RESUMO
A quanta image sensor (QIS) is a class of single-photon imaging devices that measure light intensity using oversampled binary observations. Because of the stochastic nature of the photon arrivals, data acquired by QIS is a massive stream of random binary bits. The goal of image reconstruction is to recover the underlying image from these bits. In this paper, we present a non-iterative image reconstruction algorithm for QIS. Unlike existing reconstruction methods that formulate the problem from an optimization perspective, the new algorithm directly recovers the images through a pair of nonlinear transformations and an off-the-shelf image denoising algorithm. By skipping the usual optimization procedure, we achieve orders of magnitude improvement in speed and even better image reconstruction quality. We validate the new algorithm on synthetic datasets, as well as real videos collected by one-bit single-photon avalanche diode (SPAD) cameras.
RESUMO
Given a set of image denoisers, each having a different denoising capability, is there a provably optimal way of combining these denoisers to produce an overall better result? An answer to this question is fundamental to designing an ensemble of weak estimators for complex scenes. In this paper, we present an optimal combination scheme by leveraging the deep neural networks and the convex optimization. The proposed framework, called the Consensus Neural Network (CsNet), introduces three new concepts in image denoising: 1) a provably optimal procedure to combine the denoised outputs via convex optimization; 2) a deep neural network to estimate the mean squared error (MSE) of denoised images without needing the ground truths; and 3) an image boosting procedure using a deep neural network to improve the contrast and to recover the lost details of the combined images. Experimental results show that CsNet can consistently improve the denoising performance for both deterministic and neural network denoisers.