ANPR
© Nedap AVI, P.O. Box 103, NL-7140 AC GROENLO Page 14 of 27
Temporal Integration
The ANPR system processes multiple images for each vehicle, which allows for higher OCR reading effectiveness
and reliability. Section Temporal Integration contains the parameters for managing the whole packet of
processed images for each single event.
Max Time Transit: This parameter is relevant only in FREE-RUN mode. This is the maximum time period
allowed for any number plate transition. If, for example, this parameter is set to
1000ms, then the ANPR system reads the number plate once, but will wait 1000ms
before generating the event.
During this time, the system keeps grabbing and processing images of the same
vehicle whose number plate was read. This allows for a highly reliable number plate
reading process.
During this same interval, the system may detect a vehicle with a different number
plate number. In that case a new event is immediately generated (no waiting for the
1000ms interval to expire). The images subsequently acquired and processed must
be related to the new event.
The MaxTimeTransit value should be set to the highest possible value while of course
complying with the specific installation requirements. Setting a too low
MaxTimeTransit value means less images are processed for the same vehicle, which
leads to lower reliability in OCR reading.
Min Time Same Plate (Enable Multi Out Same Plate = 0):
It represents the minimum time in milliseconds during which the camera will not
generate an event even if the number plate has already been recognized. In other
words, during this time a previously recognized number plate does not need be in
the ANPR field of action in order to generate another event. If the vehicle remains in
the ANPR field of action, the same plate recognition event is generated only once.
Min Time Same Plate (Enable Multi Out Same Plate = 1):
It represents the length of time in milliseconds that must elapse before generating a
new recognition event associated with a plate that was already recognized. In this
case, if vehicle remains within the camera field, then the ANPR system will repeat
generating a recognition event every Min Time Same Plate.
Image Selection Mode: Indicates the selection mode of the image containing the recognized plate. Possible
values are: FIRST-PLATE, LAST-PLATE, BIGGEST-PLATE or BEST-LUMINANCE.
5.2.4 DIGITAL TRIGGER
This page configures the digital input to trigger image processing on the ANPR system. When the ANPR is
configured to FREE RUN mode, the settings below are ignored. The Digital Input Trigger page contains the
following fields:
Start Input Num: Set the number of the digital input associated with the start trigger.
Start Input Edge: Set the start trigger state (rising edge or falling edge).
Stop Input Num: Set the number of the digital input associated with the stop trigger.
Stop Input Edge: Set the stop trigger state (rising edge or falling edge).
GateTimeMax: It allows setting the value, in milliseconds, of the maximum period between start and
stop of the trigger. The values may range from 40 to 30000 (=30 seconds).
Trigger Shift Time: It allows setting a delay to be applied to the start and stop triggers. This may be
useful in order to insert a delay between trigger detection and processing
initialization. Specify value in milliseconds. Default 0 is no delay.
To Next Page
Loading...
Need help?
General
