| java.lang.Object
 jj2000.j2k.quantization.dequantizer.DequantizerParams
jj2000.j2k.quantization.dequantizer.StdDequantizerParams
| StdDequantizerParams | | public class StdDequantizerParams extends DequantizerParams (Code) | | 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 Also: StdDequantizer |
| Field Summary | |
| public int | exp
The quantization step "exponent" value, for each resolution level and
subband, as it appears in the codestream. | | public float | nStep
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. |
| Method Summary | |
| public int | getDequantizerType()
Returns the type of the dequantizer for which the parameters are. |
| exp | | public int exp(Code) | | 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 Also: Subband |
| nStep | | public float nStep(Code) | | 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 Also: Subband |
| getDequantizerType | | public int getDequantizerType()(Code) | | Returns the type of the dequantizer for which the parameters are. The
types are defined in the Dequantizer class.
The type of the dequantizer for which the parametersare. Always Q_TYPE_SCALAR_DZ.
See Also: Dequantizer |
| Methods inherited from jj2000.j2k.quantization.dequantizer.DequantizerParams | abstract public int getDequantizerType()(Code)(Java Doc)
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