Improving the spatial dynamic range of digital inline particle holography
Digital in-line holography (DIH) has been proven to provide three-dimensional droplet position, size, and velocity distributions with a single-camera. This data is crucial for understanding multi-phase flows. In this work, we examine the performance of this diagnostic in the limit of very small particles, on the order of a pixel in diameter and smaller, and propose a post-processing method to improve them: Lanczos interpolation. The Lanczos interpolation kernel is the digital implementation of the Whittaker sinc filter, and strikes a compromise between maintaining the spatial frequency ceiling of the original digital image and computational cost of the interpolation. Without Lanczos interpolation, or super-sampling, the ultimate detectable particle size floor is on the order of 4 pixel widths. We show in this work that this limit can be reduced by 50% or more with super-sampling, depending upon the desired diameter accuracy, and examine the effect of super-sampling on the resulting accuracy of the extracted size and position of spherical particles. Extending this resolution limit increases the overall detection efficiency of the diagnostic. Since this increases the spatial dynamic range of the diagnostic, it can also allow a larger field-of-view to be captured with the same particle size floor.
- Research Organization:
- Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
- Sponsoring Organization:
- USDOE National Nuclear Security Administration (NNSA)
- Grant/Contract Number:
- AC04-94AL85000; NA0003525
- OSTI ID:
- 1485852
- Alternate ID(s):
- OSTI ID: 1484332
- Report Number(s):
- SAND-2018-13054J; APOPAI; 669942
- Journal Information:
- Applied Optics, Vol. 58, Issue 5; ISSN 1559-128X
- Publisher:
- Optical Society of AmericaCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
Design and Validation of a Holographic Particle Counter
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journal | November 2019 |
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