org.dcm4che3.imageio.codec.jpeg

Enum PatchJPEGLS

java.lang.Object

java.lang.Enum<PatchJPEGLS>

org.dcm4che3.imageio.codec.jpeg.PatchJPEGLS

All Implemented Interfaces:

Serializable, Comparable<PatchJPEGLS>

public enum PatchJPEGLS
extends Enum<PatchJPEGLS>

The JAI-ImageIO JPEG-LS CLibJPEGImageReader/CLibJPEGImageWriter contain a bug that makes them calculate non-default JPEG-LS coding parameters for images with more than 12 bits per pixel, resulting in two problems:

1. JPEG-LS streams created by CLibJPEGImageWriter are not compliant with the JPEG-LS specification and can therefore not be decoded using standard-compliant decoders. (Note: Some commercial decoders can automatically detect such faulty JPEG-LS streams and are able to decode them correctly, e.g. Agfa/Pegasus.)
2. Reading a correct JPEG-LS stream using default coding parameters (i.e. not containing an LSE segment) with CLibJPEGImageReader will result in a corrupted image.

This enum contains different options to use with a PatchJPEGLSImageInputStream or PatchJPEGLSImageOutputStream to both patch faulty JPEG-LS streams created by JAI-ImageIO to make them readable by standard-compliant decoders and to make correct JPEG-LS streams (created by other encoders) readable by JAI-ImageIO.

Author:

Gunter Zeilinger , Hermann Czedik-Eysenberg

See Also:

http://www.dcm4che.org/jira/browse/DCMEE-1144, http://dcm4che.org/jira/browse/DCMEEREQ-799, https://java.net/jira/browse/JAI_IMAGEIO_CORE-183, http://charls.codeplex.com/discussions/230307

Enum Constant Summary

Enum Constants

Enum Constant and Description
ISO2JAI Amend default JPEG-LS Coding parameters (for streams that do not contain them yet).
ISO2JAI_IF_APP_OR_COM Amend default JPEG-LS Coding parameters (for streams that do not contain them yet), but only if the stream contains APPn or COM segments - so it was certainly not created by JAI-ImageIO.
JAI2ISO Amend JPEG-LS Coding parameters actually used by JAI-ImageIO.
JAI2ISO_IF_NO_APP_OR_COM Amend JPEG-LS Coding parameters actually used by JAI-ImageIO, but only if the stream does NOT contain APPn or COM segments and is therefore more likely to have been actually created by JAI-ImageIO.

Method Summary

Modifier and Type	Method and Description
JPEGLSCodingParam	createJPEGLSCodingParam(byte[] jpeg)
static PatchJPEGLS	valueOf(String name) Returns the enum constant of this type with the specified name.
static PatchJPEGLS[]	values() Returns an array containing the constants of this enum type, in the order they are declared.

Methods inherited from class java.lang.Enum

clone, compareTo, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Enum Constant Detail

JAI2ISO

public static final PatchJPEGLS JAI2ISO

Amend JPEG-LS Coding parameters actually used by JAI-ImageIO.

Used to patch faulty JPEG-LS streams created by JAI-ImageIO CLibImageWriter, so the resulting JPEG-LS stream can be decoded by JPEG-LS compliant decoders.

Warning: Patching a correct JPEG-LS (not created by JAI-ImageIO) with this option is likely to corrupt it (if it has more than 12 bits per pixel and uses default coding parameters, i.e. doesn't contain an LSE segment). Use JAI2ISO_IF_NO_APP_OR_COM to prevent this problem in some cases.

JAI2ISO_IF_NO_APP_OR_COM

public static final PatchJPEGLS JAI2ISO_IF_NO_APP_OR_COM

Amend JPEG-LS Coding parameters actually used by JAI-ImageIO, but only if the stream does NOT contain APPn or COM segments and is therefore more likely to have been actually created by JAI-ImageIO.

This option can be used, if you are not 100% sure whether the stream has actually been created by JAI-ImageIO and you want to decrease the likeliness of corrupting a correct stream by incorrectly patching it. It will prevent patching streams of some correct encoders (e.g. Agfa/Pegasus) that add APPn or COM segments. But as some correct encoders (e.g. dcmtk in the current version 3.6.0) also do not create APPn or COM segments, this option might still patch a correct stream and thereby make it corrupt.

ISO2JAI

public static final PatchJPEGLS ISO2JAI

Amend default JPEG-LS Coding parameters (for streams that do not contain them yet).

Used to patch correct JPEG-LS streams, so they can be decompressed by the faulty JAI-ImageIO CLibImageReader. The resulting stream will still be correct JPEG-LS and can also be decoded by other decoders.

Warning: Patching faulty JPEG-LS streams created by JAI-ImageIO with this option will make them corrupt (i.e. unreadable by both JAI-ImageIO and standard-compliant decoders).

ISO2JAI_IF_APP_OR_COM

public static final PatchJPEGLS ISO2JAI_IF_APP_OR_COM

Amend default JPEG-LS Coding parameters (for streams that do not contain them yet), but only if the stream contains APPn or COM segments - so it was certainly not created by JAI-ImageIO.

This option can be used to prevent adding those default parameters to faulty streams created by JAI-ImageIO which would make them unreadable for both JAI-ImageIO and standard-compliant decoders. On the other hand some correct encoders (e.g. dcmtk 3.6.0) also do not add APPn or COM segments and will therefore not be patched, which prevents them from getting decompressed correctly with JAI-ImageIO, if this option is used. (Use the ISO2JAI option for reading such streams with JAI-ImageIO.)

Method Detail

values

public static PatchJPEGLS[] values()

Returns an array containing the constants of this enum type, in the order they are declared. This method may be used to iterate over the constants as follows:

for (PatchJPEGLS c : PatchJPEGLS.values())
    System.out.println(c);

Returns:

an array containing the constants of this enum type, in the order they are declared

valueOf

public static PatchJPEGLS valueOf(String name)

Returns the enum constant of this type with the specified name. The string must match exactly an identifier used to declare an enum constant in this type. (Extraneous whitespace characters are not permitted.)

Parameters:

name - the name of the enum constant to be returned.

Returns:

the enum constant with the specified name

Throws:

IllegalArgumentException - if this enum type has no constant with the specified name

NullPointerException - if the argument is null

createJPEGLSCodingParam

public JPEGLSCodingParam createJPEGLSCodingParam(byte[] jpeg)