Vision

Introduction

The VEX AIR Hornet’s Vision Sensor detects and tracks AprilTags. This allows the Hornet to analyze its surroundings, follow objects, and react based on detected visual data.

Below is a list of all available blocks:

Actions – Control the Vision feed and capture object data.

• get object data – Captures data for AprilTags.

Settings – Adjust which detected objects are accessed.

• set Vision object item – Selects a specific object from the detected object list.

Values – Retrieve object presence, classification, and properties.

• Vision object exists? – Reports whether an object is detected.

• Vision object is? – Checks if a detected object matches a specific classification.

• Vision object is AprilTag ID – Checks if a detected AprilTag matches a specific ID.

• Vision object count – Returns the number of detected objects.

• Vision object property – Retrieves details such as:

  • width & height – Size of the object.

  • centerX & centerY – Center position coordinates in the sensor’s view.

  • bearing – Horizontal angle relative to the front of the Vision Sensor.

  • angle – Angle of a detected Color Code.

  • rotation – Orientation of the object.

  • originX & originY – Top-left corner position coordinates in the sensor’s view.

  • id – Identification number of an AprilTag.

  • score – Identification number of an AprilTag.

  • type – Identification number of an AprilTag.

Actions

get object data

The get object data block filters data from the Vision Sensor frame. The Vision Sensor can detect AprilTags.

The dataset stores objects ordered from largest to smallest by width, starting at index 0. Each object’s properties can be accessed using Vision object property block. An empty dataset is returned if no matching objects are detected.

The Get object data stack block.

  get [all AprilTags v] data from Vision [forward v] camera

Parameter	Description
signature	Filters the dataset to only include data of the given signature. Available signatures are: AprilTag ID 0-37

Note: AprilTags 5 through 37 can be obtained by using the printed AprilTags from AIM Printables.

Example

Example coming soon!

Settings

set Vision object item

The set Vision object item block sets which item in the dataset to use.

The Set AI Vision object item stack block.

  set Vision object item to [1]

Parameters	Description
item	The number of the item in the dataset to use.

Example

Example coming soon!

Values

Vision object exists?

The Vision object exists? block reports if the Vision Sensor currently detects any objects. This block returns a Boolean value:

• True – The Vision Sensor detects an object.

• False – The Vision Sensor does not detect an object.

Note: The get data block returns an empty list if no objects are detected, so if no objects exist, interacting with the empty list of Vision Objects will result in an error.

Theshow or hide AI Vision dashboard stack block.

  <Vision object exists?>

Parameter	Description
	This block has no parameters.

Example

Example coming soon!

Vision object type is?

The Vision object type is? block reports if the item in the dataset is a specific object type. This block returns a Boolean value.

• True – The item in the dataset is the specific object type.

• False – The item in the dataset is not the specific object type.

The AI Vision AI Classification is object Boolean block.

  <Vision object type is [all AprilTags v] ?>

Parameter	Description
object	Which object to compare the item to: all AprilTags

Example

Example coming soon!

Vision object is AprilTag ID

The Vision object is AprilTag ID? block reports if the AprilTag is a specific ID number. This block returns a Boolean value:

• True – The AprilTag ID is the number.

• False – The AprilTag ID is not the number.

The AI Vision detected AprilTag is Boolean block.

  <Vision object is AprilTag [1]>

Parameters	Description
AprilTag number	The number to compare against the detected AprilTag’s ID number from 0 to 37.

Example

Example coming soon!

Vision object count

The Vision object count block returns the amount of detected objects in the dataset.

The Set AI Vision object item stack block.

  (Vision object count)

Parameters	Description
	This block has no parameters.

Example

Example coming soon!

Vision object property

There are nine properties that are included with each object (shown below) stored after the get object data block is used.

The AI Vision object property reporter block.

  (Vision object [width v])

Some property values are based off of the detected object’s position in the Vision Sensor’s view at the time that the Get object data block was used. The Vision Sensor has a resolution of 240 by 320 pixels.

Parameter	Description
property	Which property of the detected object to use: width height centerX centerY bearing angle rotation originX originY id score type

width

width returns the width of the detected object in pixels as an integer from 1 to 320.

The AI Vision object property stack block with its parameter set to width.

  (Vision object [width v])

Example

Example coming soon!

height

height returns the height of the detected object in pixels as an integer from 1 to 240.

The AI Vision object property stack block with its parameter set to height.

  (Vision object [height v])

Example

Example coming soon!

centerX

centerX returns the x-coordinate of the center of the detected object in pixels as an integer from 0 to 320.

The AI Vision object property stack block with its parameter set to centerX.

  (Vision object [centerX v])

Example

Example coming soon!

centerY

centerY returns the y-coordinate of the center of the detected object in pixels as an integer from 0 to 240.

The AI Vision object property stack block with its parameter set to centerY.

  (Vision object [centerY v])

Example

Example coming soon!

bearing

bearing reports how far an object is to the left or right of the center of the Vision Sensor’s view as a degree. A value of 0 means it’s centered, positive values mean the object is to the right, and negative values mean the object is to the left.

The AI Vision object property stack block with its parameter set to centerY.

  (Vision object [bearing v])

Example

Example coming soon!

angle

Documentation Coming Soon

rotation

rotation returns the orientation of the detected AprilTag as an integer in degrees from 0 to 359.

The AI Vision object property stack block with its parameter set to rotation.

  (Vision object [rotation v])

Example

Example coming soon!

originX

originX returns the x-coordinate of the top-left corner of the detected object’s bounding box in pixels as an integer from 0 to 320.

The AI Vision object property stack block with its parameter set to originX.

  (Vision object [originX v])

Example

Example coming soon!

originY

originY returns the y-coordinate of the top-left corner of the detected object’s bounding box in pixels as an integer from 0 to 240.

The AI Vision object property stack block with its parameter set to originY.

  (Vision object [originY v])

Example

Example coming soon!

id

id returns the identification number of the detected AprilTag as an integer.

The AI Vision object property stack block with its parameter set to tagID.

  (Vision object [id v])

Example

Example coming soon!

score

score returns the confidence score of the detected AI Classification as an integer from 1 to 100, representing a percentage.

The AI Vision object property stack block with its parameter set to tagID.

  (Vision object [score v])

Example

Example coming soon!

type

type returns the returns what type of object is detected. It will return the following:

Object Type	Included Objects
AiVision.TAG_OBJECT	AprilTags

The AI Vision object property stack block with its parameter set to tagID.

  (Vision object [type v])

Example

Example coming soon!