deletions | additions       diff --git a/The_IR_projector_is_an__.tex b/The_IR_projector_is_an__.tex  index 7c60d7d..d5a6884 100644  --- a/The_IR_projector_is_an__.tex  +++ b/The_IR_projector_is_an__.tex 
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The IR projector is an IR laser that passes through a diffraction grating and turns into a set of IR dots. Figure \textbf{_} shows the IR dots seen by the IR camera. Figure \textbf{_} shows demonstrates  the depth map produced by the Kinect sensor for the IR image in Figure \textbf{_}. Thedepth value is encoded with gray values; the darker a pixel, the  closer the point IR dot  is to the camera in space. space the darker the pixel. These depth values are represented in gray values.  The black pixels indicate that no depth values are available for those pixels. This might happen if the points are too far (and the depth values cannot be computed accurately), are too close (there is a blind region area  due to limited fields of view for the projector and the camera), are in the cast shadow of the projector (there are no IR dots), or reflect poor IR lights (such as hairs or specular surfaces). The depth values produced by the Kinect sensor are sometimes inaccurate because the calibration between the IR projector and the IR camera becomes invalid. This could be caused by heat or vibration during transportation or a drift in the IR laser.