Also watch a demo video ‘Capture and Select’ at following URL:
http://nxtcamview.sourceforge.net/DemoScreenCam.htm
Tips on using NXTCam in your environment
Object Colors in Line Tracking Vs Object Tracking Modes
In the object tracking mode, you can track objects comprising of 8 distinct colors.
While selecting colors, avoid any overlap between colors of different objects.
In line tracking mode, only the first color from the Colormap is used, and it is
recommended to limit the number of colors to one.
Lighting conditions
The NXTCam is designed to operate under
white fluorescent light
. If you notice
reddish image color, which tends to happen when your environment has lot of
ambient Infrared light, try to find the source of Infrared light and reduce it by
replacing it with fluorescent light.
For advanced operations it is possible to change color gain, brightness and contrast
of NXTCam by manipulating the I2C register values.
Focus
As a factory default, NXTCam lens is set for optimal focus between 2 and 4 feet.
The lens is screwed in it’s holder and it is designed to be tight to prevent accidental
rotation and loss of focus. To refocus the lens, gently turn the lens from the holder,
capture images and see if the new focus is satisfactory. Do not apply excessive
force, as it may damage the lens. For better grip while turning lens, you may wrap a
rubber-band around the exposed threads of the lens. To check the focus, you can
use Viewer software and perform a 'capture' to see the new focus results.
Updating your Colormap
Human eye (and brain) is conditioned to adapt to ambient light conditions and see.
Whereas based on ambient light, the colors of objects appear different to a camera
CCD. In other words, a blue ball in your laboratory lighting conditions will appear to
be a different shade of blue in Gymnasium lighting. Considering this aspect, ensure
to update your NXTCam Colormap based on your final lighting conditions.
Selecting Colors of your Target Object for Colormap
Due to angle of light and shadows cast on the object, to
NXTCam, the object appears to be a mix of dark and
light shades. In choosing color for your colormap, try to
select the lighter shade of your object’s colors. If with
lighter shades you have trouble tracking darker shades,
then select complete range of colors.
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