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MedicalHelper Class Reference

VSG extension (Preview feature) [Medical] Utility class for medical applications. More...

#include <Medical/helpers/MedicalHelper.h>

Public Types

enum  Axis {
  AXIAL = 2 ,
  TRANSVERSE = 2 ,
  CORONAL = 1 ,
  SAGITTAL = 0
}
 Medical axis names. More...
 

Public Member Functions

SbVec3f getVoxelSize (const SoVolumeData *volume) const
 Returns the voxel size in 3D space.
 
SbVec3f getPhysicalSize (const SoVolumeData *volume) const
 Returns the volume's physical size in 3D space.
 
SbVec3f getDicomOrigin (const SoVolumeData *volume) const
 Returns the DICOM volume origin in 3D space.
 

Static Public Member Functions

static SbBool orientView (MedicalHelper::Axis axis, SoCamera *camera, const SoVolumeData *volume=NULL, float slack=1.01)
 Orient view.
 
static SbBool dicomAdjustVolume (SoVolumeData *volume, SbBool useImagePosition=TRUE)
 Optimize volume data node for DICOM volumes.
 
static SbBool dicomAdjustVolume (SoVolumeData *volume, SoMatrixTransform *imgToPatient)
 Similar to dicomAdjustVolume( SoVolumeData*, SbBool ) above but returns an SoMatrixTransform that can be used to properly locate VolumeData in patient space in case of non axis aligned acquisition:
 
static SbBool dicomAdjustDataRange (SoDataRange *rangeNode, const SoVolumeData *volume)
 Adjust data range based on values in the DICOM file, i.e.
 
static SbBool dicomCheckMonochrome1 (SoTransferFunction *cmapNode, const SoVolumeData *volume, SbBool forceReverse=FALSE)
 Automatically adjusts the color map (transferFunction) if the specified volume is a DICOM data set (reader is SoVRDicomFileReader) and the the Photometric Interpretation (0028,0004) value is MONOCHROME1.
 
static SbBool dicomGetImagePosition (const SoVolumeData *volume, SbVec3f &imagePos)
 Get the "Image Position (Patient)" attribute (0020,0032) from a DICOM volume.
 
static SbBool dicomGetWindowCenterWidth (const SoVolumeData *volume, SbVec2f &winCW)
 Get the window center (level) and width values from a DICOM volume.
 
static SbVec2f dicomGetWindowCenterWidth (const SoDataRange *dataRange)
 Get the window center (level) and width values from an SoDataRange node.
 
static SbBool dicomSetWindowCenterWidth (SoDataRange *dataRange, const SbVec2f &winCW)
 Set an SoDataRange node from the window center (level) and width values.
 
static int dicomFindFilesbySeries (const SbString &firstFile, std::vector< SbString > &files)
 Get files in DICOM series.
 
static int dicomFindFilesbySeries (const SbString &firstFile, SbStringList &files)
 Get files in DICOM series.
 
static void dollyZoom (float value, SoCamera *camera)
 Make the scene appear larger or smaller.
 
static SbBool setFilenameList (SoVRDicomFileReader &reader, const std::vector< SbString > &list)
 Set filename list using a list of strings (file names).
 
static SoMemoryDataAdapter * getImageDataAdapter (const SoVolumeData *volume)
 Make a VolumeViz data set available in ImageViz.
 
static SoVolumeDatagetVolumeData (const SoImageDataAdapter *adapter)
 Make an ImageViz data set available in VolumeViz.
 
static SoSeparatorbuildSliceOrientationMarkers (const SoOrthoSlice *orthoSlice)
 Build a scene graph to display slice orientation markers.
 
static SoSeparatorbuildSliceScaleBars (const SoCamera *camera)
 Build a scene graph to display dynamic scale bars for slice viewing.
 
static SoSeparatorbuildSliceAnnotation (const SoCamera *camera, const SoOrthoSlice *sliceNode, const SbString *dicomFilename)
 Slice viewer annotations.
 
static const SbVec2sexampleWindowSize ()
 Returns standard window size for Open Inventor medical examples.
 
static SoNodeexampleLogoNode ()
 Returns a logo image node for Open Inventor medical examples.
 
static SoNodeexampleDicomAnnotation (const SbString &filename)
 Returns a collection of DicomInfo annotation nodes for Open Inventor medical examples.
 
static Axis MedicalAxisFromViewAxis (openinventor::inventor::Axis::Type viewAxis, const SoVolumeData *volData)
 Returns the medical axis (AXIAL, CORONAL, SAGITTAL) corresponding to the specified view axis (X, Y, Z) based on the DICOM Image Orientation element (0x0020,0x0037).
 
static Axis MedicalAxisFromViewAxis (openinventor::inventor::Axis::Type viewAxis, const SbMatrix &orientationMatrix)
 Returns the medical axis (AXIAL, CORONAL, SAGITTAL) corresponding to the specified view axis (X, Y, Z) based on the specified orientation matrix.
 
static openinventor::inventor::Axis::Type ViewAxisFromMedicalAxis (Axis medicalAxis, const SoVolumeData *volData)
 Returns the view axis (X, Y, Z) corresponding to the specified medical axis (AXIAL, CORONAL, SAGITTAL) based on the DICOM Image Orientation element (0x0020,0x0037).
 
static openinventor::inventor::Axis::Type ViewAxisFromMedicalAxis (Axis medicalAxis, const SbMatrix &orientationMatrix)
 Returns the view axis (X, Y, Z) corresponding to the specified medical axis (AXIAL, CORONAL, SAGITTAL) based on the DICOM Image Orientation element (0x0020,0x0037).
 
template<typename NodeType >
static NodeType * find (SoNode *root, const SbString &nodeName=SbString(), const bool okIfNotFound=false)
 Convenience function to find first specified node in specified scene graph.
 
template<typename NodeType >
static std::vector< NodeType * > findNodes (SoNode *scene)
 Convenience function to find all node of specified type in specified graph.
 
static SbBox3f getBoundingBox (SoNode *node)
 Convenience function to retrieve bounding box of specified node.
 
static SoSeparatorcreateCube (const SbBox3f &bbox)
 Convenience function to draw a cube representing the specified bounding box.
 
static SoSeparatorcreateBoundingBox (const SbBox3f &bbox, SbColor *color=NULL)
 Convenience function to draw a wireframe box representing the specified bounding box.
 
static SoSeparatorreadFile (const char *filename)
 Convenience function to read a .iv file and return pointer to the root of the created scenegraph.
 

Detailed Description

VSG extension (Preview feature) [Medical] Utility class for medical applications.

Utility functions for medical visualization using Open Inventor.

Open Inventor includes a general purpose 3D graphics core library plus optimized extensions for specific data types and markets, including medical visualization. We recommend using these utility functions (and the Medical utility nodes) to get the best performance and productivity from Open Inventor for medical applications.

SUMMARY

  • dicomAdjustVolume():
    Call this method to adjust VolumeViz parameters for optimal performance with medical data and to position a DICOM volume correctly in 3D space.
  • dicomAdjustDataRange():
    Call this method to set the VolumeViz data range based on the Window Center and Window Width tags in a DICOM file. If those tags are not present, automatically sets the data range to the actual range of values in the data.
  • dicomSetWindowCenterWidth() and dicomGetWindowCenterWidth():
    In Open Inventor the range of voxel values that map onto the color map are specified as the 'min' and 'max' values of the range (see SoDataRange). These methods provide a convenient way to set and query the data range using the medical convention of 'window center' and 'window width'.
  • dicomFindFilesbySeries():
    Call this method to build a list of DICOM image files in a directory that belong to the same series as the specified file. This list can be passed to the DICOM volume reader using the setFilenameList() method.
  • getImageDataAdapter():
    Call this method to get an ImageViz data set (for image processing) from a VolumeViz data set. It's faster than using SoVolumeReaderAdapter.
  • getVolumeData():
    Call this method to get a VolumeViz data set (for visualization) from an ImageViz data set. It's faster than using SoVRImageDataReader directly.
  • orientView():
    This method is useful for orienting the camera to view a single image (a slice in VolumeViz jargon) along one of the standard axes (Axial, Coronal or Sagittal). But remember that the volume is always a 3D object to Open Inventor and you must also set the 'axis' field on the SoOrthoSlice node. See the dicomImageViewer example.

EXAMPLE

EXAMPLE

    // Start a filter pipeline from a VolumeViz data set
    SoMemoryDataAdapter* adapter = MedicalHelper::getImageDataAdapter( volume );
    // Add a filter
    SoDeblurProcessing2d* filter = new SoDeblurProcessing2d();
    filter->sharpeningFactor = 2;
    filter->inImage = adapter;
    static SoMemoryDataAdapter * getImageDataAdapter(const SoVolumeData *volume)
    Make a VolumeViz data set available in ImageViz.

SEE ALSO

InventorMedical, DicomInfo, Gnomon, Magnifier, PlaneBoxIntersection, PlaneGeometryIntersection, Ruler, SliceOrientationMarkers, SliceScaleBar, TextBox, VolumeMarchingCubes

Definition at line 146 of file MedicalHelper.h.

Member Enumeration Documentation

◆ Axis

Medical axis names.

These names are mapped to the corresponding XYZ enum value in Open Inventor.

Enumerator
AXIAL 

Axial (Z axis)

TRANSVERSE 

Transverse (synonym for Axial)

CORONAL 

Coronal (Y axis)

SAGITTAL 

Sagittal (X axis)

Definition at line 151 of file MedicalHelper.h.

Member Function Documentation

◆ buildSliceAnnotation()

static SoSeparator * MedicalHelper::buildSliceAnnotation ( const SoCamera camera,
const SoOrthoSlice sliceNode,
const SbString dicomFilename 
)
static

Slice viewer annotations.

This is just a convenience method and helps keep the demo/example programs consistent. Applications can use SliceScaleBar (etc) directly.

Calls the buildSliceOrientationMarkers() and buildSliceScaleBars() methods and also creates some DicomInfo nodes using tag info from the optional image filename.

◆ buildSliceOrientationMarkers()

static SoSeparator * MedicalHelper::buildSliceOrientationMarkers ( const SoOrthoSlice orthoSlice)
static

Build a scene graph to display slice orientation markers.

This is just a convenience method and helps keep the demo/example programs consistent. Applications can use SliceOrientationMarkers directly.

Creates a SliceOrientationMarkers node with a default color and background and connects its 'axis' field to the 'axis' field of the specified slice node.

◆ buildSliceScaleBars()

static SoSeparator * MedicalHelper::buildSliceScaleBars ( const SoCamera camera)
static

Build a scene graph to display dynamic scale bars for slice viewing.

This is just a convenience method and helps keep the demo/example programs consistent. Applications can use SliceScaleBar directly.

Note that a typical length, 10 cm, is assumed.

Creates horizontal and vertical SliceScaleBar nodes with a default color and line width and sets their 'trackedCamera' field to the specified camera node.

◆ createBoundingBox()

static SoSeparator * MedicalHelper::createBoundingBox ( const SbBox3f bbox,
SbColor color = NULL 
)
static

Convenience function to draw a wireframe box representing the specified bounding box.

Default color is red (1,0,0).

◆ createCube()

static SoSeparator * MedicalHelper::createCube ( const SbBox3f bbox)
static

Convenience function to draw a cube representing the specified bounding box.

Color is inherited.

◆ dicomAdjustDataRange()

static SbBool MedicalHelper::dicomAdjustDataRange ( SoDataRange rangeNode,
const SoVolumeData volume 
)
static

Adjust data range based on values in the DICOM file, i.e.

the window center (0028,1050) and window width (0028,1051) values. Returns true if successful. Assigns default values if necessary. If there are multiple slices, values are taken from the first slice. Volume is needed to get DICOM attributes, but is not modified.

◆ dicomAdjustVolume() [1/2]

static SbBool MedicalHelper::dicomAdjustVolume ( SoVolumeData volume,
SbBool  useImagePosition = TRUE 
)
static

Optimize volume data node for DICOM volumes.

Returns true if successful. The volume properties are modified (but not the data values). Do not call this method before setting the volume data node's fileName field or calling setReader.

  • First, adjusts the LDM tile size to optimize data loading.
    Note this adjustment is valid for any data format that is not already tiled, i.e. most formats except .lda and .ldm.
  • Second, adjusts the volume extent in 3D to be the actual physical extent of the data set measured from outside edge to outside edge of the voxels. This is a DICOM specific adjustment.
  • Third, if 'useImagePosition' is true, adjusts the volume extent so the center of the first voxel is positioned at the coordinates specified in the data set's "Image position" (0020,0032) attribute. By default the DICOM volume reader sets the volume extent so the center of the volume is positioned at 0,0,0 in 3D space. This is a DICOM specific adjustment.

Note that this method doesn't support non axis aligned acquisition. In such a case, prefer using the dicomAdjustVolume( SoVolumeData*, SoMatrixTransform* ) below.

◆ dicomAdjustVolume() [2/2]

static SbBool MedicalHelper::dicomAdjustVolume ( SoVolumeData volume,
SoMatrixTransform imgToPatient 
)
static

Similar to dicomAdjustVolume( SoVolumeData*, SbBool ) above but returns an SoMatrixTransform that can be used to properly locate VolumeData in patient space in case of non axis aligned acquisition:

...
SoMatrixTransform* matrixTransform = new SoMatrixTransfrom();
dicomAdjustVolume(volumeData, matrixTransfrom)
root->addChild(matrixTransform);
root->addChild(volumeData);
...

The computed matrix embeds the image position and image orientation as described here: https://dicom.innolitics.com/ciods/ct-image/image-plane/00200037 Scaling part is embedded in VolumeData extent.

If SoVolumeData is not a DICOM volume, matrixTransform will be set to identity.

Returns true if successful.

◆ dicomCheckMonochrome1()

static SbBool MedicalHelper::dicomCheckMonochrome1 ( SoTransferFunction cmapNode,
const SoVolumeData volume,
SbBool  forceReverse = FALSE 
)
static

Automatically adjusts the color map (transferFunction) if the specified volume is a DICOM data set (reader is SoVRDicomFileReader) and the the Photometric Interpretation (0028,0004) value is MONOCHROME1.

Specifically, if the above conditions are true, this method reverses the values in the current color map.

Typically used as a convenience call when rendering slices. For intensity based rendering of slices, set the transfer function to the predefined color map INTENSITY. This is an intensity ramp from black to white that is appropriate for Photometric Interpretation MONOCHROME2 (the most common case). When reversed it is appropriate for P.I. MONOCHROME1.

Returns true if change was needed and was successful. Volume is needed to get DICOM attributes, but is not modified. Transfer function is modified if necessary.

◆ dicomFindFilesbySeries() [1/2]

static int MedicalHelper::dicomFindFilesbySeries ( const SbString firstFile,
SbStringList files 
)
static

Get files in DICOM series.

We recommend using the alternate version of this method. Note that SbStringList is a list of pointers to SbString objects, not a list of SbString objects.

◆ dicomFindFilesbySeries() [2/2]

static int MedicalHelper::dicomFindFilesbySeries ( const SbString firstFile,
std::vector< SbString > &  files 
)
static

Get files in DICOM series.

Given the path to a DICOM file, returns a list containing all the files in the same directory that are part of the same DICOM series, based on the series UID (0x0020,0x000E). File name extensions are not considered.

Returns 0 if the specified file was not found or is not a valid DICOM file.

This allows the application user to select a DICOM series in a file selection dialog box by just selecting one file instead of having to select all the files explicitly.

To load the series in Open Inventor, create an SoVRDicomFileReader and call the setFilenameList() method with the file list. Then set this reader in the SoVolumeData node using the setReader() method. Note that SbStringList is a list of pointers to SbString objects, not a list of SbString objects.

The file names in the returned list are not in any particular order. It doesn't matter for loading the volume because the DICOM volume reader automatically sorts the images by their 'Slice Location' attribute (0x0020,0x1041).

See also: SbFileHelper::listFiles(). This method returns a list of files based on a specified pattern (regular expression) for the filenames.

◆ dicomGetImagePosition()

static SbBool MedicalHelper::dicomGetImagePosition ( const SoVolumeData volume,
SbVec3f imagePos 
)
static

Get the "Image Position (Patient)" attribute (0020,0032) from a DICOM volume.

DICOM calls this the upper left hand corner of the image, but more precisely it's the center of the first voxel, in millimeters (mm). For VolumeViz the upper left hand corner of the image is literally the corner of the voxel, one-half voxel different from Image Position. Returns true if the query is successful. If not successful, imagePos is 0,0,0. If there are multiple slices, value is taken from the first slice.

Note the SoVRDicomData getPosition() method does not return the value of the Image Position attribute. It returns a value computed from Image Position.

◆ dicomGetWindowCenterWidth() [1/2]

static SbVec2f MedicalHelper::dicomGetWindowCenterWidth ( const SoDataRange dataRange)
static

Get the window center (level) and width values from an SoDataRange node.

Returns 0,0 on failure. Convenient for displaying data range in medical terms.

◆ dicomGetWindowCenterWidth() [2/2]

static SbBool MedicalHelper::dicomGetWindowCenterWidth ( const SoVolumeData volume,
SbVec2f winCW 
)
static

Get the window center (level) and width values from a DICOM volume.

If the query fails, returns false and sets 'winCW' to 0,0.

Uses the Window Center (0028,1050) and Window Width (0028,1051) tags from the first image in the stack. If these tags do not exist in the volume, then window center and width are computed from the actual data min and max values. (Note that querying the actual min and max values may take some time because every voxel must be loaded.)

This method may be called with a non-DICOM volume. In that case the actual min and max data values are used.

◆ dicomSetWindowCenterWidth()

static SbBool MedicalHelper::dicomSetWindowCenterWidth ( SoDataRange dataRange,
const SbVec2f winCW 
)
static

Set an SoDataRange node from the window center (level) and width values.

Returns true if successful. Convenient for converting from medical user interface to data range.

◆ dollyZoom()

static void MedicalHelper::dollyZoom ( float  value,
SoCamera camera 
)
static

Make the scene appear larger or smaller.

Provided as a convenience to simplify application code. Effect is the same as creating an SoCameraInteractor and calling the dolly() method, but note that the value expected by that method is the inverse which is less intuitive. Using this method, values greater than 1 make the scene appear larger and values less than 1 make the scene appear smaller. For example a of 2 will make the scene approximately 2 times larger. The specific effect on the camera is a 'dolly' or a 'zoom' depending on the type of camera.

This is often useful after calling ViewAll(). That method sets the camera parameters based on a bounding sphere around the scene which often leaves the scene not "filling" the viewport.

Details:

  • SoPerspectiveCamera: changes the camera 'position' field. For example, values greater than 1 move the camera closer to the focal point (divide the camera's distance from the focal point by the given value), which makes the scene appear larger. This is a 'dolly'.
  • SoOrthographicCamera: changes the camera 'height' field. For example, values greater than 1 decrease the view volume height (scale the height by the inverse of the given value), which makes the scene appear larger. This is a 'zoom' operation.
  • No effect if value is <= 0 or camera is null.

◆ exampleDicomAnnotation()

static SoNode * MedicalHelper::exampleDicomAnnotation ( const SbString filename)
static

Returns a collection of DicomInfo annotation nodes for Open Inventor medical examples.

This method is not important for customer appications, but the technique can be useful for adding annotation text to an application window.

  • filename is the path to a DICOM file from which info will be extracted.

◆ exampleLogoNode()

static SoNode * MedicalHelper::exampleLogoNode ( )
static

Returns a logo image node for Open Inventor medical examples.

This method is not important for customer applications, but the technique can be useful for adding logo images to an application window. Returns an SoImageBackground node, but as an SoNode. The returned node has a ref count of zero.

◆ exampleWindowSize()

static const SbVec2s & MedicalHelper::exampleWindowSize ( )
static

Returns standard window size for Open Inventor medical examples.

This method is not important for customer applications.

◆ find()

template<typename NodeType >
static NodeType * MedicalHelper::find ( SoNode root,
const SbString nodeName = SbString(),
const bool  okIfNotFound = false 
)
inlinestatic

Convenience function to find first specified node in specified scene graph.

Definition at line 602 of file MedicalHelper.h.

◆ findNodes()

template<typename NodeType >
static std::vector< NodeType * > MedicalHelper::findNodes ( SoNode scene)
inlinestatic

Convenience function to find all node of specified type in specified graph.

Definition at line 651 of file MedicalHelper.h.

◆ getBoundingBox()

static SbBox3f MedicalHelper::getBoundingBox ( SoNode node)
static

Convenience function to retrieve bounding box of specified node.

If node is a group that contains an SoVolumeData, uses SoVolumeData extent.

◆ getDicomOrigin()

SbVec3f MedicalHelper::getDicomOrigin ( const SoVolumeData volume) const

Returns the DICOM volume origin in 3D space.

This is just a convenience. In DICOM terms the image/volume origin is the center of the first voxel, but in VolumeViz the minimum point of the 3D extent is the outer edge of the first voxel. The difference is 1/2 voxel.

Note: dicomGetImagePosition returns the actual value of the Image Position Patient attribute from the DICOM file (if possible).

◆ getImageDataAdapter()

static SoMemoryDataAdapter * MedicalHelper::getImageDataAdapter ( const SoVolumeData volume)
static

Make a VolumeViz data set available in ImageViz.

Creates and returns an SoMemoryDataAdapter with the same dimensions, extent and data as the SoVolumeData. Returns NULL on failure, e.g. if volume is empty.

Note that this operation makes a copy of the data set. So it must be possible to allocate a contiguous block of memory large enough to hold the whole volume. It is not currently possible for ImageViz and VolumeViz to share a data set.

You can use SoVolumeReaderAdapter to get the same result but the performance is much slower because SoVolumeReaderAdapter loads data using the volume's associated volume reader class and re-reads the data from disk. This convenience method is much faster because it loads data using the LDMDataAccess interface which takes advantage of data that VolumeViz already has in memory.

Performance depends on the 'tile size' set for the source volume. It will be slow (but still faster than SoVolumeReaderAdapter) if you use the default tile size (64) with a 512^3 volume. We recommend setting the volume's tile size equal to the volume size (or calling the dicomAdjustVolume() method which does this automatically).

◆ getPhysicalSize()

SbVec3f MedicalHelper::getPhysicalSize ( const SoVolumeData volume) const

Returns the volume's physical size in 3D space.

This is just a convenience. The physical size in 3D is simply the span of the volume extent.

◆ getVolumeData()

static SoVolumeData * MedicalHelper::getVolumeData ( const SoImageDataAdapter *  adapter)
static

Make an ImageViz data set available in VolumeViz.

Creates an SoVRImageDataReader to access the data and automatically sets the SoVolumeData's 'tile size' to an optimal value. Note that this operation makes a copy of the data set. It is not currently possible for ImageViz and VolumeViz to share a data set. Returns NULL on failure.

You can use SoVRImageDataReader directly, but the resulting volume may be slow to access if you do not set the tile size and the volume dimensions are larger than the default tile dimension (64). Setting the tile size allows VolumeViz to access the data as a single tile when the dimensions are <= 512 or at least to access the data using a larger tile size (which means a smaller number of tiles).

◆ getVoxelSize()

SbVec3f MedicalHelper::getVoxelSize ( const SoVolumeData volume) const

Returns the voxel size in 3D space.

This is just a convenience. The voxel size is simply the volume extent in 3D space divided by the number of voxels.

◆ MedicalAxisFromViewAxis() [1/2]

static Axis MedicalHelper::MedicalAxisFromViewAxis ( openinventor::inventor::Axis::Type  viewAxis,
const SbMatrix orientationMatrix 
)
static

Returns the medical axis (AXIAL, CORONAL, SAGITTAL) corresponding to the specified view axis (X, Y, Z) based on the specified orientation matrix.

See MedicalAxisFromViewAxis(Axis, const SoVolumeData*) for details.

Normally this matrix is computed from the DICOM Image Orientation element. This version of the method allows the application to extract the orientation matrix and save it. The orientation matrix can be created from the DICOM Image Orientation vectors or conveniently queried using SoVRDicomData::getOrientation().

◆ MedicalAxisFromViewAxis() [2/2]

static Axis MedicalHelper::MedicalAxisFromViewAxis ( openinventor::inventor::Axis::Type  viewAxis,
const SoVolumeData volData 
)
static

Returns the medical axis (AXIAL, CORONAL, SAGITTAL) corresponding to the specified view axis (X, Y, Z) based on the DICOM Image Orientation element (0x0020,0x0037).

Use this method when you know the camera will be aligned with one of the 3D world coordinate axes and you need to know which medical axis the view axis corresponds to. You need the medical axis in order to display the correct slice orientation letters. For example, if the Image Orientation is identity and the camera is aligned with the Z axis, then this is an Axial view.

The conversion may not be valid if the DICOM Image Orientation is not approximately axis aligned. The conversion uses the largest component of each direction cosine to detemine the associated axis.

volData parameter: This parameter is used to get the DICOM Image Orientation element. If the element is not available or the volume is not a DICOM data set (reader is not an SoVRDicomFileReader), then the method returns the value of the specified axis.

In many cases the medical axis and view axis are the same. However this depends on the DICOM Image Orientation element (0x0020,0x0037). If Image Orientation is missing or has the default value "1/0/0/0/1/0" (identity matrix), then the view and medical axes have the default DICOM relationship:

  • View X axis is the medical SAGITTAL (RL) axis
  • View Y axis is the medical CORONAL (AP) axis
  • View Z axis is the medical AXIAL (FH) axis

But, for example, if Image Orientation is "0/1/0/0/0/-1", then the view Z axis is actually the medical SAGITTAL (RL) axis.

Applications should use the view axis (e.g. Z) to set the camera direction and slice axis (see SoOrthoSlice), but use the medical axis (e.g. AXIAL) to select the slice orientation labels (see SliceOrientationMarkers).

Notes:

  • VolumeViz (SoVRDicomFileReader) always loads the images along the 3D world coordinate Z axis. Image viewer applications should normally default to a Z axis view of a Z axis OrthoSlice.
  • DICOM Image Orientation specifies the direction cosines of the first row and the first column of image pixels with respect to the patient. Essentially two vectors defining the (possibly rotated) directions of the volume X and Y axes in 3D space. Open Inventor assumes these vectors are orthogonal. That is normally true but not required by DICOM.
  • This is not a complete solution to the medical vs 3D space view conversion. This method correctly returns which axis, but does not tell you which direction the camera should be pointed (+ or -) along that axis.

◆ orientView()

static SbBool MedicalHelper::orientView ( MedicalHelper::Axis  axis,
SoCamera camera,
const SoVolumeData volume = NULL,
float  slack = 1.01 
)
static

Orient view.

The camera is rotated to give the conventional orientation for the specified axis, then if a volume data node was specified:

  • If the camera is an SoOrthographicCamera (the usual case for viewing a slice), viewAll() is called and, in addition, the view volume height is adjusted to make the slice image fill the window (subject to the 'slack' parameter). This is convenient because viewAll() computes a very loose fit around the slice image.
  • If the camera is an SoPerspectiveCamera (commonly used for viewing a 3D volume), ViewAll() is called, but no additional adjustment is done to the camera.

For a 3D volume rendering view, typically specify the Coronal axis.

The orientation calculation is based on the DICOM LPS (Left, Posterior, Superior) reference coordinate system for a bipedal patient, where:

  • +X direction is right to left.
  • +Y direction is front to back (anterior to posterior).
  • +Z direction is feet to head (inferior to superior).

This works correctly in many, but not all, cases. In particular it does not handle non-default values for the DICOM Image Orientation attribute.

Parameters:

  • axis:
    • Axial :
      Looking from feet to head, i.e looking toward +Z, with -Y up and +X to the right.
    • Coronal :
      Looking at front of patient, i.e Looking toward +Y, with +Z up and +X to the right.
    • Sagittal :
      Looking at left side of patient, i.e. Looking toward -X, with +Z up and +Y to the right.
  • camera: The camera node that will be modified (fails if null).
  • volume: [optional] The data volume that is being viewed (used to compute view volume, not modified). May be null, but a default volume extent of -1 to 1 will be used and viewAll() is not called.
  • slack: Values greater than 1 will leave additional space between image and window edge when using an SoOrthographicCamera.

Returns true if the operation succeeded.

◆ readFile()

static SoSeparator * MedicalHelper::readFile ( const char *  filename)
static

Convenience function to read a .iv file and return pointer to the root of the created scenegraph.

◆ setFilenameList()

static SbBool MedicalHelper::setFilenameList ( SoVRDicomFileReader reader,
const std::vector< SbString > &  list 
)
static

Set filename list using a list of strings (file names).

This is a convenient alternative to calling SoVRDicomFileReader's method setFilenameList() directly. That method requires an SbStringList object which is a simple list of pointers, not a list of objects.

◆ ViewAxisFromMedicalAxis() [1/2]

static openinventor::inventor::Axis::Type MedicalHelper::ViewAxisFromMedicalAxis ( Axis  medicalAxis,
const SbMatrix orientationMatrix 
)
static

Returns the view axis (X, Y, Z) corresponding to the specified medical axis (AXIAL, CORONAL, SAGITTAL) based on the DICOM Image Orientation element (0x0020,0x0037).

See ViewAxisFromMedicalAxis(Axis, const SoVolumeData*) for details.

Normally this matrix is computed from the DICOM Image Orientation element. This version of the method allows the application to extract the orientation matrix and save it. The orientation matrix can be created from the DICOM Image Orientation vectors or conveniently queried using SoVRDicomData::getOrientation().

◆ ViewAxisFromMedicalAxis() [2/2]

static openinventor::inventor::Axis::Type MedicalHelper::ViewAxisFromMedicalAxis ( Axis  medicalAxis,
const SoVolumeData volData 
)
static

Returns the view axis (X, Y, Z) corresponding to the specified medical axis (AXIAL, CORONAL, SAGITTAL) based on the DICOM Image Orientation element (0x0020,0x0037).

Use this method when you know the medical axis that should be displayed and you need to know the view axis (X, Y, Z) that corresponds to that. For example, if the Image Orientation is identity and an Axial view should be displayed, then the camera and the SoOrthoSlice should be set to Z.


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