38 citations · 91 across the 11 of their papers we have counts for
15 papers
MetaTele: Compact Refractive Metasurface Computational Telephoto Camera
Harshana Weligampola, Yuanrui Chen, Abhiram Gnanasambandam +4
Smartphone cameras face fundamental form-factor constraints that limit their optical magnification, primarily due to the difficulty of reducing a lens assembly's telephoto ratio, t…
Direct Kernel Optimization: Efficient Design for Opto-Electronic Convolutional Neural Networks
Ali Almuallem, Harshana Weligampola, Abhiram Gnanasambandam +5
Hybrid opto-electronic neural networks combine optical front-ends with electronic back-ends to perform vision tasks, but joint end-to-end (E2E) optimization of optical and electron…
Quanta Video Restoration
Prateek Chennuri, Yiheng Chi, Enze Jiang +5
The proliferation of single-photon image sensors has opened the door to a plethora of high-speed and low-light imaging applications. However, data collected by these sensors are of…
The Secrets of Non-Blind Poisson Deconvolution
Abhiram Gnanasambandam, Yash Sanghvi, Stanley H. Chan
Non-blind image deconvolution has been studied for several decades but most of the existing work focuses on blur instead of noise. In photon-limited conditions, however, the excess…
Photon-Limited Blind Deconvolution using Unsupervised Iterative Kernel Estimation
Yash Sanghvi, Abhiram Gnanasambandam, Zhiyuan Mao +1
Blind deconvolution is a challenging problem, but in low-light it is even more difficult. Existing algorithms, both classical and deep-learning based, are not designed for this con…
Exposure-Referred Signal-to-Noise Ratio for Digital Image Sensors
Abhiram Gnanasambandam, Stanley H. Chan
The signal-to-noise ratio (SNR) is a fundamental tool to measure the performance of an image sensor. However, confusions sometimes arise between the two types of SNRs. The first on…
Graph-Based Depth Denoising & Dequantization for Point Cloud Enhancement
Xue Zhang, Gene Cheung, Jiahao Pang +3
A 3D point cloud is typically constructed from depth measurements acquired by sensors at one or more viewpoints. The measurements suffer from both quantization and noise corruption…
Photon Limited Non-Blind Deblurring Using Algorithm Unrolling
Yash Sanghvi, Abhiram Gnanasambandam, Stanley H. Chan
Image deblurring in photon-limited conditions is ubiquitous in a variety of low-light applications such as photography, microscopy, and astronomy. However, the presence of photon s…
Optical Adversarial Attack
Abhiram Gnanasambandam, Alex M. Sherman, Stanley H. Chan
We introduce OPtical ADversarial attack (OPAD). OPAD is an adversarial attack in the physical space aiming to fool image classifiers without physically touching the objects (e.g.,…
HDR Imaging with Quanta Image Sensors: Theoretical Limits and Optimal Reconstruction
Abhiram Gnanasambandam, Stanley H. Chan
High dynamic range (HDR) imaging is one of the biggest achievements in modern photography. Traditional solutions to HDR imaging are designed for and applied to CMOS image sensors (…
Dynamic Low-light Imaging with Quanta Image Sensors
Yiheng Chi, Abhiram Gnanasambandam, Vladlen Koltun +1
Imaging in low light is difficult because the number of photons arriving at the sensor is low. Imaging dynamic scenes in low-light environments is even more difficult because as th…
Image Classification in the Dark using Quanta Image Sensors
Abhiram Gnanasambandam, Stanley H. Chan
State-of-the-art image classifiers are trained and tested using well-illuminated images. These images are typically captured by CMOS image sensors with at least tens of photons per…
One Size Fits All: Can We Train One Denoiser for All Noise Levels?
Abhiram Gnansambandam, Stanley H. Chan
When training an estimator such as a neural network for tasks like image denoising, it is often preferred to train one estimator and apply it to all noise levels. The de facto trai…
Megapixel Photon-Counting Color Imaging using Quanta Image Sensor
Abhiram Gnanasambandam, Omar Elgendy, Jiaju Ma +1
Quanta Image Sensor (QIS) is a single-photon detector designed for extremely low light imaging conditions. Majority of the existing QIS prototypes are monochrome based on single-ph…
On the Sum Capacity of Many-to-one and One-to-many Gaussian Interference Channels
Abhiram Gnanasambandam, Ragini Chaluvadi, Srikrishna Bhashyam
We obtain new sum capacity results for the Gaussian many-to-one and one-to-many interference channels in channel parameter regimes where the sum capacity was known only up to a con…