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Yunong Sun

Publications and source records attributed to Yunong Sun.

3 recordsLinked to original sources

NeOTF: Guidestar-free neural representation for broadband dynamic imaging through scattering

Dynamic imaging through time-varying scattering media is ubiquitous in real-world settings, yet it remains a defining unsolved problem as rapid spatiotemporal fluctuations overwhelm standard reconstruction pipelines that often rely on speckles with high signal-to-noise ratio. Existing approaches fall into two categories. Guidestar-based methods employ a guidestar to recover the system transfer function; however, in dynamic media, the speckle decorrelates rapidly, making the calibration quickly invalid. Guidestar-free methods infer information from speckle statistics, but rapid changes and noise often break phase retrieval. To overcome these limitations, we introduce NeOTF, a guidestar-free and neural-representation-based OTF retrieval method that enables dynamic imaging through time-varying scattering media. By optimizing this neural representation with only a few speckle images from unknown objects, NeOTF robustly retrieves the system's OTF without a guidestar. We experimentally demonstrate robust dynamic imaging through scattering with NeOTF at extremely low signal-to-noise ratio and broadband incoherent illumination (up to 300 nm spectral bandwidth) scenarios, and we numerically validate its dynamic imaging performance in time-varying scattering media leveraging spatio-temporal memory effect. Finally, we discuss and analyze its computational efficiency and generalization capabilities across anisotropic scattering media. These results establish NeOTF's promise as a practical and robust solution for dynamic imaging through scattering media. Open-sourced code and models are available at https://github.com/Xia-Research-Lab/NeOTF.

physics.optics

Non-invasive color imaging through scattering medium under broadband illumination

Due to the complex of mixed spectral point spread function within memory effect range, it is unreliable and slow to use speckle correlation technology for non-invasive imaging through scattering medium under broadband illumination. The contrast of the speckles will drastically drop as the light source's spectrum width increases. Here, we propose a method for producing the optical transfer function with several speckle frames within memory effect range to image under broadband illumination. The method can be applied to image amplitude and color objects under white LED illumination. Compared to other approaches of imaging under broadband illumination, such as deep learning and modified phase retrieval, our method can provide more stable results with faster convergence speed, which can be applied in high speed scattering imaging under natural light illumination.

physics.optics

Delta interferometer: A polarization sensitive interferometer

A new type of polarization sensitive interferometer is proposed, which is named as Delta interferometer due to the geometry of the simplest interferometer looks like Greek letter, Delta. To the best of our knowledge, it is the first time that this type of interferometer is proposed. The main difference between Delta interferometer and other existed interferometer, such as Michelson interferometer, Mach-Zehnder interferometer, Young\rq{}s double-slit interferometer, is that the two interfering paths are asymmetrical in Delta interferometer, which makes it polarization sensitive. The visibility of the first-order interference pattern observed in Delta interferometer is dependent on the polarization of the incidental light. Optical coherence theory is employed to interpret the phenomenon and a single-mode continuous-wave laser is employed to verify the theoretical predictions. The theoretical and experimental results are consistent. Delta interferometer provides a perfect tool to study the reflection of electric field in different polarizations and may find applications in polarization sensitive scenarios.

physics.optics