This articles gives a short introduction to scripting alarm and counter tasks with Intelligent and Essential Video Analytics in FW 7.60. It also provides a broad selection of example scripts for explanation as well as including real world application examples.

Step-by-step guide

1 What is the VCA task script language?

VCA stands for video content analysis. The VCA task script language:

• describes every predefined and configured Intelligent Video Analytics, Essential Video Analytics and MOTION+ task and task wizard
• can combine tasks to form more complex ones
• can NOT configure the metadata generation

1.1 When to use the VCA task scripts?

The VCA task scripts are used implicitly whenever an Intelligent Video Analytics, Essential Video Analytics or MOTION+ task is configured via the GUI. However, manual configuration of the VCA task scripts is also possible and advised whenever the predefined tasks are not enough:

• For backup and exchange of the configured tasks, the script can be copied from and pasted into the task script editor.
• When more than 8 alarm tasks are needed: 16 external alarm tasks are configurable via VCA task scripts.
• Fine tuning the position of lines and fields.
• Line combinations for counting with FW < 6.30.
• Don’t touch (museum mode) with FW < 6.10: Alarm needs to be triggered by any part of bounding box, not only by the object center.
• Logical combinations of predefined events are needed.

1.2 How to use VCA task scripts?

(1) Define all tasks via task wizards as far as possible.
(2) Change to the VCA task script editor. The already defined tasks can be found there with all details.
(3) Make your modifications.
(4) Change the defined tasks into task type scripted so accidental use of the task wizards will not overwrite your changes.

1.3 How to access the VCA task script language?

Go to the Intelligent Video Analytics, Essential Video Analytics or MOTION+ configuration and open the task page.

Right-click on the video and select Advanced -> VCA Task Editor. A separate popup with the current VCA task script will appear:

1.4 Task & object filter overview

A task consists of

• A task primitive
• An object state or interaction with a task primitive
• A filter on the object properties if task is based on objects

Note that not all tasks and filters are available in every FW version.

MOTION+:

Intelligent Video Analytics & Essential Video Analytics (the latter w/o flow tasks):

1.5 Object state and event overview

From the task primitives, the tasks and the object filter as defined in the GUI via the task wizards, target object states and events are derived. These can also be defined directly in the VCA task script language.

Events are always temporal relations

• Up to 8 external events can be shown in GUI
• Up to 16 external events can be defined in total
• Up to 32 events can be defined in total

States can be, amongst others, spatial relations, object properties, tamper states, counter values

• Up to 16 external states can be defined
• Up to 32 states in total can be defined

Events and states can be internal or external. Only external events and states are outputted.

Simple states are used whenever a property has no corresponding objects. Examples are Motion+, Flow, counter values and tamper states.

1.6 Combining & converting object states and events

The combinations of object states and events listed below are possible. Object states can be also converted into events, but only the onset or leaving of an object state is an actual event, not the actual duration of the object in this state.

1.7 Temporary states for time evaluations

Starting with FW 6.60 and in order to create temporary states triggered by an event, the keyword within can used after an event. This can be used to

- delay or debounce an alarm based on an object state: within(0,)

- to extend an alarm state similarly to the aggregation time: within(,*)

- debouncing object properties: By checking the target values is currently met, and has not changed during the debounce time

- temporarily combine an event with other states

1.8 Position descriptions

There are two different ways to describe the position information of lines, fields and routes:

• Absolute pixel position, e.g. Point(103, 30). You need to know exactly which resolution is used in the video analytics for that.
• Relative coordinates, e.g. specifying
  Resolution := { Min(-1, -1) Max(1, 1) };
  Line #1 := { Point(-0.85, 0.95) Point(-0,6, 0.4)};

Here, the coordinates are defined within the specified resolution and transferred automatically to the real resolution used in the video analytics.

2 Examples & Explanations

2.1 Understanding the VCA task script language: Line Crossing, GUI

2.2 Understanding the VCA task script language: Polygonal lines

2.3 Understanding the VCA task script language: Line crossing with object filters

2.4 Understanding the VCA task script language: Fields

2.5 Understanding the VCA task script language: Routes

2.6 Example: Alarm if object enters a field and afterwards crosses the line

2.7 Example: Alarm if object enters first one field and then the other

2.8 Example: Perimeter protection with two fields

2.9 Example: Combining lines for counting

2.10 Example: Crossing line1 with 60km/h and line 2 with 20km/h

2.11 Example: Stopping in area after crossing line

2.12 Example: Alarm When Object Touches Area

2.13 Example: Alarm when object enters an area at least 4 times

2.14 Example: Alarm when a second object crosses a line within 3 seconds of the first

2.15 Example: Alarm when at least 2 object are in an area

2.16 Example: Count the number of objects in an area

2.17 Example: Alarm on empty reception desk

2.18 Example: Alarm if one queue is empty and the other has at least 3 persons

2.19 Example: Virtual room for counting with one in and one out line

2.20 Example: Virtual room for counting with two in and one out line

2.21 Example: Alarm on any object that is not yellow

2.22 Example: Count all red objects

2.23 Example: Debouncing object size by 5 seconds

2.24 Example: Give 30 sec alarm on any object (aggregation time)