GlSweepReconstruction Class Reference

#include <ImFusion/US/GlSweepReconstruction.h>

Reconstruction of pixel data of one or multiple UltrasoundSweep image sets into an arbitrary 2D frame in 3D space. More...

Inheritance diagram for GlSweepReconstruction:

Detailed Description

Reconstruction of pixel data of one or multiple UltrasoundSweep image sets into an arbitrary 2D frame in 3D space.

This class tries to sample from all the sweep's 2D frames positioned in space in an optimal way to efficiently reconstruct a single 2D image without streaks. It is needed everywhere in the framework where image information is sampled in 3D space regardless of where the underlying 2D frames of the (freehand) UltrasoundSweep are located. As such, it is - among others - used in the framework to:

• Display sweeps in MPR views by rendering, see GlSliceRendererSweep
• Compound a 3D volume / reconstruct into a regular 3D grid, see GlSweepCompounding
• Reconstruct one sweep into the original frames of another to compute a 2D similarity metric, see UltrasoundCalibration

This class performs the inverse operation of VolumeReslicingAlgorithm.

Note

Masks and deformations are supported, as long as the same ones are used for each frame. It will use the mask/deformation assigned to the focus image of the sweep.

Fundamentally, there are two GPU-based reconstructions available:

• The direct reconstruction directly renders fragments between adjacent frames. This approach is fast but requires the frames to be ordered sequentially in space. There are two sub-types: parallel and orthogonal reconstruction, which are tuned to exploit prior knowledge on the main orientation of the sweep's frames. In MPR settings, the axial MPR would typically use the parallel mode, the other two MPRs the orthogonal one. DUAL mode blends between these two.
• The backward reconstruction builds a binary space partitioning (BSP) tree iterates over the target frame's pixels, and tries to sample from the surrounding frames. It produces qualitatively better reconstructions but is more expensive to compute, limited by the OpenGL texture array size, and may also exhibit reconstruction artifacts when the sweep follows zig-zag motion.

Example for rendering into an MPR view:

MySweepRenderer::MySweepRenderer()
{
    m_comp = std::make_unique<GlSweepReconstruction>();
    m_comp->setMode(GlSweepReconstruction::DUAL);
    m_comp->setNearestNeighbor(false);
    m_comp->setEncodeAngleInformation(false);
}
 
void MySweepRenderer::render(const GL::ViewState& viewState,
                             const Slice& slice,
                             const Data& data,
                             const DisplayOptions2d& displayOptions,
                             bool encodeDistance)
{
    auto sweep = dynamic_cast<const UltrasoundSweep*>(&data);
    if (!sweep)
        return;
 
    GL::StateGuard guard({GL::StateGuard::FBO, GL::StateGuard::Program});
    m_comp->setEncodeDistToBorder(encodeDistance);
    m_comp->setSweep(sweep);
    m_comp->renderSlice(viewState, slice, displayOptions);
}

Classes
struct	FourCorners

Public Types
enum	Mode { ORTHOGONAL = 0 , PARALLEL = 1 , DUAL = 2 , BACKWARD_COMPOUNDING = 3 }
	Enumeration of possible reconstruction modes. More...

Public Member Functions
	GlSweepReconstruction ()
	Constructor, which does not initialize shaders and working variables yet.
void	setSweep (const UltrasoundSweep *sweep, const Selection *sel=0)
	Set the freehand sweep data and optional selection.
void	setSweeps (const std::vector< const UltrasoundSweep * > &sweeps)
	Set multiple sweeps to render.
Mode	mode () const
	Returns the reconstruction mode.
void	setMode (Mode mode)
	Set the reconstruction mode.
double	thickness () const
	Returns the slice thickness (mm) in backward compounding mode; 0 if using automatic setting.
void	setThickness (double value)
	Sets the slice thickness (mm) in backward compounding mode; set to 0 to use automatic setting.
bool	nearestNeighbor () const
	Returns the flag whether to use nearest neighbor interpolation.
void	setNearestNeighbor (bool value)
	Sets the flag whether to use nearest neighbor interpolation.
bool	encodeDistToBorder () const
	Returns the flag whether to encode the distance to the border into the second FBO attachment.
void	setEncodeDistToBorder (bool value)
	Sets the flag whether to encode the distance to the border in into the second FBO attachment.
bool	encodeAngleInformation () const
	Returns the flag whether to write out angle between US frame and render slice into the third FBO attachment.
void	setEncodeAngleInformation (bool value)
	Sets the flag whether to write out angle between US frame and render slice into the third FBO attachment.
void	setMaxDistance (double dist)
	Sets the maximum distance between slices to render if dist is positive, otherwise uses automatic setting (10% of max. sweep extent)
void	renderSlice (const GL::ViewState &viewState, const Slice &slice)
	Render a 2D slice specified by the given matrix using default display options.
void	renderSlice (const GL::ViewState &viewState, const Slice &slice, const DisplayOptions2d &displayOptions)
	Render a 2D slice specified by the given matrix using the given display options.

Protected Member Functions
void	updateOrthogonal (const Slice &s)
	Update the orthogonal reconstruction.
void	updateParallel (const GL::ViewState &viewState, const Slice &s, const DisplayOptions2d &displayOptions)
	Update the parallel reconstruction.
void	updateParallelDrawSlices (const Slice &slice, int unit=0)
	Auxiliary method used in parallel reconstruction.
void	drawOrthogonal (const GL::ViewState &viewState, const Slice &slice, const DisplayOptions2d &displayOptions)
	Draw the orthogonal reconstruction.
void	drawParallel (const DisplayOptions2d &displayOptions)
	Draw the parallel reconstruction.
void	drawBackward (const GL::ViewState &viewState, const Slice &slice, const DisplayOptions2d &displayOptions)
	Draw the backward reconstruction.
void	updateMdmc ()
	Updates the MaskDistanceMapComponent if needed.

Protected Attributes
Mode	m_mode = DUAL
	Reconstruction mode.
const UltrasoundSweep *	m_sweep = nullptr
	Sweep to reconstruct.
std::unique_ptr< UltrasoundSweep >	m_proxySweep
	Optional proxy sweep in case setSweeps was called; owns the data there created.
std::vector< int >	m_gaps
	Textures who are followed by a gap.
std::unique_ptr< GlProgramIncludeManager >	m_progOrthogonal
	Shader program for orthogonal reconstruction.
std::unique_ptr< GlProgramIncludeManager >	m_progParallelDist
	Distance shader program.
std::unique_ptr< GL::Program >	m_progParallelInterp
	Interpolation shader program.
std::unique_ptr< GlProgramIncludeManager >	m_modernProg
	Shader used for backward compounding.
std::unique_ptr< GL::Framebuffer >	m_fbo
std::unique_ptr< GL::VertexBuffer >	m_vbo
std::unique_ptr< GL::Sampler >	m_sampler
	Sampler for specifying interpolation.
std::vector< std::unique_ptr< GlImage > >	m_parTex
	Auxiliary textures.
bool	m_mdmcDirty = false
SweepReconDirectComponent *	m_srdc = nullptr
	DataComponent caching per-sweep geometry data.
detail::MaskDistanceMapComponent *	m_mdmc = nullptr
	DataComponent storing mask-aware distance-to-border image.
double	m_desiredMaxDist = 0.5
	Desired maximum distance between slices to render, used only if m_autoChooseMaxDist is true.
double	m_maxDist = 0.0
	Effective maximum distance between slices to render.
double	m_thickness = 0.0
	Slice thickness (mm) in backward compounding mode.
bool	m_nearestNeighbor = false
	Use nearest neighbor interpolation instead of linear interpolation.
bool	m_encodeDistToBorder = false
	Flag whether to encode the distance to the border into the second FBO attachment.
bool	m_encodeAngleInformation = false
	Flag whether to write out angle between US frame and render slice to the third FBO attachment.
bool	m_autoChooseMaxDist = true
	Flag whether maximum distance between slices to render should be automatically determined.

Member Enumeration Documentation

Mode

enum Mode

Enumeration of possible reconstruction modes.

Enumerator
ORTHOGONAL	Best mode if reconstruction plane is orthogonal to sweep slices.
PARALLEL	Best mode if reconstruction plane is approximately parallel to sweep slices.
DUAL	Blending of both modes for good visual result in any reconstruction plane.
BACKWARD_COMPOUNDING	On-the-fly backward compounding.

Member Function Documentation

encodeDistToBorder()

bool encodeDistToBorder

(

)

const

Returns the flag whether to encode the distance to the border into the second FBO attachment.

See GlSliceRenderer::render for more details.

setEncodeDistToBorder()

void setEncodeDistToBorder

(

bool

value

)

Sets the flag whether to encode the distance to the border in into the second FBO attachment.

See GlSliceRenderer::render for more details.

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

• ImFusion/US/GlSweepReconstruction.h