Watcher

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Watcher
Watcher objects are plain object descriptors providing Lampix with the required information to start watching areas based on the behaviors described.
Properties
name (string): Literal string describing the Python class to instantiate and define the watcher's behavior (e.g 'NeuralNetworkClassifier', 'MovementBasedSegmenter' etc.).
shape (Object): Plain object with two properties, type and shape that defines the surface area for the watcher.
type (string): Defines shape type, and controls what the expected structure of shape.data will be. Accepted values:
'rectangle'
'polygon'
data (Object): Actual descriptor object for the contour of the watcher.
If shape.type is 'rectangle', the expected data structure is:
posX (number): top left X coordinate of rectangle
posY (number): top left Y coordinate of rectangle
width (number)
height (number)
If shape.type is 'polygon', a list of points is expected, with each point having the following data structure:
x (number): X coordinate of point
y (number): Y coordinate of point
onClassification (Function): Callback used by Lampix to send information about recognized objects as a list with with recognized objects of the following structure:
classTag (string): Recognized class of the described object.
objectId? (number, Optional): ID representing the object. Useful when determining whether Lampix considers an object as new.
outline? (Array, Optional): Object with a property of points that describes the contour of the object as a polygon:
metadata? (string, Optional): Watcher specific information
onLocation (Function): Callback used only by watchers that locate first, then classify. Called with a list of located objects that with a similar structure to the one above, except classTag is not mentioned since it has not been determined at the time of this call.
params? (Object): Plain object with arbitrary props that can differ from watcher to watcher. See standard watchers​
Notes
The only required property is classTag. Certain watchers that do not support more than one object at a time (e.g NeuralNetworkClassifier), will always provide a list with one recognized object that only has the classTag property. This is by design, to ensure consistency in the data format returned by the standard watchers.
Example
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{
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  name: 'DepthClassifier',
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  shape: {
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    type: "rectangle",
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    data: {
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      posX: 0,
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      posY: 0,
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      width: window.innerWidth,
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      height: window.innerHeight
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    }
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  },
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  params: {
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    frames_until_stable: 5
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  },
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  onClassification: (objects) => draw(objects);
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}
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Tips
In the example above, you can use shape: lampix.helpers.rectangle(0, 0, window.innerWidth, window.innerHeight) to achieve the same result.
API Reference
RegisteredWatcher
Last modified 3yr ago
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