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A Fast Double Shutter for CCD-Based Metrology

Geisler, Reinhard (2016) A Fast Double Shutter for CCD-Based Metrology. The 31st International Congress on High-speed Imaging and Photonics, 07. - 10. Nov. 2016, Osaka, Japan.

Full text not available from this repository.

Abstract

Image based metrology such as Particle Image Velocimetry (PIY) depends on the comparison of two or more images of an object taken in fast succession. Cameras designed for these applications provide the so-called 'dou­ ble shutter' mode: One frame is captured with a short exposure time and in direct succession a second frame with a long exposure time can be recorded. The difference in the exposure times is typically no problem since illum i­ nation is provided by a pulsed light source such as a laser and the measurements are performed in a darkened environment to prevent ambient light from accumulating in the long second exposure time. However, measure­ ments of self-luminous processes (e.g. plasma, combustion „.) as weil as experiments in ambient light are diffi­ cult to perform and req uire special equipment (external shutters, high-speed image sensors, multi-camera sys­ tems „.). Unfortunately , all these methods incorporate different drawbacks such as reduced resolution , degraded image quality, decreased light sensitivity or increased susceptibility to decalibration. In the solution presented here, off-the-shelf CCD sensors are used with a special timing to combi ne neighbouring pixels in a binning- 1ike way. As a result, two frames of short exposure time (-10 µs each) can be captured in fast succession (- 200 ns interframe time). They are stored in the on-chip vertical register in a line-interleaved pat­ tern, read out in the common way and separated again by software. The two resultant frames are completely congruent; they expose no insensitive l ines or line shi fts (interlace artefacts) and thus enable sub-pixel accurate measurements. A third frame can be captured at the füll resolution analogue to the double shutter tech niq ue. Image based measurement techniques such as Particle Image Yelocimetry (PJV) can benefit from th is mode when applied in bright environments. The third frame is useful e.g. for acceleration measurements or for particle tracking applicati ons.

Item URL in elib:https://elib.dlr.de/104835/
Document Type:Conference or Workshop Item (Speech)
Additional Information:S. 246-251; USB-Stick (Conference Proceedings)
Title:A Fast Double Shutter for CCD-Based Metrology
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Geisler, Reinhardreinhard.geisler (at) dlr.deUNSPECIFIED
Date:2016
Refereed publication:No
Open Access:No
Gold Open Access:No
In SCOPUS:No
In ISI Web of Science:No
Status:Published
Keywords:CCD, double shutter, Particle Image Velocimetry (PIV), Particle Tracking Velocimetry (PTV), multi-pulse PIV
Event Title:The 31st International Congress on High-speed Imaging and Photonics
Event Location:Osaka, Japan
Event Type:international Conference
Event Dates:07. - 10. Nov. 2016
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Aeronautics
HGF - Program Themes:fixed-wing aircraft
DLR - Research area:Aeronautics
DLR - Program:L AR - Aircraft Research
DLR - Research theme (Project):L - Simulation and Validation
Location: Göttingen
Institutes and Institutions:Institute for Aerodynamics and Flow Technology > Experimental Methods, GO
Deposited By: Bachmann, Barbara
Deposited On:02 Dec 2016 12:54
Last Modified:01 Aug 2017 09:37

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