Biomedical Engineering Reference
In-Depth Information
6.0
5.0
Recom-
mended
sync time
PF-300
Shutter
speed
Lumen
seconds
PF-200
4.0
PF-300: Up to 1/30th
PF-200: Up to 1/30th
1/60th
1/125th
1/250th
1/500th
106,200
16 ms
60,600
16 ms
47,400
35,000
21,100
12,800
3.0
2.0
1.0
0
0
20
40
60
80
100
120
Time (ms)
FIGURE 2.34
Flashbulb characteristics.
Bulbs are flashed, for instance, at 28 ms prior to the key portion of a video
stream, so that for a 5- to 10-ms window, the target scene is illuminated
at or above 90% of the peak flash output. The timing of the peak flash
output and the character of the flash event were confirmed with .cine files
obtained with a Vision Research Phantom V7.3 high-speed digital imaging
system.
An example of the next-brightest light source, arc discharge tubes,
currently identified and used for high-speed imaging, is the Luminys
Corporation 6.5-K Blast high-intensity light. This source produces 25,863 cd,
but for a significantly longer duration, depending on the charging charac-
teristics. A typical illumination event for the 6.5-K Luminys light is shown
in Figure 2.35.
11.32 second light pulse, Luminys 6.5 K
6
5
4
3
2
1
0
-2
3
8
13
18
Time
FIGURE 2.35
Time history of Luminys Corporation's 6.5-K light system.
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