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Chapter 3
NI Smart Camera Image Sensor
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3-3
Image Sensor Spectral Response
The spectral response curve describes the relative sensitivity of the sensor
to different wavelengths of light. The peak responsiveness of the VGA and
SXGA sensors is to light with a wavelength of approximately 500 nm.
If you are imaging a dim scene, this information can be useful when
selecting a light source to use in your application as the camera is most
sensitive at its peak responsiveness. It also helps determine what, if any,
filters your application might require to remove undesired wavelengths of
light from the scene.
to different wavelengths of light. The peak responsiveness of the VGA and
SXGA sensors is to light with a wavelength of approximately 500 nm.
If you are imaging a dim scene, this information can be useful when
selecting a light source to use in your application as the camera is most
sensitive at its peak responsiveness. It also helps determine what, if any,
filters your application might require to remove undesired wavelengths of
light from the scene.
Refer to Appendix A,
, to find the normalized spectral
response curves for the VGA and SXGA sensors.
Partial Scan Mode
Partial scan mode is a method of obtaining higher frame rates by reading
out only a portion of the image from the sensor. Partial scan is frequently
used when an application requires higher speed but less resolution than the
sensor offers in full scan mode. The NI Smart Camera supports 1/2 scan
and 1/4 scan. In 1/2 scan, shown in Figure 3-2b, one half of the image is
read out from the center of the sensor and the rest of the image is discarded
to enable a faster start of the next frame. In 1/4 scan, only one quarter of the
image is read out. Figure 3-2 illustrates the portion of the sensor exposed
during partial scanning.
out only a portion of the image from the sensor. Partial scan is frequently
used when an application requires higher speed but less resolution than the
sensor offers in full scan mode. The NI Smart Camera supports 1/2 scan
and 1/4 scan. In 1/2 scan, shown in Figure 3-2b, one half of the image is
read out from the center of the sensor and the rest of the image is discarded
to enable a faster start of the next frame. In 1/4 scan, only one quarter of the
image is read out. Figure 3-2 illustrates the portion of the sensor exposed
during partial scanning.
Figure 3-2. Partial Scan Modes
a
Full Scan
b
1/2 Scan
c
1/4 Scan
a
b
c