Implementing highly efficient internal volume codec that is targeting the volumes upsampled using the NN-interpolation.  This is a critical function during the PET-4D to MR registration.
User optimally desires best available resolution for both registered volume, which is typically a MR resolution.  However, for high timepoint # the resulting volumes might reach upto 7 GB  (compressed with the regular FireVoxel compression).
This new codec will allow much higher compression of such registered PET volumes.

It is lossless.

High-accuracy PET-to-MR registration using an approximate BrainMask with 4X speed gain.

Presently, it is very hard to achieve PET-to-MR registration without additional guidance.
From previous registration experience, a quick  Brain ROI was obtained using the BrainMask\EdgeWave tool.

This ROI is just an approximation of an anatomically precise mask of the brain. FireVoxel can obtained a much more precise BrainMask by adding the non-uniformity correction to that workflow.



After obtaining BrainMask ROI, the regular  PET-to-MR registration runs that uses ROI as a guidance.  Resulting registration has a very high accuracy.
The whole processing is less than 4 minutes on the reference ($1K) PC.

Single volume Edge-constrained smoothing:  partially combined the code with the similar logic of "Inter-volume constrained smoothing".  Reused the dialog common for both functions.

Corrected the logic for the Registration3D: TargetROI.  Included a new  dialog item that explicitly displays the name of the layer to be used as a Target ROI.

Implemented an initial variant of the "Inter-volume Edge Constrained Smoothing".  In this  test:
a) MR and PET4D were registered with very high accuracy.
b) MR-edges (as 3D surfaces) were detected using the texture-edge detector (URAL)
c) PET-volume was smoothed, with smoothing apperture that was constrained by the presence
of edges within vicinity of every voxel.

This just a prototype as many options are available.
Specialized dialog box was developed.

Implemented the two-compartment Sokoloff'77 model (long formula) also used in Reivich'85. Results are identical (to 0.01% precision) with the Sokoloff'79 interpretation (short formula)
in the initial tests.

PET:  Latest version of the IDIF.  User does NOT have to specify the dominant direction anymore.  Also the meaning of the seed is changed - User just have to place the center of the seed on the vessel.  Other parameters, such as max vessel length, are enabled.

Added L1/L2 optional residual metric to  Sokoloff'79 (short) model.

Completely re-enginered the Sokoloff-79 model (as in Wai's implementation = short formula).

a) Enabling the analytic integration, instead of PWL-functions.  This also eliminates the need for the 1-sec upsampling of the TAC data used in the old version.

b) More streamlined and corrected implementation of the Ta-arterial delay.

Re-enabled ABT subtest for the "Liver DCDI-standard model"

Dynamic Experiment module (Parametric maps) flow:  correcting a significant inefficiency of dealing with the Void voxels (as in  "Process ROI only"  mode).  Entirely reengineered a parallel processing structure for the Voxelwise parametric map, especially for "ROI only" mode.

Liver DCDI model defect:  when voxelwise map (over the ROI) is requested calculation "hangs" and performance monitor shows only a single core loaded.

ABT: added an automatic subtest for PET4D to MR4D registration, with several layers each, to Best Resolution option.

ABT:   adding automatic subtest for   PET4D<->MR4D multilayer registration.

ABT:  adding the "WM lesions \FLAIR"  segmentation to the automatic build test.
Also the corresponding dialog for "WM lesions \FLAIR"  parameters is automatically tested by Open\Close.

IDIF function:  "Keep high filter" is an effective way to reduce partial volume voxel effect and deviation outside the vessel.  This is an example on Aorta (Liver DCDI dataset)

Red ROI:  All the preliminary voxels were kept  (Keep high signal=1)
Blue ROI:  Only highest half of the voxels was kept.

Automatic Build Test:  adding the IDIF (vessel segmentation) subtest.
Also the corresponding dialog for IDIF parameters is automatically tested by Open\Close.

Automatic IDIF (input function):  added an option to restrict the length of the vessel from the start point. This is requested by all the users of this functionality.

Unconstrained-length segmentation    vs.    15mm-constrained segmentation.

Updated the IDIF user interface and algorithm:
a) Adding a drop down combo box where user can select the direction {X,Y,Z} of the Vessel.
b) Adding an experimental option {Auto} for the direction of the vessel.  In this mode, all 3 directions will be checked and the largest (by voxel count) resulting vessel would be selected.

New features seem to provide a substantial improvement in usability and quality of the result. F.e. in liver, we would like to always work in Axial projection where the Portal Vein direction is often along {X,Y} axis.

So in new version, user does not have to choose the direction of the vessel.  So for portal vein the "Auto" direction is set by default.

Another change is that the seed does not have to cover the vessel.  Instead, it is only assumed that the center of the seed should be very close to the vessel in question.

Provided a basic documentation for Liver DCDI registration workflow.