[fitsbits] SAOImage DS9 verison 7.0

[William Joye]

Apologies for the repeat posting. It is unclear if the previous message was properly distributed.

SAOImage DS9: Astronomical Image Display
Public Release 7.0
June 2012

We are pleased to announce the availability of the new public release
of SAOImage DS9 7.0.  More information about this package (including
download links) is available at our web site:
http://hea-www.harvard.edu/RD/ds9/

New to SAOImage DS9: 3-D Data Visualization

Previous versions of SAOImage DS9 would allow users to load 3-D data
into traditional 2-D frames, and would allow users to step through
successive z-dimension pixel slices of the data cube. To visualize 3-D
data in DS9 v. 7.0, a new module, encompassed by the new Frame 3D
option, allows users to load and view data cubes in multiple
dimensions.

The new module implements a simple ray-trace algorithm. For each pixel
on the screen, a ray is projected back into the view volume, based on
the current viewing parameters, returning a data value if the ray
intersects the FITS data cube. To determine the value returned, there
are 2 methods available, Maximum Intensity Projection (MIP) and
Average Intensity Projection (AIP). MIP returns the maximum value
encountered, AIP returns an average of all values encountered. At this
point, normal DS9 operations are applied, such as scaling, clipping
and applying a color map.

Rendering time is independent of the actual data cube size. Instead,
the time it takes to render is based on how many rays are needed to
project the data cube upon the screen in the view volume and the
current zoom factor. The new module requires no special hardware or
graphical processor unit (GPU) and the rendering time is adequate for
interactive GUI manipulation on most computers. The rendering engine
is developed using the POSIX thread library, allowing multiple light
weight processes to be spawned to complete an image in parallel. The
number of threads actually generated is a user specified
parameter. Since all modern hardware contain multiple CPU cores, the
default value is 8 threads. For larger work stations, this number can
be increase. For every doubling in the number of CPU cores available,
rendering times decrease approximately 75%.

The new module is support on all hardware platforms currently
supported by DS9, including 32-bit and 64-bit versions of Linux and
MacOSX, and 32-bit versions of Windows and Solaris.

All 2-D graphics, regions, cross hairs, contours, and coordinate
grids, are applied to the current slice, which is selected by the
user. When the user wishes to match or lock a 2-D image and to a 3-D
data cube, the current slice is used to determine the rendering
solution. The user can crop the data cube for all 3 axes via the
command line or the GUI. The new module also supports FITS event files
binned into a data cube.

All printing support has been extended to the new 3-D module. The user
may generate 3-D images in Postscript, JPEG, TIFF, and other formats,
just as in the 2-D case. Furthermore, native printing is supported for
the Windows version.

DS9 analysis macros have been enhanced to fully support the new 3-D
module, allowing the user to invoke external analysis tasks based on
the current view parameters and to return results back into DS9 in the
form of text, plot, 2-D image, or 3-D image.

For a comprehensive list of other new features, please see:
http://hea-www.harvard.edu/RD/ds9/new.html