Abstract

Spatial multiplexing cameras (SMCs) acquire a (typically static) scene through a series of coded projections using a spatial light modulator (e.g., a digital micromirror device) and a few optical sensors. This approach finds use in imaging applications where full-frame sensors are either too expensive (e.g., for short-wave infrared wavelengths) or unavailable. Existing SMC systems reconstruct static scenes using techniques from compressive sensing (CS). For videos, however, existing acquisition and recovery methods deliver poor quality. In this paper, we propose the CS multiscale video (CS-MUVI) sensing and recovery framework for high-quality video acquisition and recovery using SMCs. Our framework features novel sensing matrices that enable the efficient computation of a low-resolution video preview, while enabling high-resolution video recovery using convex optimization. To further improve the quality of the reconstructed videos, we extract optical-flow estimates from the low-resolution previews and impose them as constraints in the recovery procedure. We demonstrate the efficacy of our CS-MUVI framework for a host of synthetic and real measured SMC video data, and we show that high-quality videos can be recovered at roughly $60\times$ compression.

Highlights

  • Compressive sensing (CS) enables one to sample signals that admit a sparse representation in some transform basis well-below the Nyquist rate, while still enabling their faithful recovery [3, 7]

  • We demonstrate the efficacy of our compressive sensing (CS)-MUVI framework for a host of synthetic and real measured spatial-multiplexing camera (SMC) video data, and we show that high-quality videos can be recovered at roughly 60× compression

  • We focus on such SMC designs, which acquire random projections of a scene using a spatial light modulator (SLM) in combination with a small number of optical sensors, such as single photodetectors or bolometers

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Summary

Introduction

Compressive sensing (CS) enables one to sample signals that admit a sparse representation in some transform basis well-below the Nyquist rate, while still enabling their faithful recovery [3, 7]. We focus on such SMC designs, which acquire random (or coded) projections of a (typically static) scene using a spatial light modulator (SLM) in combination with a small number of optical sensors, such as single photodetectors or bolometers. The use of a small number of optical sensors—in contrast to full-frame sensors having millions of pixel elements—turns out to be advantageous when acquiring scenes at non-visible wavelengths. Suppose that we have a signal acquisition system characterized by y = Ax∗ + e, where x∗ ∈ RN is the signal to be sensed and y ∈ RN is the measurement obtained using the matrix A ∈ RN×N.

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