Ghost Projection

TL;DR

Ghost projection is a novel imaging method that uses random masks and optimization techniques to produce desired spatial exposure distributions, with potential applications in various fields such as lithography and additive manufacturing.

Contribution

This paper introduces three methods for ghost projection, including analytical and numerical approaches, expanding the capabilities of ghost imaging techniques for projection tasks.

Findings

Analytical protocols for weighting and selecting random masks are effective.

Numerical optimization improves projection accuracy over analytical methods.

Potential applications include lithography, volumetric manufacturing, and specialized projectors.

Abstract

Ghost imaging is a developing imaging technique that employs random masks to image a sample. Ghost projection utilizes ghost-imaging concepts to perform the complementary procedure of projection of a desired image. The key idea underpinning ghost projection is that any desired spatial distribution of radiant exposure may be produced, up to an additive constant, by spatially-uniformly illuminating a set of random masks in succession. We explore three means of achieving ghost projection: (i) weighting each random mask, namely selecting its exposure time, according to its correlation with a desired image, (ii) selecting a subset of random masks according to their correlation with a desired image, and (iii) numerically optimizing a projection for a given set of random masks and desired image. The first two protocols are analytically tractable and conceptually transparent. The third is more efficient but less amenable to closed-form analytical expressions. A comparison with existing image-projection techniques is drawn and possible applications are discussed. These potential applications include: (i) a data projector for matter and radiation fields for which no current data projectors exist, (ii) a universal-mask approach to lithography, (iii) tomographic volumetric additive manufacturing, and (iv) a ghost-projection photocopier.