Varun Sundar

I am a first second third fourthfifth year PhD student at the University of Wisconsin Madison, working with Mohit Gupta at the WISION Lab.

Previously, I was an undergraduate at the Indian Institute of Technology Madras, where I obtained a bachelors degree in Electrical Engineering. At IIT Madras, I was associated with the Computational Imaging Lab, headed by Kaushik Mitra.

I spent the summer of 2019 working with Ram Nevatia at the University of Southern California. I've also been fortunate to be work with some amazing mentors, including Salaman Siddique and Arka Sadhu.

Email  /  CV  /  Google Scholar  /  Twitter  /  Github

profile photo
Research Focus

I'm interested in computer vision, computational imaging and machine learning. Broadly, I wish to harness a conjuction of newer hardware and smarter algorithms to tackle a variety of problems. My undergraduate research focussed on developing deep learning techniques to recover high-quality images from lensless cameras.

News
  • (June 19th, 25) One first-authored paper accepted to ICCV! See you in Hawaii!
  • (June 3rd, 25) One co-first-authored paper accepted to ICCP! See you in Toronto!
  • (May 19th, 25) I will be interning at Snap, New York City this summer!
  • (Jan 10th, 25) XRDS magazine published our invited article!
  • (Aug 1st, 24) Our single-photon demo was recognized with the "best in show" award at SIGGRAPH E-Tech!
  • (Jul 19th, 24) Demoing single-photon applications at SIGGRAPH. Say hi if you're at Denver next week!
  • (Feb 26th, 24) One first-authored paper accepted at CVPR! See you in Seattle!
  • (Jul 13th, 23) One first-authored paper accepted at ICCV as an oral presentation!
Publications
Point tracker video using QNNs Quanta Neural Networks: From Photons to Perception
Varun Sundar*, Tianyi Zhang*, Sacha Jungerman, Mohit Gupta.
ICCV 2025
project page / bibtex

A learnable temporal aggregation layer that transforms many image- and video-based neural networks into neural networks that work on the acquisition of quanta image sensors.

XRDS graphic Predicting Important Photons for Energy-Efficient Single-Photon Videography
Shantanu Gupta*, Varun Sundar*, Lucas J. Koerner, Claudio Bruschini, Edoardo Charbon, Mohit Gupta.
TPAMI Special Issue (ICCP 2025)
project page / bibtex

Reducing avalanche power consumption in passive video capture with SPAD sensors, by restricting measurements to salient pixels identified dynamically from the data.

XRDS graphic Quanta Computer Vision
Varun Sundar and Mohit Gupta.
XRDS: Crossroads, The ACM Magazine for Students, 2025.
ACM page / bibtex

An invited article in the Crossroads (XRDS) magazine, explaining single-photon imaging in an accessible manner.

Single-photon sensor A Live Demo of Single-Photon Imaging and Applications
Sacha Jungerman*, Varun Sundar*, Mohit Gupta.
SIGGRAPH Emerging Technologies 2024
* denotes equal contribution.
Best in show award
project page / ACM page / bibtex

A demonstration of single-photon imaging capabilities---including high-speed, high-dynamic range, and low-light vision---at SIGGRAPH's emerging technologies track.

Table tennis ball being slingshotted Generalized Event Cameras
Varun Sundar*, Matt Dutson*, Andrei Ardelean, Claudio Bruschini, Edoardo Charbon, Mohit Gupta.
CVPR 2024
* denotes equal contribution.
project page / video / bibtex

Single-photon cameras can not only emulate event cameras, but also facilitate a generalized space of intensity-preserving event cameras.

Falling Die SoDaCam: Software-defined Cameras via Single-Photon Imaging
Varun Sundar, Andrei Ardelean, Tristan Swedish, Claudio Bruschini, Edoardo Charbon, Mohit Gupta.
ICCV 2023 (Oral)
project page / video / bibtex

Photon-level software-defined cameras can emulate a diverse range of imaging modalities.

color SPAD Seeing Photons in Color
Sizhuo Ma, Varun Sundar, Paul Mos, Claudio Bruschini, Edoardo Charbon, Mohit Gupta.
SIGGRAPH 2023
project page / video / bibtex

Color filter and algorithm design for single-photon color imaging in low light.

Single-Photon-SL Single-Photon Structured Light
Varun Sundar, Sizhuo Ma, Aswin Sankarnarayanan, Mohit Gupta.
Computer Vision and Pattern Recognition (CVPR) 2022
project page / arXiv / video / bibtex

Single-Photon Avalanche Diodes (SPADs) can be operated as extremely high-speed binary imagers and find a synergistic application in Structuered Light.

RigL_png [Reproducibility Report]: Rigging the Lottery: Making All Tickets Winners
Varun Sundar, Rajat Vadiraj Dwaraknath.
ML Reproducibility Challenge 2020, Rescience-C Journal
OpenReview / arXiv / YouTube / W&B Report / bibtex

Reproducibility Report on the ICML 2020 paper "Rigging the Lottery: Making All Tickets Winners".

Deep Atrous Guided Filter for Image Restoration in Under Display Cameras
Varun Sundar*, Sumanth Hegde*, Divya K Raman, Kaushik Mitra.
ECCV RLQ-TOD Workshop, 2020
* denotes equal contribution.
project page / arXiv / video / bibtex

Guided Filters when incorporated in a deep network can efficiently recover severely degraded, mega-pixel resolution images.

FlatNet: Towards Photorealistic Scene Reconstruction from Lensless Measurements
Salman S. Khan*, Varun Sundar*, Vivek Boominathan, Ashok Veeraraghavan, Kaushik Mitra.
IEEE Transactions on Pattern Analysis and Machine Intelligence, 2020
* denotes equal contribution.
project page / arXiv / video / bibtex

We propose a general learning based framework to recover photorealistic scenes from lensless captures for both separable and non-separable forward models.


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