Vision#

The Vision Sensor for VEX V5 detects and tracks Color Signatures and Color Codes. This allows the Vision Sensor to analyze its surroundings and react based on detected visual data. Below is a list of all methods:

Methods – Get data from the Vision Sensor.

  • take_snapshot – Captures data for a specific Color Signature or Color Code.

  • largest_object – Immediately select the largest object from the snapshot.

  • installed – Whether the Vision Sensor is connected to the V5 Brain.

Properties – Object data returned from take_snapshot.

  • .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.

  • .angle – Orientation of the Color Code 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.

Constructors – Manually initialize and configure the Vision Sensor.

In VEXcode, the initialization of the Vision Sensor and its configured Color Signatures and Color Codes is done automatically. For the examples below, the configured Vision Sensor will be named vision_1. To manually initialize and construct a Vision Sensor and its Color Signatures and Color Codes, refer to the Constructors section on this page.

Methods#

take_snapshot#

take_snapshot filters the data from the Vision Sensor frame to return a tuple. The Vision Sensor can detect configured Color Signatures and Color Codes.

Color Signatures and Color Codes must be configured first in the Vision Utility before they can be used with this method.

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

Usage:
vision_1.take_snapshot(SIGNATURE)

Parameters

Description

SIGNATURE

What signature to get data of. This is the name of the Vision Sensor, two underscores, and then the Color Signature’s or Color Code’s name. For example: vision_1__RED_BOX.

 
# Move forward if a red object is detected
while True:
    red_box = vision_1.take_snapshot(vision_1__RED_BOX)
    if red_box:
        drivetrain.drive_for(FORWARD, 10, MM)
    wait(5, MSEC)

Color Signatures#

A color signature is a unique color that the Vision Sensor can recognize. These signatures allow the sensor to detect and track objects based on their color. Once a Color Signature is configured, the sensor can identify objects with that specific color in its field of view. Color signatures are used with take_snapshot to process and detect colored objects in real-time.

In order to use a configured Color Signature in a project, its name must be the name of the Vision Sensor, two underscores, and then the Color Signature’s name. For example: vision_1__RED_BOX.

# Display if any objects match the RED_BOX signature
while True:
    brain.screen.set_cursor(1, 1)
    brain.screen.clear_row(1)
    # Change to any configured Color Signature
    red_box = vision_1.take_snapshot(vision_1__RED_BOX)
    if red_box:
        brain.screen.print("Color signature detected!")
        wait(100, MSEC)

Color Codes#

A color code is a structured pattern made up of color signatures arranged in a specific order. These codes allow the Vision Sensor to recognize predefined patterns of colors. Color codes are useful for identifying complex objects or creating unique markers for autonomous navigation.

In order to use a configured Color Code in a project, its name must be the name of the Vision Sensor, two underscores, and then the Color Code’s name. For example: vision_1__BOX_CODE.

# Display if any objects match the BOX_CODE code
while True:
    brain.screen.set_cursor(1, 1)
    brain.screen.clear_row(1)
    # Change to any configured Color Code
    box_code = vision_1.take_snapshot(vision_1__BOX_CODE)
    if box_code:
        brain.screen.print("Color code detected!")
        wait(100, MSEC)

largest_object#

largest_object retrieves the largest detected object to get data from in the tuple returned from the latest use of take_snapshot.

This method can be used to always get the largest object from a tuple without specifying an index.

Usage:
vision_1.largest_object

# Turn slowly until the largest object is centered in
# front of the Vision Sensor
drivetrain.set_turn_velocity(10, PERCENT)
drivetrain.turn(RIGHT)

while True:
    red_box = vision_1.take_snapshot(vision_1__RED_BOX)

    if red_box:
        if 140 < vision_1.largest_object().centerX < 180: 
            drivetrain.stop()

    wait(10,MSEC)

installed#

installed returns a Boolean indicating whether the Vision Sensor is currently connected to the V5 Brain.

  • True – The Vision Sensor is connected to the V5 Brain.

  • False – The Vision Sensor is not connected to the V5 Brain.

Parameters

Description

This method has no parameters.

 
# Display a message if the Vision Sensor is connected
if vision_1.installed():
    brain.screen.print("Vision Sensor Installed!")

Properties#

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

Some property values are based off of the detected object’s position in the Vision Sensor’s view at the time that take_snapshot was used. The Vision Sensor has a resolution of 316 by 212 pixels.

.exists#

.exists returns a Boolean indicating if the index exists in the tuple or not.

  • True: The index exists.

  • False: The index does not exist.

# Check if at least one red objects is detected
# You will receive an error if no objects are detected

while True:
    brain.screen.clear_screen()
    brain.screen.set_cursor(1, 1)
    red_objects = vision_1.take_snapshot(vision_1__RED_BOX)

    if red_objects:
        if red_objects[0].exists:
            brain.screen.print("At least 1")
            
    else:
        brain.screen.print("No red objects")

    wait(0.5, SECONDS)

.width#

.width returns the width of the detected object in pixels, which is an integer between 1 and 316.

# Move towards a blue object until its width is
# larger than 100 pixels
while True:
    blue_box = vision_1.take_snapshot(vision_1__BLUE_BOX)

    if blue_box:
        if blue_box[0].width < 100:
            drivetrain.drive_for(FORWARD, 10, MM)
    else:
        drivetrain.stop()

    wait(50, MSEC)

.height#

.height returns the height of the detected object in pixels, which is an integer between 1 and 212.

# Move towards a blue object until its height is
# larger than 100 pixels
while True:
    blue_box = vision_1.take_snapshot(vision_1__BLUE_BOX)

    if blue_box:
        if blue_box[0].height < 100:
            drivetrain.drive_for(FORWARD, 10, MM)
    else:
        drivetrain.stop()

    wait(50, MSEC)

.centerX#

.centerX returns the x-coordinate of the detected object’s center in pixels, which is an integer between 0 and 316.

# Turn slowly until the largest blue object is centered
# in front of the Vision Sensor.
drivetrain.set_turn_velocity(10, PERCENT)
drivetrain.turn(RIGHT)

while True:
    blue_box = vision_1.take_snapshot(vision_1__BLUE_BOX)

    if blue_box:
        if 140 < vision_1.largest_object().centerX < 180: 
            drivetrain.stop()

    wait(10,MSEC)

.centerY#

.centerY returns the y-coordinate of the detected object’s center in pixels, which is an integer between 0 and 212.

# Move towards a blue object until its
# center y-coordinate is more than 140 pixels
while True:
    blue_box = vision_1.take_snapshot(vision_1__BLUE_BOX)

    if blue_box:
        if blue_box[0].centerY < 140:
            drivetrain.drive(FORWARD)
    else:
        drivetrain.stop()

    wait(50, MSEC)

.angle#

.angle returns the orientation of the detected object in degrees, which is an integer between 0 and 316.

# Turn left or right depending on how a
# configured box code is rotated
while True: 
    box_code = vision_1.take_snapshot(vision_1__BOX_CODE)

    if box_code: 
        if 70 < box_code[0].angle < 110:
            drivetrain.turn_for(RIGHT, 45, DEGREES)
            
        elif 250 < box_code[0].angle < 290:
            drivetrain.turn_for(LEFT, 45, DEGREES)
        
        else:
            drivetrain.stop()

    wait(50, MSEC)

.originX#

.originX returns the x-coordinate of the top-left corner of the detected object’s bounding box in pixels, which is an integer between 0 and 316.

# Display if a red object is to the
# left or the right
while True:
    brain.screen.clear_screen()
    brain.screen.set_cursor(1,1)
    
    red_box = vision_1.take_snapshot(vision_1__RED_BOX)
    
    if red_box:
        if red_box[0].originX < 160:
            brain.screen.print("To the left!")
        else: 
            brain.screen.print("To the right!")

    wait(50, MSEC)

.originY#

.originY returns the y-coordinate of the top-left corner of the detected object’s bounding box in pixels, which is an integer between 0 and 212.

# Display if a red object is close or far
# from the robot
while True:
    brain.screen.clear_screen()
    brain.screen.set_cursor(1,1)
    
    red_box = vision_1.take_snapshot(vision_1__RED_BOX)

    if red_box:
        if red_box[0].originY < 80:
            brain.screen.print("Far")
        else: 
            brain.screen.print("Close")

    wait(50, MSEC)

Constructors#

Constructors are used to manually create Vision, Signature, and Code objects, which are necessary for configuring the Vision Sensor outside of VEXcode.

For the examples below, the configured Vision Sensor will be named vision_1, and the configured Color Signature objects, such as RED_BOX, will be used in all subsequent examples throughout this API documentation when referring to Vision class methods.

Vision Sensor#

Vision creates a Vision Sensor.

Usage

Vision(port, brightness, sigs)

Parameters

Description

port

A valid Smart Port that the Vision Sensor is connected to.

brightness

Optional. The brightness value for the Vision Sensor, from 1 to 100.

sigs

Optional. The name of one or more Color Signature or Color Code objects.

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

# Move forward if a red object is detected
while True:
    red_object = vision_1.take_snapshot(RED_BOX)
    if red_object:
        drivetrain.drive_for(FORWARD, 10, MM)
    wait(5, MSEC)

Color Signature#

Signature creates a Color Signature. Up to seven different Color Signatures can be stored on a Vision Sensor at once.

Usage:

Signature(index, uMin, uMax, uMean, vMin, vMax, vMean, rgb, type)

Parameter

Description

index

The Signature object’s index, from 1 - 7. Note: Creating two Signature objects with the same index number will cause the second created object to override the first.

uMin

The value from uMin in the Vision Utility.

uMax

The value from uMax in the Vision Utility.

uMean

The value from uMean in the Vision Utility.

vMin

The value from vMin in the Vision Utility.

vMax

The value from vMax in the Vision Utility.

vMean

The value from vMean in the Vision Utility.

rgb

The value from rgb in the Vision Utility.

type

The value from type in the Vision Utility.

In order to obtain the values to create a Color Signature, go to the Vision Utility. Once a Color Signature is configured, copy the parameter values from the Configuration window.

# Create a new Signature RED_BOX with the Colordesc class
RED_BOX = Signature(1, 10121, 10757, 10439,-1657, -1223, -1440,2.5, 1)
# Create a new Vision Sensor "vision_1" with the Vision
# class, with the RED_BOX Signature.
vision_1 = Vision(Ports.PORT1, 100, RED_BOX)

# Move forward if a red object is detected
while True:
    red_object = vision_1.take_snapshot(RED_BOX)
    if red_object:
        drivetrain.drive_for(FORWARD, 10, MM)
    wait(5, MSEC)

Color Code#

Code creates a Color Code. It requires at least two already defined Color Signatures in order to be used. Up to eight different Color Codes can be stored on a Vision Sensor at once.

Usage:

Code(sig1, sig2, sig3, sig4, sig5)

Parameter

Description

sig1

A previously created Color Signature.

sig2

A previously created Color Signature.

sig3

Optional. A previously created Color Signature.

sig4

Optional. A previously created Color Signature.

sig5

Optional. A previously created Color Signature.

 
# Create two new Signatures for a red and blue box
RED_BOX = Signature(1, 10121, 10757, 10439,-1657, -1223, -1440, 2.5, 1)
BLUE_BOX = Signature(2, -4443, -3373, -3908,6253, 7741, 6997, 2.5, 1)
# Create a Color Code for a red box to the left of a blue box
RED_BLUE = Code(RED_BOX, BLUE_BOX)
# Create a new Vision Sensor "vision_1" with the Vision
# class, with the red_box and blue_box Signatures.
vision_1 = Vision(Ports.PORT1, 100, RED_BOX, BLUE_BOX)

# Display a message if Color Code is detected
while True:
    brain.screen.set_cursor(1, 1)
    brain.screen.clear_row(1)
    # Change to any configured Color Code
    box_code = vision_1.take_snapshot(RED_BLUE)
    if box_code:
        brain.screen.print("Color code detected!")
        wait(100, MSEC)
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