OpenIGTLink & PLUS Surgical Navigation (.igtl, .plus.xml)

@modelscript/igtl (languages/igtl) provides native WebAssembly parsing, $SE(3)$ homogeneous transform orthogonality (${\mathbf{R}}^{\mathrm{\top }}\mathbf{R}=\mathbf{I}$, $det\mathbf{R}=+1$) and coordinate-frame graph connectivity verification, stylus pivot calibration, Fitzpatrick (1998) Target Registration Error ($\text{TRE}$) estimation, DAEBuilder lowering, and ROS 2 URDF / Modelica projections for OpenIGTLink and PLUS Toolkit image-guided surgical navigation systems.

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Supported Extensions & Standards

Extension	Format	Description
.plus.xml, .xml	PLUS Toolkit Config	PlusConfiguration XML defining optical/EM trackers (DataCollection), <CoordinateDefinitions> $SE(3)$ transforms, pivot/phantom calibration, and <PlusOpenIGTLinkServer> streams
.igtl	OpenIGTLink Stream	Surgical navigation TRANSFORM, POSITION, TRACKING_DATA, IMAGE, and STATUS message definitions

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Key Capabilities

1. $SE(3)$ Coordinate Frame Graph & Matrix Orthogonality

• Parses $4\times 4$ homogeneous transformations ${\mathbf{T}}_{\text{From}\to \text{To}}\in SE(3)$ across surgical coordinate frames (Tracker, Patient, Reference, Stylus, StylusTip, Probe, UltrasoundImage, RAS) and computes composite chains via breadth-first graph traversal with automatic matrix inversion ${\mathbf{T}}^{-1}=\left[\begin{array}{cc}{\mathbf{R}}^{\mathrm{\top }}& -{\mathbf{R}}^{\mathrm{\top }}\mathbf{t}\\ {\mathbf{0}}^{\mathrm{\top }}& 1\end{array}\right]$.

2. Stylus Pivot Calibration & Fitzpatrick Target Registration Error ($\text{TRE}$)

• Solves least-squares spherical pivot calibration (solveTransformChainAndPivot) to determine stylus tip offset ${\mathbf{p}}_{\text{tip}}$, pivot point ${\mathbf{p}}_{\text{pivot}}$, and RMS calibration residual ($<1.5\text{ mm}$).
• Evaluates expected surgical Target Registration Error at target $\mathbf{r}$ from $N$ fiducial markers with Fiducial Localization Error ($\text{FLE}$) using Fitzpatrick's formula:$$⟨{\text{TRE}}^2(\mathbf{r})⟩=\frac{⟨{\text{FLE}}^2⟩}{N}(1+\frac{1}{3}\sum _{k=1}^3\frac{d_k^2}{f_k^2})$$

3. ROS 2 URDF & Modelica Projections

• Projects surgical tracker coordinate trees into ROS 2 URDF (igtlToUrdf) and Modelica 3.x (igtlToModelica).

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Pre-Flight Diagnostics

10 rules9 error1 warning

Code	Rule	Severity	Message
M9801	igtl-non-orthogonal-rotation	error	Transform '<from> -> <to>' has non-orthogonal or reflection 3x3 rotation block (||R^T R - I||_F = <frobErr>, det(R) = <det>).
M9802	igtl-invalid-homogeneous-bottom-row	error	Transform '<from> -> <to>' has invalid 4x4 homogeneous bottom row '[<rowStr>]' (expected '[0, 0, 0, 1]').
M9803	igtl-disconnected-coordinate-frame	error	Coordinate frame graph is disconnected: <detail>.
M9804	igtl-cyclic-transform-chain	error	Directed cycle detected in coordinate transform definitions: '<cycleStr>'.
M9805	igtl-excessive-registration-error	warning	Registration or calibration RMS error '<errorMm> mm' on '<contextName>' exceeds clinical safety threshold '<thresholdMm> mm'.
M9806	igtl-invalid-acquisition-rate	error	Device '<deviceId>' has invalid AcquisitionRate '<rateHz> Hz' (must be > 0 Hz).
M9807	igtl-unresolved-device-or-channel	error	'<contextName>' references undeclared <refKind> '<refId>'.
M9808	igtl-self-transform-identity-mismatch	error	Self-transform '<frameName> -> <frameName>' must be the 4x4 identity matrix.
M9809	igtl-invalid-server-port	error	OpenIGTLink server '<serverId>' ListeningPort '<port>' is outside valid TCP port range [1024, 65535].
M9810	igtl-duplicate-transform-edge	error	Duplicate '<Transform>' defined for coordinate frame pair '(<from>, <to>)'.

Generated from languages/igtl/src/lints/rules.ts. All languages →

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CLI Usage

# Inspect tracking devices, SE(3) transforms, and OpenIGTLink servers
msx igtl inspect LaparoscopicTracker.plus.xml

# Validate SE(3) rotation orthogonality, frame connectivity, and TRE limits
msx igtl validate LaparoscopicTracker.plus.xml

# Solve coordinate frame chains, stylus pivot calibration, and Fitzpatrick TRE
msx igtl calibrate LaparoscopicTracker.plus.xml

# Project surgical navigation frame tree to ROS 2 URDF or Modelica
msx igtl to-urdf LaparoscopicTracker.plus.xml > SurgicalTracker.urdf
msx igtl to-modelica LaparoscopicTracker.plus.xml > SurgicalTracker.mo