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Ultra-fast Lensless Computational Imaging through 5D Frequency Analysis of Time-resolved Light Transport


Light transport has been analyzed extensively, in both the primal domain and the frequency domain. Frequency analyses often provide intuition regarding effects introduced by light propagation and interaction with optical elements; such analyses encourage optimal designs of computational cameras that efficiently capture tailored visual information. However, previous analyses have relied on instantaneous propagation of light, so that the measurement of the time dynamics of light–scene interaction, and any resulting information transfer, is precluded. In this paper, we relax the common assumption that the speed of light is infinite. We analyze free space light propagation in the frequency domain considering spatial, temporal, and angular light variation. Using this analysis, we derive analytic expressions for information transfer between these dimensions and show how this transfer can be exploited for designing a new lensless imaging system. With our frequency analysis, we also derive performance bounds for the proposed computational camera architecture and provide a mathematical framework that will also be useful for future ultra-fast computational imaging systems.

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  1. The concept of light cones is commonly used in space–time physics; see e.g.


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The work of the MIT affiliated coauthors was funded by the Media Lab Consortium Members. Gordon Wetzstein was supported by an NSERC Postdoctoral Fellowship. Tsinghua University affiliated coauthors were supported by China National Basic Research Project (No. 2010CB731800) and the Key Project of NSFC (Nos. 61120106003 and 61035002).

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Correspondence to Gordon Wetzstein.

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Wu, D., Wetzstein, G., Barsi, C. et al. Ultra-fast Lensless Computational Imaging through 5D Frequency Analysis of Time-resolved Light Transport. Int J Comput Vis 110, 128–140 (2014).

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  • Computational photography
  • Light transport
  • Frequency analysis
  • Lensless imaging