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CompressorTest.java
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/**
* JUnit test cases for data compression using wavelets.
*
* @author Christian (graetz23@gmail.com)
* @date 09.01.2016 07:29:24
*
* CompressorTest.java
*/
package jwave;
import jwave.compressions.Compressor;
import jwave.compressions.CompressorMagnitude;
import jwave.tools.MathToolKit;
import jwave.transforms.FastWaveletTransform;
import jwave.transforms.wavelets.Wavelet;
import jwave.transforms.wavelets.WaveletBuilder;
import org.junit.Test;
/**
* JUnit test cases for data compression using wavelets.
*
* @author Christian (graetz23@gmail.com)
* @date 09.01.2016 07:29:24
*/
public class CompressorTest extends Base {
/**
* Test the Compressor classes by giving an example for a strong data
* compression with several wavelets for a sampled (generated) sine signal.
*
* @author Christian (graetz23@gmail.com)
* @date 06.01.2016 23:34:05
*/
@Test public void testCompressionSine( ) {
Compressor compressor = new CompressorMagnitude( 1.0 );
Wavelet[ ] arrOfWaveletObjects = WaveletBuilder.create2arr( ); // over 50 wavelets :-p
int noOfWavelets = arrOfWaveletObjects.length;
int samplingRate = 1024 * 1024; // sampling rate
int noOfOscillations = 1024;
// generate sampled (discrete) sine over 2 pi
double[ ] arrTime =
MathToolKit.createSineOscillation( samplingRate, noOfOscillations );
// go for Fast Wavelet Transforms
for( int w = 0; w < noOfWavelets; w++ ) {
Wavelet wavelet = arrOfWaveletObjects[ w ];
System.out
.println( "Testing example with FWT using " + wavelet.getName( ) );
Transform fwt = new Transform( new FastWaveletTransform( wavelet ) );
double[ ] arrHilb = fwt.forward( arrTime );
double[ ] arrComp = compressor.compress( arrHilb );
double[ ] arrReco = fwt.reverse( arrComp );
// calculate and print the absolute difference
int pos = 0;
double maxDiff = 0.;
for( int i = 0; i < arrReco.length; i++ ) {
double diff = Math.abs( arrTime[ i ] - arrReco[ i ] );
if( diff > maxDiff ) {
maxDiff = diff;
pos = i;
} // if
} // i
System.out.println( "absolute max difference at position " + pos
+ " is: " + maxDiff );
//calculate the compression rate
double compressionRate = compressor.calcCompressionRate( arrComp );
System.out.println( "The achieved compression rate: " + compressionRate );
System.out.println( );
} // w
} // testCompressionSine
/**
* Test the Compressor classes by giving an example for data compression with
* wavelets.
*
* @author Christian (graetz23@gmail.com)
* @date 14.05.2015 18:26:03
*/
@Test public void testCompressionSteps( ) {
Compressor compressor = new CompressorMagnitude( 1.0 );
Wavelet[ ] arrOfWaveletObjects = WaveletBuilder.create2arr( ); // over 50 wavelets :-p
int noOfWavelets = arrOfWaveletObjects.length;
// go for Fast Wavelet Transforms
for( int w = 0; w < noOfWavelets; w++ ) {
Wavelet wavelet = arrOfWaveletObjects[ w ];
System.out
.println( "Testing example with FWT using " + wavelet.getName( ) );
Transform fwt = new Transform( new FastWaveletTransform( wavelet ) );
double[ ] arrTime =
{ 1., 2., 3., 4., 5., 4., 3., 2., 1., 0., -1., -2., -3, -2., -1., 0. };
double[ ] arrHilb = fwt.forward( arrTime );
double[ ] arrComp = compressor.compress( arrHilb );
double[ ] arrReco = fwt.reverse( arrComp );
showTime( arrTime );
showHilb( arrHilb );
showHilb( arrComp );
showTime( arrReco );
} // w
} // testCompressionSteps
} // CompressorTest