Visión#

Introducción #

El sensor de visión del dron VEX AIR detecta y rastrea los identificadores de AprilTag. Esto permite al dron analizar su entorno, seguir objetos y reaccionar según los datos visuales detectados. A continuación, se muestra una lista de todos los métodos y propiedades disponibles:

Getters – Detecta si el dron sostiene un objeto.

get_data – Returns a tuple of detected objects based on a given signature.

Properties – Object data returned from get_data.

exists – Whether the object exists in the current detection as a Boolean.
width – Width of the detected object in pixels.
height – Height of the detected object in pixels.
centerX – X position of the object’s center in pixels.
centerY – Y position of the object’s center in pixels.
bearing – Angle of the object relative to the front Vision Sensor or the degrees needed for the drone to face the object.
rotation – Orientation of the object in degrees.
originX – X position of the object’s top-left corner in pixels.
originY – Y position of the object’s top-left corner in pixels.
id – Tag ID of the object.
type – Returns the object’s type.

Captadores #

get_data #

get_data filters the data from the Vision Sensor frame to return a tuple. The Vision Sensor can detect AprilTag IDs.

La tupla almacena objetos ordenados de mayor a menor por ancho, comenzando en el índice 0. Se puede acceder a las propiedades de cada objeto mediante su índice. Si no se detectan objetos coincidentes, se devuelve una tupla vacía.

Usage:
drone.vision.get_data(camera, signature, count)

Parámetros	Descripción
`camera`	The camera to retrieve data from: `DOWNWARD_CAMERA` `FORWARD_CAMERA`
`signature`	What signature to get data of. Available signatures are: `ALL_TAGS` - All AprilTags `TAG0` through `TAG37` - A single AprilTag with an ID from 0 to 37
`count`	Opcional. Establece el número máximo de objetos que se pueden devolver, de 1 a 24 (valor predeterminado: 8).

Parámetros

Descripción

camera

The camera to retrieve data from:

DOWNWARD_CAMERA
FORWARD_CAMERA

signature

What signature to get data of. Available signatures are:

ALL_TAGS - All AprilTags
TAG0 through TAG37 - A single AprilTag with an ID from 0 to 37

count

Opcional. Establece el número máximo de objetos que se pueden devolver, de 1 a 24 (valor predeterminado: 8).

# Climb upward when an AprilTag is detected
drone.take_off(climb_to=500)
while True:
    vision_data = drone.vision.get_data(FORWARD_CAMERA, ALL_TAGS)
    if vision_data[0].exists:
        drone.climb_for(direction=UP, distance=200)

Propiedades #

There are multiple properties that are included with each object stored in a tuple after get_data is used.

Some property values are based off of the detected object’s position in the Vision Sensor’s view at the time that get_data was used. Each Vision Sensor has a different resolution:

Orientado hacia adelante: 640 x 480 píxeles
Mirando hacia abajo: 640 x 400 píxeles

.exists #

.exists returns if the index exists in the tuple or not. This property returns a Boolean value. Returns an error if there are no detected objects.

True – The index exists.
False – The index does not exist.

# Climb upward when an AprilTag is detected
drone.take_off(climb_to=500)
while True:
    vision_data = drone.vision.get_data(FORWARD_CAMERA, ALL_TAGS)
    if vision_data[0].exists:
        drone.climb_for(direction=UP, distance=200)

.width #

.width returns the width of the detected object in pixels as an integer from 1 to 640.

# Show if the AprilTag ID appears large or small
while True:
    vision_data = drone.vision.get_data(FORWARD_CAMERA, ALL_TAGS)
    clear_console()
    if vision_data[0].exists:
        if vision_data[0].width > 100:
            print("Large")
        else:
            print("Small")
    wait(0.2, SECONDS)

.height #

.height returns the height of the detected object in pixels as an integer from 1 to 480.

# Show if the AprilTag ID appears large or small
while True:
    vision_data = drone.vision.get_data(FORWARD_CAMERA, ALL_TAGS)
    clear_console()
    if vision_data[0].exists:
        if vision_data[0].height > 100:
            print("Large")
        else:
            print("Small")
    wait(0.2, SECONDS)

.centerX #

.centerX returns the x-coordinate of the center of the detected object in pixels as an integer from 1 to 640.

# Show if an AprilTag is to the left or the right of the camera
while True:
    clear_console()
    vision_data = drone.vision.get_data(FORWARD_CAMERA, ALL_TAGS)
    if vision_data[0].exists:
        if vision_data[0].centerX < 320:
            print("To the left!")
        else:
            print("To the right!")
    wait(0.2, SECONDS)

.centerY #

.centerY returns the y-coordinate of the center of the detected object in pixels as an integer from 1 to 480.

# Take off and align drone with AprilTag ID on wall
# Change drone.take_off parameter to see different results
drone.take_off(climb_to=800)
vision_data = drone.vision.get_data(FORWARD_CAMERA, ALL_TAGS)
if vision_data[0].exists:
    if vision_data[0].centerY < 240:
        print("Below the target!")
    else:
        print("Above the target!")
else:
    print("No target found!")

.bearing #

.bearing returns an angle indicating an object’s position relative to the drone. The behavior depends on which Vision Sensor is used.

Un valor de 0° indica que el centro del objeto y el sensor están alineados. Los valores positivos indican que el objeto está a la derecha, mientras que los negativos indican que está a la izquierda.

Sensor	Devoluciones
Hacia abajo	Grados que debe girar la parte frontal del dron para alinearse con el centro del objeto, de –180º a 180º.
Adelante	Grados en los que el objeto se desplaza hacia la izquierda o la derecha del centro del sensor de visión, de –180º a 180º.

# Align the front of the drone to an AprilTag ID
drone.set_turn_velocity(15)
drone.take_off(climb_to=500)
while True:
    vision_data = drone.vision.get_data(DOWNWARD_CAMERA, ALL_TAGS)
    if vision_data[0].exists:
        if -20 < vision_data[0].bearing < 20:
            # Hover once sensor is centered on AprilTag ID
            drone.hover()
            controller.sound.play(SUCCESS)
            while controller.sound.is_active():
                wait(50, MSEC)
        elif vision_data[0].bearing < -21:
            drone.turn(LEFT)
        else:
            drone.turn(RIGHT)
    wait(5, MSEC)

.rotation #

.rotation returns the orientation of the detected AprilTag as an integer in degrees from 1 to 359.

# Turn left or right based on the rotation of an AprilTag ID
drone.take_off(climb_to=1000)
while True:
    vision_data = drone.vision.get_data(FORWARD_CAMERA, ALL_TAGS)
    if vision_data[0].exists:
        if 240 < vision_data[0].rotation < 300:
            drone.turn_for(LEFT, 90)
        elif 60 < vision_data[0].rotation < 120:
            drone.turn_for(RIGHT, 90)
        else:
            drone.hover()
    wait(0.2, SECONDS)

.originX #

.originX returns the x-coordinate of the top-left corner of the detected object’s bounding box in pixels as an integer from 1 to 640.

# Draw lines to the AprilTag origin from all corners
while True:
    controller.screen.clear_screen()
    vision_data = drone.vision.get_data(FORWARD_CAMERA, ALL_TAGS)
    if vision_data[0].exists:
        controller.screen.draw_line(0, 0, vision_data[0].originX, vision_data[0].originY)
        controller.screen.draw_line(0, 480, vision_data[0].originX, vision_data[0].originY)
        controller.screen.draw_line(640, 0, vision_data[0].originX, vision_data[0].originY)
        controller.screen.draw_line(640, 480, vision_data[0].originX, vision_data[0].originY)
    wait(0.2, SECONDS)

.originY #

.originY returns the y-coordinate of the top-left corner of the detected object’s bounding box in pixels as an integer from 1 to 480.

# Draw lines to the AprilTag origin from all corners
while True:
    controller.screen.clear_screen()
    vision_data = drone.vision.get_data(FORWARD_CAMERA, ALL_TAGS)
    if vision_data[0].exists:
        controller.screen.draw_line(0, 0, vision_data[0].originX, vision_data[0].originY)
        controller.screen.draw_line(0, 480, vision_data[0].originX, vision_data[0].originY)
        controller.screen.draw_line(640, 0, vision_data[0].originX, vision_data[0].originY)
        controller.screen.draw_line(640, 480, vision_data[0].originX, vision_data[0].originY)
    wait(0.2, SECONDS)

.id #

.id returns the identification number of the detected AprilTag ID as an integer from 0 to 37.

# Display the detected AprilTag ID
while True:
    vision_data = drone.vision.get_data(FORWARD_CAMERA, ALL_TAGS)
    clear_console()
    if vision_data[0].exists:
        print(vision_data[0].id)
    wait(0.2, SECONDS)

.type #

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

Tipo de objeto	Valor numérico	Objetos incluidos
`drone.vision.TAG_OBJECT`	8	Identificadores de AprilTag
`drone.vision.COLOR_OBJECT`	1	Firmas de color - ¡Próximamente!
`drone.vision.CODE_OBJECT`	2	Códigos de colores - ¡Próximamente!

# Display what AprilTag ID is detected
while True:
    controller.screen.clear_screen()
    controller.screen.set_cursor(1, 1)
    vision_data = drone.vision.get_data(FORWARD_CAMERA, ALL_TAGS)
    if vision_data[0].exists:
        if vision_data[0].type == drone.vision.TAG_OBJECT:
            controller.screen.print("AprilTag ID: ")
            controller.screen.print(vision_data[0].id)
        
    wait(0.1, SECONDS)