public abstract class Dequantizer extends MultiResImgDataAdapter implements CBlkWTDataSrcDec
This class provides default implemenations for most of the methods (wherever it makes sense), under the assumption that the image and component dimensions, and the tiles, are not modifed by the dequantizer. If that is not the case for a particular implementation then the methods should be overriden.
Sign magnitude representation is used (instead of two's complement) for the input data. The most significant bit is used for the sign (0 if positive, 1 if negative). Then the magnitude of the quantized coefficient is stored in the next most significat bits. The most significant magnitude bit corresponds to the most significant bit-plane and so on.
The output data is either in floating-point, or in fixed-point two's complement. In case of floating-point data the the value returned by getFixedPoint() must be 0. If the case of fixed-point data the number of fractional bits must be defined at the constructor of the implementing class and all operations must be performed accordingly. Each component may have a different number of fractional bits.
| Modifier and Type | Field and Description |
|---|---|
static char |
OPT_PREFIX
The prefix for dequantizer options: 'Q'
|
protected int[] |
rb
The "range bits" for each transformed component
|
protected CBlkQuantDataSrcDec |
src
The entropy decoder from where to get the quantized data (the
source).
|
protected int[] |
utrb
The "range bits" for each un-transformed component
|
mressrc, tIdx| Constructor and Description |
|---|
Dequantizer(CBlkQuantDataSrcDec src,
int[] utrb,
DecoderSpecs decSpec)
Initializes the source of compressed data.
|
| Modifier and Type | Method and Description |
|---|---|
int |
getCbULX()
Returns the horizontal code-block partition origin.
|
int |
getCbULY()
Returns the vertical code-block partition origin.
|
int |
getNomRangeBits(int c)
Returns the number of bits, referred to as the "range bits",
corresponding to the nominal range of the data in the specified
component.
|
static String[][] |
getParameterInfo()
Returns the parameters that are used in this class and
implementing classes.
|
SubbandSyn |
getSynSubbandTree(int t,
int c)
Returns the subband tree, for the specified tile-component.
|
void |
nextTile()
Advances to the next tile, in standard scan-line order (by rows then
columns).
|
void |
setTile(int x,
int y)
Changes the current tile, given the new indexes.
|
getCompImgHeight, getCompImgWidth, getCompSubsX, getCompSubsY, getImgHeight, getImgULX, getImgULY, getImgWidth, getNomTileHeight, getNomTileWidth, getNumComps, getNumTiles, getNumTiles, getResULX, getResULY, getTile, getTileCompHeight, getTileCompWidth, getTileHeight, getTileIdx, getTilePartULX, getTilePartULY, getTileWidthclone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, waitgetCodeBlock, getFixedPoint, getInternCodeBlockgetCompImgHeight, getCompImgWidth, getCompSubsX, getCompSubsY, getImgHeight, getImgULX, getImgULY, getImgWidth, getNomTileHeight, getNomTileWidth, getNumComps, getNumTiles, getNumTiles, getResULX, getResULY, getTile, getTileCompHeight, getTileCompWidth, getTileHeight, getTileIdx, getTilePartULX, getTilePartULY, getTileWidthpublic static final char OPT_PREFIX
protected CBlkQuantDataSrcDec src
protected int[] rb
protected int[] utrb
public Dequantizer(CBlkQuantDataSrcDec src, int[] utrb, DecoderSpecs decSpec)
src - From where to obtain the quantized data.rb - The number of "range bits" for each component (must be the
"range bits" of the un-transformed components. For a definition of
"range bits" see the getNomRangeBits() method.getNomRangeBits(int)public int getNomRangeBits(int c)
The returned value corresponds to the nominal dynamic range of the reconstructed image data, not of the wavelet coefficients themselves. This is because different subbands have different gains and thus different nominal ranges. To have an idea of the nominal range in each subband the subband analysis gain value from the subband tree structure, returned by the getSynSubbandTree() method, can be used. See the Subband class for more details.
If this number is b then for unsigned data the nominal range is between 0 and 2^b-1, and for signed data it is between -2^(b-1) and 2^(b-1)-1.
getNomRangeBits in interface CBlkWTDataSrcDecc - The index of the componentSubbandpublic SubbandSyn getSynSubbandTree(int t, int c)
The number of magnitude bits ('magBits' member variable) for each subband may have not been not initialized (it depends on the actual dequantizer and its implementation). However, they are not necessary for the subsequent steps in the decoder chain.
getSynSubbandTree in interface InvWTDatagetSynSubbandTree in interface MultiResImgDatat - The index of the tile, from 0 to T-1.c - The index of the component, from 0 to C-1.public int getCbULX()
public int getCbULY()
public static String[][] getParameterInfo()
public void setTile(int x,
int y)
This default implementation changes the tile in the source and re-initializes properly component transformation variables..
setTile in interface MultiResImgDatasetTile in class MultiResImgDataAdapterx - The horizontal index of the tile.y - The vertical index of the new tile.public void nextTile()
This default implementation just advances to the next tile in the source and re-initializes properly component transformation variables.
nextTile in interface MultiResImgDatanextTile in class MultiResImgDataAdapterCopyright © 2015–2022 SCIFIO. All rights reserved.