Example of using a frame detector from Affectiva's Affdex Unity asset

CameraInput.cs

// Unity derives Camera Input Component UI from this file
using UnityEngine;
using System.Collections;

namespace Affdex
{
    /// <summary>
    /// Provides WebCam access to the detector.  Sample rate set per second.  Use 
    /// </summary>
    [RequireComponent(typeof(Detector))]
    public class CameraInput : MonoBehaviour, IDetectorInput
    {
        /// <summary>
        /// Number of frames per second to sample.  Use 0 and call ProcessFrame() manually to run manually.
        /// Enable/Disable to start/stop the sampling
        /// </summary>
        public float sampleRate = 20;

        protected WebCamDevice[] devices;

        protected WebCamDevice device;

        /// <summary>
        /// Should the selected camera be front facing?
        /// </summary>
        public bool isFrontFacing = true;

        /// <summary>
        /// Desired width for capture
        /// </summary>
        public int targetWidth = 640;

        /// <summary>
        /// Desired height for capture
        /// </summary>
        public int targetHeight = 480;
        
        /// <summary>
        /// Web Cam texture
        /// </summary>
        private WebCamTexture webcamTexture;

        /// <summary>
        /// The detector that is on this game object
        /// </summary>
        public Detector detector
        {
            get; private set;
        }

        /// <summary>
        /// The texture that is being modified for processing
        /// </summary>
        public Texture Texture
        {
            get
            {
                return webcamTexture;
            }
        }

        void Awake()
        {
            detector = GetComponent<Detector>();
            detector.Initialize(false);
            devices = WebCamTexture.devices;
            SelectCamera(isFrontFacing);
            webcamTexture = new WebCamTexture(device.name, targetWidth, targetHeight,(int)sampleRate);
            webcamTexture.Play();
        }
        
        /// <summary>
        /// Set the target device based on orientation
        /// </summary>
        /// <param name="isFrontFacing">Should the device be forward facing?</param>
        private void SelectCamera(bool isFrontFacing)
        {
            
            foreach(WebCamDevice d in devices)
            {
                if(d.isFrontFacing == isFrontFacing)
                {
                    device = d;
                    return;
                }

            }

        }
        
        void OnEnable()
        {

            //get the selected camera!

            if (sampleRate > 0)
                StartCoroutine(SampleRoutine());
        }

        /// <summary>
        /// Coroutine to sample frames from the camera
        /// </summary>
        /// <returns></returns>
        private IEnumerator SampleRoutine()
        {
            while (enabled)
            {
                
                yield return new WaitForSeconds(1 / sampleRate);
                ProcessFrame();
            }
        }


        /// <summary>
        /// Sample an individual frame from the webcam and send to detector for processing.
        /// </summary>
        public void ProcessFrame()
        {

            if(webcamTexture != null)
            {
                Frame frame = new Frame(webcamTexture.GetPixels32(),webcamTexture.width, webcamTexture.height, Time.realtimeSinceStartup);
                detector.ProcessFrame(frame);
            }
            

        }

        void OnDestroy()
        {
            if (webcamTexture != null)
            {
                webcamTexture.Stop();
            }
        }
    }
}