nom.tam.image.compression.hdu

Class CompressedImageHDU

java.lang.Object

nom.tam.fits.BasicHDU<T>

nom.tam.fits.TableHDU<BinaryTable>

nom.tam.fits.BinaryTableHDU

nom.tam.image.compression.hdu.CompressedImageHDU

All Implemented Interfaces:

FitsElement

public class CompressedImageHDU
extends BinaryTableHDU

A compressed image is a normal binary table with a defined structure. The image is split in tiles and each tile is compressed on its own. The compressed data is then stored in the 3 data columns of this binary table (compressed, gzipped and uncompressed) depending on the compression type used in the tile.

Field Summary

Fields inherited from class nom.tam.fits.BasicHDU

BITPIX_BYTE, BITPIX_DOUBLE, BITPIX_FLOAT, BITPIX_INT, BITPIX_LONG, BITPIX_SHORT, isPrimary, myData, myHeader

Constructor Summary

Constructors

Constructor and Description
CompressedImageHDU(Header hdr, CompressedImageData datum)

Method Summary

Modifier and Type	Method and Description
ImageHDU	asImageHDU()
void	compress()
CompressedImageHDU	forceNoLoss(int x, int y, int width, int heigth) Specify an areaWithin the image that will not undergo a lossy compression.
static CompressedImageHDU	fromImageHDU(ImageHDU imageHDU, int... tileAxis) Prepare a compressed image hdu for the specified image.
<T extends ICompressOption> T	getCompressOption(Class<T> clazz)
CompressedImageData	getData()
Buffer	getUncompressedData()
boolean	isHeader() Check that this HDU has a valid header.
static boolean	isHeader(Header hdr) Check that this HDU has a valid header for this type.
static CompressedImageData	manufactureData(Header hdr)
CompressedImageHDU	preserveNulls(String compressionAlgorithm) preserve the null values in the image even if the compression algorithm is lossy.
CompressedImageHDU	setCompressAlgorithm(String compressAlgorithm)
CompressedImageHDU	setQuantAlgorithm(String quantAlgorithm)

Methods inherited from class nom.tam.fits.BinaryTableHDU

addColumn, columnKeyStems, encapsulate, info, isData, manufactureHeader, setComplexColumn, write

Methods inherited from class nom.tam.fits.TableHDU

addRow, deleteColumnsIndexOne, deleteColumnsIndexOne, deleteColumnsIndexZero, deleteColumnsIndexZero, deleteRows, deleteRows, findColumn, getColumn, getColumn, getColumnFormat, getColumnMeta, getColumnName, getColumns, getElement, getNCols, getNRows, getRow, setColumn, setColumn, setColumnMeta, setColumnMeta, setColumnMeta, setColumnMeta, setColumnMeta, setColumnMeta, setColumnName, setCurrentColumn, setCurrentColumn, setElement, setRow

Methods inherited from class nom.tam.fits.BasicHDU

addValue, addValue, addValue, addValue, addValue, addValue, addValue, addValue, card, getAuthor, getAxes, getBitPix, getBlankValue, getBScale, getBUnit, getBZero, getCreationDate, getDummyHDU, getEpoch, getEquinox, getFileOffset, getGroupCount, getHeader, getInstrument, getKernel, getMaximumValue, getMinimumValue, getObject, getObservationDate, getObserver, getOrigin, getParameterCount, getReference, getSize, getTelescope, getTrimmedString, getTrimmedString, read, reset, rewrite, rewriteable, saveReplaceCard

Methods inherited from class java.lang.Object

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

Constructor Detail

CompressedImageHDU

public CompressedImageHDU(Header hdr,
                          CompressedImageData datum)

Method Detail

fromImageHDU

public static CompressedImageHDU fromImageHDU(ImageHDU imageHDU,
                                              int... tileAxis)
                                       throws FitsException

Prepare a compressed image hdu for the specified image. the tile axis that are specified with -1 are set to the corresponding axis of the image. The image will be compressed in "sqaures" that ar defined by the tile size. Next step would be to set the compression options into the hdu and then compress it.

Parameters:

imageHDU - the image to compress

tileAxis - the axis of the tiles in the image

Returns:

the prepared compressed image hdu.

Throws:

FitsException - if the image could not be used to create a compressed image.

isHeader

public static boolean isHeader(Header hdr)

Check that this HDU has a valid header for this type.

Parameters:

hdr - header to check

Returns:

true if this HDU has a valid header.

manufactureData

public static CompressedImageData manufactureData(Header hdr)
                                           throws FitsException

Throws:

FitsException

asImageHDU

public ImageHDU asImageHDU()
                    throws FitsException

Throws:

FitsException

compress

public void compress()
              throws FitsException

Throws:

FitsException

forceNoLoss

public CompressedImageHDU forceNoLoss(int x,
                                      int y,
                                      int width,
                                      int heigth)

Specify an areaWithin the image that will not undergo a lossy compression. This will only have affect it the selected compression (including the options) is a lossy compression. All tiles touched by this region will be handled so that there is no loss of any data, the reconstruction will be exact.

Parameters:

x - the x position in the image

y - the y position in the image

width - the width of the area

heigth - the height of the area

Returns:

this

getCompressOption

public <T extends ICompressOption> T getCompressOption(Class<T> clazz)

getData

public CompressedImageData getData()

Overrides:

getData in class BasicHDU<BinaryTable>

Returns:

the associated Data object

getUncompressedData

public Buffer getUncompressedData()
                           throws FitsException

Throws:

FitsException

isHeader

public boolean isHeader()

Check that this HDU has a valid header.

Overrides:

isHeader in class BinaryTableHDU

Returns:

true if this HDU has a valid header.

preserveNulls

public CompressedImageHDU preserveNulls(String compressionAlgorithm)

preserve the null values in the image even if the compression algorithm is lossy. I the image that will be compressed a BLANK header should be available if the pixel value is one of the integer types.

Parameters:

compressionAlgorithm - compression algorithm to use for the null pixel mask

Returns:

this

setCompressAlgorithm

public CompressedImageHDU setCompressAlgorithm(String compressAlgorithm)
                                        throws FitsException

Throws:

FitsException

setQuantAlgorithm

public CompressedImageHDU setQuantAlgorithm(String quantAlgorithm)
                                     throws FitsException

Throws:

FitsException