National Instruments NI Vision NI 17xx 用户手册
Chapter 5
Image Acquisition
5-8
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Determining the Exposure Time
The minimum frame period depends on exposure time, lighting mode, and
trigger delay.
trigger delay.
A longer exposure time results in a longer frame period, and a slower
maximum frame rate.
maximum frame rate.
Determining the Lighting Mode
If you are not strobing a light using the Direct Drive or the external strobe
outputs of the smart camera, the smart camera can expose one image while
it is reading out the previous image, allowing for the highest possible frame
rates. Figure 5-3 illustrates this relationship. The smart camera receives the
trigger for the second image while it is still reading out the first image. The
first image readout finishes before the second image readout begins.
outputs of the smart camera, the smart camera can expose one image while
it is reading out the previous image, allowing for the highest possible frame
rates. Figure 5-3 illustrates this relationship. The smart camera receives the
trigger for the second image while it is still reading out the first image. The
first image readout finishes before the second image readout begins.
Figure 5-3. Image Acquisition Without Strobing
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Beginning of First Image Readout
2
Beginning of Second Image Exposure
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Beginning of Second Image Readout
Trigger
Exposure
Image Readout
2
1
3