Vision#

Initializing the Vision Class#

A Vision Sensor is created by using the following constructor:

Vision(port, brightness, sigs)

This constructor uses three parameter:

Parameter	Description
`port`	A valid Smart Port that the AI Vision Sensor is connected to.
`brightness`	Optional. The brightness value for the Vision Sensor, from 1 - 100.
`sigs`	Optional. The name of one or more Signature objects.

# Create a new Signature "dark_blue" with the Colordesc class.
dark_blue = Signature(1, -3911, -3435, -3673,10879, 11421, 11150,2.5, 0)
# Create a new Vision Sensor "vision_1" with the Vision
# class, with the "dark_blue" Signature.
vision_1 = Vision(Ports.PORT1, 100, dark_blue)

This vision_1 AiVision object and dark_blue Signature object will be used in all subsequent examples throughout this API documentation when referring to Vision class methods.

Related Classes

Class Methods#

take_snapshot()#

The take_snapshot(index, count) method takes the current snapshot visible to the Vision Sensor and detects the objects of a given Signature or Code.

Before taking a snapshot you must configure signatures for the Vision Sensor to look for.

Parameters	Description
index	A Signature or Code.
count	Optional. The maximum number of objects to obtain. The default is 8.

Returns: A tuple of detected objects or an empty tuple if nothing is available.

while True: 
    # Create a tuple named "darkblue_objects" of detected objects
    # matching the "dark_blue" Signature.
    darkblue_objects = vision_1.take_snapshot(dark_blue)

    # Clear the screen/reset so that we can display 
    # new information.
    brain.screen.clear_screen()
    brain.screen.set_cursor(1, 1)

    # Print the amount of objects detected that matched
    # the "dark_blue" Signature using the len command.
    brain.screen.print("object count:", len(vision_objects))
    # Wait 0.5 seconds before repeating the loop and
    # taking a new snapshot.
    wait(0.5, SECONDS)

largest_object()#

The largest_object() method retrieves the largest object detected by the Vision Sensor in the latest snapshot.

Vision Object Properties	Description
`id`	The unique ID of the object.
`originX`	The top left x position of the object.
`originY`	The top left y position of the object.
`centerX`	The center x position of the object.
`centerY`	The center y position of the object.
`width`	The width of the object.
`height`	The height of the object.
`angle`	The angle of the object.
`exists`	If the Vision camera detects the object.

Returns: A Vision object or None if it does not exist.

while True: 
    # Create a tuple named "darkblue_objects" of detected objects
    # matching the "dark_blue" Signature.
    darkblue_objects = vision_1.take_snapshot(dark_blue)
    
    # Clear the screen/reset so that we can display
    # new information.
    brain.screen.clear_screen()
    brain.screen.set_cursor(1, 1)

    # Print the largest detected object's CenterX
    # coordinate to the Brain's screen.
    brain.screen.print("Center X: ", vision_1.largest_object.centerX)
    # Wait 0.5 seconds before repeating the loop and
    # taking a new snapshot.
    wait(0.5, SECONDS)

installed()#

The installed() method checks if the Vision Sensor is connected.

Returns: True if the Vision Sensor is connected. False if it is not.

timestamp()#

The timestamp() method returns the timestamp of the last received status packet from the Vision Sensor.

Returns: The timestamp of the last received status packet in milliseconds.