Last update: 1 Aug 2018

7.1 Camera and Facial Expressions

A simple webcam can be used as an interesting input device, especially by recognizing and tracking faces and facial expressions.

7.1.1 Challenges

Facial expression is a relevant interaction modality because it requires little effort to change facial expression and it can be performed in parallel to manual activities like moving the mouse or performing a gesture. On the downside, facial expressions can lead to social awkwardness when done in public. Moreover, one has to be careful to ensure that no unintentional actions are triggered.

7.1.2 Student Projects

Check out various student projects using camera input, and specifically facial expression, for interaction (there are several more):

7.2 OpenCV for Processing

OpenCV is a powerful "computer vision" library developed by Intel. Computer vision is the science of extracting meaningful information from images or video.

Originally developed in C++, there is a port for Processing called OpenCV for Processing

For interaction, the following functionality may be interesting:

7.2.1 FaceDetection

Allows to identify a face in the frame. This becomes more unreliable when the person is not directly facing the camera.

7.2.2 BrightestPoint

Detects the brightest point in the frame. Can be used to interact with a small flashlight.

7.2.3 BackgroundSubtraction

Detects moving objects by comparing the current image frame with the previous one and subtracting pixels. Works with a static camera and constant light conditions.

7.3 Facial Expression

FaceOSC is a tool that recognizes your face and puts a 3D mesh over it so that mouth shape, eyebrows and other features can be recognized. As the name implies the tool sends recognized key values via OSC to other tools (like Processing). Here's an example of what you can do:

Here's another example: the student project faceTYPE by Alice Strunkmann‐Meister and Rodrigo Blásquez at Augsburg University of Applied Sciences.

7.3.1 Installation

FaceOSC work under Windows and on Macs. You will have to run a separate program (FaceOSC) that performs the recognition and then sends the data to a Processing sketch (FaceOSCReceiver).

For installation, do the following:

  1. Install FaceOSC
    • From the releases, pick the file for your OS (e.g. or
    • Unpack the ZIP file
    • You should find an executable, e.g. bin/FaceOSC.exe for Windows
  2. Install Processing 3
  3. In Processing, install the library oscP5 (under Sketch > import library)
  4. Go to the FaceOSC-Templates project and - in the processing folder - download FaceOSCReceiver

7.3.2 Starting Recognition

To start the recognition process, do the following:

  1. Start FaceOSC (not in processing but by clicking e.g. on the exe file in Windows): you will see a window with your camera screen and - if a face is present - a mesh over the face.
  2. In Processing, open and start FaceOSCReceiver: you will see a stylized face that mimics your facial movements

This is what Processing shows you:

Now you can think up all kinds of actions and features that you control with your eyebrows or mouth.

Here's a list of signals that you receive on the Processing side (from FaceOSCReceiver):

public void found(int i)
public void poseScale(float s)
public void posePosition(float x, float y)
public void poseOrientation(float x, float y, float z)
public void mouthWidthReceived(float w)
public void mouthHeightReceived(float h)
public void eyeLeftReceived(float f)
public void eyeRightReceived(float f)
public void eyebrowLeftReceived(float f)
public void eyebrowRightReceived(float f)
public void jawReceived(float f)
public void nostrilsReceived(float f)