prelim_plus
Preliminary facts about Plus
- Every device has its own thread and manages a number of data sources (one or more). Examples of devices: EM tracker, optical tracker, US, webcam, etc. A single tracking device includes one or more tracked tools (eg US probe, needle, reference)
- Data is bundled in channels for communication. There are input and output channels
- Each channel can include ONLY ONE video stream and several tracking streams (transform streams)
- See Data Collection Configuration http://perk-software.cs.queensu.ca/plus/doc/nightly/user/Configuration.html#DataCollection
- A “tracked device” includes a video stream (eg ultrasound) and one or more tracked streams (eg transforms for body, needle and probe) bundled in a single output channel
- Virtual mixers are used to create new devices by combining incoming data (through input channels) from other devices (supplied through their output channels) and, in turn, providing new output channels. This is used, for example, to create tracked devices, or to combine several tracking devices. http://perk-software.cs.queensu.ca/plus/doc/nightly/user/DeviceVirtualMixer.html
- Data flowing from output channels can be recorded to disk as File Sequence Metafiles (.mha and .mhd) using a Virtual Capture device: http://perk-software.cs.queensu.ca/plus/doc/nightly/user/DeviceVirtualCapture.html
- .mha (text file), .mhd (text header and raw data): http://perk-software.cs.queensu.ca/plus/doc/nightly/user/FileSequenceFile.html#FileSequenceMetafile
- The Virtual Capture device ONLY includes ToolsToReference transforms in .mha (ie just the tracking Information. Plus Server can send derived transformations over OpenIGTLink as defined in the PlusOpenIGTLinkServer of the configuration file. Hence, if such transforms are also needed they must be computed (eg using the EditSeqMetaFile application bundled with Plus)
- Data recorded on disk can be replayed using the SavedDataSource device and the corresponding .mha or .mhd sequence files. Replaying disk is identical to external software such Slicer as receiving realtime data from trackers. Hence, capturing and replaying can be used to facilitate later experiments, when hardware is not available: http://perk-software.cs.queensu.ca/plus/doc/nightly/user/DeviceSavedDataSource.html
- The section CoordinateDefinitions of the Plus configuratioon files includes the fixed transforms obtained by calibration. This is necessary to compute on-the-fly the derived transforms that are transmitted via OpenIGTLink (not recorded in the sequence files): http://perk-software.cs.queensu.ca/plus/doc/nightly/user/CoordinateSystemDefinitions.html
- The section PlusOpenIGTLinkServer of the Plus configuration files includes the communication parameters and transforms: http://perk-software.cs.queensu.ca/plus/doc/nightly/user/ApplicationPlusServer.html#ApplicationPlusServerConfigSettings
prelim_plus.txt · Last modified: 2024/01/24 19:00 by costin