1. NAC: Optimized registration in Slicer
Goals
Optimize ITK registration framework
Targets:
Multi-processor and multi-core, shared memory systems
Medium and large-size problems
Transforms, Interpolators, and metrics
Thread, pre-compute, and integrate
Maximize backward compatibility
Monitor project’s progress
Deliver as Slicer3 modules

2. Optimize registration
Threaded base classes: interpolators, transforms, and metrics
TransformPoint(itk::Point, unsigned int threadID)
GetValue(itk::Point, unsigned int threadID)
Reduce creation/destruction of local vars
Increase memory requirements (minimal)

3. Optimize registration
Extend ImageToImageMetric base class
Samples
Random, entire image, or passed as list
Detect BSpline transform
pre-compute weights, relevant control points, and rigid transform of samples
Integrate transform and metric
Detect BSpline interpolator
Optimize derivative computation
Threaded metric computation
ThreadedPreProcess
ThreadedProcessSample
ThreadedPostProcess

4. Optimize registration
Other optimizations
Memset
Floor
Do not use MUTEX
Limit amount of data distribution and integration when threads created/destroyed
Method-specific optimizations
E.g., MattesMIMetric
JointPDF – one per thread during process sample
JointPDF – re-integrated using one region per thread

5. Monitor RealTimeHighPriorityTimer BatchMake BatchBoards
SetPriority, SetThreadAffinity
BatchMake
GetCPUInfo
# of cores, speed, etc
GetMemoryInfo
Physical memory
SendToBatchBoard
Parameters, results
Available as commands, function calls, and CMake variables
BatchBoards

6. Results

7. NAC: Optimized registration in Slicer
Slicer Modules
BWHITKOptimization/Code/Applications/SlicerRegistrationModules
Same GUI as current registration modules