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DIRAS cells
DIRAS
The DIRAS, infrared detection cells developed by Automatic Systems, are strips of cells of the
Transmitter/Receiver type. They are grouped by 8 on electronic boards.
The transmitter cells are located in the left unit, and the receiver cells in the right unit.
Each lane is equipped with 24 pairs of T/R cells (48 cells). The physical distance between two cells is
approx. 45 mm, but thanks to the virtual beams created by the cross beams, this distance is reduced to
23 mm.
Cross beam principle
This high cell density allows the use of a detection algorithm, called a tracking algorithm, which predicts
the position of the user and is able to detect objects/spaces greater than 23 mm (which is very small
compared to commercially available networks of cells). This algorithm manages passages and
determines violations based on the match between this prediction and the cell masking sequence.
The advance leg tracking algorithm, combined with the location of the DIRAS and the high cell density,
allows for:
•
Effective detection of Tailgating
•
Trolleys have a specific signature that allows them to be differentiated from human beings
•
Detection of children of all sizes
•
Detection of U-turn before/after the obstacle
•
Detection of users moving in the wrong direction
•
Detection of crawling users (highly unlikely)
Direct beam
Cross beam
Virtual beam
Transmitter:
Receiver:
E R E R E R
