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Navigation: Gatekeeper > Hardware and installation

Positioning of the camera

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Proper positioning of the camera is crucial to ensure optimum performance under all conditions.

The charts below give an indication of proper distances to mount the Gatekeeper.

Keep in mind all circumstances are different. For the best recognition each installation must be examined with care.

 

Note: CortexClient offers the tools to finetune the settings, so recognition can be optimal. The GatekeeperAxon viewpanel can be put in debug mode to see exact measurements of the license plate at current settings. Keep in mind that the width of the license plate in the images used for detection can never be below 100 pixels or more then 300 pixels.

The chapters starting with Optimize ANPR contain all the information for  a proper recognition. More insights about the individual axons can be read here.

 

Horizontal and vertical angles from the Gatekeeper to the license plate

 

For the best performance it is advised to keep the horizontal and vertical angles as small as possible. Stated angles are maximum angles. For the best recognition each installation must be examined with care.

Maximum angles are set according to the LED beam. Angles can be bigger during the day or in controlled light circumstances.

 

Distance from the Gatekeeper to the license plate

 

The distance from Gatekeeper to license plate must never be larger than 25 meters when a GK1250 is mounted.

The distance from Gatekeeper to license plate must never be larger than 8 meters when a GK410 is mounted.

 

See the range charts of GK410 and GK1250 for detailed information on angle range.

 

Calculate the correct viewing angles:

 

Optimal recognition results can be achieved by a proper projection. The mounting place forms the base for a good functioning sensor system.

The AVUTEC support team offers the projection service. A report is made to advise the best combination of Gatekeeper model and mounting place.

 

 

Rule of thumb for vertical angle and distance

Rule of thumb horizontal angle and distance

 

GK_Rule vertical angle GK installation

 

GK_Rule vertical angle GK installation

 

 

Calculations

GK_FourCoordinateMeasuremntHorizontalAngles

 

0,84 is the AVUTEC viewing angle coefficient. It is used to calculate and check horizontal and vertical angles and distances. See calculations below for a better understanding.

 

1.Calculation for camera 1:
Max. installation height GK:
Calculate maximum height:
Measured distance to A * max AVUTEC viewing angle coefficient = maximum mounting height
6  meter x 0.84  = 5.04 meter.
Calculate horizontal angle:
Measure width to A / measured perpendicular distance to A
2.75 meter /  5.5 meter <= 0.84
Angle is okay.
 
Repeat these steps for all (A,B,C,D) points to ensure recognition for all area.
 

2.Calculation for camera 2
Calculate horizontal angle:
Measure width with respect to D / measured perpendicular distance to D
6.75 meter/ 4.50 meter > 0.84
The angle  is to wide. This mounting position is not good.

 

A,B,C,D:
Regions of interest: The location at which a license plate should be recognized.  
 
Red circles:
Optional Gatekeeper mounting positions

 

 

 

Tilted angle of a license plate: z-axis rotation

 

GK_tilted_angle_lp_in_xy_plane