jj2000.j2k.quantization.dequantizer.StdDequantizerParams Maven / Gradle / Ivy
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/*
* $RCSfile: StdDequantizerParams.java,v $
* $Revision: 1.1 $
* $Date: 2005/02/11 05:02:19 $
* $State: Exp $
*
* Class: StdDequantizerParams
*
* Description: Parameters for the scalar deadzone dequantizers
*
*
*
* COPYRIGHT:
*
* This software module was originally developed by Raphaël Grosbois and
* Diego Santa Cruz (Swiss Federal Institute of Technology-EPFL); Joel
* Askelöf (Ericsson Radio Systems AB); and Bertrand Berthelot, David
* Bouchard, Félix Henry, Gerard Mozelle and Patrice Onno (Canon Research
* Centre France S.A) in the course of development of the JPEG2000
* standard as specified by ISO/IEC 15444 (JPEG 2000 Standard). This
* software module is an implementation of a part of the JPEG 2000
* Standard. Swiss Federal Institute of Technology-EPFL, Ericsson Radio
* Systems AB and Canon Research Centre France S.A (collectively JJ2000
* Partners) agree not to assert against ISO/IEC and users of the JPEG
* 2000 Standard (Users) any of their rights under the copyright, not
* including other intellectual property rights, for this software module
* with respect to the usage by ISO/IEC and Users of this software module
* or modifications thereof for use in hardware or software products
* claiming conformance to the JPEG 2000 Standard. Those intending to use
* this software module in hardware or software products are advised that
* their use may infringe existing patents. The original developers of
* this software module, JJ2000 Partners and ISO/IEC assume no liability
* for use of this software module or modifications thereof. No license
* or right to this software module is granted for non JPEG 2000 Standard
* conforming products. JJ2000 Partners have full right to use this
* software module for his/her own purpose, assign or donate this
* software module to any third party and to inhibit third parties from
* using this software module for non JPEG 2000 Standard conforming
* products. This copyright notice must be included in all copies or
* derivative works of this software module.
*
* Copyright (c) 1999/2000 JJ2000 Partners.
*/
package jj2000.j2k.quantization.dequantizer;
import jj2000.j2k.quantization.QuantizationType;
import jj2000.j2k.wavelet.Subband;
/**
* This class holds the parameters for the scalar deadzone dequantizer
* (StdDequantizer class) for the current tile. Its constructor decodes the
* parameters from the main header and tile headers.
*
* @see StdDequantizer
* */
public class StdDequantizerParams extends DequantizerParams {
/**
* The quantization step "exponent" value, for each resolution level and
* subband, as it appears in the codestream. The first index is the
* resolution level, and the second the subband index (within the
* resolution level), as specified in the Subband class. When in derived
* quantization mode only the first resolution level (level 0) appears.
*
* For non-reversible systems this value corresponds to ceil(log2(D')),
* where D' is the quantization step size normalized to data of a dynamic
* range of 1. The true quantization step size is (2^R)*D', where R is
* ceil(log2(dr)), where 'dr' is the dynamic range of the subband samples,
* in the corresponding subband.
*
*
For reversible systems the exponent value in 'exp' is used to
* determine the number of magnitude bits in the quantized
* coefficients. It is, in fact, the dynamic range of the subband data.
*
*
In general the index of the first subband in a resolution level is
* not 0. The exponents appear, within each resolution level, at their
* subband index, and not in the subband order starting from 0. For
* instance, resolution level 3, the first subband has the index 16, then
* the exponent of the subband is exp[3][16], not exp[3][0].
*
* @see Subband
* */
public int exp[][];
/**
* The quantization step for non-reversible systems, normalized to a
* dynamic range of 1, for each resolution level and subband, as derived
* from the exponent-mantissa representation in the codestream. The first
* index is the resolution level, and the second the subband index (within
* the resolution level), as specified in the Subband class. When in
* derived quantization mode only the first resolution level (level 0)
* appears.
*
*
The true step size D is obtained as follows: D=(2^R)*D', where
* 'R=ceil(log2(dr))' and 'dr' is the dynamic range of the subband
* samples, in the corresponding subband.
*
*
This value is 'null' for reversible systems (i.e. there is no true
* quantization, 'D' is always 1).
*
*
In general the index of the first subband in a resolution level is
* not 0. The steps appear, within each resolution level, at their subband
* index, and not in the subband order starting from 0. For instance, if
* resolution level 3, the first subband has the index 16, then the step
* of the subband is nStep[3][16], not nStep[3][0].
*
* @see Subband
* */
public float nStep[][];
/**
* Returns the type of the dequantizer for which the parameters are. The
* types are defined in the Dequantizer class.
*
* @return The type of the dequantizer for which the parameters
* are. Always Q_TYPE_SCALAR_DZ.
*
* @see Dequantizer
* */
public int getDequantizerType() {
return QuantizationType.Q_TYPE_SCALAR_DZ;
}
}