How to Tune the Vision Sensor - VEXcode V5 Blocks

A Vision Sensor can be used to see objects and allow your robot to interact with the world around it. Occasionally, the robot may have difficulty detecting known objects. Known objects are objects that have been previously configured to be recognized by the Vision Sensor. Often times an object is configured to be recognized by the Vision Sensor in one environment, for example, in a classroom. When the Vision Sensor is then taken into a different environment such as a competition setting, the object may not be recognized by the Vision Sensor. This is often due to a change in lighting after the Vision Sensor has already been configured. To solve this problem, you may have to tune your Vision Sensor. 

There are three ways to tune the Vision Sensor:

  • Adjusting the signature slider
  • Adjusting the brightness
  • Resetting the signature

In this article, we will be using the Detecting Objects (Vision) example project.


In VEXcode V5 Blocks, open the configuration window.

Choose the Vision Sensor from the Devices list and select “Configure” to launch the Vision Utility.

In this project, the Vision Sensor has been configured to detect a blue, red, or green object. Place a known object in front of the Vision Sensor.     

Here, the Vision Sensor should detect that this is a red object. However, since the lighting conditions have changed, the Vision Sensor is having trouble detecting the red object.  


Adjusting the Signature Slider

Select the signature slider of the red object. 

Move the slider to detect more of the red object. The slider determines the width of the color to be detected. Increasing the width means including lighter and darker shades of a color.

Note: It is important to keep in mind that changing the slider too much could hinder the accuracy of the reading.


Adjusting the Brightness

Another way to tune the Vision Sensor is to change the brightness. Changing the brightness increases or decreases the Vision Sensor’s sensitivity to light. This allows the Vision Sensor to be used in different environments. 

Select the brightness slider.

Note: Adjusting the brightness affects all colors.    

Move the slider to adjust the Vision Sensor’s sensitivity to light for it to be able to detect the color signatures more accurately. 

Note: It is important to keep in mind that changing the slider too much could hinder the accuracy of the reading.


Resetting the Signature

Depending on the environment and the color of the signature set, adjusting the brightness or the signature slider may not work. Another option is to clear the color signature and reset the signature.

Clear the set signature.

Place the object in front of the Vision Sensor and select “Freeze” to still the image.

Select a colored area on the object that will be used to configure the color. The “Set” icons will turn green when a new signature is being configured.

Once the colored area has been selected, configure the color by selecting the “Set” button.

The signature has been reset and the “Set” icons have returned back to blue.