Chapter 6
Image Acquisition
NI 177x Smart Camera User Manual
6-2
ni.com
horizontally across the field of view, use Equation 6-1 to calculate the
maximum exposure time.
(6-1)
where
E
max
is the maximum exposure time without blurring,
R
is the rate of motion of the object either horizontally or
vertically,
FOV
is the field of view in the direction of motion, and
N
is the number of sensor pixels in the direction of motion
For many applications that include moving objects, additional lighting is
necessary to achieve good image contrast due to the short exposure time
required to avoid motion blur.
Additionally, in many environments, the ambient light conditions vary too
significantly to obtain consistent results without adding dedicated lighting.
For example, in a building with windows, the ambient light can vary
significantly with weather. Also, standard fluorescent lighting flickers at a
rate that is perceivable by the NI 177x Smart Camera. In these situations,
the ambient light must be overridden with a dedicated light source to ensure
reproducible results.
Acquiring Images
You can configure the NI 177x Smart Camera to acquire images based on
internal timing or an external trigger signal. In both cases, the NI 177x
Smart Camera can acquire images at the camera’s maximum frame rate.
Refer to the
section for information about factors
that affect the maximum frame rate.
Internal Timing
The NI 177x Smart Camera features two types of internally-timed modes:
free-run mode and fixed-frame-rate mode.
In free-run mode, the device acquires images at the maximum frame rate
allowed by the configuration.
In fixed-frame-rate mode, you can specify a frame rate that is less than or
equal to the maximum frame rate.
E
max
R
Horizontal
2
×
FOV
Horizontal
(
)
N
Horizontal
(
)
⁄
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=
