Welcome to my website (prof.irfanessa.com). Here you will find information related to my academic pursuits. This includes updates on my research projects, list of publications, classes I teach and my collaborators/students. If you'd like to contact me, I suggest please see the FAQ. Students wanted to contact me about working with me are highly encouraged to read the FAQ. My bio is also available. Use the menu bar above, or the TAGS and CATEGORIES listed in the columns to find relevant information.
A. Zia, Y. Sharma, V. Bettadapura, E. Sarin, M. Clements, and I. Essa (2015), “Automated Assessment of Surgical Skills Using Frequency Analysis,” in International Conference on Medical Image Computing and Computer Assisted Interventions (MICCAI), 2015. [PDF][BIBTEX]
@InProceedings{ 2015-Zia-AASSUFA,
author = {A. Zia and Y. Sharma and V. Bettadapura and E.
Sarin and M. Clements and I. Essa},
booktitle = {International Conference on Medical Image Computing
and Computer Assisted Interventions (MICCAI)},
month = {October},
pdf = {http://www.cc.gatech.edu/~irfan/p/2015-Zia-AASSUFA.pdf},
title = {Automated Assessment of Surgical Skills Using
Frequency Analysis},
year = {2015}
}
Abstract
We present an automated framework for a visual assessment of the expertise level of surgeons using the OSATS (Objective Structured Assessment of Technical Skills) criteria. Video analysis technique for extracting motion quality via frequency coefficients is introduced. The framework is tested in a case study that involved analysis of videos of medical students with different expertise levels performing basic surgical tasks in a surgical training lab setting. We demonstrate that transforming the sequential time data into frequency components effectively extracts the useful information differentiating between different skill levels of the surgeons. The results show significant performance improvements using DFT and DCT coefficients over known state-of-the-art techniques.
Participated in the Dagstuhl Workshop on “Modeling and Simulation of Sport Games, Sport Movements, and Adaptations to Training” at the Dagstuhl Castle, September 13 – 16, 2015.
Motivation
Computational modeling and simulation are essential to analyze human motion and interaction in sports science. Applications range from game analysis, issues in training science like training load-adaptation relationship, motor control & learning, to biomechanical analysis. The motivation of this seminar is to enable an interdisciplinary exchange between sports and computer scientists to advance modeling and simulation technologies in selected fields of applications: sport games, sport movements and adaptations to training. In addition, contributions to the epistemic basics of modeling and simulation are welcome.
E. Thomaz, I. Essa, and G. D. Abowd (2015), “A Practical Approach for Recognizing Eating Moments with Wrist-Mounted Inertial Sensing,” in Proceedings of ACM International Conference on Ubiquitous Computing (UBICOMP), 2015. [PDF][BIBTEX]
@InProceedings{ 2015-Thomaz-PAREMWWIS,
author = {Edison Thomaz and Irfan Essa and Gregory D. Abowd},
booktitle = {Proceedings of ACM International Conference on
Ubiquitous Computing (UBICOMP)},
month = {September},
pdf = {http://www.cc.gatech.edu/~irfan/p/2015-Thomaz-PAREMWWIS.pdf},
title = {A Practical Approach for Recognizing Eating Moments
with Wrist-Mounted Inertial Sensing},
year = {2015}
}
Abstract
Recognizing when eating activities take place is one of the key challenges in automated food intake monitoring. Despite progress over the years, most proposed approaches have been largely impractical for everyday usage, requiring multiple onbody sensors or specialized devices such as neck collars for swallow detection. In this paper, we describe the implementation and evaluation of an approach for inferring eating moments based on 3-axis accelerometry collected with a popular off-the-shelf smartwatch. Trained with data collected in a semi-controlled laboratory setting with 20 subjects, our system recognized eating moments in two free-living condition studies (7 participants, 1 day; 1 participant, 31 days), with Fscores of 76.1% (66.7% Precision, 88.8% Recall), and 71.3% (65.2% Precision, 78.6% Recall). This work represents a contribution towards the implementation of a practical, automated system for everyday food intake monitoring, with applicability in areas ranging from health research and food journaling.
D. Castro, S. Hickson, V. Bettadapura, E. Thomaz, G. Abowd, H. Christensen, and I. Essa (2015), “Predicting Daily Activities from Egocentric Images Using Deep Learning,” in Proceedings of International Symposium on Wearable Computers (ISWC), 2015. [PDF][WEBSITE] [arXiv][BIBTEX]
@InProceedings{ 2015-Castro-PDAFEIUDL,
arxiv = {http://arxiv.org/abs/1510.01576},
author = {Daniel Castro and Steven Hickson and Vinay
Bettadapura and Edison Thomaz and Gregory Abowd and
Henrik Christensen and Irfan Essa},
booktitle = {Proceedings of International Symposium on Wearable
Computers (ISWC)},
month = {September},
pdf = {http://www.cc.gatech.edu/~irfan/p/2015-Castro-PDAFEIUDL.pdf},
title = {Predicting Daily Activities from Egocentric Images
Using Deep Learning},
url = {http://www.cc.gatech.edu/cpl/projects/dailyactivities/},
year = {2015}
}
Abstract
We present a method to analyze images taken from a passive egocentric wearable camera along with the contextual information, such as time and day of a week, to learn and predict everyday activities of an individual. We collected a dataset of 40,103 egocentric images over a 6 month period with 19 activity classes and demonstrate the benefit of state-of-the-art deep learning techniques for learning and predicting daily activities. Classification is conducted using a Convolutional Neural Network (CNN) with a classification method we introduce called a late fusion ensemble. This late fusion ensemble incorporates relevant contextual information and increases our classification accuracy. Our technique achieves an overall accuracy of 83.07% in predicting a person’s activity across the 19 activity classes. We also demonstrate some promising results from two additional users by fine-tuning the classifier with one day of training data.
E. Thomaz, C. Zhang, I. Essa, and G. D. Abowd (2015), “Inferring Meal Eating Activities in Real World Settings from Ambient Sounds: A Feasibility Study,” in Proceedings of ACM Conference on Intelligence User Interfaces (IUI), 2015. (Best Short Paper Award)[PDF][BIBTEX]
@InProceedings{ 2015-Thomaz-IMEARWSFASFS,
author = {Edison Thomaz and Cheng Zhang and Irfan Essa and
Gregory D. Abowd},
awards = {(Best Short Paper Award)},
booktitle = {Proceedings of ACM Conference on Intelligence User
Interfaces (IUI)},
month = {May},
pdf = {http://www.cc.gatech.edu/~irfan/p/2015-Thomaz-IMEARWSFASFS.pdf},
title = {Inferring Meal Eating Activities in Real World
Settings from Ambient Sounds: A Feasibility Study},
year = {2015}
}
Abstract
Dietary self-monitoring has been shown to be an effective method for weight-loss, but it remains an onerous task despite recent advances in food journaling systems. Semi-automated food journaling can reduce the effort of logging, but often requires that eating activities be detected automatically. In this work we describe results from a feasibility study conducted in-the-wild where eating activities were inferred from ambient sounds captured with a wrist-mounted device; twenty participants wore the device during one day for an average of 5 hours while performing normal everyday activities. Our system was able to identify meal eating with an F-score of 79.8% in a person-dependent evaluation, and with 86.6% accuracy in a person-independent evaluation. Our approach is intended to be practical, leveraging off-the-shelf devices with audio sensing capabilities in contrast to systems for automated dietary assessment based on specialized sensors.
V. Bettadapura, E. Thomaz, A. Parnami, G. Abowd, and I. Essa (2015), “Leveraging Context to Support Automated Food Recognition in Restaurants,” in Proceedings of IEEE Winter Conference on Applications of Computer Vision (WACV), 2015. [PDF][WEBSITE] [DOI] [arXiv][BIBTEX]
@InProceedings{ 2015-Bettadapura-LCSAFRR,
arxiv = {http://arxiv.org/abs/1510.02078},
author = {Vinay Bettadapura and Edison Thomaz and Aman
Parnami and Gregory Abowd and Irfan Essa},
booktitle = {Proceedings of IEEE Winter Conference on
Applications of Computer Vision (WACV)},
doi = {10.1109/WACV.2015.83},
month = {January},
pdf = {http://www.cc.gatech.edu/~irfan/p/2015-Bettadapura-LCSAFRR.pdf},
publisher = {IEEE Computer Society},
title = {Leveraging Context to Support Automated Food
Recognition in Restaurants},
url = {http://www.vbettadapura.com/egocentric/food/},
year = {2015}
}
Abstract
The pervasiveness of mobile cameras has resulted in a dramatic increase in food photos, which are pictures reflecting what people eat. In this paper, we study how taking pictures of what we eat in restaurants can be used for the purpose of automating food journaling. We propose to leverage the context of where the picture was taken, with additional information about the restaurant, available online, coupled with state-of-the-art computer vision techniques to recognize the food being consumed. To this end, we demonstrate image-based recognition of foods eaten in restaurants by training a classifier with images from restaurant’s online menu databases. We evaluate the performance of our system in unconstrained, real-world settings with food images taken in 10 restaurants across 5 different types of food (American, Indian, Italian, Mexican and Thai).
V. Bettadapura, I. Essa, and C. Pantofaru (2015), “Egocentric Field-of-View Localization Using First-Person Point-of-View Devices,” in Proceedings of IEEE Winter Conference on Applications of Computer Vision (WACV), 2015. (Best Paper Award)[PDF][WEBSITE] [DOI] [arXiv][BIBTEX]
@InProceedings{ 2015-Bettadapura-EFLUFPD,
arxiv = {http://arxiv.org/abs/1510.02073},
author = {Vinay Bettadapura and Irfan Essa and Caroline
Pantofaru},
awards = {(Best Paper Award)},
booktitle = {Proceedings of IEEE Winter Conference on
Applications of Computer Vision (WACV)},
doi = {10.1109/WACV.2015.89},
month = {January},
pdf = {http://www.cc.gatech.edu/~irfan/p/2015-Bettadapura-EFLUFPD.pdf},
publisher = {IEEE Computer Society},
title = {Egocentric Field-of-View Localization Using
First-Person Point-of-View Devices},
url = {http://www.vbettadapura.com/egocentric/localization/},
year = {2015}
}
Abstract
We present a technique that uses images, videos and sensor data taken from first-person point-of-view devices to perform egocentric field-of-view (FOV) localization. We define egocentric FOV localization as capturing the visual information from a person’s field-of-view in a given environment and transferring this information onto a reference corpus of images and videos of the same space, hence determining what a person is attending to. Our method matches images and video taken from the first-person perspective with the reference corpus and refines the results using the first-person’s head orientation information obtained using the device sensors. We demonstrate single and multi-user egocentric FOV localization in different indoor and outdoor environments with applications in augmented reality, event understanding and studying social interactions.
Y. Sharma, V. Bettadapura, T. Ploetz, N. Hammerla, S. Mellor, R. McNaney, P. Olivier, S. Deshmukh, A. Mccaskie, and I. Essa (2014), “Video Based Assessment of OSATS Using Sequential Motion Textures,” in Proceedings of Workshop on Modeling and Monitoring of Computer Assisted Interventions (M2CAI), 2014. (Best Paper Honorable Mention Award)[PDF][BIBTEX]
@InProceedings{ 2014-Sharma-VBAOUSMT,
author = {Yachna Sharma and Vinay Bettadapura and Thomas
Ploetz and Nils Hammerla and Sebastian Mellor and
Roisin McNaney and Patrick Olivier and Sandeep
Deshmukh and Andrew Mccaskie and Irfan Essa},
awards = {(Best Paper Honorable Mention Award)},
booktitle = {{Proceedings of Workshop on Modeling and Monitoring
of Computer Assisted Interventions (M2CAI)}},
month = {September},
pdf = {http://www.cc.gatech.edu/~irfan/p/2014-Sharma-VBAOUSMT.pdf},
title = {Video Based Assessment of OSATS Using Sequential
Motion Textures},
year = {2014}
}
Abstract
A fully automated framework for video-based surgical skill assessment is presented that incorporates the sequential and qualitative aspects of surgical motion in a data-driven manner. The Objective Structured Assessment of Technical Skills (OSATS) assessments is replicated, which provides both an overall and in-detail evaluation of basic suturing skills required for surgeons. Video analysis techniques are introduced that incorporate sequential motion aspects into motion textures. Significant performance improvement over standard bag-of-words and motion analysis approaches is demonstrated. The framework is evaluated in a case study that involved medical students with varying levels of expertise performing basic surgical tasks in a surgical training lab setting.
Awarded the Best Paper Honorable Mention (2nd place) Award at M2CAI 2014.
Today, two of my Ph. D. Students defended their Dissertations. Back to back. Congrats to both as they are both done.
Thesis title: Surgical Skill Assessment Using Motion Texture analysis
Student: Yachna Sharma, Ph. D. Candidate in ECE http://users.ece.gatech.edu/~ysharma3/
Date/Time : 2nd April, 1:00 pm
Title : Temporally Consistent Semantic Segmentation in Videos
S. Hussain Raza, Ph. D. Candidate in ECE https://sites.google.com/site/shussainraza5/
Date/Time : 2nd April, 1:00 pm
Location : CSIP Library, Room 5186, CenterGy One Building
R. Hamid, R. Kumar, J. Hodgins, and I. Essa (2013), “A Visualization Framework for Team Sports Captured using Multiple Static Cameras,” Computer Vision and Image Understanding, p. -, 2013. [PDF][WEBSITE][VIDEO] [DOI][BIBTEX]
@Article{ 2013-Hamid-VFTSCUMSC,
author = {Raffay Hamid and Ramkrishan Kumar and Jessica
Hodgins and Irfan Essa},
doi = {10.1016/j.cviu.2013.09.006},
issn = {1077-3142},
journal = {{Computer Vision and Image Understanding}},
number = {0},
pages = {-},
pdf = {http://www.cc.gatech.edu/~irfan/p/2013-Hamid-VFTSCUMSC.pdf},
title = {A Visualization Framework for Team Sports Captured
using Multiple Static Cameras},
url = {http://raffayhamid.com/sports_viz.shtml},
video = {http://www.youtube.com/watch?v=VwzAMi9pUDQ},
year = {2013},
bdsk-url-3 = {http://raffayhamid.com/sports_viz.shtml}
}
Abstract
We present a novel approach for robust localization of multiple people observed using a set of static cameras. We use this location information to generate a visualization of the virtual offside line in soccer games. To compute the position of the offside line, we need to localize players′ positions, and identify their team roles. We solve the problem of fusing corresponding players′ positional information by finding minimum weight K-length cycles in a complete K-partite graph. Each partite of the graph corresponds to one of the K cameras, whereas each node of a partite encodes the position and appearance of a player observed from a particular camera. To find the minimum weight cycles in this graph, we use a dynamic programming based approach that varies over a continuum from maximally to minimally greedy in terms of the number of graph-paths explored at each iteration. We present proofs for the efficiency and performance bounds of our algorithms. Finally, we demonstrate the robustness of our framework by testing it on 82,000 frames of soccer footage captured over eight different illumination conditions, play types, and team attire. Our framework runs in near-real time, and processes video from 3 full HD cameras in about 0.4 seconds for each set of corresponding 3 frames.
