PDS_VERSION_ID         = PDS3
RECORD_TYPE            = STREAM
OBJECT                 = TEXT
  PUBLICATION_DATE     = 2016-03-04
  INTERCHANGE_FORMAT   = ASCII
  NOTE                 = "Description file referenced by DEM JP2 PDS labels"
END_OBJECT             = TEXT
END

                      MESSENGER Digital Elevation Model
                        JPEG 2000 Format Description
                              December 18, 2014


JPEG2000 Standard -

MESSENGER Digital Elevation Model (DEM) image data are stored in the
JPEG2000 ISO/IEC Part 1 standard [1] format (http://www.jpeg.org/jpeg2000/),
which was accepted as a PDS Standard in October 2005 [2, Appendix I].
The JPEG2000 standard offers benefits with distinct advantages for storage of
and access to very large images. With DEM products reaching sizes exceeding
30,000 x 70,000 pixels the use of JPEG2000 was recognized as a suitable
solution for the storage and distribution of these data products. Advantages
include excellent compression performance, multiple resolution levels from a
single image data set, progressive decompression quality layers, lossless
and lossy compression (DEM products use lossless compression per
the PDS Standard), pixel datum precision up to 38 bits, multiple image
components (or bands), and selective image area access. These features
are achieved by the use of a sophisticated image coding system based on
discrete wavelet transforms (DWT) combined with other coding techniques
to generate a JPEG2000 codestream that can be rendered to image pixel
rasters using inverse transform algorithms.

The PDS Standard specifies that a JPEG2000 codestream will be stored in a
"JP2" file as described by the JPEG2000 Part 1 standard [1, Appendix I].
This file format encapsulates one or more codestreams plus characterizing
metadata in a contiguous sequence of binary data "boxes". The first two
boxes of a JP2 file must be Signature and File Type specification boxes
that uniquely identify the file as a JP2 file. This must be followed by a
JP2 Header box that contains sub-boxes that characterize the Codestream
box that follows with information such as the image dimensions, pixel
datum precision, compression technique and color space mapping for image
display purposes. The JP2 file may also contain additional boxes that
contain UUID (universally unique identifier) signatures, URL (uniform
resource locator) references, and XML (extended markup language)
sequences that can be used as desired by the data provider.


JPEG2000 Codestream -

All of the information necessary to successfully decompress JPEG2000
image data are contained in the JPEG2000 Codestream box of the JP2 file.
The flexibility of the format, however, allows for significant
variability in how the codestream is structured which can have a
significant impact on the performance of client software accessing the
codestream during rendering operations.

While the JPEG2000 standard supports an exceptionally efficient lossy
image coding technique, to ensure the preservation of the science
information of the image data the PDS requires that only lossless image
compression be used. Therefore DEM image data are compressed using
the JPEG2000 5-3 reversible transform. The JPEG2000 codestream may be
partitioned into quality layers to enable rendering software to provide
progressing quality displays. DEM image data are compressed with a
single quality layer.


JPEG2000 Software -

Part 5 of the JPEG2000 offers reference software implementations of the
Part 1 core-coding standard. The JasPer Project provides a C language API
and demonstration applications
(http://www.ece.uvic.ca/~mdadams/jasper/).  JJ2000
(http://jj2000.epfl.ch/) provides pure Java classes. Both of these
implementations are employed in two J2K plugins for the Image I/O Tools
from Sun Microsystems' Java Advanced imaging (JAI).
(http://java.sun.com/javase/6/docs/technotes/guides/imageio/)
(http://java.sun.com/javase/technologies/desktop/media/jai/)

Dr. David Taubman, one of the principle JPEG2000 standard developers,
implemented the Kakadu software. Kakadu offers a full range of
application utilities and highly optimized C++ classes
(http://www.kakadusoftware.com/).

The JP2_Info utility, in the Image_Tools package of the PIRL Java
Packages
(http://pirlwww.lpl.arizona.edu/software/PIRL_Java_Packages.shtml)
provides a detailed report on the contents of a JP2 file.


References -

1. JPEG 2000 image coding system: Core coding system, ISO/IEC 15444-1
   September 15, 2004

2. Planetary Data System Data Standards Reference, Version 3.7, JPL
   D-7669, Part 2, March 20, 2006