A small JavaFX enabled program using OpenCV to do image processing on a still taken by a ISight webcam

OpenCVISight.scala

package net.ladstatt.apps.isight

import java.io.File
import java.io.FileInputStream

import org.opencv.core.Core
import org.opencv.core.MatOfRect
import org.opencv.core.Point
import org.opencv.core.Scalar
import org.opencv.highgui.Highgui
import org.opencv.objdetect.CascadeClassifier

import javafx.application.Application
import javafx.scene.Group
import javafx.scene.Scene
import javafx.scene.image.Image
import javafx.scene.image.ImageView
import javafx.stage.Stage

object HelloOpenCVUsingIsight {

  def main(args: Array[String]): Unit = {
    Application.launch(classOf[HelloOpenCVUsingIsight], args: _*)
  }
}

// this can get more complicated if you use a "native" approach
// using a jni based solution
// see http://iharder.sourceforge.net/current/macosx/imagesnap/
trait ImageSource {

  def sourceImage: File = {
    val runtime = Runtime.getRuntime()
    // without options, it will just put the image snapshot to a file named "snapshot.jpg"
    // we use it in quiet mode
    val process = runtime.exec(Array("/opt/local/bin/imagesnap", "-q"))
    assert(process.waitFor() == 0)
    val input = new File("snapshot.jpg")
    input.deleteOnExit()
    input
  }

}

trait FaceScanner {

  def scanFace(inputFile: File): File = {

    // Create a face detector from the cascade file in the resources
    // directory.
    val faceDetector = new CascadeClassifier(getClass().getResource("/lbpcascade_frontalface.xml").getPath())
    val image = Highgui.imread(inputFile.getPath())

    // Detect faces in the image.
    // MatOfRect is a special container class for Rect.
    val faceDetections = new MatOfRect()
    faceDetector.detectMultiScale(image, faceDetections)

    // Draw a bounding box around each face.
    for (rect <- faceDetections.toArray()) {
      Core.rectangle(image, new Point(rect.x, rect.y), new Point(rect.x + rect.width, rect.y + rect.height), new Scalar(0, 255, 0))
    }

    // Save the visualized detection.
    val fileName = "faceDetection.png"
    Highgui.imwrite(fileName, image)
    val f = new File(fileName)
    f.deleteOnExit()
    f
  }

}

class HelloOpenCVUsingIsight extends javafx.application.Application with ImageSource with FaceScanner {

  override def init(): Unit = {
    // important to have this statement on the "right" thread
    System.load(new File("/opt/local/share/OpenCV/java/libopencv_java244.dylib").getAbsolutePath())
  }

  override def start(stage: Stage): Unit = {

    stage.setTitle("Webcam snapshot with face detection")

    val group = new Group
    val imageView = new ImageView(new Image(new FileInputStream(scanFace(sourceImage))))
    group.getChildren.add(imageView)
    val scene = new Scene(group)

    stage.setScene(scene)
    stage.show()
  }

}