Makefile

SBT=~/bin/sbt

gen: mse
	cat $(d)/result.txt

mse:
	$(SBT) 'runMain mse.MSE $(d)'

MSE.scala

package mse

import java.io._
import org.bytedeco.javacpp.helper.opencv_core.AbstractCvMat
import org.bytedeco.javacpp.opencv_core._
import org.bytedeco.javacpp.opencv_highgui._

object MSE {
  def main(args: Array[String]) {
    val ms =
      new File(args(0))
        .listFiles
        .filter(_.getName.endsWith(".png"))

    val stream = new FileOutputStream(args(0) + "/result.txt")
    val out = new PrintStream(stream)

    val mses = ms.zip(ms.tail).map {
      p =>
        for {
          i1 <- load(p._1)
          i2 <- load(p._2)
        } yield out.println(
          List(p._2.getName.substring(23,31), apply(i1, i2))
            .mkString("\t"))
    }
  }

  def load(file: File, flags: Int = CV_LOAD_IMAGE_COLOR): Option[CvMat] =
    Option(cvLoadImageM(file.getAbsolutePath, flags))

  /**
   * see http://stackoverflow.com/a/19290458
   */
  def apply(mat1: CvMat, mat2: CvMat): Double = {
    val s1: CvMat = AbstractCvMat.create(mat1.rows(), mat1.cols(), mat1.depth(), mat1.nChannels())
    cvAbsDiff(mat1, mat2, s1)

    val s1Squared: CvMat = cvCreateMat(s1.rows(), s1.cols(), CV_32FC3)
    cvMul(s1, s1, s1Squared, 1)

    val scalar: CvScalar = cvSum(s1Squared)
    val sse: Double = scalar.getVal(0) + scalar.getVal(1) + scalar.getVal(2)
    val mse: Double = sse / (s1.channels() * s1.total()).toDouble
    mse
  }
}