Class GammaCorrection
java.lang.Object
net.sourceforge.jiu.ops.Operation
net.sourceforge.jiu.ops.ImageToImageOperation
net.sourceforge.jiu.ops.LookupTableOperation
net.sourceforge.jiu.color.adjustment.GammaCorrection
Corrects the gamma of an image.
Works with
GrayIntegerImage
,
RGBIntegerImage
and
Paletted8Image
.
Only the palette is manipulated for paletted images.
Changes intensity values by applying the formula
f(x) = MAX * (x / MAX)(1 / gamma) to each
x from [0 ; MAX] to them.
The MAX value is the maximum value allowed for an intensity value of the
corresponding channel.
It is determined by calling IntegerImage.getMaxSample(int)
on
the input image.
The gamma parameter must be given to a GammaCorrection
operation
before the call to process(net.sourceforge.jiu.data.Paletted8Image, net.sourceforge.jiu.data.Paletted8Image)
is made.
The valid interval for gamma is (0.0 ; MAX_GAMMA
]
(so 0.0 is not a valid value).
Gamma values smaller than 1 will make the image darker, values
larger than 1 will make it brighter.
Usage example
GammaCorrection gamma = new GammaCorrection(); gamma.setInputImage(image); gamma.setGamma(2.2); gamma.process(); PixelImage correctedImage = gamma.getOutputImage();
- Author:
- Marco Schmidt
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Field Summary
Fields -
Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionprivate final int[]
createLookupTable
(int numSamples) Creates a lookup table that holds all new values for samples 0 to numSamples - 1.double
getGamma()
Returns the gamma value to be used for this operation.void
process()
This method does the actual work of the operation.private void
process
(Paletted8Image in, Paletted8Image out) void
setGamma
(double newGamma) Sets a new gamma value to be used in this operation.Methods inherited from class net.sourceforge.jiu.ops.LookupTableOperation
getNumTables, getTable, prepareImages, setNumTables, setTable, setTables
Methods inherited from class net.sourceforge.jiu.ops.ImageToImageOperation
canInputAndOutputBeEqual, ensureImagesHaveSameResolution, ensureInputImageIsAvailable, ensureOutputImageResolution, getInputImage, getOutputImage, setCanInputAndOutputBeEqual, setInputImage, setOutputImage
Methods inherited from class net.sourceforge.jiu.ops.Operation
addProgressListener, addProgressListeners, getAbort, removeProgressListener, setAbort, setProgress, setProgress
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Field Details
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MAX_GAMMA
public static final double MAX_GAMMAThe maximum allowed value for gamma.- See Also:
-
gamma
private double gamma
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Constructor Details
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GammaCorrection
public GammaCorrection()
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Method Details
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createLookupTable
private final int[] createLookupTable(int numSamples) Creates a lookup table that holds all new values for samples 0 to numSamples - 1. -
getGamma
public double getGamma()Returns the gamma value to be used for this operation.- Returns:
- gamma value between 0 (not included) and
MAX_GAMMA
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process
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process
Description copied from class:Operation
This method does the actual work of the operation. It must be called after all parameters have been given to the operation object.- Overrides:
process
in classLookupTableOperation
- Throws:
MissingParameterException
- if any mandatory parameter was not given to the operationWrongParameterException
- if at least one of the input parameters was not initialized appropriately (values out of the valid interval, etc.)
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setGamma
public void setGamma(double newGamma) Sets a new gamma value to be used in this operation.- Parameters:
newGamma
- the new gamma value must be > 0.0 and <= MAX_GAMMA- Throws:
IllegalArgumentException
- if the argument is not in the described interval
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