# Summary of changes in PARAPET release 0.91 (dated 19/07/2000)

## General changes:

- added conversion to ecat6 and handle ecat7
- software is now tested on Linux (on Pentium) with gcc 2.95.2 (this only needed some changes to PPhead/Makefile_common)
- Interfile parser follows now the 3.3 standard, and some of the proposed extensions there-in on vectored keys (Note: this is the parser only, NOT the keywords).
- corrected some problems with Makefiles
- added the extract_segments utility

## OSEM related changes:

- corrected a bug that caused problems with parsing .par files (for instance, the interiteration filtering setting was ignored on some architectures)
- thresholding after filter operations (to obtain positive image values) is changed to make it insensitive to spurious peaks in the image

## Other:

- fixed a bug that made the truncate_end_planes in manip_image do nothing.
- the Absolute Difference operation in manip_image (MATH MODE option 2) is now applied to all voxels.
- compare_image uses a slightly higher threshold now
- made utilities/do_linear_regression compile
- added PPhead/test/input/test_linear_regression.in to the archives. (Needed for make run_tests)

Last modified: Wed Jul 19 15:54:43 BST 2000