Sep 2026  Version 7.0.0

	The previous release was 6.0.2, in 2010.  This one is a rewrite of the
	parts a user touches -- the interface, the build, the file formats --
	around the same reconstruction arithmetic, which is unchanged to the
	last bit.  Only what is new is listed; the faults corrected along the
	way are in the commit history.

	The program

	* The graphical interface is ported from wxWidgets to Qt 6, and CTSim
	  builds and runs on Windows for the first time, and on macOS as a
	  signed application bundle

	* One program, built twice: ctsim with the interface, ctsim-nogui
	  without it, for a machine with no display or no Qt.  Both offer the
	  same functions, either named on the command line -- "ctsim phm2if
	  head.if 255 255" -- or typed at a prompt, with "ctsim --shell" or
	  File - New Shell.  ctsimtext was the old name of the program without
	  the interface

	* "help" lists the commands and describes any one of them; "bench"
	  runs a standard benchmark and prints each step's time

	Scripts

	* "ctsim --script file" runs a list of commands that make phantoms,
	  scan and reconstruct them, measure the results and assert things
	  about them.  File - Run Script lists the demonstrations CTSim finds

	* A script run from File - Run Script is given a temporary directory
	  of its own, as a --script run is.  Without one it wrote the files it
	  made beside the script, which for a demonstration meant into the
	  directory the demonstrations ship in

	* --workdir names the directory a run writes into, and --script-save
	  fills it: every window the script made, a copy of the script, and a
	  record of the run -- the tool behind each window, its parameters, how
	  long it took, and the distances measured -- as text and as JSON, both
	  naming the version, commit, Qt, platform and architecture that made
	  them

	* Ten demonstrations follow the standard geometry of Herman's
	  "Fundamentals of Computerized Tomography": a 243 by 243 picture over
	  a view 1.05934 times the phantom, which is the book's pixel spacing
	  of 0.0752 cm, scanned with 345 detectors.  They compare scan
	  geometries, reconstruction filters, interpolation methods and view
	  counts, draw every filter in the spatial domain, compare a divergent
	  scan reconstructed directly against one rebinned to parallel, and
	  one reproduces the book's section 5.4 to its last quoted digit, and
	  one draws the linogram sampling pattern

	* A "plot-points" script command draws a scatter of x,y pairs read from
	  a file, with a symbol every n points and the points joined or not.
	  "linogram n d --xy" prints such a file; anything else that prints one
	  can be drawn the same way.  The points are black unless a colour is
	  asked for, a colour asked for in a plot file is no longer overwritten
	  by the curve palette, and "xtitle" and "ytitle" set the axis labels
	  rather than reporting themselves unimplemented

	* The helical chain -- phm2helix, pjHinterp and pjrec -- has a test

	* ctconvert produced noise for every HDF5 to legacy conversion of an
	  image: Array2dFile::readHDF5 left m_arraySize at zero, and labelsWrite
	  seeks to m_headersize + m_arraySize, so the labels were written over
	  the pixel plane.  The other three directions were unaffected, and
	  phm2if --legacy-format, which never goes through that reader, always
	  worked.  ctconvert had no test; it has five now

	* pjHinterp, interpolating a helical scan to one plane, read and wrote
	  through a pointer one past the end of its view array: the array is
	  sized by truncating (pi+fan)/dbeta while the index is rounded, so
	  where that quotient has a fractional part of a half or more the two
	  disagree by one.  At CTSim's 60 degree fan that is 100, 250 or 400
	  views to the turn, though not 360 or 720.  The sample at that edge
	  is now dropped

	* Rebinning a divergent scan to parallel records how long it took,
	  which it used to report as zero

	Reconstruction

	* Reconstruction is about a third quicker, and unchanged to the last
	  bit

	* The defaults are Herman's: Abs_Hanning at 0.8 with linear
	  interpolation

	* Filters are named for what they do rather than for who devised them:
	  abs_bandlimit is the plain ramp of Ramachandran and Lakshminarayanan,
	  abs_sinc that ramp windowed by a sinc, published by Shepp and Logan

	* The number of detectors, the samples per pixel when rasterizing, and
	  the size of a reconstructed image must be odd, so that a detector
	  lies on the central ray, a sample on the centre of each pixel, and a
	  pixel on the axis of rotation, as Herman and SNARK require

	Files

	* Files can be written in HDF5 as well as the historical format, and
	  images imported from and exported to DICOM

	* A file records its own history: every tool that made it, with the
	  parameters that tool received and the time it took

	The build and the source

	* CMake rather than Autotools, with scripts/build.sh and
	  scripts/build.bat, each of which configures, builds, tests and
	  packages from one command and installs its own dependencies with
	  --init.  DICOM is no longer optional; DCMTK is required

	* Modern C++: sized types, string_view and span at the interfaces,
	  std::vector in place of new[] and delete[], and diagnostics whose
	  arguments are checked as the program is built

	* Some seven hundred and eighty unit checks, a regression suite that
	  pins the arithmetic against reference images generated by 6.0.2, and
	  a benchmark harness


Sep 2026  Version 6.5.0
	* NEW: HDF5 is the default format for newly written image and
	  projection files.  CTSim's own binaries were readable only by CTSim,
	  and stored pixels as 32-bit float even after 6.1.0 made memory double.
	  HDF5 stores all floating point as double and opens directly in numpy,
	  MATLAB, ImageJ and HDFView.  Layout is documented at the top of
	  libctsim/hdf5file.cpp (format_version 1)
	* Reading detects the format from the file itself -- the HDF5 signature
	  or the legacy two-byte signature -- so every existing .if and .pj file
	  keeps working with no flag and no conversion
	* NEW: "ctsimtext ctconvert in out [--to hdf5|legacy]" converts in either
	  direction.  It detects both the format and whether the file holds an
	  image or projections, so neither needs to be specified.  Round trips are
	  exact for data already at float32 precision (d=r=e=0)
	* Escape hatch: CTSIM_FILE_FORMAT=legacy restores the old writer without
	  rebuilding.  Files written by 6.5.0 cannot be read by 6.4 and earlier,
	  which is the one compatibility break in this release
	* Golden test data stays in the legacy format on purpose: it is the
	  continuity link back to 6.0.2, so "run-tests.sh generate" sets
	  CTSIM_FILE_FORMAT=legacy
	* Build: CTSIM_WITH_HDF5 (default ON).  Without HDF5 the library reads and
	  writes only the legacy format and says so at configure time
	* tests/unit_tests.cpp grew to 98 checks: HDF5 round trips at three image
	  sizes including non-square, complex images, axis extents, history
	  labels, projection geometry and raysums, format detection, and a check
	  that double precision survives HDF5 where the legacy format quantizes
	* NEW: "--legacy-format" is accepted by every command-line tool.  It is
	  stripped by the ctsimtext dispatcher before the sub-command sees it, so
	  the behaviour is uniform rather than per-tool.  CTSIM_FILE_FORMAT=legacy
	  still sets it for a whole shell session
	* NEW: structured history.  A history entry now carries an operation name
	  and key/value parameters as well as the text, so two files can be
	  compared by what produced them instead of by reading prose.  phm2if,
	  phm2pj, pjrec, pjfourier, dicomimport and ctconvert all record their
	  full parameter set.  The human-readable label is composed from the
	  structured form, so existing displays are unchanged, and the legacy
	  format still stores that text
	* NEW: extensible metadata.  setUserAttribute()/getUserAttribute() on both
	  ImageFile and Projections store arbitrary key/value fields under /user
	  in HDF5.  Fields an older build does not understand are preserved
	  through a read/modify/write cycle rather than dropped, which is what
	  makes it safe to add fields in a later version.  The unit tests assert
	  that preservation directly
	* NEW: "ctsimtext ctdump file" prints format, content, dimensions,
	  geometry or axis extents, the full history with its parameters, and any
	  user attributes.  h5dump shows the raw container; ctdump interprets
	  CTSim's schema and also handles legacy files
	* Timing uses std::chrono::steady_clock.  It is monotonic, so a wall-clock
	  adjustment cannot make an elapsed time jump or go negative, and the
	  resolution is the system clock's rather than gettimeofday's microsecond
	  ticks.  Note that std::clock() would have been wrong here: it measures
	  CPU time, so under OpenMP it reports roughly thread-count times the real
	  elapsed time
	* Fix: Array2dFileLabel's hand-written copy constructor and assignment
	  operator did not copy the new structured fields, so history was lost
	  whenever a label was copied
	* The HDF5 layout stays at format_version 1: the additions are new
	  optional datasets and groups, so a reader written against the original
	  version 1 files still reads these correctly
	* format_version is now checked when reading.  A file claiming a newer
	  layout is refused with a message naming both versions, rather than
	  being half-read; a file with no format_version attribute is refused as
	  not being a CTSim file.  Within a version the layout only grows, so an
	  older build still reads a newer file of the same version correctly
	* Line editing in the ctsimtext shell now prefers libedit over GNU
	  readline, selectable with -DCTSIM_READLINE=auto|editline|readline.
	  Both provide the readline()/add_history() entry points CTSim uses.  The
	  licensing concern that led Debian to patch this away is no longer
	  relevant -- readline is GPL-3-or-later and CTSim has been
	  GPL-3-or-later since 6.1.0, so the old GPL-2-only incompatibility is
	  gone -- but libedit is BSD licensed, ships with macOS, and is what
	  Debian already links against, so preferring it removes the need for a
	  distribution patch
	* ctsimtext help lists every sub-command.  Both the command-line and the
	  interactive listings had drifted: the interactive one was missing if1,
	  if2, pj2if, phm2if, phm2pj and phm2helix as well as the new tools
	* Removed the diagnostic --no-density-comp option from pjfourier, and the
	  bDensityCompensation parameter from reconstructFourierGrid().  Without
	  the density weighting the result is not normalized at all, so it was
	  never a meaningful choice; the corresponding test and documentation are
	  gone with it
	* Man pages for dicomimport, pjfourier, ctconvert and ctdump.  Every
	  command-line tool now has one.  Also fixed a stray \P escape in
	  pjrec.1 that groff reported
	* Manual figures converted from EPS to SVG (doc/convert-figures.sh,
	  doc/manual/figures/); the one Photoshop original becomes PNG.  The
	  manual had been building with no figures at all, because tex2rtf's
	  \image macro means nothing to pandoc and was dropped silently;
	  convert-manual.sh now rewrites it first.  The manual and manual-pdf
	  targets copy the figures alongside the output
	* NEW: .gitlab-ci.yml, mirroring the GitHub workflow, with an added job
	  that builds with every optional feature switched off.  The macOS and
	  Windows jobs are manual until runners with those tags exist
	* Fix: the interactive ctsimtext shell mis-parsed every command after the
	  first.  getopt keeps its position in the global optind and none of the
	  sub-commands reset it, so the second command started scanning wherever
	  the first stopped: its options were never seen and its positional
	  arguments landed in the wrong places, which looked like "No phantom
	  defined" followed by a usage dump.  optind is now reset before each
	  dispatch (optreset as well on the BSDs)
	* Fix: the version was left at 6.4.0 when the 6.5.0 tree was created, so
	  the shell banner, --version and the ctsim_version recorded in HDF5
	  files were all wrong.  The suite now checks that the built version
	  matches the newest ChangeLog entry, so this cannot pass silently again
	* --version prints the version and stops.  It used to fall through into
	  the help text and print an unexpanded "$Id$" RCS keyword left from CVS;
	  the keyword is gone from every tool
	* The ctsimtext shell keeps its command history between sessions in
	  $HOME/.ctsimtext.history, 500 lines, overridable with $CTSIM_HISTORY.
	  Works with both libedit and readline
	* Each HDF5 history entry records the CTSim version that wrote it, so a
	  file that passed through several versions says so; ctdump prints it
	* NEW: packaging/ctsim.desktop and a vector application icon
	  (packaging/ctsim.svg, rendered to the hicolor sizes).  The icon redraws
	  the original logo.gif as SVG: source, fan beam, head phantom and
	  detector arc inside the scan circle.  Debian's local copies of the
	  desktop entry were dropped in favour of these
	* CPack builds source tarballs as well: "cmake --build build --target
	  package_source" produces .tar.gz and .tar.xz, excluding build trees
	* Removed the empty TODO file, the stale .deps directories, and the
	  manual chapter on the CGI web interface (removed from the code in 6.1.0)

Sep 2026  Version 6.4.0
	* Library/GUI decoupling.  libctsupport/syserror.cpp and globalvars.cpp
	  included ../src/ctsim.h and posted wxWidgets events; libctsim's
	  procsignal.cpp opened an EZPlotDialog.  A library reaching up into
	  whichever GUI happens to be linked is the main obstacle to replacing
	  that GUI, so these are now callbacks (include/ctsupport_hooks.h):
	  sysErrorSetHandler() for diagnostics and traceSetPlotHandler() for the
	  signal-processing trace plots.  Nothing is installed by default, so the
	  command-line tools get console behaviour; a GUI installs handlers at
	  start-up.  libctsupport no longer compiles against or links any toolkit
	* Removed tools/nographics.cpp and include/nographics.h, which existed
	  only to stub out the GUI dialog that libctsim used to call
	* Removed the last dead experimental macros: HAVE_GD, HAVE_GIF,
	  HAVE_BSPLINE_INTERP, HAVE_FREQ_PREINTERP
	* Array2d<T> uses std::vector.  It kept a hand-written destructor that
	  released each row with a scalar delete; that particular bug was fixed
	  in 6.2.1, but the class now owns nothing by hand.  A column pointer
	  table preserves the T** accessor its callers use.  The two shuffle
	  templates in fourier.h likewise use std::vector.  No raw new[] remains
	  in any header
	* Fix: readImagePNG divided 16-bit samples by 65536 while writeImagePNG
	  scales by (1<<bitdepth)-1 = 65535, so full-scale white read back as
	  0.9999847 -- a systematic 1.5e-5 error on every 16-bit PNG import,
	  including raster phantoms
	* Fix: Phantom::addPElem pushed geometric elements onto the front of the
	  list while addRasterPElem appended, so writing a phantom and reading it
	  back reversed the element order, and mixed phantoms came back scrambled.
	  Both now append.  Attenuations sum, so images are unaffected
	* NEW: tests/unit_tests.cpp, run by ctest as "unit_tests" and by the shell
	  suite.  56 checks over pieces with analytically known behaviour:
	  Siddon line integrals through a raster element (chord lengths, rotation,
	  translation, rays along grid lines, attenuation scaling), phantom file
	  round trips including comments and unknown element types, image file
	  round trips at four sizes including non-square, non-square
	  rasterization, and byte-order stream round trips
	* NEW: .github/workflows/ci.yml -- Linux (warnings as errors), Linux with
	  the wxWidgets GUI, Linux under address and undefined sanitizers, macOS
	  (clang, Homebrew) and Windows (MSVC, vcpkg).  Until now only Linux was
	  ever exercised, which is the largest risk to the Qt port
	* Debian packaging converted from autoreconf to dh --buildsystem=cmake;
	  ctn-dev replaced by libdcmtk-dev; the regression suite runs during build
	* Manual moved off tex2rtf, unmaintained for about twenty years and the
	  reason the shipped PDF was still the 2002 CTSim 3.5 text.  The chapters
	  were converted once to Markdown (doc/manual/, doc/convert-manual.sh) and
	  CMake gained "manual" and "manual-pdf" targets built with pandoc.  See
	  doc/manual/README.md for what still needs a human pass

Sep 2026  Version 6.3.2
	* NEW: gridding (non-uniform FFT) reconstruction --
	  Projections::reconstructFourierGrid().  Each polar sample is
	  convolved onto an oversampled Cartesian grid with a Kaiser-Bessel
	  kernel (shape parameter per Beatty 2005), weighted by the polar
	  sampling density, inverse transformed and then deapodized.  This is
	  the standard remedy for the two weaknesses of point interpolation:
	  crowding of polar samples near the origin and angular gaps at high
	  frequency
	* NEW: density compensation.  Polar samples cover an area |nu|*dNu*dTheta,
	  so without weighting, the low frequencies are counted many times over.
	  The central sample stands for the disc of radius dNu/2, shared among
	  the views.  The weights carry du*dv, so no separate frequency-area
	  factor is applied
	* pjfourier gained --method interp|gridding, --oversample and
	  --kernel-width so the effect of each can be measured rather than
	  assumed
	* Measured against the true phantom at 256x256, 367 detectors,
	  320 views.  Gridding reaches unpadded what interpolation needs
	  4x zero-padding to reach:
	      herman       zeropad 0:  interp d=0.278 r=0.186
	                              gridding d=0.177 r=0.100   (36%/46% better)
	      shepp-logan  zeropad 0:  interp d=0.393 r=0.735
	                              gridding d=0.294 r=0.329   (25%/55% better)
	  With generous zero-padding the two converge, gridding staying slightly
	  better in mean absolute error and slightly worse in RMS.  Neither
	  closes the gap to filtered backprojection (herman d=0.066), which is
	  expected: what remains is angular undersampling, not interpolation
	* tests/: gridding cases for both phantoms -- gridding beats
	  interpolation without padding, and gridding amplitude agrees with FBP

Sep 2026  Version 6.3.1
	* Fix: direct Fourier reconstruction was scaled wrongly.  The forward
	  transform used "iInterpDet / (viewDiameter * 0.05)" and was then
	  divided by the square of the *unpadded* transform length, so the
	  result was both geometry dependent (measured 11.1x too large for the
	  Herman phantom, 18.4x for Shepp-Logan) and zeropad dependent (11.1x
	  falling to 10.2x from zeropad 1 to 4).  The central-slice theorem
	  fixes the scale as the projection sample spacing and nothing else;
	  with that, and 1/FOV^2 for the unnormalized inverse transform, the
	  reconstructed mean now matches filtered backprojection to 0.02% and
	  is identical across zeropad 0..4
	* Fix: the reconstruction field is proj.phmLen(), what Backproject uses,
	  not viewDiameter (the larger scan circle)
	* Fix: the radial axis put DC at (n-1)/2 instead of n/2 for an
	  even-length shuffled transform -- a half-sample offset, i.e. a linear
	  phase error across every projection
	* Fix: Projections::interpolatePolar bounded its x loop with ny.  Square
	  images hid it; with nx != ny it either wrote past the end of a column
	  or left columns unset
	* Fix: Fourier::shuffleFourierToNaturalOrder(ImageFile&) copied rows
	  through a std::vector<float>, truncating double pixels to single
	  precision (two places)
	* NEW: Projections::reconstructFourier() performs the whole sequence, so
	  the GUI and the command line cannot disagree about normalization.  It
	  keeps the real part rather than the magnitude, so negative values
	  survive instead of being folded positive
	* NEW: "ctsimtext pjfourier in.pj out.if nx ny [--zeropad N] [--interp
	  nearest|bilinear]" exposes direct Fourier reconstruction on the command
	  line, where it had been reachable only from the graphical program
	* tests/: Fourier group -- amplitude agreement with FBP, invariance
	  across zeropad 0..4, image agreement, and the requirement that more
	  padding improves agreement.  Run for both Herman and Shepp-Logan
	* Note: POLAR_INTERP_BICUBIC exists in the library but remains commented
	  out of Projections::s_aszInterpName upstream, so it is not selectable
	  by name from either interface

Sep 2026  Version 6.3.0
	* tests/validate_dicom_recon.py: physics validation of the raw-scan
	  pipeline.  Registers CTSim's reconstruction against the scanner's own
	  reconstruction of the same acquisition and checks structure
	  (correlation >= 0.95; measured 0.974) and intensity (implied mu_water
	  0.01908 /mm and air -1012 HU, from a single linear fit).  Needs only
	  python3 + numpy; registered with ctest as dicom_physics_validation and
	  skipped cleanly when unavailable
	* DICOM support reimplemented on DCMTK, replacing the unmaintained CTN
	  library.  libctsim/ctndicom.cpp and include/ctndicom.h are now
	  libctsim/dicom.cpp and include/dicom.h; the HAVE_CTN_DICOM macro is
	  now HAVE_DCMTK; CMake locates DCMTK with find_package(DCMTK).
	  DicomImporter and DicomExporter keep their interfaces, so callers are
	  unchanged
	* The regression suite added in 6.2.1 verifies the port: the golden
	  reconstruction from the raw Somatom scan matches the CTN result bit
	  for bit (d=r=e=0), as does the sinogram and the scanner geometry
	* Behaviour correction: the importer now applies Rescale Slope and
	  Intercept.  The CTN code intended to (it read them into a zero-length
	  buffer, so they silently stayed 1 and 0) and therefore returned stored
	  values rather than real units.  For the test image this shifts every
	  value by the intercept, -1024; stddev is unchanged, confirming a pure
	  offset.  Test reference values updated accordingly
	* Behaviour correction: the exporter writes the real CT Image Storage
	  SOP class UID (1.2.840.10008.5.1.4.1.1.2).  The CTN code wrote
	  1.2.840.10008.5.4.1.1.2, which is not a valid UID.  Files are now
	  written as Part 10 explicit little endian with a meta header and
	  pass dcmftest
	* "ifexport --format dicom" exposes DICOM export on the command line
	  (it had been reachable only from the graphical program), and the
	  suite now round-trips an image out through DicomExporter and back
	  through DicomImporter
	* Build requirement: DCMTK >= 3.6.5 (Debian/Ubuntu libdcmtk-dev; macOS
	  "brew install dcmtk"; Windows "vcpkg install dcmtk").  libnsl is NOT
	  required: Debian's DCMTKTargets.cmake lists "nsl" in DCMTK::ofstd's
	  link interface, so every consumer was asked to link -lnsl, but that is
	  only needed by DCMTK's network module (dcmnet), which CTSim does not
	  use.  CMake now drops it from the interface when libnsl is absent, and
	  the resulting binary has no libnsl dependency either way

Sep 2026  Version 6.2.1
	* NEW: "ctsimtext dicomimport <file.dcm> <output>" makes DICOM import
	  reachable from the command line (it previously existed only in the
	  graphical program) and therefore from the regression suite
	* tests/: DICOM import test group using an anonymized Siemens SOMATOM
	  AR.STAR raw scan and a reconstructed CT image (tests/data/dicom/).
	  Covers both importer paths -- raw projections and image -- plus a
	  golden reconstruction.  Skipped unless built with CTSIM_WITH_DICOM=ON;
	  set CTSIM_REQUIRE_DICOM=1 to make a missing feature a failure
	* CMake can now locate the CTN library (CTSIM_WITH_DICOM=ON)
	* Fix: Projections::initFromSomatomAR_STAR read the 32-bit fields of each
	  view record through "long*".  On any LP64 build that read 8 bytes, so
	  the exponent scale was garbage and every raysum came out infinite --
	  Somatom raw import had never worked on 64-bit.  Now uses kint32, with
	  a static_assert on its size
	* Fix: Array2d<T>::deleteArray released each row with scalar delete
	  (allocated with new[]).  With 1024-detector reconstructions this
	  corrupted the heap and crashed pjrec.  Found by AddressSanitizer
	* Fix: vectorNumericStatistics computed an unguarded histogram bin index;
	  a constant or non-finite image indexed far outside the array (ifinfo
	  crashed).  The index is now clamped and NaN-safe
	* Fix (regression introduced in 6.2.0): ImageFile::writeImagePNG called
	  "delete rowp.data()" on vector-owned storage -- a double free on every
	  PNG export

Sep 2026  Version 6.2.0
	* Build system converted from autoconf/automake to CMake (>= 3.22).
	  Removed configure.ac, Makefile.am, bootstrap.sh, scripts/*.m4,
	  msvc/, rpm/, Makefile.nt.  FFTW3 and libpng are now mandatory;
	  DCMTK is detected for the DICOM port (CTSIM_WITH_DICOM)
	* Zero-warning build with -Wall -Wextra; CTSIM_WERROR=ON for CI.
	  Fixed every warning: 48 mismatched new[]/delete, 1218 ignored
	  const qualifiers on by-value return types, implicit switch
	  fall-throughs (now [[fallthrough]]), unsigned >= 0 comparisons,
	  and catching std::exception by value
	* Fix (found by AddressSanitizer): heap-buffer-overflow writing the
	  FFTW wisdom path in ctsimtext (one byte past the buffer); now a
	  std::string
	* Fix: several alloc/dealloc mismatches invisible to the compiler,
	  including PhantomElement outlines, Projections view data and the
	  libpng row buffers
	* 17 function-local raw arrays converted to std::vector; phantom
	  element outlines are std::vector<double> members
	* Loop strength reduction: floating-point coordinates advance by
	  addition (x += xInc) instead of a multiply per iteration, in the
	  rasterizer (both the OpenMP and serial paths, all inner levels),
	  both backprojector coordinate loops, the polar-conversion grid,
	  the filter convolution and the plot-axis loops.  Loops that OpenMP
	  parallelizes still compute their index variable (x = x0 + i*dx),
	  since a running accumulator cannot be shared across threads
	* Removed a nested "#pragma omp parallel for" in
	  SignalFilter::spatialResponseCalc: its caller createSpatialFilter
	  is already a parallel loop
	* getArray()/getImaginaryArray() const are now genuinely read-only
	  (the const_cast is gone).  20 read-only call sites now use
	  ImageFileArrayConst
	* API: ImageFile::fftRows/ifftRows/fftCols/ifftCols no longer take an
	  ImageFile& parameter.  They transform the image in place, and every
	  caller had to pass the same object twice (rIF.fftRows (rIF));
	  the redundant argument and its vacuous self-comparison are gone
	* The wxWidgets GUI builds again (cmake -DCTSIM_GUI=wx).  The 6.1.0
	  container change had not reached the code behind HAVE_SGP: array
	  handles compared against NULL, a memcpy between image columns, an
	  EZPlot::addCurve call, and Graph3dFileDocument's array member
	  (now a non-owning pointer).  Also applies Debian's wx3.2 fix for
	  the removed wxDEFAULT_DOCMAN_FLAGS
	* The GUI configuration (cmake -DCTSIM_GUI=wx) is also warning-free
	  under -Wall -Wextra -Werror.  Fixed: deprecated wxPen::SetStyle(int)
	  (now wxPENSTYLE_* constants), ++/-- on volatile (removed in C++20),
	  double-vs-enum comparisons in the POL parser, a strncpy that could
	  leave inputline unterminated, partially initialized
	  wxCmdLineEntryDesc entries, and mismatched new[]/delete in EZPlot
	* GUI and plotting code now uses std::vector for temporary buffers,
	  matching the rest of 6.2.0: 16 stack arrays in views.cpp,
	  dialogs.cpp and dlgprojections.cpp, plus EZPlot's conversion
	  buffers.  EZPlotCurve owns std::vector data; it previously leaked
	  its x array on every curve and deleted y with scalar delete.
	  No raw new[] remains in src/ or libctgraphics/
	* The full test suite runs clean under -fsanitize=address,undefined

Sep 2026  Version 6.1.0 (on the 6.0.3 git tree, including its OpenMP work)
	* Relicense to GPL-3.0-or-later (COPYING, COPYRIGHT, all source headers,
	  SPDX-License-Identifier tags)
	* Require C++20 (-std=c++20); compile-time guard in include/ct.h
	* Image pixel storage converted from new/delete unsigned char** arrays to
	  std::vector<std::vector<double> > (column-major, m_real[ix][iy]); the
	  on-disk file format is unchanged.  ImageFileArray/ImageFileColumn are now
	  reference/pointer aliases, so existing call sites are unchanged
	* std::unique_ptr ownership for dynamically created phantom elements.
	  The Array2dFile allocArray/freeArray new[]/delete mismatch is gone with
	  the storage change; the remaining -Wmismatched-new-delete sites
	  (procsignal.cpp, projections.cpp, if2.cpp, hashtable.cpp and others)
	  are unchanged and remain a TODO for 6.2.x
	* NEW: raster phantom elements.  A PNG image can be used as a phantom
	  element:  raster <file.png> cx cy u v rot attenMin attenMax
	  Grayscale [0,1] maps to [attenMin,attenMax]; (u,v) are half-extents.
	  Projections use an exact line integral through the pixel grid (Siddon's
	  algorithm in element coordinates), so phm2pj/phm2helix/pjrec and phm2if
	  all work with raster phantoms
	* Phantom file parser rewritten: '#' comments, blank lines, per-line error
	  messages, unknown element types are skipped instead of crashing
	* Fix: writeImagePNG wrote 16-bit samples in host byte order; PNG requires
	  big-endian (png_set_swap)
	* Fix: Array2dFile::setAxisExtent assigned m_maxY = maxX and never set
	  m_maxX / m_minY
	* Remove dead code: LAM/MPI, CGI web front end, g2, dmalloc, ElectricFence.
	  OpenMP multithreading is retained and unchanged
	* tests/: raster phantom test group activated (registration, parallel and
	  equiangular projections, reconstruction, scanner-geometry identity)

Sep 10, 2026  Version 6.0.3
	* Add test suite in tests/ directory
	* Add more OpenMP multithreading support, several loop optimizations

Mar 21, 2018  Version 6.0.2
	* Add more OpenMP parallelism
	* Improve testing script comparing results between OpenMP and non-OpenMP builds
	* Fix all remaining compiler warnings

Mar 20, 2018  Version 6.0.0
	* Migrate to wxgtk3.0
	* Add OpenMP parallelism and use by default

Dec 21, 2012  Version 5.2.1
	* tools/phm2helix.cpp: Fix spelling mistake

Nov  7, 2010  Version 5.2.0
	* tools/ifexport.cpp: Add Text output option (thanks to
	Christian Thibaudeau)

Aug 22, 2009  Version 5.1.3
	* src/ctsim.cpp
	- Improve numbering of unnamed documents. Reduce cut-and-paste code.
	* configure.ac
	- Use new AC_INIT form to include package information, email, url

Aug 21, 2009  Version 5.1.2
	* Conditionalize debugging output

Aug 20, 2009  Version 5.1.1
	* Use new wxFont constructor. Adjust font sizes.

Aug 12, 2009  Version 5.1.0
	* All known wxwidgets 2.8 compatibility issues have been fixed

Aug 6, 2009  Version 5.0.6
	* Use wxWidgets command-line processing rather than existing
	native processing.
	* ezset.cpp: Initialize scale settings in constructor
	* Improve titles of frames
	* configure.ac: Use wx-config to determine name of wxGL library
	* src/graph3dview.cpp: wx2.8 compatibility changes to eliminate
	segv crash when creating 3D objects

Aug 3, 2009  Version 5.0.5
	* Fix plots when maximum plot value is the same as minimum

Aug 3, 2009  Version 5.0.5
	* More wx2.8 compatibility fixes.
	* Fix initial size of Log TextCtrl at start-up.
	* Fix display of values in Log window by cleaning up string
	transformtions.

Aug 2, 2009  Version 5.0.4
	* More wx2.8 compatibility fixes. Ensure that a resize of a window
	causes a full repaint for phantom, plot, and graph3d canvases.

Aug 1, 2009  Version 5.0.1
	* missing: Update to latest automake version
	* configure: make compatible with wxMac
	* update few source files for non-unicode wxWidgets 2.8 compatibility

Aug 1, 2009  Version 5.0.0
	* Major revision of wxWidgets code to port from wx2.4 to wx2.8
	Currently, code compiles without warnings, but there are
	GUI visual problems at the momemt running with wx2.8

Sep 17, 2007  Version 4.5.5
	* better cleaning in makefiles
	* use "const char" variables for string literals

Sep 10, 2007  Version 4.5.4
	* configure.ac: Fix builds with multiple versions of wx-config
	-- thanks to Steve White

Apr 1, 2007  Version 4.5.3
	* include/timer.h: Fix building on GCC 4.3
	-- thanks to Martin Michlmayr

Oct 19, 2006  Version 4.5.2
	* src/lipctsim/imagefile.cpp: Change delete to fftw_free
	-- thanks to Sven Huth

Oct 18, 2006  Version 4.5.1
	* configure: rebuild from configure.ac

Oct 15, 2006  Version 4.5.0
	* libctsim/backprojectors.cpp: Fix for iteration bug in backprojection
	and simply computing rotScale -- thanks to Dan Martin.

Mar 16, 2006  Version 4.4.4
	* Changes for g++ 4.1 support

Aug 22, 2005  Version 4.4.2
 	* New URL for downloading CTSim

Aug 22, 2005  Version 4.4.1
        * work-around for compilation problems on Fedora 4 and wxWin 2.4.2

Aug 22, 2005  Version 4.4.0
        * Changes in configure.ac for X.org compatibility with Debian Etch
	and FC4. May not be backward compatibility with XFree86.

Aug 10, 2004  Version 4.3.2, Version 4.3.3
	* Minor changes in man pages to fix groff warnings

Nov 1, 2003  Version 4.3.1
	* Add support for SuSE AMD64

Oct 5, 2003  Version 4.3.0
	* Ported to incompatible FFTW3 library. CTSim will no longer compile or
	run with FFTW2.
	* Save FFTW3 in $HOME/.fftw3-wisdom on platforms where getenv function
	is available

Oct 3, 2003  Version 4.2.7
	* Add support for building on RedHat AMD64

Sep 30, 2003  Version 4.2.7
	* Fix minor issue with floating point difference backprojection, add
	optimization

	* Fix building with newest versions of automake 1.7

	* Add support for 8-byte longs [for example, Athlon64] in
	integer difference backprojection allowing for 64-bit integer
	math.

Mar 22, 2003  Version 4.2.3

	* Added Fourier reconstruction method

	* Support gcc 3.2, wxWindows 2.4, and MacOS X

	* Fix polar interpolation

Jun 26, 2002  Version 3.5.6

	* Fix minor color PNG image importing bug

	* Bug fix for building on Debian alpha platform

	* Fix g++ compilation warnings

Jun 13, 2002  Version 3.5.5

	* Fix printing of version number

	* Minor bug fixes

	* Updated Win32 compatibility

Jun 8, 2002  Version 3.5.4

	* Print version number in log window with About command

	* Fix problem with captions not showing on some windows. Reworked
	creation of new windows.

	* Disabled status bar on 3d views

	* Fix bug in configure.ac that prevented using compiler
	optimizations.

	* Updated About splash screen

May 29, 2002  Version 3.5.3
	* Added support for g++ 3.04 compiler

May 8, 2002  Version 3.5.2
	* configure: improved CTN (DICOM) installation search
	* src/ctsim.cpp: Fixed initial image size with import command

May 5, 2002  Version 3.5.1

	New Features:

	* ctsim: Added tips to be displayed at startup and via the help menu.
	* ctsim: Added center-detector concept. Allow for detector array
	to be any arbitrary distance from center of scanner. As a result,
	projection files are not incompatible with previous version of
	CTSim.
	* ctsim: Added threaded tasks and background manager for
	background processing as well as taking advantage of multiple-CPU's
	on SMP systems.  (Microsoft Windows only)
	* ctsim: Added plot t-theta sampling to projection file menu.
	* ctsim: Added Reconstruction with Rebinning for faster
	divergent beam reconstructions.
	* ctsim: Added import and export of DICOM image files.
	* ctsim: Added PPM, PGM, and PNG file import to imagefile.
	* ctsim: Added FFT/IFFT of columns of image files.
	* ctsim: Added clipboard cut/copy/paste for image files.
	* ctsim: Added region of interest to reconstructions.
	* ctsim: Added Convert Rectangular Image to Projection files
	* ctsim: Added "Verbose Logging", "Startup Tips", and
	"Background processes" options 	to Preferences dialog.
	* ctsim: Added plotting of projection file histograms.
	* plotfile: Added scattergram plot functions
	* ctsim: Added accelerator key for File-Properties
	* ctsim: Improved wireframe 3-d display to remove hidden
	surfaces.
	* backprojectors.cpp: Added setting of axis extent and increment
	to reconstructions.
	* projections.cpp: Can read and reconstruct SIEMENS AR.STAR DICOM
	projection data files.

	Bug Fixes:

	* views.cpp: reduced calls to progress bar update, significant speedup
	* views.cpp,ctsim.cpp: Fixed bug with window frames sometimes
	not being displayed on Unix platforms.
	* views.cpp: Added out-of-memory checks to display for huge
	image and projection files.
	* filter.cpp: Fixed Hanning parameter to be 0.5 rather than 0.54
	* imagefile.cpp: Fixed scaling factor in fftRows
	* imagefile.cpp: Fixed bug when performing magnitude() on real-valued
	image.
	* sgp.cpp: Fixed bug in drawCircle.
	* distribution: fixed problem with documentation files not
	being included with the distribution (Reported by Ian Kay).
	* sgp.cpp/ezplot.cpp: Improved plotting with markers.
	* fixed ctsimtext shell when giving no parameters to function-name
	* phm2if, phm2pj: Updated help messages for renamed phantoms

3.0.3 - Released 2/20/01

	* ctsim: Fixed core dump on Linux with OpenGL

	* ctsim: Fixed context-sensitive help on Linux

	* ctsim: Fixed About box on Linux

3.0.2 - Released 2/20/01

	* scanner.cpp: Fixed bug when number of detectors was even.

	* ctsim: Improved error handling when trying to convert
	divergent projections into polar form.

3.0.1 - Released 2/19/01

	* ctsim: Fixed dialog box for reconstruction so that
	rotation angle setting will stay fixed in-between use
	of the dialog box.

	* syserror: Fixed display bug for trace messages

	* ctsim: MSVC optimization bug work-around, compiler
	options changed.

3.0.0 - Released 2/19/01

	* ctsim: Massive update/fix to online help and print manual.

	* ctsim: Added context-sensitive help to dialog boxes

	* ctsim: Reformated all dialog boxes, much nicer now.

	* ctsim: Improved accelerator key handling

	* global: Added Hanning filter.

	* global: Improved default parameters to that all defaults give
	sensible output.

3.0.0beta1 - Released 2/11/01

	* ctsim: Added most-recently-used files to File menu with
	registry storage between executions.

	* ctsim: Hides arcane features unless enabled by Preferences dialog

	* ctsim: Added MDI interface for Windows version and made it default for Windows.

	* ctsim: Added 3-D wireframe view of images (uses OpenGL)

	* ctsim: Added graphical About box

	* ctsim: Escape key now removes cursor lines from image file view

	* ctsim: Added Revert to ImageFile menu

	* ctsim: Added accelerator (hotkeys) to frames

	* ctsim: Online help added!

	* backprojector: Added cubic interpolation

	* ctsim: Added icons to Frames on X-Window and MS Windows versions

	* ctsim: Fixed tick-label placement for plots on projection and
	reconstruction dialogs.

	* timer.h: Add use of _ftime when compiling on MSVC

	* global: Projection files are not compatible with previous version
	due to new scanner definitions.

	* global: deleted concept of field-of-view and added
	  view ratio and scan ratio concepts.

	* ctsim: Fixed crash on shutdown bug

	* pjinfo: Fixed bug when doing --dump and not specifing --endview

	* phm2pj: Fixed MPI bug with broadcasting of variables

	* ctsimtext-lam: Changes for first version to compile under lam


3.0.0alpha5 - Released 1/12/00

	* ctsim: Added EZPlotDialog, used by debugging plots in
	procsignal.cpp

	* ctsimtext: Fixed bugs for MSVC and with empty input lines. Fixed
	bug in parsing command-line parameters.

	* views.cpp: Fixed bug in copying of labels from images to
	plotfiles

	* syserror.cpp: fixed reporting for fatal errors

	* projections.cpp: fixed MSVC failure with std:: namespace

	* procsignal.cpp: fixed bug in equiangular reconstructions
	for frequency/inverse-fourier filtering

3.0.0alpha4 - Released 1/09/01

	* ctsim: Added reset to full-intensity scale menu item

	* ctsim: Add conversion of projections to polar plot [Thanks to
	Ian Kay for reference and math hints in polar bilinear scaling]

	* ctsim: improve bilinear scaling of image size [Thanks to Ian Kay
	for math tips]

	* ctsim: imagefile labels are now copied to plotfiles

	* ctsim: Added more analyze menuitems

	* ctsimtext: First version. All command-line tools are now accessed
	through this master shell. Has both command-line and interactive
	interface

	* ctsim: Fixed initialization of min/max bug for PlotFiles

	* ezplot: Cleaned up y-tick label placement

	* sgp: Added better support for projection/reconstruction animation

3.0.0alpha3 - Released 1/02/01

	* ctsim: Added plotting of histograms

	* imagefile.cpp: fixed bug in generation of 16-bit PNG images

	* ezplot.cpp: adjusted xtick label displays for better placement

3.0alpha2 - Released 1/02/01

 	* ctsim: All functions of command-line tools are now in graphical ctsim

	* ctsim: added generation of filter images

	* ctsim: Added 2-image math functions (mul, add, div, sub)

	* ctsim: Added export of imagefiles to graphic file formats

	* ctsim: Added support for scaling imagefiles in new sizes

	* ctsim: Added ability to save standard phantom definitions as
	text files suitable for reading.

	* ctsim: Add labels for image transformations and display of labels
	when performing properties of images.

	* processsignal.cpp: Fixed "off by one" bug in
	shuffleNaturalToFourierOrder when n is even. Moved functions to
	fourier.cpp

	* imagefile.cpp: Added FFTW library to imagefile processing. Converted
	image math functions to complex-valued math.

	* phantom.cpp: Added ability to save phantom files as ASCII text.

3.0alpha1 - Released 12/29/00

	* Added PlotFile class to system, used by if2 and ctsim for row
	and column plots and comparison plots

	* ctsim: Added image comparison statistics and image subtraction

	* ctsim: Added plotting of rows & columns with y-axis scaling

	* ctsim: Added row and column plot comparisons between two image
	files.

	* ctsim: Added "Process" menu to image file display with math
	functions. Added 2-dimensional inverse Fourier to math
	functions. Added support for complex (real/imaginary) images.

	* mathfuncs.cpp: Reworked statistics algorithm to share between
	imagefile and plotfile classes.

	* imagefile.cpp: Fixed scaling bug when rasterizing Phantom with
	nsamples > 2.  Added generic mage math functions, moved from
	if1.cpp and if2.cpp to imagefile.cpp. Added support complex
	images.

	* array2dfile.cpp: Added code to support complex (real/imaginary)
	images.

	* if1: Updated to handle error conditions, such as sqrt of a
	negative number. Converted to use new ImageFile math functions.

	* if2: Updated to output plot files and use new ImageFile class
	math functions

	* if1: Updated to use new ImageFile class math functions

	* ezplot: Reworked to better store colors/linestyles/symbols with
	individual curves. Improved display of labels and ticks. Updated
	to use POL class member variable. Updated to more C++ conventions.

	* pol: converted to C++ class. Extracted HashTable to separate
	class.

	* sgp: Added linestyle settings

2.5.0 - 12/18/00
   First Microsoft Windows GUI version
   Modifications for Microsoft Visual C++ compilation.
   Improved pjinfo to output binary headers and view data, useful
	when manually compiling phantoms that vary during projection
	process. Thanks to Ian Kay for idea and code submission.
   Improved sorting to find median in ImageFile::statistics
   Fixed core-dump bug in Array2dFile::labelsCopy() function (Ian Kay)
   Changed reconstruction dialog to fix onto smaller screens
   Fixed display of plotting in Projection views
   Improved animation displays for Projections and Reconstructions
   Changed code to explicitly use std:: namespace rather than
	"namespace using std" statements
   Fixed reconstruction scaling bug introduced in 2.0.6
   Renamed if2img to ifexport, if-1 to if1, if-2 to if2

2.0.6 - 12/03/00
   Fixed minor compilation problem with procsignal.h
   Updated README file
   Fixed bug when simulating projections and Trace == CONSOLE
   Fixed scaling bug when performing redundant rotations around object

2.0.5 - 12/01/00
   Improved compilation on RedHat 7
   Changed some of ANSI C header files to C++ header files
   Removed README.RedHat7

2.0.4 - 11/25/00
   Added documentation for --geometry setting
   Added README.RedHat7 document

2.0.3 - 11/20/00
   Fixed bug in generation of binary PGM files
   Fixed MPI compilation bug in phm2pj.cpp
   Inverted y-axis output for pj2if (bug alert from Ian Kay)

2.0.2 - 11/8/00
   Additions to man pages (Ian Kay)
   Fix problem with reading of ASCII phantom files (Ian Kay)

2.0.1 - 10/1/00
   Fixed syntax error in fftw configuration
   Slight modifications to support gcc v2.9.6

2.0.0 - 9/7/00
   Version 2.0.0 released!
   ctsim: Added Window menu to Main frame
   ctsim: Disabled not support reconstruction method
   Fixed obscure bug in sys_error
   Fixed compilation in mingw environment not present
   Fixed compilation in non-graphical environments

2.0.0-b12 - 9/4/00
   ctsim: Added animation of reconstruction
   ctsim: Added saving of dialog parameters for Projection & Reconstruction
   ctsim: Added progress dialog for rasterization of phantom
   ctsim: used setpriority to set lower priority
   ctsim: fixed pReconstruct not being deleted causing scaling problem
   ctsim: fixed projection animation dialog buttons

2.0.0-b11 - 9/1/00
   ctsim: Added projection graph to animation of projection collection
   ctsim: Added single stepping to projection collection animation
   ctsim: improved File/Properties display for projection files
   ctsim: Added progress dialog for reconstructions
   ctsim: Added file labels for projection and reconstruction images
   ctsim: Made File/Properties bring up modal dialogs
   Added reconstruction for Equilinear and Equiangular geometries
   Changed theta to be -PI/2 to make compliant with Kak-Slaney formulas
   Separated reconstruction into Reconstructor class
   Fixed center of detector adjustment for even number of detectors
   Added --enable-static to generate statically linked programs

2.0.0-b10 - 8/25/00
   ctsim: Added animation of projection collection processs
   ctsim: Added Auto Scaling for image windows
   ctsim: Change menus from "windowing" to "display scaling"
   Added FieldOfView and FocalLength ratio parameters to projection collection
   Added FocalLength & FieldOfView fields to projection data files
   Added Projection collection for Equilinear and Equiangular geometries
   Changed name of Rowland Phantom to correct name of Shepp-Logan
   Fixed bug in backprojection selection

2.0.0-b9 - 8/22/00
   Added RCS Id strings to executable files
   Added RPM Spec file for RPM package creation
   Added loading of ASCII phanthom definitions from files
   Fixed compilation for non-SGP architectures
   Decomposed SignalFilter class into ProcessSignal and SignalFilter classes
   Added Filter-Generation option to reconstruction to allow direct or
	inverse_fourier construction of filters
   Added median to statistics and to auto-windowing

2.0.0-b8 - 8/1/00
   Added line color support to SGP
   Fixed lineAbs bug

2.0.0-b7 - 7/25/00
   Finished support for dmallocxx library
   Fixed bug in SignalFilter::convertFilterMethodNameToID()
   Rewrote SGP & EZPlot to use C++ object-oriented. SGP can now write to
	G2 windows and well as WXWindows.
   ctsim program: "Create Phantom" now shows phantom object
   Fixed row-plot bug in if-2
   Reworked EZPlot's multiple plot operation

2.0.0-b6 - 7/22/00
   ctsim program: improved initial size and scroll area for image
	and projection files
   ctsim program: added rasterization parameters, projections parameters,
	and reconstruction parameters dialogs
   Moved char[] static definition from header files to c++ files
   Completely reorganized option processing in classes to improve
	expandability and to assist ctsim graphical user interface.

2.0.0-b5 - 7/17/00
   ctsim program: Added dialog to set minimum/maximum display levels
   Started ctsim.tex document file

2.0.0-b4 - 7/13/00
   Fixed compiler warnings at -Wall level
   Began work on CTSim program to be graphical front-end of all functions
   Moved current src/*.cpp to tools/*.cpp
   Made CTSim graphical front-end's home to be src/

2.0.0-b3 - 7/10/00
   Added highly optimized backprojection method idiff3
   Moved comparative stats to if-2 program from ifinfo
   Fixed image display in if2img using G2 library
   Added column-plot and row-plot options to if-2
   Added autoselection of analytic/calculated spatial responses to SignalFilter
   Added frequency-based preinterpolation to SignalFilter and idiff3
	backprojection method. Currently, this technique is still under
	development and debugging
   Moved graphic file writing to ImageFile class from if2img program

2.0.0-b2 - 7/07/00
   Cleaned up SignalFilter class
   Added zeropad option to pjrec
   Added zeropad options to html and cgi files
   Added fourier_table and rfttw filter methods
   Added FFTW routines to use real/half-complex transformations

2.0.0-b1 - 7/05/00
   Updated trace level processing
   Added trace level to SignalFilter
   Fixed magnitude vs. real output bug in FFT/Fourier filter

1.9.9 - 7/04/00
   Fixed const issue with ImageFileArray
   Fixed Array2dFile::labelsCopy()
   Added copy constructor and assignment for Array2dFileLabel class
   Added Timer to if-2.cpp and ifinfo.cpp
   Added beginning of frequency-based (DFT & FFT) filter to SignalFilter
   Added option processing for filter-method for pjrec to choose
	between convolution, dft, & fft filtering
   Fixed format string for EZPlot so axis labels now print
   Added support for FFTW library

1.9.8 - 6/27/2000
   Rewrote Array2dFile class to be non-templated
   Rewrote Array2dFile class to make reads and writes atomic. No disk files are kept open.
   Rewrote Array2dFileLabel class to make members private, added access routines
   Removed timedate.cpp in favor of standard C library time/date functions
   Renamed ctrec to pjrec, sample-ctrec.sh to sample-ctsim
   Added signature tag and creation date/time to projection files

1.9.7 - 6/25/2000
   Standardized string option processing by classes. All classes use character strings
	to select options rather than numeric constants. Added fail() and failMessage()
	methods to verify that objects are created correctly by character strings.
   Hid C++ assignment and copy constructors in classes that should not have assignment/copy
   Rewrote ImageFile class
   Started support for dmallocxx library, not finished
   Added G.T. Herman image comparision statistics to ifinfo (see imagefile.cpp)
   Updated ifinfo to show comparative statistics
   Added printLabels() to Array2dFile class
   Added printStatistics() to ImageFile class

1.9.6 - 6/22/2000
   Moved conversion filter name/id to Filter class
   Moved conversion backprojection name/id to Backproj class
   Added MPI broadcasting of strings

1.9.5 - 6/21/2000
   Merged proj_reconstr into class Projections
   Used auto_ptr in Projections::reconstruct to make sure destructor is always called
   Code cleanup in projections.cpp
   Moved conversion of phantom names/id to Phantom class

1.9.4 - 6/20/2000
   Converted projection files to C++ library with frnetorderstream
   Converted image files to C++ library with frnetorderstream
   Converted filter and convolution to object-oriented code
   Changed default image file to float from double -- Changable in imagefile.h
   Optimized image file writing on little-endian architectures
   Updated README and INSTALL

1.9.3 - 6/19/2000
   Reorganized source files
   MPI bug fixed to phm2pj.cpp

1.9.2 - 6/18/2000
   Reorganized include files
   Fixed const pointers in strfuncs

1.9.1 - 6/16/2000
   Renamed directories, moved source files, combined source files
   to change from 6 libraries to 3 libraries (libctsim, libctsupport,
   and libctgraphics)

1.9.0 - 6/15/2000
   Skip versions to make version 2.0 the first fully C++ version
   Renamed Raysums to Projections throughout files
   Renamed Detector to Scanner
   Converted Scanner and Projecions to full object-oriented

0.6.1 - 6/12/2000
   Converted Phantom and PhantomElements to Object-Oriented
   Converted Detector to Object-Oriented

0.6.0-b3 - 6/10/2000
   Improved Integer backprojection method
	Fixed nearest neighbor to be truly nearest neighbor
	Made linear interpolation more integer arithmetic -> speed improvement
   Finished converting all C files to C++
   Converted all use of malloc/free to C++ new/delete
   Began object-oriented conversion of Phantom and Projection structures

0.6.0-b2 - 6/8/2000
   Converted MPI data structures to C++ object
   Made ImageFile directly inherit from Array2dFile

0.6.0-b1 - 6/6/2000
   First C++ conversions
   Portable IF (image file) format implemented with objects (SDF removed)
	- Now all data files are cross-platform compatible
   Converted from MPI to MPI++
   Converted backprojection to object-oriented
   Removed MTX from libkmath as no longer need -- replaced with C++ matrices

0.5.4 - 6/4/2000
   Simpilifed endian handling

0.5.4-b3 - 6/1/2000
   Added support for 64-bit (IA64) CPU
   Removed broken B-spline interpolation
   Added support for cygwin platform under Windows 2000
   Added support for 16-bit PNG graphics

0.5.4-b2 - 5/16/2000
   Added compile-time configuration of endian order

0.5.4-b1 - 5/14/2000
   Modified the raysum file format to be platform independent

0.5.3 - 5/11/2000
   Added Microsoft VC compatibility
   Cleaned up compilation warnings in libgraph

0.5.2-b5 - 5/7/2000
   Continued conversion to ANSI C
   Removed old CRT routines

0.5.2-b4 - 5/4/2000
   Renamed pictures to phantoms, objects to phantom elements
   Continued code cleanup

0.5.2-b3 - 4/30/200
    More code cleanup with reorganizing libraries
    Added --log and --exp to sdf-1
    Allowed negative numbers for window levels in CGI interface

0.5.2-b2 - 4/30/200
    Continued code cleanup

0.5.2-b1 - 4/29/2000
    Fixed a few MPI bugs
    Better documented, coded raysum in-memory on on-disk options

0.5.1 - 4/28/2000
    Cleaned out library that wasn't being used by CTSim
    Modified ctsim.cgi to read in configuration file ctsim.conf

0.5.0 - 4/27/2000
    First open source distribution for GNU/Linux

6/1999
  Converted to GNU/Linux
  added MPI support via LAM library

1983-84
  Developed under MS-DOS and IBM EGA graphics
