Title :
Signal processing schemes for Doppler global velocimetry
Author :
Meyers, James F. ; Lee, Joseph W. ; Cavone, Angelo A.
Author_Institution :
NASA Langley Res. Center, Hampton, VA, USA
Abstract :
Two schemes for processing signals obtained from the Doppler global velocimeter are described. The analog approach is a simple, real-time method for obtaining an RS-170 video signal containing the normalized intensity image. Pseudocolors are added using a monochromatic frame grabber producing a standard NTSC video signal that can be monitored and/or recorded. The digital approach is more complicated, but maintains the full resolution of the acquisition cameras with the ability to correct the signal image for pixel sensitivity variations band to remove background light. Prototype circuits for each scheme are described, and example results from the investigation of the vortical flow field above a 75° delta wing are presented
Keywords :
Doppler effect; computerised instrumentation; computerised picture processing; digital signals; flow visualisation; physics computing; video signals; vortices; CCD camera; Doppler global velocimetry; RS-170 video signal; acquisition cameras; analogue signals; background light; digital signals; flow visualisation; monochromatic frame grabber; pixel sensitivity variations; pseudocolours; real-time; signal processing; standard NTSC video signal; vortical flow field; wind tunnel; Cameras; Computational fluid dynamics; Fluid flow measurement; Frequency; Light scattering; Optical scattering; Particle scattering; Signal processing; Time measurement; Velocity measurement;
Conference_Titel :
Instrumentation in Aerospace Simulation Facilities, 1991. ICIASF '91 Record., International Congress on
Conference_Location :
Rockville, MD
DOI :
10.1109/ICIASF.1991.186255
