450.
| Date | Speaker | Title |
|---|---|---|
| January 24 | (no meeting) | |
| January 31 | Mohammad Rastegari | Scalable object-class retrieval with approximate and top-k ranking |
| February 7 | Angjoo Kanazawa | Dog Breed Classification Using Part Localization |
| February 14 | Stephen Xi Chen | Piecing Together the Segmentation Jigsaw using Context |
| February 21 | Guangxiao Zhang | |
| February 28 | Kota Hara | |
| March 7 | Arijit Biswas | |
| March 14 | ||
| March 21 | (Spring Break, no meeting) | |
| March 28 | (Midterms, no meeting) | |
| April 4 | ||
| April 11 | (ICCV deadline, no meeting) | |
| April 18 | Raviteja Vemulapalli | |
| April 25 | ||
| May 2 | Xavier Gibert Serra |
Talk Abstracts Spring 2013[edit]
Scalable object-class retrieval with approximate and top-k ranking[edit]
Speaker: Mohammad Rastegari -- Date: January 31, 2013
In this paper we address the problem of object-class retrieval in large image data sets: given a small set of training examples defining a visual category, the objective is to efficiently retrieve images of the same class from a large database. We propose two contrasting retrieval schemes achieving good accuracy and high efficiency. The first exploits sparse classification models expressed as linear combinations of a small number of features. These sparse models can be efficiently evaluated using inverted file indexing. Furthermore, we introduce a novel ranking procedure that provides a significant speedup over inverted file indexing when the goal is restricted to finding the top-k (i.e., the k highest ranked) images in the data set. We contrast these sparse retrieval models with a second scheme based on approximate ranking using vector quantization. Experimental results show that our algorithms for object-class retrieval can search a 10 million database in just a couple of seconds and produce categorization accuracy comparable to the best known class-recognition systems.
Dog Breed Classification Using Part Localization[edit]
Speaker: Angjoo Kanazawa -- Date: February 7, 2013
We propose a novel approach to fine-grained image classification in which instances from different classes share common parts but have wide variation in shape and appearance. We use dog breed identification as a test case to show that extracting corresponding parts improves classification performance. This domain is especially challenging since the appearance of corresponding parts can vary dramatically, e.g., the faces of bulldogs and beagles are very different. To find accurate correspondences, we build exemplar-based geometric and appearance models of dog breeds and their face parts. Part correspondence allows us to extract and compare descriptors in like image locations. Our approach also features a hierarchy of parts (e.g., face and eyes) and breed-specific part localization. We achieve 67% recognition rate on a large real-world dataset including 133 dog breeds and 8,351 images, and experimental results show that accurate part localization significantly increases classification performance compared to state-of-the-art approaches.
Past Semesters[edit]
Funded By[edit]
- Computer Vision Faculty
- Northrop Grumman
Current Seminar Series Coordinators[edit]
Emails are at umiacs.umd.edu.
| Ejaz Ahmed, ejaz@ | (student of Professor Larry Davis) |
| Angjoo Kanazawa, kanazawa@ | (student of Professor David Jacobs) |
| Jie Ni, jni@ | (student of Professor Rama Chellappa) |
| Ching Lik Teo, cteo@ | (student of Professor Yiannis Aloimonos) |
Gone but not forgotten.
| Anne Jorstad | now PostDoc at EPFL |
| Sameh Khamis | off this semester |
| Sima Taheri |
