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SoVRDicomFileReader Class

DICOM file reader.

Inheritance Hierarchy

Namespace: OIV.VolumeViz.Readers
Assembly: OIV.VolumeViz (in OIV.VolumeViz.dll) Version: 10.12.3.0 (10.12.3.0)
Syntax
public class SoVRDicomFileReader : SoVolumeReader

The SoVRDicomFileReader type exposes the following members.

Constructors
  NameDescription
Public methodSoVRDicomFileReader

Constructor.

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Methods
  NameDescription
Public methodCloseAllHandles
Close all file handles currently opened by the reader.
(Inherited from SoVolumeReader.)
Public methodCopyFieldValues(SoFieldContainer)
Calls CopyFieldValues(fc, false).
(Inherited from SoFieldContainer.)
Public methodCopyFieldValues(SoFieldContainer, Boolean)

Copies the contents of fc's fields into this object's fields.

(Inherited from SoFieldContainer.)
Public methodDispose
Releases all resources used by SoDisposable.
(Inherited from SoDisposable.)
Public methodEnableNotify

Notification at this Field Container is enabled (if flag == true) or disabled (if flag == false).

(Inherited from SoFieldContainer.)
Public methodEquals
Determines whether the specified Object is equal to the current Object.
(Inherited from Object.)
Public methodFieldsAreEqual

Returns true if this object's fields are exactly equal to fc's fields.

(Inherited from SoFieldContainer.)
Public methodGet

Returns the values of the fields of this object in the Open Inventor ASCII file format in the given string.

(Inherited from SoFieldContainer.)
Public methodGetAllFields

Returns a list of fields, including the eventIn's and eventOut's.

(Inherited from SoFieldContainer.)
Public methodGetBorderFlag
Returns border flag if stored in file.
(Inherited from SoVolumeReader.)
Public methodGetConfiguredWriter
Returns a writer that correspond to this reader (same format, same parameters, etc...).
(Inherited from SoVolumeReader.)
Public methodGetDataChar (Overrides SoVolumeReaderGetDataChar(SbBox3f, SoDataSetDataTypes, SbVec3i32).)
Public methodGetDicomData

Returns an instance of OIV.VolumeViz.Readers.SoVRDicomData for the first image of this volume.

Public methodGetDicomDataSet

Returns a DICOM data object for the specified slice containing all the DICOM attributes.

Public methodGetDirectCoordSys
Return whether the coordinate system used is direct or not.
(Inherited from SoVolumeReader.)
Public methodGetDirectCoordSysAutoDetection
Return automatic detection value.
(Inherited from SoVolumeReader.)
Public methodGetEventIn

Returns a the eventIn with the given name.

(Inherited from SoFieldContainer.)
Public methodGetEventOut

Returns the eventOut with the given name.

(Inherited from SoFieldContainer.)
Public methodGetField

Returns a the field of this object whose name is fieldName.

(Inherited from SoFieldContainer.)
Public methodGetFieldName

Returns the name of the given field in the fieldName argument.

(Inherited from SoFieldContainer.)
Public methodGetFields

Appends references to all of this object's fields to resultList, and returns the number of fields appended.

(Inherited from SoFieldContainer.)
Public methodGetHashCode
Overrides GetHashCode().
(Inherited from SoNetBase.)
Public methodGetHistogram
Returns histogram if stored in file.
(Inherited from SoVolumeReader.)
Public methodGetMinMax(Double, Double)
Returns min max if stored in file for float data type
(Inherited from SoVolumeReader.)
Public methodGetMinMax(Int32, Int32)
Returns min max if stored in file (obsolete)
(Inherited from SoVolumeReader.)
Public methodGetMinMax(Int64, Int64)
Returns min max if stored in file for integer data type
(Inherited from SoVolumeReader.)
Public methodGetName

Returns the name of an instance.

(Inherited from SoBase.)
Public methodGetNumSignificantBits
This method is optional. It returns the number of significant bits of the volume data.
(Inherited from SoVolumeReader.)
Public methodGetOriginalFilename
Returns original file name from which the data has been converted to LDM format if stored in file.
(Inherited from SoVolumeReader.)
Public methodGetReaderType
Returns type of reader.
(Inherited from SoVolumeReader.)
Public methodGetStringName (Inherited from SoBase.)
Public methodGetSubSlice
Method required by VolumeViz 3.0. Must copy the rectangular part defined by subSlice of the XY slice sliceNumber to the memory pointed to by data. Slices will not always be read sequentially.
(Inherited from SoVolumeReader.)
Public methodGetTileMinMax
Returns the minimum and maximum data values for the given tile. Used only if data is organized for the LDM module. It allows to profit of optimizations such as SoLDMGlobalResourceParameters.setIgnoreFullyTransparentTiles(). Default implementation return new SbVec2d(System.Double.MaxValue, -System.Double.MaxValue))
(Inherited from SoVolumeReader.)
Public methodGetTileSize
Returns tile size if using data stored in tiles. Return FALSE if data is not stored in tiles.
(Inherited from SoVolumeReader.)
Public methodGetType
Gets the Type of the current instance.
(Inherited from Object.)
Public methodHasDefaultValues

Returns true if all of the object's fields have their default values.

(Inherited from SoFieldContainer.)
Public methodIsNotifyEnabled

Notification is the process of telling interested objects that this object has changed.

(Inherited from SoFieldContainer.)
Public methodIsSynchronizable

Gets the ScaleViz synchronizable state of this object.

(Inherited from SoBase.)
Public methodLoadInMemory

Load the DICOM data into contiguous memory if possible.

Public methodLoadSliceDicomData

Loads the Dicom data of the given slice.

Public methodReadTile(Int32, SbBox3i32)
Given an index, reads a tile if the data is organized in tiles (for LDM).
(Inherited from SoVolumeReader.)
Public methodReadTile(Int32, SbNativeArrayByte, SbBox3i32) Obsolete.
Given an index, reads a tile if the data is organized in tiles (for LDM). In the default LDM architecture, the LDM data is based on an octree topology (see SoVRLdmFileReader). The index passed is 0 for the tile of lowest resolution representing the entire volume (octree root node). The index increments linearly going down through the octree.
(Inherited from SoVolumeReader.)
Public methodSet

Sets one or more fields in this object to the values specified in the given string, which should be a string in the Open Inventor file format.

(Inherited from SoFieldContainer.)
Public methodSetDirectCoordSysAutoDetection
Sets whether or not the reader should automatically try to detect if the coordinate system used is direct or not. The function will return FALSE if the feature is not supported by the current reader. Default is false.
(Inherited from SoVolumeReader.)
Public methodSetDirectCoorSys
Specify if the coordinate system used is direct or not. The function will return FALSE if the feature is not supported by the current reader. Default is false.
(Inherited from SoVolumeReader.)
Public methodSetDirectory

Specify a directory containing DICOM files to load.

Public methodSetFilename
Specifies the path of the file. Returns 0 for success. Any other return value indicates failure.
(Inherited from SoVolumeReader.)
Public methodSetFilenameList(IListString)
Specifies the list of a DICOM files to load.
Public methodSetFilenameList(String)
Calls SetFilenameList(format, System.Int32(0), INT_MAX, 1).
Public methodSetFilenameList(String, Int32)
Calls SetFilenameList(format, startIndex, INT_MAX, 1).
Public methodSetFilenameList(String, Int32, Int32)
Calls SetFilenameList(format, startIndex, endIndex, 1).
Public methodSetFilenameList(String, Int32, Int32, Int32)

Specify a list of DICOM files to load, using a sprintf-like format.

Public methodSetFilenameListFromSeries

Specify a DICOM file and load all image files in the same directory that are part of the same "series" based on the series UID (0x0020,0x000E).

Public methodSetFilenamePattern

Specify a pattern of DICOM files to load.

Public methodSetName (Inherited from SoBase.)
Public methodSetOutputDataType
Sets the output data type. Returns FALSE if the reader does not support this feature.
(Inherited from SoVolumeReader.)
Public methodSetSynchronizable

Sets this to be a ScaleViz synchronizable object.

(Inherited from SoBase.)
Public methodSetToDefaults

Sets all fields in this object to their default values.

(Inherited from SoFieldContainer.)
Public methodSetUserData
Stores the userData (for example the filename string) in the m_data protected variable.
(Inherited from SoVolumeReader.)
Public methodToString
Converts this SoBase structure to a human readable string.
(Inherited from SoBase.)
Public methodTouch

Marks an instance as modified, simulating a change to it.

(Inherited from SoBase.)
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Properties
  NameDescription
Public propertyDataConverted
The returned boolean indicates if the data is already organized for the LDM module. If TRUE, VolumeViz will use the readTile method.
(Inherited from SoVolumeReader.)
Public propertyIsDisposable
ISafeDisposable interface implementation.
(Inherited from SoDisposable.)
Public propertyIsThreadSafe
Let the system know if the reader is thread safe or not. this function is called by VolumeViz when using the multiIO mode.
(Inherited from SoVolumeReader.)
Public propertyUserData
Gets or sets the user data to be contained by the field container.
(Inherited from SoFieldContainer.)
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Remarks

Volume reader for the DICOM file format. VolumeViz automatically selects this reader if a filename is given and the file extension is ".dc3", ".dic", ".dcm", or ".dicom".

DICOM is a widely used format for storing medical image data (CT, MRI, etc), defined by the National Electrical Manufacturers Association (NEMA) (http://medical.nema.org).

OIV.VolumeViz.Readers.SoVRDicomFileReader can load a volume from a single DICOM file or from a list of DICOM files (stack of images). Loading a volume from a single DICOM file is the same as loading any other format supported by VolumeViz (see ()). Loading a volume from a list of DICOM files can be done by:

Unlike a raster stack, the position of each slice in a DICOM volume is determined by the location value in its file header and not by the order of the file name in the list. Also unlike a raster stack consisting of (for example) JPEG or PNG images, a DICOM file in the list may contain more than one slice of the volume. The reader handles this automatically. The first file in the list is considered the "reference" for the volume and all slices must be compatible with this one. Specifically this means that subsequent files must have the same width, height, data type and so on.

Note when using a list file: If the file extension is not ".dc3", ".dic" or ".dicom" VolumeViz will not automatically select the DICOM volume reader. You can either give the list file one of the DICOM file extensions or force VolumeViz to use the DICOM reader by explicitly creating an instance of OIV.VolumeViz.Readers.SoVRDicomFileReader and calling the OIV.VolumeViz.Nodes.SoVolumeData method setReader().

The volume reader will automatically get the volume dimensions, data type, extent (voxel size/spacing) and number of significant bits from the DICOM file header. The reader will also apply the data adjustment (if any) specified by the RescaleSlope and RescaleIntercept tags in the DICOM file header, i.e.: actualValue = slope * storedValue + intercept. As part of this process the reader will automatically convert unsigned data to the corresponding signed data type if necessary (in other words if the rescale calculation produces negative values). The application can also explicitly specify the volume data type. This allows, for example, converting float data values to more compact integer values. Note: The DICOM reader only uses the rescale slope and intercept values from the first file in the list. It does not currently handle the (less common) case where each file contains different rescale values.

Photometric Interpretation:

Volume extent:

The volume reader will compute the volume's width in X and height in Y from the volume dimensions and the voxel size. For example, if the volume dimension in X is 512 (voxels) and the voxel size in X is 0.408 mm, then the volume width is (approximately) 209 mm. The reader will compute the volume's depth in Z from the min and max slice locations specified in the file header(s). Note that for a DICOM data set, the volume 'position' is considered to be the center of the first voxel, however VolumeViz considers the volume extent (SoVolumeData.extent) to include all of the first and last voxels. Therefore the extent 'min' is alwaya the outside corner of the first voxel.

NOTE: By default, the reader does not consider the DICOM volume origin (Image Position Patient attribute) when setting the volume extent. The volume extent set by the reader is always centered at 0,0,0 in 3D world coordinates. There are two options to get the volume correctly positioned in 3D space:

  • Call the MedicalHelper method dicomAdjustVolume() after setting the files to be loaded. (Recommended)

  • Set the preference variable VOLUMEVIZ_CENTERED_DICOM to false (default is true).

Data Range:

Use an OIV.LDM.Nodes.SoDataRange node to specify the actual (or desired) range of data values to be mapped. For example, a typical initial data range for DICOM data calibrated in Hounsfield units might be -1000 to 3000.

NOTE: By default, VolumeViz does not use the Window Center and Window Width values (if any) in the DICOM image file. Instead it maps the entire range of the voxel's data type (e.g. 0..65535 for unsigned short) into the colormap. There are two options to use the data range specified in the image file:

Coordinate Systems:

In a medical imaging application there are at least three related coordinate systems.

  • 3D world coordinates: Also called XYZ coordinates. This is the Cartesian coordinate system in which rendering objects (volumes, geometry), cameras, lights, etc. are positioned. In Open Inventor this is a right-handed coordinate system (same as OpenGL). The default camera creates a view look down the Z axis, i.e. +Z is toward the user, +X is to the right and +Y is up.

  • Voxel coordinates: Also called "IJK" coordinates. Each voxel's position in the volume can be described by an IJK coordinate. In VolumeViz this is also a right-handed coordinate system, corresponding to the positive XYZ axes, i.e. in the default camera's view K is toward the user, I is to the right and J is up. You can convert between IJK and XYZ coordinates based on the volume dimensions and extent or use the conversion methods provided in the OIV.VolumeViz.Nodes.SoVolumeData class, e.g. voxelToXYZ().

  • Anatomical coordinates: The three standard viewing planes are Axial, Coronal and Sagittal. The Axial plane divides the body into Superior (head) and Inferior (foot) sections. The Coronal plane is a vertical plane dividing the body into Anterior (front) and Posterior (back) sections. The Sagittal plane divides the body longitudinally into Right and Left sections. The orientation of the patient in a medical data set is often specified using three letters to identify the primary axes, where each letter is one of the section names. DICOM volumes typically have LPS (Left, Posterior, Superior) orientation. In this case VolumeViz considers that the direction:

    • Toward the left side of the body (Left) is the I / +X / Sagittal axis,

    • Toward the back of the body (Posterior) is the J / +Y / Coronal axis, and

    • Toward the head (Superior) is the K / +Z / Axial axis.

    In other words, the default camera view is looking at the top of the head with the body "face down".

NOTE: By default Open Inventor does not display DICOM images with the usual orientation. A convenient way to get the standard DICOM view orientations is to use the MedicalHelper method orientView(). This method is useful for orienting the camera to view along one of the standard medical axes (Axial, Coronal or Sagittal).

When viewing a slice, also remember that the volume is always a 3D object to Open Inventor and you must also set the 'axis' field on the OIV.VolumeViz.Nodes.SoOrthoSlice node. See the dicomImageViewer example in the examples/source/Medical/Input directory.

DICOM Attributes

All DICOM attributes, including hierarchical data like Structured Reports, can be traversed and queried using OIV.VolumeViz.Readers.Dicom.SiDicomDataSet (see OIV.VolumeViz.Readers.SoVRDicomFileReader.GetDicomDataSet(System.UInt64)). See the DicomSimpleViewer example in the examples/source/VolumeViz/examples directory.

See Also