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NI 17xx Smart Camera User Manual
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.
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.
Figure 3-2.
Partial Scan Modes
a
Full Scan
b
1/2 Scan
c
1/4 Scan
a
b
c
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