/* Find the Signal to Noise ratio between two signals
 @Copyright (c) 1998-2005 The Regents of the University of California.
 All rights reserved.

 Permission is hereby granted, without written agreement and without
 license or royalty fees, to use, copy, modify, and distribute this
 software and its documentation for any purpose, provided that the
 above copyright notice and the following two paragraphs appear in all
 copies of this software.

 IN NO EVENT SHALL THE UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY
 FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
 ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF
 THE UNIVERSITY OF CALIFORNIA HAS BEEN ADVISED OF THE POSSIBILITY OF
 SUCH DAMAGE.

 THE UNIVERSITY OF CALIFORNIA SPECIFICALLY DISCLAIMS ANY WARRANTIES,
 INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE
 PROVIDED HEREUNDER IS ON AN "AS IS" BASIS, AND THE UNIVERSITY OF
 CALIFORNIA HAS NO OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT, UPDATES,
 ENHANCEMENTS, OR MODIFICATIONS.

 PT_COPYRIGHT_VERSION 2
 COPYRIGHTENDKEY
 */
package ptolemy.domains.sdf.lib.vq;

import ptolemy.actor.TypedAtomicActor;
import ptolemy.actor.TypedIOPort;
import ptolemy.data.DoubleToken;
import ptolemy.data.IntMatrixToken;
import ptolemy.data.type.BaseType;
import ptolemy.kernel.CompositeEntity;
import ptolemy.kernel.util.IllegalActionException;
import ptolemy.kernel.util.NameDuplicationException;
import ptolemy.math.ExtendedMath;

//////////////////////////////////////////////////////////////////////////
//// PSNR

/**
 This actor consumes an IntMatrixToken from each input port, and calculates the
 Power Signal to Noise Ratio (PSNR) between them.  The PSNR is output on the
 output port as a DoubleToken.

 @author Michael Leung, Steve Neuendorffer
 @version $Id$
 @since Ptolemy II 0.4
 @Pt.ProposedRating Green (neuendor)
 @Pt.AcceptedRating Yellow (neuendor)
 */
public class PSNR extends TypedAtomicActor {
    /** Construct an actor in the specified container with the specified
     *  name.
     *  @param container The container.
     *  @param name The name of this adder within the container.
     *  @exception IllegalActionException If the actor cannot be contained
     *   by the proposed container.
     *  @exception NameDuplicationException If the name coincides with
     *   an actor already in the container.
     */
    public PSNR(CompositeEntity container, String name)
            throws IllegalActionException, NameDuplicationException {
        super(container, name);

        output = new TypedIOPort(this, "output", false, true);
        output.setTypeEquals(BaseType.DOUBLE);

        signal = new TypedIOPort(this, "signal", true, false);
        signal.setTypeEquals(BaseType.INT_MATRIX);

        distortedSignal = new TypedIOPort(this, "distortedSignal", true, false);
        distortedSignal.setTypeEquals(BaseType.INT_MATRIX);
    }

    ///////////////////////////////////////////////////////////////////
    ////                      ports and parameters                 ////

    /** The input signal. */
    public TypedIOPort signal;

    /** A distorted version of the input signal. */
    public TypedIOPort distortedSignal;

    /** The calculated PSNR between the two inputs. */
    public TypedIOPort output;

    /** Fire the actor.
     *  Consume one image on each of the input ports.   Calculate the
     *  PSNR as follows:
     *  noise = signal-distortedSignal;
     *  signalPower = Power(signal);
     *  noisePower = Power(noise);
     *  PSNR = 10 * log10(signalPower/noisePower);
     *  @exception IllegalActionException If the dimensions of the
     *  input tokens do not match.
     */
    public void fire() throws IllegalActionException {
        super.fire();
        int i;
        int j;
        int signalPower = 0;
        int noisePower = 0;
        int element1;
        int element2;

        double PSNRValue;

        IntMatrixToken signalToken = (IntMatrixToken) signal.get(0);
        IntMatrixToken distortedSignalToken = (IntMatrixToken) distortedSignal
                .get(0);
        int columns = signalToken.getColumnCount();
        int rows = signalToken.getRowCount();

        if ((distortedSignalToken.getColumnCount() != columns)
                || (distortedSignalToken.getRowCount() != rows)) {
            throw new IllegalActionException("Input token dimensions "
                    + "must match!");
        }

        for (j = 0; j < rows; j++) {
            for (i = 0; i < columns; i++) {
                element1 = signalToken.getElementAt(j, i);
                element2 = distortedSignalToken.getElementAt(j, i);

                signalPower = signalPower + (element1 * element1);
                noisePower = noisePower
                        + ((element1 - element2) * (element1 - element2));
            }
        }

        PSNRValue = 10 * ExtendedMath.log10((double) signalPower / noisePower);

        DoubleToken message = new DoubleToken(PSNRValue);
        output.send(0, message);
    }
}