From 1e3ac43a7d1ab60acc383b1839683c288269b4b8 Mon Sep 17 00:00:00 2001 From: Willem Jan Palenstijn Date: Fri, 17 Jan 2020 17:43:28 +0100 Subject: [PATCH] Update for consistency branch --- conf.py | 4 ++-- index.rst | 4 ++-- news.rst | 20 ++++++++++++++++++++ 3 files changed, 24 insertions(+), 4 deletions(-) diff --git a/conf.py b/conf.py index 076212d..aafcd00 100644 --- a/conf.py +++ b/conf.py @@ -60,9 +60,9 @@ # built documents. # # The short X.Y version. -version = '1.9.0.dev11' +version = '1.9.9.dev1' # The full version, including alpha/beta/rc tags. -release = '1.9.0.dev11' +release = '1.9.9.dev1' # The language for content autogenerated by Sphinx. Refer to documentation # for a list of supported languages. diff --git a/index.rst b/index.rst index 1fa9991..5d1fe97 100644 --- a/index.rst +++ b/index.rst @@ -19,6 +19,8 @@ The source code of the ASTRA Toolbox is available on `GitHub `_ for more information. + * For those visiting `ICTMS 2019 `_ in Australia, we will host `an ASTRA workshop `_ there on 22 July 2019. * Windows Matlab/Python packages of the current 1.9.0.dev version of ASTRA @@ -26,8 +28,6 @@ Latest News * We now have development Python packages available from ASTRA git master on conda. Quick installation instructions: ``conda install -c astra-toolbox/label/dev astra-toolbox`` . -* From 5 to 7 April 2017, the Vision Lab organizes an ASTRA Toolbox training session at the University of Antwerp. - * 7 dec 2016: ASTRA v1.8 released diff --git a/news.rst b/news.rst index c123df4..6211d48 100644 --- a/news.rst +++ b/news.rst @@ -4,6 +4,26 @@ News and version history News ---- +* 2020-01-17: Consistency changes in development version of ASTRA + + We have changed the way gray values in forward projections, backprojections and reconstructions scale with the size of detector pixels. This does not impact geometries where the detector pixels have size 1 in 2D, or 1x1 in 3D. + + In the upcoming ASTRA 2.0, and starting from version 1.9.9.dev, for all geometries and projectors, the value of a pixel in a forward projection is approximately the value of the line integral of the corresponding ray through the volume. + + Of course the interpolation/projection method used will still determine the exact set of pixels contributing to a ray and the exact value as before. + + All backprojectors and reconstruction algorithms have been adapted to match the forward projection. + + Before this change, a decision made in the early pre-1.0 days of ASTRA to make detector values scale linearly with the area of detector pixels led to some in hindsight mathematically unresolvable inconsistencies in behaviour between parallel and fan/cone geometries, and behaviour with oblique projections. The new definition resolves this inherent inconsistency. + + Specific changes: + + * all parallel beam 2D projectors (CPU and CUDA) have been changed as above + * the 2D fan beam CPU projectors have been changed as above + * the 2D fan beam CUDA projector did not require changing + * the 3D CUDA backprojectors have been changed as above. The forward projectors did not require changing + * the 2D fan beam and 3D cone beam CUDA backprojectors now have an improved approximate match with the respective forward projectors + * 2019-07-09: Development packages of 1.9.0.dev are now available for download. The Windows packages now require CUDA 9.0 or higher.