Zone Algorithm

An algorithm that monitors the area within and around a zone.

Table 1. Available fields in blickfeld.percept_pipeline.config.ZoneAlgorithm
Field	Type	Default	Unit
name	string	-	-
name	The user readable zone algorithm name
uuid	string	-	-
uuid	The uuid of the zone algorithm (uuid4)
shape	base.geometry.Shape	-	-
shape	Geometric shape (usually a Box) in which the algorithm detects certain behaviors/scenarios
disabled	bool	-	-
disabled	Disable this zone, setting this flag to `true` disables the evaluation of the zone
metadata	optional google.protobuf.Struct	-	-
metadata	Arbitrary metadata storage for client applications
volume	Volume	-	-
volume	Run volume monitoring within the zone
security	Security	-	-
security	Run alarm detection within the zone
exclusion	Exclusion	-	-
exclusion	Run exclusion zone
object_based_security	ObjectBasedSecurity	-	-
object_based_security	Run object-based alarm detection within the zone
occupancy	Occupancy	-	-
occupancy	Run occupancy zone
traversal_security	TraversalSecurity	-	-
traversal_security	Run traversal zone

Volume

Algorithm that measure the volume of a zone

The volume of a zone is approximated by computing a 'volume map' from the input point clouds. The volume map discretize the zone into 'tiles' in the xy-plane with a side-length of 'resolution'. Each tile contains the height information about the points that fall into this tile. The volume of the volume map can be calculated by adding up the volumes of the tiles in the volume map.

Table 2. Available fields in blickfeld.percept_pipeline.config.ZoneAlgorithm.Volume
Field	Type	Default	Unit
resolution	float	-	m
resolution	Grid resolution per tile used to measure the volume. Reasonable default: 0.1
empty_volume	float	-	m^3
empty_volume	The measured volume while area covered by the zone is considered 'empty'. The value can be set using TareVolume method while the area of the zone is empty. Reasonable default: 0
disable_when_occupied_zone_uuids	repeated string	-	-
disable_when_occupied_zone_uuids	Link volume zone to occupancy zones (by uuid). Disables the volume zone state when one of the occupancy zones is occupied.
angle_of_repose	optional float	-	rad
angle_of_repose	Angle of repose. Steepest angle of descent when the measured material is piled. See https://en.wikipedia.org/wiki/Angle_of_repose.
minimum_coverage	optional float	-	-
minimum_coverage	Minimum coverage value for zone. When the estimated coverage is below the configured threshold, the state output will be disabled. This can be used to automatically disable zones when the viewport to the zone area is blocked or the sensor is temporarily failed. Default: 0

Security

Algorithm that triggers an alarm if movement was detected in the zone

Table 3. Available fields in blickfeld.percept_pipeline.config.ZoneAlgorithm.Security
Field	Type	Default	Unit
min_points	uint32	-	-
min_points	Minimum number of (foreground) points in the security zone to trigger the alarm. Reasonable default: 10
max_points	uint32	-	-
max_points	Maximum number of (foreground) points in the security zone that still triggers an alarm. More points will disable the alarm. This logic can be disabled by setting max_points to '0'. Default: 0
minimum_intruding_duration	float	-	s
minimum_intruding_duration	Minimum active intrusion duration before alarm is triggered. Default: 0
minimum_intrusion_confidence	float	-	-
minimum_intrusion_confidence	Minimum intrusion confidence before alarm is triggered. Only applicable when the minimum intruding duration is configured. Default: 1
hold_duration	float	-	s
hold_duration	Alarm is kept active for the given duration to reduce jitter. Default: 0

Object Based Security

Algorithm that triggers an alarm when an object of one of the selected sizes is in the zone

Table 4. Available fields in blickfeld.percept_pipeline.config.ZoneAlgorithm.ObjectBasedSecurity
Field	Type	Default	Unit
alarm_sizes	repeated ObjectSize	-	-
alarm_sizes	Selection of sizes which trigger an alarm. Each size in the array will only trigger an alarm for the interval of that size.
minimum_intruder_lifetime	float	-	s
minimum_intruder_lifetime	Minimum lifetime of object before alarm is triggered. Default: 0
minimum_intruder_track_length	float	-	m
minimum_intruder_track_length	Minimum track length of object before alarm is triggered. Default: 0
minimum_intruding_duration	float	-	s
minimum_intruding_duration	Minimum active intrusion duration before alarm is triggered. Default: 0
objects_in_background	bool	-	-
objects_in_background	Trigger alarm for objects with the "in_background" property. Enabling this might increase the false alarm rate.
minimum_intrusion_confidence	float	-	-
minimum_intrusion_confidence	Minimum intrusion confidence before alarm is triggered. Only applicable when the minimum intruding duration is configured. Default: 1
hold_duration	float	-	s
hold_duration	Alarm is kept active for the given duration to reduce jitter. Default: 0

Exclusion

Algorithm that excludes points from the input point cloud

Occupancy

Algorithm that detects if a zone is occupied

Table 5. Available fields in blickfeld.percept_pipeline.config.ZoneAlgorithm.Occupancy
Field	Type	Default	Unit
min_points	uint32	-	-
min_points	Minimum number of points to mark the zone as occupied. Reasonable default: 10
adaptive_baseline_time_constant	optional float	-	s
adaptive_baseline_time_constant	If set, the min_points is not compared against zero but against an adaptive baseline. The baseline is calculated with an exponential filter with the zone point count as input. The given time constant is used to calculate the alpha for the exponential filter. After a restart, the baseline is initialized with the current zone point count. Reasonable default: 3600s (1 hour)
voxel_size	optional float	-	m
voxel_size	The point cloud inside the zone is down sampled with a voxel grid. This is done to achieve a distance-independent parametrization. The size of a voxel cell can be configured with this parameter. Default: 0.05m
invert	bool	-	-
invert	Invert the state of the zone This might be useful in situations where e.g. a static crane should be detected in its home position.

Traversal Security

Algorithm that detects if objects are traversing through the zone.

Table 6. Available fields in blickfeld.percept_pipeline.config.ZoneAlgorithm.TraversalSecurity
Field	Type	Default	Unit
alarm_sizes	repeated ObjectSize	-	-
alarm_sizes	Selection of sizes which trigger an alarm. An alarm will only be triggered by objects of sizes specified in the array.
hold_duration	float	-	s
hold_duration	Alarm is kept active for the given duration to reduce jitter. Default: 0