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this video supplement is composed of

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eight sequences each of which is

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referenced in the report these dynamic

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demonstrations primarily of f-106 being

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flight vapor screen images obtained

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using a rotating light sheet have been

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designed to provide insight into the

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process of developing quantifiable

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results from this data for a complete

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description of the image data is

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analysis and the analyses of other types

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of data as well the formal document

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this flight experiment was done in order

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to examine vortical flow field

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characteristics on a highly swept wing

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at full-scale flight conditions an F

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106b fighter interceptor airplane was

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chosen because of its wide flight

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envelope allowing data to be gathered

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over a range of angles of attack and

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Mach numbers as well as reynold numbers

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the test aircraft was outfitted with

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flow visualization equipment adapted

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from wind tunnel experimentation a

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rotating thin sheet of light was

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produced by a mercury arc lamp with a

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slit and lens arrangement this

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illumination permitted the general

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characteristics of the vortex made

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visible by an trained seated vapor to be

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recorded by two video cameras focused

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over the wings upper surface flight

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planning to obtain desired flight

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conditions resulted in two types of

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maneuvers 1g flight at various speeds

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and altitudes and descending spiral

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turns meteorological conditions were a

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chief limiting constraint test

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instrumentation onboard the aircraft was

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restricted from flight through clouds or

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precipitation flights could only be made

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at night during periods of no moon

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elimination to ensure sufficient

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contrast to the video cameras the light

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sheet and vapor generator were

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controlled by an engineer in the aft

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cockpit a video display showed the image

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from either camera along with angle of

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attack and light sheet position flight

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data were recorded on board and

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telemetered to a ground station at NASA

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Langley the primary data collected was

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video at night the wing was not visible

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and only the light sheet and vapor

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cross-section over the wing could be

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seen on point data collection proceeded

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with a light sheet sweep across the wing

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as well as several discrete light sheet

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locations for post flight analysis

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additional flights were made during

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daylight with an oil mixture painted on

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an integrated computer process combining

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image processing computer graphics and

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photogrammetric reconstruction

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techniques was utilized to aid in

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three-dimensional visualization of

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images produced by the rotating light

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sheet accurate surface definition of the

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aircraft was simulated through original

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engineering drawings including geometric

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description of wings fuselage and

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vertical tail all of which were

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collectively rendered to produce a

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smooth three-dimensional model an

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additional input into this environment

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was a set of parameters describing the

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placement of the two cameras on board

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the f-106 be several targets were placed

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upon the wing upper surface and record

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that's measured to facilitate the

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calibration of the cameras the WHA video

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footage captured by the cameras in

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flight provided only qualitative

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information as to the size and placement

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of vortices above the wing each image

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had a perspective distortion produced as

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the light sheet rotates away from the

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stationary cameras to account for these

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irregularities and extract quantitative

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geometric information from the images a

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photogrammetric reconstruction technique

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was developed this technique map each

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point in the image plane of a camera to

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a precise location in the plane of the

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light sheet camera orientation and

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imaging properties as well as white

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sheet position and angle were measured

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to provide accurate calculations once a

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set of data for a specified test

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condition was constructed the 3d

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coordinate of any point in the flow

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field could be determined vortex core

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paths determined from image centroids as

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well as the approximate reattachment

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lines could be extracted and displayed

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in simultaneously the same sequence of

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operations was applied to the side

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camera image such that both camera data

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sets were combined into one interactive

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selected frames from videotapes for each

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flight were digitized on the data

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visualization and animation labs video

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image processing system the video image

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processing system is a combination of

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hardware and software designed to

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provide interactive capability for

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processing videotaped images of wind

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tunnel or in flight experiments the

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system controlled from a host computer

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consists of an image processing system

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video equipment and a real-time digital

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disc the software interface is a

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commercially available image processing

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software system the system is designed

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to accept common video formats including

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the s VHS and VHS formats used in this

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flight test the software allows VCR

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control from the computer station video

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footage is digitized and stored a

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digital disc at 30 frames per second

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once rendered to real time disk the

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images are slowed down during playback

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and examined in slow motion timecode

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information appearing in the lower left

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corner uniquely identifies each image

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selected images were stored on a disc

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with the use of extractor software the

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poor locations for a vortex system were

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determined by examining each printed

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image the show movie of this directory

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option enables an overall impression of

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flow over the wing at the test condition

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and allows the determination of how many

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vortices are present and the progression

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beginning with the first image to be

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examined invoked the defined region of

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interest for this image option and use

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the mouse to circumscribe the region

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where the core is thought to be located

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the horizontal and vertical pixel values

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for this core is saved however if other

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cores are present on this image they

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must also be determined and saved before

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proceeding the same steps are repeated

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for other images after all the images

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for the data set up in process the wave

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program is exited and the core pixel

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values up to four sets per image are

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moved to a permanent file to determine

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the reattachment points the extractor

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software is once again used the outer

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part of the vortex is projected

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vertically to the forward part of the

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light sheet footprint this is followed

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by a circumscription of a small region

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on the footprint with the mouse after

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the horizontal and vertical pixel values

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for the pointer found they are saved

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what other reattachment points are

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present on this image they must also be

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determined and saved before proceeding

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prior to saving all these pixel values

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consistency in the criterion used to

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determine reattachment points is checked

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these steps are repeated for the other

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images after all the images for the data

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set have been processed the wave program

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is exited and the reattachment point

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pixel values up to four sets per image

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to display vortex flow features is

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characterized by the vapor screen image

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in poor location with reattachment

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points in a three-dimensional mode a

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Silicon Graphics iris workstation and

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the flow analysis software toolkit

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called fast was utilized once logged

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onto the iris a remote login is done to

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a host computer containing the image

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files along with poor location and

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reattachment point trials with a fast

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script written for this purpose it is

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simple to obtain the vortex system

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features on a wing by keying in the

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corresponding points this generates the

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feature from both the top and side

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cameras in terms of the

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three-dimensional coordinates consistent

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with the aircraft and then displays them

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on the surface geometry by using the

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capabilities of fast the resulting

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three-dimensional representation would

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be moved until it resembles the NASA

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in 1985 the stationary light sheet was

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used to illuminate a fixed cross section

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of a flow field above the wing of the f1

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or 6 be a camera calibration was not

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performed at the time of his flight thus

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the photo prometric reconstruction

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technique could not be applied spatial

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information was obtained before the

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flights by placing a physical grid of

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regularly spaced 6 inch squares in

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refrain of the light sheet when the grid

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was photographed by the camera in its

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flight position a prospective distortion

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was introduced the distortion was

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corrected using a warping procedure to

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produce an image in which the gridlines

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were regularly spaced the warping

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technique was applied to selecting vapor

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screen images from 1985 and the

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resulting images were evenly distributed

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across the light sheet plane to

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reconstruct 3d coordinates when loaded

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into the fast program the vapour screen

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images produced by the stationary light

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sheet in 1985 could be correlated with

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those obtained from the rotating light

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sheet of 1991 the vortex core paths and

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reattachment lines extracted from the

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1991 flight data could be displayed

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with the enhancer software the vortex

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system details can be enhanced the code

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expects the user to key in the starting

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and ending white sheet angles as well as

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the filename containing the group of

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files to consider the code displays all

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the images in the group and asked

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whether or not a particular image is to

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be included for enhancement choosing the

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enhance this image option for the first

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image leads to yet another menu a three

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by three smoothing on each image is

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imposed a total of three times in

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combination with the continued

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enhancement to the image process option

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the contrast stretch option is used to

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spread the entire range of pseudo colors

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in such a way as to emphasize the

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existing gradation in this image the

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contour option allows selected colors to

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be set to black thereby forming contours

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finally the save enhanced flight image

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option is used which displays the image

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with an identification code and then

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the photogrammetric reconstruction

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technique which maps vapor images onto

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light sheet planes was extended to

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project imagery onto any arbitrary

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surface composed of polygons this

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extension was specifically used to

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project oil flow patterns videotaped by

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the top camera onto the political model

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of a wing surface vapor screen images

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core paths and reattachment lines

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extracted from the rotating light sheet

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but then be displayed simultaneously for

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a direct comparison this video

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supplement has been designed to

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demonstrate the computer graphics

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capabilities utilized in developing data

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which are presented in the report the

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viewers reminded that this supplement

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does not purport to present the complete

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set of various data types or the

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attendant analyses both of which are

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contained on the NASA technical paper

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therefore the view is referred to the