org.jmol.util
Class DCT

java.lang.Object
  org.jmol.util.DCT

 class DCT
extends Object

Field Summary

private static double[]	AANscaleFactor
(package private) double[][]	divisors
private double[]	DivisorsChrominance
private double[]	DivisorsLuminance
private static int	N DCT Block Size - default 8
private static int	NN
(package private) int[][]	quantum Image Quality (0-100) - default 80 (good image / good compression)
private int[]	quantum_chrominance Quantitization Matrix for chrominance.
private int[]	quantum_luminance Quantitization Matrix for luminace.

Constructor Summary

DCT(int quality)
Constructs a new DCT object.

Method Summary

private static void	AANscale(double[] divisors, int[] values, int quality)
(package private) static double[][]	forwardDCT(float[][] input)
private void	initMatrix(int quality)
(package private) static int[]	quantizeBlock(double[][] inputData, double[] divisorsCode)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

N

private static final int N

DCT Block Size - default 8

See Also:

Constant Field Values

NN

private static final int NN

See Also:

Constant Field Values

quantum

int[][] quantum

Image Quality (0-100) - default 80 (good image / good compression)

divisors

double[][] divisors

quantum_luminance

private int[] quantum_luminance

Quantitization Matrix for luminace.

DivisorsLuminance

private double[] DivisorsLuminance

quantum_chrominance

private int[] quantum_chrominance

Quantitization Matrix for chrominance.

DivisorsChrominance

private double[] DivisorsChrominance

AANscaleFactor

private static final double[] AANscaleFactor

Constructor Detail

DCT

DCT(int quality)

Constructs a new DCT object. Initializes the cosine transform matrix these are used when computing the DCT and it's inverse. This also initializes the run length counters and the ZigZag sequence. Note that the image quality can be worse than 25 however the image will be extemely pixelated, usually to a block size of N.

Parameters:

quality - The quality of the image (0 worst - 100 best)

Method Detail

initMatrix

private void initMatrix(int quality)

AANscale

private static void AANscale(double[] divisors,
                             int[] values,
                             int quality)

forwardDCT

static double[][] forwardDCT(float[][] input)

quantizeBlock

static int[] quantizeBlock(double[][] inputData,
                           double[] divisorsCode)