Tim K. Marks
- Phone: 617-621-7524
- Email:
-
Position:
Research / Technical Staff
Senior Principal Research Scientist,
Senior Team Leader -
Education:
Ph.D., University of California, San Diego, 2006 -
Research Areas:
- Computer Vision
- Artificial Intelligence
- Machine Learning
- Speech & Audio
- Robotics
- Human-Computer Interaction
- Signal Processing
External Links:
Tim's Quick Links
-
Biography
Prior to joining MERL's Imaging Group in 2008, Tim did postdoctoral research in robotic Simultaneous Localization and Mapping in collaboration with NASA's Jet Propulsion Laboratory. His research at MERL spans a variety of areas in computer vision and machine learning, including face recognition under variations in pose and lighting, and robotic vision and touch-based registration for industrial automation.
-
Recent News & Events
-
NEWS MERL researchers presenting four papers and organizing the VLAR-SMART101 Workshop at ICCV 2023 Date: October 2, 2023 - October 6, 2023
Where: Paris/France
MERL Contacts: Moitreya Chatterjee; Anoop Cherian; Michael J. Jones; Toshiaki Koike-Akino; Suhas Lohit; Tim K. Marks; Pedro Miraldo; Kuan-Chuan Peng; Ye Wang
Research Areas: Artificial Intelligence, Computer Vision, Machine LearningBrief- MERL researchers are presenting 4 papers and organizing the VLAR-SMART-101 workshop at the ICCV 2023 conference, which will be held in Paris, France October 2-6. ICCV is one of the most prestigious and competitive international conferences in computer vision. Details are provided below.
1. Conference paper: “Steered Diffusion: A Generalized Framework for Plug-and-Play Conditional Image Synthesis,” by Nithin Gopalakrishnan Nair, Anoop Cherian, Suhas Lohit, Ye Wang, Toshiaki Koike-Akino, Vishal Patel, and Tim K. Marks
Conditional generative models typically demand large annotated training sets to achieve high-quality synthesis. As a result, there has been significant interest in plug-and-play generation, i.e., using a pre-defined model to guide the generative process. In this paper, we introduce Steered Diffusion, a generalized framework for fine-grained photorealistic zero-shot conditional image generation using a diffusion model trained for unconditional generation. The key idea is to steer the image generation of the diffusion model during inference via designing a loss using a pre-trained inverse model that characterizes the conditional task. Our model shows clear qualitative and quantitative improvements over state-of-the-art diffusion-based plug-and-play models, while adding negligible computational cost.
2. Conference paper: "BANSAC: A dynamic BAyesian Network for adaptive SAmple Consensus," by Valter Piedade and Pedro Miraldo
We derive a dynamic Bayesian network that updates individual data points' inlier scores while iterating RANSAC. At each iteration, we apply weighted sampling using the updated scores. Our method works with or without prior data point scorings. In addition, we use the updated inlier/outlier scoring for deriving a new stopping criterion for the RANSAC loop. Our method outperforms the baselines in accuracy while needing less computational time.
3. Conference paper: "Robust Frame-to-Frame Camera Rotation Estimation in Crowded Scenes," by Fabien Delattre, David Dirnfeld, Phat Nguyen, Stephen Scarano, Michael J. Jones, Pedro Miraldo, and Erik Learned-Miller
We present a novel approach to estimating camera rotation in crowded, real-world scenes captured using a handheld monocular video camera. Our method uses a novel generalization of the Hough transform on SO3 to efficiently find the camera rotation most compatible with the optical flow. Because the setting is not addressed well by other data sets, we provide a new dataset and benchmark, with high-accuracy and rigorously annotated ground truth on 17 video sequences. Our method is more accurate by almost 40 percent than the next best method.
4. Workshop paper: "Tensor Factorization for Leveraging Cross-Modal Knowledge in Data-Constrained Infrared Object Detection" by Manish Sharma*, Moitreya Chatterjee*, Kuan-Chuan Peng, Suhas Lohit, and Michael Jones
While state-of-the-art object detection methods for RGB images have reached some level of maturity, the same is not true for Infrared (IR) images. The primary bottleneck towards bridging this gap is the lack of sufficient labeled training data in the IR images. Towards addressing this issue, we present TensorFact, a novel tensor decomposition method which splits the convolution kernels of a CNN into low-rank factor matrices with fewer parameters. This compressed network is first pre-trained on RGB images and then augmented with only a few parameters. This augmented network is then trained on IR images, while freezing the weights trained on RGB. This prevents it from over-fitting, allowing it to generalize better. Experiments show that our method outperforms state-of-the-art.
5. “Vision-and-Language Algorithmic Reasoning (VLAR) Workshop and SMART-101 Challenge” by Anoop Cherian, Kuan-Chuan Peng, Suhas Lohit, Tim K. Marks, Ram Ramrakhya, Honglu Zhou, Kevin A. Smith, Joanna Matthiesen, and Joshua B. Tenenbaum
MERL researchers along with researchers from MIT, GeorgiaTech, Math Kangaroo USA, and Rutgers University are jointly organizing a workshop on vision-and-language algorithmic reasoning at ICCV 2023 and conducting a challenge based on the SMART-101 puzzles described in the paper: Are Deep Neural Networks SMARTer than Second Graders?. A focus of this workshop is to bring together outstanding faculty/researchers working at the intersections of vision, language, and cognition to provide their opinions on the recent breakthroughs in large language models and artificial general intelligence, as well as showcase their cutting edge research that could inspire the audience to search for the missing pieces in our quest towards solving the puzzle of artificial intelligence.
Workshop link: https://wvlar.github.io/iccv23/
- MERL researchers are presenting 4 papers and organizing the VLAR-SMART-101 workshop at the ICCV 2023 conference, which will be held in Paris, France October 2-6. ICCV is one of the most prestigious and competitive international conferences in computer vision. Details are provided below.
-
NEWS MERL Researchers Present Thirteen Papers at the 2023 IEEE International Conference on Robotics and Automation (ICRA) Date: May 29, 2023 - June 2, 2023
Where: 2023 IEEE International Conference on Robotics and Automation (ICRA)
MERL Contacts: Anoop Cherian; Radu Corcodel; Siddarth Jain; Devesh K. Jha; Toshiaki Koike-Akino; Tim K. Marks; Daniel N. Nikovski; Arvind Raghunathan; Diego Romeres
Research Areas: Computer Vision, Machine Learning, Optimization, RoboticsBrief- MERL researchers will present thirteen papers, including eight main conference papers and five workshop papers, at the 2023 IEEE International Conference on Robotics and Automation (ICRA) to be held in London, UK from May 29 to June 2. ICRA is one of the largest and most prestigious conferences in the robotics community. The papers cover a broad set of topics in Robotics including estimation, manipulation, vision-based object recognition and segmentation, tactile estimation and tool manipulation, robotic food handling, robot skill learning, and model-based reinforcement learning.
In addition to the paper presentations, MERL robotics researchers will also host an exhibition booth and look forward to discussing our research with visitors.
- MERL researchers will present thirteen papers, including eight main conference papers and five workshop papers, at the 2023 IEEE International Conference on Robotics and Automation (ICRA) to be held in London, UK from May 29 to June 2. ICRA is one of the largest and most prestigious conferences in the robotics community. The papers cover a broad set of topics in Robotics including estimation, manipulation, vision-based object recognition and segmentation, tactile estimation and tool manipulation, robotic food handling, robot skill learning, and model-based reinforcement learning.
See All News & Events for Tim -
-
Awards
-
AWARD MERL Researchers win Best Paper Award at ICCV 2019 Workshop on Statistical Deep Learning in Computer Vision Date: October 27, 2019
Awarded to: Abhinav Kumar, Tim K. Marks, Wenxuan Mou, Chen Feng, Xiaoming Liu
MERL Contact: Tim K. Marks
Research Areas: Artificial Intelligence, Computer Vision, Machine LearningBrief- MERL researcher Tim Marks, former MERL interns Abhinav Kumar and Wenxuan Mou, and MERL consultants Professor Chen Feng (NYU) and Professor Xiaoming Liu (MSU) received the Best Oral Paper Award at the IEEE/CVF International Conference on Computer Vision (ICCV) 2019 Workshop on Statistical Deep Learning in Computer Vision (SDL-CV) held in Seoul, Korea. Their paper, entitled "UGLLI Face Alignment: Estimating Uncertainty with Gaussian Log-Likelihood Loss," describes a method which, given an image of a face, estimates not only the locations of facial landmarks but also the uncertainty of each landmark location estimate.
-
-
Research Highlights
-
Internships with Tim
-
CV2119: Conditional Video Generation
We seek a highly motivated intern to conduct original research in generative models for conditional video generation. We are interested in applications to various tasks such as video generation from text, images, and diagrams. The successful candidate will collaborate with MERL researchers to design and implement new models, conduct experiments, and prepare results for publication. The candidate should be a PhD student (or postdoc) in computer vision and machine learning with a strong publication record including at least one paper in a top-tier computer vision or machine learning venue such as CVPR, ECCV, ICCV, ICML, ICLR, NeurIPS, AAAI, or TPAMI. Strong programming skills, experience developing and implementing new models in deep learning platforms such as PyTorch, and broad knowledge of machine learning and deep learning methods are expected, including experience in the latest advances in conditional video generation. Start date is flexible; duration should be at least 3 months.
-
-
MERL Publications
- "Steered Diffusion: A Generalized Framework for Plug-and-Play Conditional Image Synthesis", IEEE International Conference on Computer Vision (ICCV), October 2023, pp. 20850-20860.BibTeX TR2023-126 PDF Presentation
- @inproceedings{Nair2023sep,
- author = {Nair, Nithin Gopalakrishnan and Cherian, Anoop and Lohit, Suhas and Wang, Ye and Koike-Akino, Toshiaki and Patel, Vishal M. and Marks, Tim K.},
- title = {Steered Diffusion: A Generalized Framework for Plug-and-Play Conditional Image Synthesis},
- booktitle = {Proceedings of the IEEE/CVF International Conference on Computer Vision},
- year = 2023,
- pages = {20850--20860},
- month = oct,
- publisher = {IEEE/CVF},
- url = {https://www.merl.com/publications/TR2023-126}
- }
, - "Unrolled IPPG: Video Heart Rate Esitmation via Unrolling Proximal Gradient Descent", IEEE International Conference on Image Processing (ICIP), DOI: 10.1109/ICIP49359.2023.10222169, September 2023, pp. 2715-2719.BibTeX TR2023-116 PDF Video
- @inproceedings{Shenoy2023sep,
- author = {Shenoy, Vineet and Marks, Tim K. and Mansour, Hassan and Lohit, Suhas},
- title = {Unrolled IPPG: Video Heart Rate Esitmation via Unrolling Proximal Gradient Descent},
- booktitle = {IEEE International Conference on Image Processing (ICIP)},
- year = 2023,
- pages = {2715--2719},
- month = sep,
- publisher = {IEEE},
- doi = {10.1109/ICIP49359.2023.10222169},
- isbn = {978-1-7281-9835-4},
- url = {https://www.merl.com/publications/TR2023-116}
- }
, - "Discriminative 3D Shape Modeling for Few-Shot Instance Segmentation", IEEE International Conference on Robotics and Automation (ICRA), DOI: 10.1109/ICRA48891.2023.10160644, May 2023, pp. 9296-9302.BibTeX TR2023-010 PDF Presentation
- @inproceedings{Cherian2023may,
- author = {Cherian, Anoop and Jain, Siddarth and Marks, Tim K. and Sullivan, Alan},
- title = {Discriminative 3D Shape Modeling for Few-Shot Instance Segmentation},
- booktitle = {IEEE International Conference on Robotics and Automation (ICRA)},
- year = 2023,
- pages = {9296--9302},
- month = may,
- publisher = {IEEE},
- doi = {10.1109/ICRA48891.2023.10160644},
- url = {https://www.merl.com/publications/TR2023-010}
- }
, - "H-SAUR: Hypothesize, Simulate, Act, Update, and Repeat for Understanding Object Articulations from Interactions", IEEE International Conference on Robotics and Automation (ICRA), DOI: 10.1109/ICRA48891.2023.10160575, May 2023, pp. 7272-7278.BibTeX TR2023-009 PDF
- @inproceedings{Ota2023may,
- author = {Ota, Kei and Tung, Hsiao-Yu and Smith, Kevin and Cherian, Anoop and Marks, Tim K. and Sullivan, Alan and Kanezaki, Asako and Tenenbaum, Joshua B.},
- title = {H-SAUR: Hypothesize, Simulate, Act, Update, and Repeat for Understanding Object Articulations from Interactions},
- booktitle = {IEEE International Conference on Robotics and Automation (ICRA)},
- year = 2023,
- pages = {7272--7278},
- month = may,
- publisher = {IEEE},
- doi = {10.1109/ICRA48891.2023.10160575},
- url = {https://www.merl.com/publications/TR2023-009}
- }
, - "Audio-Visual Scene-Aware Dialog and Reasoning Using Audio-Visual Transformers with Joint Student-Teacher Learning", IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP), April 2022, pp. 7732-7736.BibTeX TR2022-019 PDF
- @inproceedings{Shah2022apr,
- author = {Shah, Ankit Parag and Geng, Shijie and Gao, Peng and Cherian, Anoop and Hori, Takaaki and Marks, Tim K. and Le Roux, Jonathan and Hori, Chiori},
- title = {Audio-Visual Scene-Aware Dialog and Reasoning Using Audio-Visual Transformers with Joint Student-Teacher Learning},
- booktitle = {IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP)},
- year = 2022,
- pages = {7732--7736},
- month = apr,
- publisher = {IEEE},
- issn = {1520-6149},
- isbn = {978-1-6654-0540-9},
- url = {https://www.merl.com/publications/TR2022-019}
- }
,
- "Steered Diffusion: A Generalized Framework for Plug-and-Play Conditional Image Synthesis", IEEE International Conference on Computer Vision (ICCV), October 2023, pp. 20850-20860.
-
Other Publications
- "Gamma-SLAM: Visual SLAM in unstructured environments using variance grid maps", Journal of Field Robotics, Vol. 26, No. 1, pp. 26-51, 2009.BibTeX
- @Article{marks2009gamma,
- author = {Marks, Tim K and Howard, Andrew and Bajracharya, Max and Cottrell, Garrison W and Matthies, Larry H},
- title = {Gamma-SLAM: Visual SLAM in unstructured environments using variance grid maps},
- journal = {Journal of Field Robotics},
- year = 2009,
- volume = 26,
- number = 1,
- pages = {26--51},
- publisher = {Wiley Online Library}
- }
, - "NIMBLE: A kernel density model of saccade-based visual memory", Journal of Vision, Vol. 8, No. 14, 2008.BibTeX
- @Article{barrington2008nimble,
- author = {Barrington, Luke and Marks, Tim K and Hsiao, Janet Hui-wen and Cottrell, Garrison W},
- title = {NIMBLE: A kernel density model of saccade-based visual memory},
- journal = {Journal of Vision},
- year = 2008,
- volume = 8,
- number = 14,
- publisher = {Association for Research in Vision and Ophthalmology}
- }
, - "Gamma-SLAM: Using stereo vision and variance grid maps for SLAM in unstructured environments", Robotics and Automation, 2008. ICRA 2008. IEEE International Conference on, 2008, pp. 3717-3724.BibTeX
- @Inproceedings{marks2008gamma,
- author = {Marks, Tim K and Howard, Andrew and Bajracharya, Max and Cottrell, Garrison W and Matthies, Larry},
- title = {Gamma-SLAM: Using stereo vision and variance grid maps for SLAM in unstructured environments},
- booktitle = {Robotics and Automation, 2008. ICRA 2008. IEEE International Conference on},
- year = 2008,
- pages = {3717--3724},
- organization = {IEEE}
- }
, - "SUN: A Bayesian framework for saliency using natural statistics", Journal of Vision, Vol. 8, No. 7, 2008.BibTeX
- @Article{zhang2008sun,
- author = {Zhang, Lingyun and Tong, Matthew H and Marks, Tim K and Shan, Honghao and Cottrell, Garrison W},
- title = {SUN: A Bayesian framework for saliency using natural statistics},
- journal = {Journal of Vision},
- year = 2008,
- volume = 8,
- number = 7,
- publisher = {Association for Research in Vision and Ophthalmology}
- }
, - "Gamma-SLAM: Stereo visual SLAM in unstructured environments using variance grid maps", IROS visual SLAM workshop, 2007.BibTeX
- @Article{marks2007gamma,
- author = {Marks, Tim K and Howard, Andrew and Bajracharya, Max and Cottrell, Garrison W and Matthies, Larry},
- title = {Gamma-SLAM: Stereo visual SLAM in unstructured environments using variance grid maps},
- journal = {IROS visual SLAM workshop},
- year = 2007,
- publisher = {Citeseer}
- }
, - "Joint tracking of pose, expression, and texture using conditionally Gaussian filters", Advances in neural information processing systems, Vol. 17, pp. 889-896, 2005.BibTeX
- @Article{marks2005joint,
- author = {Marks, Tim K and Hershey, John and Roddey, J Cooper and Movellan, Javier R},
- title = {Joint tracking of pose, expression, and texture using conditionally Gaussian filters},
- journal = {Advances in neural information processing systems},
- year = 2005,
- volume = 17,
- pages = {889--896}
- }
, - "3d tracking of morphable objects using conditionally gaussian nonlinear filters", Computer Vision and Pattern Recognition Workshop, 2004. CVPRW'04. Conference on, 2004, pp. 190-190.BibTeX
- @Inproceedings{marks20043d,
- author = {Marks, Tim K and Hershey, John and Roddey, J Cooper and Movellan, Javier R},
- title = {3d tracking of morphable objects using conditionally gaussian nonlinear filters},
- booktitle = {Computer Vision and Pattern Recognition Workshop, 2004. CVPRW'04. Conference on},
- year = 2004,
- pages = {190--190},
- organization = {IEEE}
- }
, - "Diffusion networks, products of experts, and factor analysis", Proc. Int. Conf. on Independent Component Analysis, pp. 481-485, 2001.BibTeX
- @Article{marks2001diffusion,
- author = {Marks, Tim K and Movellan, Javier R},
- title = {Diffusion networks, products of experts, and factor analysis},
- journal = {Proc. Int. Conf. on Independent Component Analysis},
- year = 2001,
- pages = {481--485},
- publisher = {Citeseer}
- }
,
- "Gamma-SLAM: Visual SLAM in unstructured environments using variance grid maps", Journal of Field Robotics, Vol. 26, No. 1, pp. 26-51, 2009.
-
Software & Data Downloads
-
Videos
-
MERL Issued Patents
-
Title: "System and Method for Manipulating Two-Dimensional (2D) Images of Three-Dimensional (3D) Objects"
Inventors: Marks, Tim; Medin, Safa; Cherian, Anoop; Wang, Ye
Patent No.: 11,663,798
Issue Date: May 30, 2023 -
Title: "InSeGAN: A Generative Approach to Instance Segmentation in Depth Images"
Inventors: Cherian, Anoop; Pais, Goncalo; Marks, Tim; Sullivan, Alan
Patent No.: 11,651,497
Issue Date: May 16, 2023 -
Title: "Method and System for Scene-Aware Interaction"
Inventors: Hori, Chiori; Cherian, Anoop; Chen, Siheng; Marks, Tim; Le Roux, Jonathan; Hori, Takaaki; Harsham, Bret A.; Vetro, Anthony; Sullivan, Alan
Patent No.: 11,635,299
Issue Date: Apr 25, 2023 -
Title: "Scene-Aware Video Encoder System and Method"
Inventors: Cherian, Anoop; Hori, Chiori; Le Roux, Jonathan; Marks, Tim; Sullivan, Alan
Patent No.: 11,582,485
Issue Date: Feb 14, 2023 -
Title: "Low-latency Captioning System"
Inventors: Hori, Chiori; Hori, Takaaki; Cherian, Anoop; Marks, Tim; Le Roux, Jonathan
Patent No.: 11,445,267
Issue Date: Sep 13, 2022 -
Title: "System and Method for a Dialogue Response Generation System"
Inventors: Hori, Chiori; Cherian, Anoop; Marks, Tim; Hori, Takaaki
Patent No.: 11,264,009
Issue Date: Mar 1, 2022 -
Title: "System and Method for Remote Measurements of Vital Signs"
Inventors: Marks, Tim; Mansour, Hassan; Nowara, Ewa; Nakamura, Yudai; Veeraraghavan, Ashok N.
Patent No.: 11,259,710
Issue Date: Mar 1, 2022 -
Title: "Image Processing System and Method for Landmark Location Estimation with Uncertainty"
Inventors: Marks, Tim; Kumar, Abhinav; Mou, Wenxuan; Feng, Chen; Liu, Xiaoming
Patent No.: 11,127,164
Issue Date: Sep 21, 2021 -
Title: "Method and System for Determining 3D Object Poses and Landmark Points using Surface Patches"
Inventors: Jones, Michael J.; Marks, Tim; Papazov, Chavdar
Patent No.: 10,515,259
Issue Date: Dec 24, 2019 -
Title: "Method and System for Multi-Modal Fusion Model"
Inventors: Hori, Chiori; Hori, Takaaki; Hershey, John R.; Marks, Tim
Patent No.: 10,417,498
Issue Date: Sep 17, 2019 -
Title: "Method and System for Detecting Actions in Videos"
Inventors: Jones, Michael J.; Marks, Tim; Tuzel, Oncel; Singh, Bharat
Patent No.: 10,242,266
Issue Date: Mar 26, 2019 -
Title: "Method and System for Detecting Actions in Videos using Contour Sequences"
Inventors: Jones, Michael J.; Marks, Tim; Kulkarni, Kuldeep
Patent No.: 10,210,391
Issue Date: Feb 19, 2019 -
Title: "Method for Estimating Locations of Facial Landmarks in an Image of a Face using Globally Aligned Regression"
Inventors: Tuzel, Oncel; Marks, Tim; Tambe, Salil
Patent No.: 9,633,250
Issue Date: Apr 25, 2017 -
Title: "Method for Generating Representations Polylines Using Piecewise Fitted Geometric Primitives"
Inventors: Brand, Matthew E.; Marks, Tim; MV, Rohith
Patent No.: 9,613,443
Issue Date: Apr 4, 2017 -
Title: "Method for Determining Similarity of Objects Represented in Images"
Inventors: Jones, Michael J.; Marks, Tim; Ahmed, Ejaz
Patent No.: 9,436,895
Issue Date: Sep 6, 2016 -
Title: "Method for Detecting 3D Geometric Boundaries in Images of Scenes Subject to Varying Lighting"
Inventors: Marks, Tim; Tuzel, Oncel; Porikli, Fatih M.; Thornton, Jay E.; Ni, Jie
Patent No.: 9,418,434
Issue Date: Aug 16, 2016 -
Title: "Method for Factorizing Images of a Scene into Basis Images"
Inventors: Tuzel, Oncel; Marks, Tim; Porikli, Fatih M.; Ni, Jie
Patent No.: 9,384,553
Issue Date: Jul 5, 2016 -
Title: "Method and System for Tracking People in Indoor Environments using a Visible Light Camera and a Low-Frame-Rate Infrared Sensor"
Inventors: Marks, Tim; Jones, Michael J.; Kumar, Suren
Patent No.: 9,245,196
Issue Date: Jan 26, 2016 -
Title: "Method for Detecting and Tracking Objects in Image Sequences of Scenes Acquired by a Stationary Camera"
Inventors: Marks, Tim; Jones, Michael J.; MV, Rohith
Patent No.: 9,213,896
Issue Date: Dec 15, 2015 -
Title: "Method and System for Segmenting Moving Objects from Images Using Foreground Extraction"
Inventors: Veeraraghavan, Ashok N.; Marks, Tim; Taguchi, Yuichi
Patent No.: 8,941,726
Issue Date: Jan 27, 2015 -
Title: "Camera-Based 3D Climate Control"
Inventors: Marks, Tim; Jones, Michael J.
Patent No.: 8,929,592
Issue Date: Jan 6, 2015 -
Title: "Method and System for Registering an Object with a Probe Using Entropy-Based Motion Selection and Rao-Blackwellized Particle Filtering"
Inventors: Taguchi, Yuichi; Marks, Tim; Hershey, John R.
Patent No.: 8,510,078
Issue Date: Aug 13, 2013 -
Title: "Localization in Industrial Robotics Using Rao-Blackwellized Particle Filtering"
Inventors: Marks, Tim; Taguchi, Yuichi
Patent No.: 8,219,352
Issue Date: Jul 10, 2012 -
Title: "Method for Synthetically Images of Objects"
Inventors: Jones, Michael J.; Marks, Tim; Kumar, Ritwik
Patent No.: 8,194,072
Issue Date: Jun 5, 2012
-
Title: "System and Method for Manipulating Two-Dimensional (2D) Images of Three-Dimensional (3D) Objects"