All-passive pixel super-resolution of time-stretch imaging

Antony C. S. Chan, Ho-Cheung Ng, Sharat Chandra Varma B, Hayden Kwok-Hay So, Edmund Y Lam, Kevin K Tsia

Research output: Contribution to journalArticlepeer-review

11 Citations (Scopus)
42 Downloads (Pure)


Based on image encoding in a serial-temporal format, optical time-stretch imaging entails a stringent requirement of state-of-the-art fast data acquisition unit in order to preserve high image resolution at an ultrahigh frame rate — hampering the widespread utilities of such technology. Here, we propose a pixel super-resolution (pixel-SR) technique tailored for time-stretch imaging that preserves pixel resolution at a relaxed sampling rate. It harnesses the subpixel shifts between image frames inherently introduced by asynchronous digital sampling of the continuous time-stretch imaging process. Precise pixel registration is thus accomplished without any active opto-mechanical subpixel-shift control or other additional hardware. Here, we present the experimental pixel-SR image reconstruction pipeline that restores high-resolution time-stretch images of microparticles and biological cells (phytoplankton) at a relaxed sampling rate (≈2–5 GSa/s)—more than four times lower than the originally required readout rate (20 GSa/s) — is thus effective for high-throughput label-free, morphology-based cellular classification down to single-cell precision. Upon integration with the high-throughput image processing technology, this pixel-SR time-stretch imaging technique represents a cost-effective and practical solution for large scale cell-based phenotypic screening in biomedical diagnosis and machine vision for quality control in manufacturing.
Original languageEnglish
Article number44608
Pages (from-to)1-11
Number of pages11
JournalScientific Reports
Publication statusPublished (in print/issue) - 17 Mar 2017


  • Time Stretch Imaging
  • Pixel Super Resolution
  • Imaging
  • FPGA
  • High-speed optical imaging
  • Image Reconstruction pipeline
  • Imaging flow cytometry


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