DJLSDecoderBase Class Reference

abstract codec class for JPEG-LS decoders. More...

Inheritance diagram for DJLSDecoderBase:

List of all members.

Public Member Functions
	DJLSDecoderBase ()
	default constructor
virtual	~DJLSDecoderBase ()
	destructor
virtual OFCondition	decode (const DcmRepresentationParameter *fromRepParam, DcmPixelSequence *pixSeq, DcmPolymorphOBOW &uncompressedPixelData, const DcmCodecParameter *cp, const DcmStack &objStack) const
	decompresses the given pixel sequence and stores the result in the given uncompressedPixelData element.
virtual OFCondition	decodeFrame (const DcmRepresentationParameter *fromParam, DcmPixelSequence *fromPixSeq, const DcmCodecParameter *cp, DcmItem *dataset, Uint32 frameNo, Uint32 &startFragment, void *buffer, Uint32 bufSize, OFString &decompressedColorModel) const
	decompresses a single frame from the given pixel sequence and stores the result in the given buffer.
virtual OFCondition	encode (const Uint16 *pixelData, const Uint32 length, const DcmRepresentationParameter *toRepParam, DcmPixelSequence *&pixSeq, const DcmCodecParameter *cp, DcmStack &objStack) const
	compresses the given uncompressed DICOM image and stores the result in the given pixSeq element.
virtual OFCondition	encode (const E_TransferSyntax fromRepType, const DcmRepresentationParameter *fromRepParam, DcmPixelSequence *fromPixSeq, const DcmRepresentationParameter *toRepParam, DcmPixelSequence *&toPixSeq, const DcmCodecParameter *cp, DcmStack &objStack) const
	transcodes (re-compresses) the given compressed DICOM image and stores the result in the given toPixSeq element.
virtual OFBool	canChangeCoding (const E_TransferSyntax oldRepType, const E_TransferSyntax newRepType) const
	checks if this codec is able to convert from the given current transfer syntax to the given new transfer syntax
virtual OFCondition	determineDecompressedColorModel (const DcmRepresentationParameter *fromParam, DcmPixelSequence *fromPixSeq, const DcmCodecParameter *cp, DcmItem *dataset, OFString &decompressedColorModel) const
	determine color model of the decompressed image
Static Private Member Functions
static OFCondition	decodeFrame (DcmPixelSequence *fromPixSeq, const DJLSCodecParameter *cp, DcmItem *dataset, Uint32 frameNo, Uint32 &startFragment, void *buffer, Uint32 bufSize, Sint32 imageFrames, Uint16 imageColumns, Uint16 imageRows, Uint16 imageSamplesPerPixel, Uint16 bytesPerSample)
	decompresses a single frame from the given pixel sequence and stores the result in the given buffer.
static Uint16	determinePlanarConfiguration (const OFString &sopClassUID, const OFString &photometricInterpretation)
	determines if a given image requires color-by-plane planar configuration depending on SOP Class UID (DICOM IOD) and photometric interpretation.
static Uint32	computeNumberOfFragments (Sint32 numberOfFrames, Uint32 currentFrame, Uint32 startItem, OFBool ignoreOffsetTable, DcmPixelSequence *pixSeq)
	computes the number of fragments (pixel items) that comprise the current frame in the compressed pixel sequence.
static OFBool	isJPEGLSStartOfImage (Uint8 *fragmentData)
	check whether the given buffer contains a JPEG-LS start-of-image code
static OFCondition	createPlanarConfiguration1Byte (Uint8 *imageFrame, Uint16 columns, Uint16 rows)
	converts an RGB or YBR frame with 8 bits/sample from color-by-pixel to color-by-plane planar configuration.
static OFCondition	createPlanarConfiguration1Word (Uint16 *imageFrame, Uint16 columns, Uint16 rows)
	converts an RGB or YBR frame with 16 bits/sample from color-by-pixel to color-by-plane planar configuration.
static OFCondition	createPlanarConfiguration0Byte (Uint8 *imageFrame, Uint16 columns, Uint16 rows)
	converts an RGB or YBR frame with 8 bits/sample from color-by-plane to color-by-pixel planar configuration.
static OFCondition	createPlanarConfiguration0Word (Uint16 *imageFrame, Uint16 columns, Uint16 rows)
	converts an RGB or YBR frame with 16 bits/sample from color-by-plane to color-by-pixel planar configuration.

---

Detailed Description

abstract codec class for JPEG-LS decoders.

This abstract class contains most of the application logic needed for a dcmdata codec object that implements a JPEG-LS decoder. This class only supports decompression, it neither implements encoding nor transcoding.

---

Member Function Documentation

virtual OFBool DJLSDecoderBase::canChangeCoding	(	const E_TransferSyntax	oldRepType,
		const E_TransferSyntax	newRepType
	)		const [virtual]

checks if this codec is able to convert from the given current transfer syntax to the given new transfer syntax

Parameters:

oldRepType	current transfer syntax
newRepType	desired new transfer syntax

Returns:

true if transformation is supported by this codec, false otherwise.

Implements DcmCodec.

static Uint32 DJLSDecoderBase::computeNumberOfFragments	(	Sint32	numberOfFrames,
		Uint32	currentFrame,
		Uint32	startItem,
		OFBool	ignoreOffsetTable,
		DcmPixelSequence *	pixSeq
	)		[static, private]

computes the number of fragments (pixel items) that comprise the current frame in the compressed pixel sequence.

This method uses various approaches to compute the number of fragments for a frame, including a check of the offset table and checking the start of each fragment for JPEG SOI markers.

Parameters:

numberOfFrames	total number of frames of the DICOM object
currentFrame	index of current frame (0..numberOfFrames-1)
startItem	index of fragment (pixel item) the frame starts with
ignoreOffsetTable	flag instructing the method to ignore the offset table even if present and presumably useful
pixSeq	the compressed JPEG-LS pixel sequence

Returns:

number of fragments for the current frame, zero upon error

static OFCondition DJLSDecoderBase::createPlanarConfiguration0Byte	(	Uint8 *	imageFrame,
		Uint16	columns,
		Uint16	rows
	)		[static, private]

converts an RGB or YBR frame with 8 bits/sample from color-by-plane to color-by-pixel planar configuration.

Parameters:

imageFrame	pointer to image frame, must contain at least 3*columns*rows bytes of pixel data.
columns	columns
rows	rows

Returns:

EC_Normal if successful, an error code otherwise

static OFCondition DJLSDecoderBase::createPlanarConfiguration0Word	(	Uint16 *	imageFrame,
		Uint16	columns,
		Uint16	rows
	)		[static, private]

converts an RGB or YBR frame with 16 bits/sample from color-by-plane to color-by-pixel planar configuration.

Parameters:

imageFrame	pointer to image frame, must contain at least 3*columns*rows words of pixel data.
columns	columns
rows	rows

Returns:

EC_Normal if successful, an error code otherwise

static OFCondition DJLSDecoderBase::createPlanarConfiguration1Byte	(	Uint8 *	imageFrame,
		Uint16	columns,
		Uint16	rows
	)		[static, private]

converts an RGB or YBR frame with 8 bits/sample from color-by-pixel to color-by-plane planar configuration.

Parameters:

imageFrame	pointer to image frame, must contain at least 3*columns*rows bytes of pixel data.
columns	columns
rows	rows

Returns:

EC_Normal if successful, an error code otherwise

static OFCondition DJLSDecoderBase::createPlanarConfiguration1Word	(	Uint16 *	imageFrame,
		Uint16	columns,
		Uint16	rows
	)		[static, private]

converts an RGB or YBR frame with 16 bits/sample from color-by-pixel to color-by-plane planar configuration.

Parameters:

imageFrame	pointer to image frame, must contain at least 3*columns*rows words of pixel data.
columns	columns
rows	rows

Returns:

EC_Normal if successful, an error code otherwise

virtual OFCondition DJLSDecoderBase::decode	(	const DcmRepresentationParameter *	fromRepParam,
		DcmPixelSequence *	pixSeq,
		DcmPolymorphOBOW &	uncompressedPixelData,
		const DcmCodecParameter *	cp,
		const DcmStack &	objStack
	)		const [virtual]

decompresses the given pixel sequence and stores the result in the given uncompressedPixelData element.

Parameters:

fromRepParam	current representation parameter of compressed data, may be NULL
pixSeq	compressed pixel sequence
uncompressedPixelData	uncompressed pixel data stored in this element
cp	codec parameters for this codec
objStack	stack pointing to the location of the pixel data element in the current dataset.

Returns:

EC_Normal if successful, an error code otherwise.

Implements DcmCodec.

virtual OFCondition DJLSDecoderBase::decodeFrame	(	const DcmRepresentationParameter *	fromParam,
		DcmPixelSequence *	fromPixSeq,
		const DcmCodecParameter *	cp,
		DcmItem *	dataset,
		Uint32	frameNo,
		Uint32 &	startFragment,
		void *	buffer,
		Uint32	bufSize,
		OFString &	decompressedColorModel
	)		const [virtual]

decompresses a single frame from the given pixel sequence and stores the result in the given buffer.

Parameters:

fromParam	representation parameter of current compressed representation, may be NULL.
fromPixSeq	compressed pixel sequence
cp	codec parameters for this codec
dataset	pointer to dataset in which pixel data element is contained
frameNo	number of frame, starting with 0 for the first frame
startFragment	index of the compressed fragment that contains all or the first part of the compressed bitstream for the given frameNo. Upon successful return this parameter is updated to contain the index of the first compressed fragment of the next frame. When unknown, zero should be passed. In this case the decompression algorithm will try to determine the index by itself, which will always work if frames are decompressed in increasing order from first to last, but may fail if frames are decompressed in random order, multiple fragments per frame and multiple frames are present in the dataset, and the offset table is empty.
buffer	pointer to buffer where frame is to be stored
bufSize	size of buffer in bytes
decompressedColorModel	upon successful return, the color model of the decompressed image (which may be different from the one used in the compressed images) is returned in this parameter.

Returns:

EC_Normal if successful, an error code otherwise.

Implements DcmCodec.

static OFCondition DJLSDecoderBase::decodeFrame	(	DcmPixelSequence *	fromPixSeq,
		const DJLSCodecParameter *	cp,
		DcmItem *	dataset,
		Uint32	frameNo,
		Uint32 &	startFragment,
		void *	buffer,
		Uint32	bufSize,
		Sint32	imageFrames,
		Uint16	imageColumns,
		Uint16	imageRows,
		Uint16	imageSamplesPerPixel,
		Uint16	bytesPerSample
	)		[static, private]

decompresses a single frame from the given pixel sequence and stores the result in the given buffer.

Parameters:

fromPixSeq	compressed pixel sequence
cp	codec parameters for this codec
dataset	pointer to dataset in which pixel data element is contained
frameNo	number of frame, starting with 0 for the first frame
startFragment	index of the compressed fragment that contains all or the first part of the compressed bitstream for the given frameNo. Upon successful return this parameter is updated to contain the index of the first compressed fragment of the next frame. When unknown, zero should be passed. In this case the decompression algorithm will try to determine the index by itself, which will always work if frames are decompressed in increasing order from first to last, but may fail if frames are decompressed in random order, multiple fragments per frame and multiple frames are present in the dataset, and the offset table is empty.
buffer	pointer to buffer where frame is to be stored
bufSize	size of buffer in bytes
imageFrames	number of frames in this image
imageColumns	number of columns for each frame
imageRows	number of rows for each frame
imageSamplesPerPixel	number of samples per pixel
bytesPerSample	number of bytes per sample

Returns:

EC_Normal if successful, an error code otherwise.

virtual OFCondition DJLSDecoderBase::determineDecompressedColorModel	(	const DcmRepresentationParameter *	fromParam,
		DcmPixelSequence *	fromPixSeq,
		const DcmCodecParameter *	cp,
		DcmItem *	dataset,
		OFString &	decompressedColorModel
	)		const [virtual]

determine color model of the decompressed image

Parameters:

fromParam	representation parameter of current compressed representation, may be NULL
fromPixSeq	compressed pixel sequence
cp	codec parameters for this codec
dataset	pointer to dataset in which pixel data element is contained
dataset	pointer to DICOM dataset in which this pixel data object is located. Used to access photometric interpretation.
decompressedColorModel	upon successful return, the color model of the decompressed image (which may be different from the one used in the compressed images) is returned in this parameter

Returns:

EC_Normal if successful, an error code otherwise

Implements DcmCodec.

static Uint16 DJLSDecoderBase::determinePlanarConfiguration	(	const OFString &	sopClassUID,
		const OFString &	photometricInterpretation
	)		[static, private]

determines if a given image requires color-by-plane planar configuration depending on SOP Class UID (DICOM IOD) and photometric interpretation.

All SOP classes defined in the 2003 edition of the DICOM standard or earlier are handled correctly.

Parameters:

sopClassUID	SOP Class UID
photometricInterpretation	decompressed photometric interpretation

Returns:

legal value for planar configuration

virtual OFCondition DJLSDecoderBase::encode	(	const Uint16 *	pixelData,
		const Uint32	length,
		const DcmRepresentationParameter *	toRepParam,
		DcmPixelSequence *&	pixSeq,
		const DcmCodecParameter *	cp,
		DcmStack &	objStack
	)		const [virtual]

compresses the given uncompressed DICOM image and stores the result in the given pixSeq element.

Parameters:

pixelData	pointer to the uncompressed image data in OW format and local byte order
length	of the pixel data field in bytes
toRepParam	representation parameter describing the desired compressed representation (e.g. JPEG quality)
pixSeq	compressed pixel sequence (pointer to new DcmPixelSequence object allocated on heap) returned in this parameter upon success.
cp	codec parameters for this codec
objStack	stack pointing to the location of the pixel data element in the current dataset.

Returns:

EC_Normal if successful, an error code otherwise.

Implements DcmCodec.

virtual OFCondition DJLSDecoderBase::encode	(	const E_TransferSyntax	fromRepType,
		const DcmRepresentationParameter *	fromRepParam,
		DcmPixelSequence *	fromPixSeq,
		const DcmRepresentationParameter *	toRepParam,
		DcmPixelSequence *&	toPixSeq,
		const DcmCodecParameter *	cp,
		DcmStack &	objStack
	)		const [virtual]

transcodes (re-compresses) the given compressed DICOM image and stores the result in the given toPixSeq element.

Parameters:

fromRepType	current transfer syntax of the compressed image
fromRepParam	current representation parameter of compressed data, may be NULL
fromPixSeq	compressed pixel sequence
toRepParam	representation parameter describing the desired new compressed representation (e.g. JPEG quality)
toPixSeq	compressed pixel sequence (pointer to new DcmPixelSequence object allocated on heap) returned in this parameter upon success.
cp	codec parameters for this codec
objStack	stack pointing to the location of the pixel data element in the current dataset.

Returns:

EC_Normal if successful, an error code otherwise.

Implements DcmCodec.

static OFBool DJLSDecoderBase::isJPEGLSStartOfImage

(

Uint8 *

fragmentData

)

[static, private]

check whether the given buffer contains a JPEG-LS start-of-image code

Parameters:

fragmentData

pointer to 4 or more bytes of JPEG-LS data

Returns:

true if the first four bytes of the code stream indicate that this fragment is the start of a new JPEG-LS image, i.e. starts with an SOI marker followed by SOF, COM or APPn.

---

The documentation for this class was generated from the following file:

• dcmjpls/include/dcmtk/dcmjpls/djcodecd.h