Sensor-to-surface field mapper that interpolates MEG/EEG measurements onto cortical meshes and generates iso-contour overlays. More...

#include <sensorfieldmapper.h>

Public Member Functions
	SensorFieldMapper ()=default
void	setEvoked (const FIFFLIB::FiffEvoked &evoked)
bool	isLoaded () const
void	setTimePoint (int tp)
int	timePoint () const
void	setMegFieldMapOnHead (bool onHead)
bool	megFieldMapOnHead () const
void	setColormap (const QString &name)
const QString &	colormap () const
const FIFFLIB::FiffEvoked &	evoked () const
bool	hasMappingFor (const FIFFLIB::FiffEvoked &newEvoked) const
const QVector< int > &	megPick () const
const QVector< int > &	eegPick () const
QSharedPointer< Eigen::MatrixXf >	megMapping () const
QSharedPointer< Eigen::MatrixXf >	eegMapping () const
bool	buildMapping (const QMap< QString, std::shared_ptr< BrainSurface > > &surfaces, const FIFFLIB::FiffCoordTrans &headToMriTrans, bool applySensorTrans)
void	apply (QMap< QString, std::shared_ptr< BrainSurface > > &surfaces, const SubView &singleView, const QVector< SubView > &subViews)
const QString &	megSurfaceKey () const
const QString &	eegSurfaceKey () const
void	computeNormRange ()

Static Public Member Functions
static QString	findHeadSurfaceKey (const QMap< QString, std::shared_ptr< BrainSurface > > &surfaces)
static QString	findHelmetSurfaceKey (const QMap< QString, std::shared_ptr< BrainSurface > > &surfaces)
static float	contourStep (float minVal, float maxVal, int targetTicks)
static Eigen::Vector3f	fitSphereOrigin (const FIFFLIB::FiffInfo &info, float *radius=nullptr)

Detailed Description

Sensor-to-surface field mapper that interpolates MEG/EEG measurements onto cortical meshes and generates iso-contour overlays.

Encapsulates sensor-to-surface field mapping for MEG and EEG sensors.

This class owns the mapping state (evoked data, mapping matrices, channel picks, contour prefixes, surface key references) and provides methods to build mapping matrices and apply them to produce per-vertex field colours and iso-contour meshes.

The class operates on surface and contour surfaces stored in the caller's surface map. It reads from / writes to those surfaces but does not own them, keeping ownership in the BrainView.

Definition at line 73 of file sensorfieldmapper.h.

Constructor & Destructor Documentation

◆ SensorFieldMapper()

SensorFieldMapper::SensorFieldMapper ( )

default

Construct an empty (unloaded) mapper.

Member Function Documentation

◆ apply()

void SensorFieldMapper::apply	(	QMap< QString, std::shared_ptr< BrainSurface > > &	surfaces,
		const SubView &	singleView,
		const QVector< SubView > &	subViews )

Apply the precomputed mapping to the current time point.

Paints per-vertex colours onto the target surfaces and optionally generates iso-contour line meshes.

Parameters

[in,out]	surfaces	Surface map (contour surfaces may be added).
[in]	singleView	The single-view SubView for visibility flags.
[in]	subViews	The four multi-view SubViews.

Definition at line 516 of file sensorfieldmapper.cpp.

◆ buildMapping()

bool SensorFieldMapper::buildMapping	(	const QMap< QString, std::shared_ptr< BrainSurface > > &	surfaces,
		const FIFFLIB::FiffCoordTrans &	headToMriTrans,
		bool	applySensorTrans )

Build the MEG/EEG sensor-to-surface mapping matrices.

Needs the caller's surface map to locate the helmet and/or head surface. Also needs the head-to-MRI transformation and whether sensor transforms should be applied.

Parameters

[in]	surfaces	All surfaces keyed by name.
[in]	headToMriTrans	Head → MRI coordinate transform.
[in]	applySensorTrans	Whether to apply the sensor → MRI transform.

Returns: true on success (at least one mapping built).

Definition at line 193 of file sensorfieldmapper.cpp.

◆ colormap()

const QString & SensorFieldMapper::colormap ( ) const

inline

Definition at line 130 of file sensorfieldmapper.h.

◆ computeNormRange()

void SensorFieldMapper::computeNormRange ( )

Compute the normalization range anchored at the peak-GFP time.

For each modality the Global Field Power (GFP = sqrt(mean(V_i^2))) is evaluated across all time samples and we pick the time of maximum GFP. vmax = max(|mapped|) is then computed at that peak time, giving the colour-map range [-vmax, +vmax].

This matches MNE-Python's plot_field behaviour, where the initial view shows the evoked peak, so the colour scale is anchored to it. The range stays fixed during time scrubbing until explicitly recomputed (e.g. by switching to a new evoked data set).

Must be called after building or reusing a mapping matrix with new evoked data. buildMapping() calls this automatically.

Definition at line 457 of file sensorfieldmapper.cpp.

◆ contourStep()

float SensorFieldMapper::contourStep	(	float	minVal,
		float	maxVal,
		int	targetTicks )

static

Compute a "nice" iso-contour step given a value range and target number of ticks.

Definition at line 171 of file sensorfieldmapper.cpp.

◆ eegMapping()

QSharedPointer< Eigen::MatrixXf > SensorFieldMapper::eegMapping ( ) const

inline

Returns: Shared pointer to the EEG mapping matrix (may be null).

Definition at line 167 of file sensorfieldmapper.h.

◆ eegPick()

const QVector< int > & SensorFieldMapper::eegPick ( ) const

inline

Returns: Const reference to the EEG channel pick indices.

Definition at line 157 of file sensorfieldmapper.h.

◆ eegSurfaceKey()

const QString & SensorFieldMapper::eegSurfaceKey ( ) const

inline

Returns: The surface key used for the EEG mapping target.

Definition at line 210 of file sensorfieldmapper.h.

◆ evoked()

const FIFFLIB::FiffEvoked & SensorFieldMapper::evoked ( ) const

inline

Returns: Const reference to the loaded evoked data.

Definition at line 136 of file sensorfieldmapper.h.

◆ findHeadSurfaceKey()

QString SensorFieldMapper::findHeadSurfaceKey ( const QMap< QString, std::shared_ptr< BrainSurface > > & surfaces )

static

Find a BEM head surface key in the given surface map.

Looks for "bem_head" first, then any BEM surface whose tissue type is BrainSurface::TissueSkin.

Definition at line 142 of file sensorfieldmapper.cpp.

◆ findHelmetSurfaceKey()

QString SensorFieldMapper::findHelmetSurfaceKey ( const QMap< QString, std::shared_ptr< BrainSurface > > & surfaces )

static

Find the MEG helmet surface key ("sens_surface_meg") if present.

Definition at line 161 of file sensorfieldmapper.cpp.

◆ fitSphereOrigin()

Eigen::Vector3f SensorFieldMapper::fitSphereOrigin	(	const FIFFLIB::FiffInfo &	info,
		float *	radius = nullptr )

static

Fit a sphere to the digitization headshape points.

Replicates MNE-Python's fit_sphere_to_headshape (linear least- squares sphere fit). Uses FIFFV_POINT_EXTRA digitization points by default; falls back to EXTRA + EEG if fewer than 4 extra points exist. Nose/face points (z < 0 && y > 0) are excluded.

Parameters

[in]	info	FiffInfo containing the digitization points.
[out]	radius	Fitted sphere radius (metres). May be `nullptr`.

Returns: The sphere centre in head coordinates (metres). Returns (0, 0, 0.04) if the fit cannot be performed.

Definition at line 377 of file sensorfieldmapper.cpp.

◆ hasMappingFor()

bool SensorFieldMapper::hasMappingFor ( const FIFFLIB::FiffEvoked & newEvoked ) const

Check whether the current mapping matrices can be reused for a new evoked data set (i.e., same sensor configuration: same channels, same SSP projectors, same bad channels).

Parameters

[in] newEvoked The candidate new evoked data.

Returns: true if the existing mapping is compatible, false if rebuild is needed.

Definition at line 109 of file sensorfieldmapper.cpp.

◆ isLoaded()

bool SensorFieldMapper::isLoaded ( ) const

inline

Returns: true if evoked data has been loaded and is non-empty.

Definition at line 96 of file sensorfieldmapper.h.

◆ megFieldMapOnHead()

bool SensorFieldMapper::megFieldMapOnHead ( ) const

inline

Definition at line 120 of file sensorfieldmapper.h.

◆ megMapping()

QSharedPointer< Eigen::MatrixXf > SensorFieldMapper::megMapping ( ) const

inline

Returns: Shared pointer to the MEG mapping matrix (may be null).

Definition at line 162 of file sensorfieldmapper.h.

◆ megPick()

const QVector< int > & SensorFieldMapper::megPick ( ) const

inline

Returns: Const reference to the MEG channel pick indices.

Definition at line 152 of file sensorfieldmapper.h.

◆ megSurfaceKey()

const QString & SensorFieldMapper::megSurfaceKey ( ) const

inline

Returns: The surface key used for the MEG mapping target.

Definition at line 205 of file sensorfieldmapper.h.

◆ setColormap()

void SensorFieldMapper::setColormap ( const QString & name )

inline

Set the colormap name used when painting field values.

Parameters

[in] name Colormap identifier (e.g. "MNE", "hot", "RdBu_r").

Definition at line 128 of file sensorfieldmapper.h.

◆ setEvoked()

void SensorFieldMapper::setEvoked ( const FIFFLIB::FiffEvoked & evoked )

Set the evoked data that supplies measurements and channel info.

After calling this, isLoaded() returns true when non-empty.

Parameters

[in] evoked The evoked dataset (contains info + data matrix).

Definition at line 86 of file sensorfieldmapper.cpp.

◆ setMegFieldMapOnHead()

void SensorFieldMapper::setMegFieldMapOnHead ( bool onHead )

inline

Whether the MEG field should be mapped onto the head (BEM) surface rather than the helmet surface.

Parameters

[in] onHead true to map onto head, false for helmet.

Definition at line 118 of file sensorfieldmapper.h.

◆ setTimePoint()

void SensorFieldMapper::setTimePoint ( int tp )

inline

Set the active time point index into the evoked data matrix.

Parameters

[in] tp Zero-based time index.

Definition at line 104 of file sensorfieldmapper.h.

◆ timePoint()

int SensorFieldMapper::timePoint ( ) const

inline

Returns: Current time point index.

Definition at line 109 of file sensorfieldmapper.h.

The documentation for this class was generated from the following files:

src/libraries/disp3D_rhi/scene/sensorfieldmapper.h
src/libraries/disp3D_rhi/scene/sensorfieldmapper.cpp

Public Member Functions

Static Public Member Functions

Detailed Description

Constructor & Destructor Documentation

◆ SensorFieldMapper()

Member Function Documentation

◆ apply()

◆ buildMapping()

◆ colormap()

◆ computeNormRange()

◆ contourStep()

◆ eegMapping()

◆ eegPick()

◆ eegSurfaceKey()

◆ evoked()

◆ findHeadSurfaceKey()

◆ findHelmetSurfaceKey()

◆ fitSphereOrigin()

◆ hasMappingFor()

◆ isLoaded()

◆ megFieldMapOnHead()

◆ megMapping()

◆ megPick()

◆ megSurfaceKey()

◆ setColormap()

◆ setEvoked()

◆ setMegFieldMapOnHead()

◆ setTimePoint()

◆ timePoint()