+// ------------------------------------------------------------------------
+/*
+2.2.2 Orientation of DICOM images
+
+
+http://www.dclunie.com/medical-image-faq/html/part2.html#DICOMOrientation
+says :
+
+A question that is frequently asked in comp.protocols.dicom is how to determine
+ which side of an image is which (e.g. left, right) and so on.
+ The short answer is that for projection radiographs this is specified
+ explicitly using the "Patient Orientation" attribute, and for cross-sectional
+ images it needs to be derived from the "Image Orientation (Patient)" direction
+ cosines. In the standard these are explained as follows:
+
+ * "C.7.6.1.1.1 Patient Orientation.
+ The Patient Orientation (0020,0020) relative to the image
+ plane shall be specified by two values that designate the
+ anatomical direction of the positive row axis (left to right)
+ and the positive column axis (top to bottom).
+ The first entry is the direction of the rows, given by the
+ direction of the last pixel in the first row from the first
+ pixel in that row.
+ The second entry is the direction of the columns, given by
+ the direction of the last pixel in the first column from the
+ first pixel in that column.
+ Anatomical direction shall be designated by the capital
+ letters: A (anterior), P (posterior), R (right),L (left),
+ H (head), F (foot).
+ Each value of the orientation attribute shall contain at
+ least one of these characters.
+ If refinements in the orientation descriptions are to be
+ specified, then they shall be designated by one or two
+ additional letters in each value.
+ Within each value, the letters shall be ordered with the
+ principal orientation designated in the first character."
+
+ * "C.7.6.2.1.1 Image Position And Image Orientation.
+ The "Image Position (Patient)" (0020,0032) specifies the x, y,
+ and z coordinates of the upper left hand corner of the image;
+ it is the center of the first voxel transmitted.
+ The "Image Orientation (Patient)" (0020,0037) specifies the
+ direction cosines of the first row and the first column
+ with respect to the patient.
+ These Attributes shall be provided as a pair.
+ Row value for the x, y, and z axes respectively followed by
+ the Column value for the x, y, and z axes respectively.
+ The direction of the axes is defined fully by the patient's
+ orientation.
+ The x-axis is increasing to the left hand side of the patient.
+ The y-axis is increasing to the posterior side of the patient.
+ The z-axis is increasing toward the head of the patient.
+ The patient based coordinate system is a right handed system,
+ i.e. the vector cross product of a unit vector along the
+ positive x-axis and a unit vector along the positive y-axis
+ is equal to a unit vector along the positive z-axis."
+
+Some simple code to take one of the direction cosines (vectors) from the
+Image Orientation (Patient) attribute and generate strings equivalent to one
+of the values of Patient Orientation looks like this (noting that if the vector
+is not aligned exactly with one of the major axes, the resulting string will
+have multiple letters in as described under "refinements" in C.7.6.1.1.1):
+
+*/
+
+/**
+ * \brief Computes the Patient Orientation relative to the image plane
+ * from the 'Image Orientation (Patient)'
+ * - or from 0020 0035Image Orientation (RET) -
+ * - The first entry is the direction of the rows, given by the
+ * direction of the last pixel in the first row from the first
+ * pixel in that row.
+ * - The second entry is the direction of the columns, given by
+ * the direction of the last pixel in the first column from the
+ * first pixel in that column.
+ * Anatomical direction is designated by the capital
+ * letters: A (anterior), P (posterior), R (right),L (left),
+ * H (head), F (foot).
+ * - Refinements in the orientation descriptions are designated
+ * by one or two additional letters in each value.
+ * Use it when "Patient Orientation" (0020,0020) is not found
+ * @return orientation string as "rowsOrientation\columnsOrientation"
+ */
+std::string Orientation::GetOrientation ( File *f )
+{
+ float iop[6];
+ if ( !f->GetImageOrientationPatient( iop ) )
+ return GDCM_UNFOUND;
+
+ std::string orientation;
+ orientation = GetSingleOrientation ( iop )
+ + "\\"
+ + GetSingleOrientation ( iop + 3 );
+ return orientation;
+}
+
+
+std::string Orientation::GetSingleOrientation ( float *iop)
+{
+ std::string orientation;
+
+ char orientationX = iop[0] < 0 ? 'R' : 'L';
+ char orientationY = iop[1] < 0 ? 'A' : 'P';
+ char orientationZ = iop[2] < 0 ? 'F' : 'H';
+
+ double absX = iop[0];
+ if (absX < 0) absX = -absX;
+ double absY = iop[1];
+ if (absY < 0) absY = -absY;
+ double absZ = iop[2];
+ if (absZ < 0) absZ = -absZ;
+
+ for (int i=0; i<3; ++i)
+ {
+ if (absX>.0001 && absX>absY && absX>absZ)
+ {
+ orientation = orientation + orientationX;
+ absX=0;
+ }
+ else if (absY>.0001 && absY>absX && absY>absZ)
+ {
+ orientation = orientation + orientationY;
+ absY=0;
+ }
+ else if (absZ>.0001 && absZ>absX && absZ>absY)
+ {
+ orientation = orientation + orientationZ;
+ absZ=0;
+ }
+ else
+ break;
+ }
+ return orientation;
+}
+
+
+/*-------------------------------------------------------------------
+
+Some more stuff, from XMedcon
+
+---> Personal remark from JPRx :
+--> patient_position (0x0018,0x5100) can be "HFS ", "FFS ", "HFP ", "FFP "
+--> or, not so common,
+// HFDR = Head First-Decubitus Right
+// HFDL = Head First-Decubitus Left
+// FFDR = Feet First-Decubitus Right
+// FFDL = Feet First-Decubitus Left
+--> the cosines may have any value -1.< <+1., for MR images !
+
+enum patient_slice_orientation_type
+ {
+ patient_slice_orientation_unknown = 0,
+ supine_headfirst_transaxial,
+ supine_headfirst_sagittal,
+ supine_headfirst_coronal,
+ supine_feetfirst_transaxial,
+ supine_feetfirst_sagittal,
+ supine_feetfirst_coronal,
+ prone_headfirst_transaxial,
+ prone_headfirst_sagittal,
+ prone_headfirst_coronal,
+ prone_feetfirst_transaxial,
+ prone_feetfirst_sagittal,
+ prone_feetfirst_coronal
+ };
+
+void GetImageOrientationPatient(gdcm::File &h,F32 image_orientation_patient[6])
+{
+ h.GetImageOrientationPatient(image_orientation_patient);
+}
+
+#if 0
+//
+// this is all completely cribbed from the xmedcon library, since
+// we're trying to do what it does, mostly.
+patient_slice_orientation_type
+GetPatSliceOrient(gdcm::File &h)
+{
+ F32 image_orientation_patient[6];
+
+ // protected, do it the hard way
+ // h.GetImageOrientationPatient(image_orientation_patient);
+ GetImageOrientationPatient(h,image_orientation_patient);
+
+ enum { headfirst, feetfirst } patient_orientation;
+ enum { supine, prone } patient_rotation;
+ enum { transaxial, sagittal, coronal } slice_orientation;
+
+ std::string patient_position = h.GetEntryByNumber(0x0018,0x5100);
+ if(patient_position == GDCM_UNFOUND)
+ {
+ patient_position = "HF";
+ }
+ if(patient_position.find("HF") != std::string::npos)
+ {
+ patient_orientation = headfirst;
+ }
+ else if(patient_position.find("FF") != std::string::npos)
+ {
+ patient_orientation = feetfirst;
+ }
+
+ if(patient_position.find("S") != std::string::npos)
+ {
+ patient_rotation = supine;
+ }
+ else if(patient_position.find("P") != std::string::npos)
+ {
+ patient_rotation = prone;
+ }
+
+ if((image_orientation_patient[0] == 1 || image_orientation_patient[0] == -1) &&
+ (image_orientation_patient[4] == +1 || image_orientation_patient[4] == -1))
+ {
+ slice_orientation = transaxial;
+ }
+ else if((image_orientation_patient[1] == 1 || image_orientation_patient[1] == -1) &&
+ (image_orientation_patient[5] == +1 || image_orientation_patient[5] == -1))
+ {
+ slice_orientation = sagittal;
+ }
+ else if((image_orientation_patient[0] == 1 || image_orientation_patient[0] == -1) &&
+ (image_orientation_patient[5] == +1 || image_orientation_patient[5] == -1))
+ {
+ slice_orientation = coronal;
+ }
+ //
+ // combine results
+ patient_slice_orientation_type patient_slice_orientation =
+ patient_slice_orientation_unknown;
+ switch (patient_rotation)
+ {
+ case supine:
+ switch (patient_orientation)
+ {
+ case headfirst:
+ switch (slice_orientation)
+ {
+ case transaxial:
+ patient_slice_orientation = supine_headfirst_transaxial;
+ break;
+ case sagittal:
+ patient_slice_orientation = supine_headfirst_sagittal;
+ break;
+ case coronal:
+ patient_slice_orientation = supine_headfirst_coronal;
+ break;
+ }
+ break;
+ case feetfirst:
+ switch (slice_orientation)
+ {
+ case transaxial:
+ patient_slice_orientation = supine_feetfirst_transaxial;
+ break;
+ case sagittal:
+ patient_slice_orientation = supine_feetfirst_sagittal;
+ break;
+ case coronal:
+ patient_slice_orientation = supine_feetfirst_coronal;
+ break;
+ }
+ break;
+ }
+ break;
+ case prone:
+ switch (patient_orientation)
+ {
+ case headfirst:
+ switch (slice_orientation)
+ {
+ case transaxial:
+ patient_slice_orientation = prone_headfirst_transaxial;
+ break;
+ case sagittal:
+ patient_slice_orientation = prone_headfirst_sagittal;
+ break;
+ case coronal:
+ patient_slice_orientation = prone_headfirst_coronal;
+ break;
+ }
+ break;
+ case feetfirst:
+ switch (slice_orientation)
+ {
+ case transaxial:
+ patient_slice_orientation = prone_feetfirst_transaxial;
+ break;
+ case sagittal:
+ patient_slice_orientation = prone_feetfirst_sagittal;
+ break;
+ case coronal:
+ patient_slice_orientation = prone_feetfirst_coronal;
+ break;
+ }
+ break;
+ }
+ break;
+ }
+ if(patient_slice_orientation != patient_slice_orientation_unknown)
+ return patient_slice_orientation;
+ //
+ // this is what xmedcon does
+ if ((image_orientation_patient[0] == +1) &&
+ (image_orientation_patient[4] == +1))
+ patient_slice_orientation = supine_headfirst_transaxial;
+ else if ((image_orientation_patient[0] == -1) &&
+ (image_orientation_patient[4] == +1))
+ patient_slice_orientation = supine_feetfirst_transaxial;
+ else if ((image_orientation_patient[0] == -1) &&
+ (image_orientation_patient[4] == -1))
+ patient_slice_orientation = prone_headfirst_transaxial;
+ else if ((image_orientation_patient[0] == +1) &&
+ (image_orientation_patient[4] == -1))
+ patient_slice_orientation = prone_feetfirst_transaxial;
+
+ else if ((image_orientation_patient[1] == +1) &&
+ (image_orientation_patient[5] == -1))
+ patient_slice_orientation = supine_headfirst_sagittal;
+ else if ((image_orientation_patient[1] == +1) &&
+ (image_orientation_patient[5] == +1))
+ patient_slice_orientation = supine_feetfirst_sagittal;
+ else if ((image_orientation_patient[1] == -1) &&
+ (image_orientation_patient[5] == -1))
+ patient_slice_orientation = prone_headfirst_sagittal;
+ else if ((image_orientation_patient[1] == -1) &&
+ (image_orientation_patient[5] == +1))
+ patient_slice_orientation = prone_feetfirst_sagittal;
+
+ else if ((image_orientation_patient[0] == +1) &&
+ (image_orientation_patient[5] == -1))
+ patient_slice_orientation = supine_headfirst_coronal;
+ else if ((image_orientation_patient[0] == -1) &&
+ (image_orientation_patient[5] == +1))
+ patient_slice_orientation = supine_feetfirst_coronal;
+ else if ((image_orientation_patient[0] == -1) &&
+ (image_orientation_patient[5] == -1))
+ patient_slice_orientation = prone_headfirst_coronal;
+ else if ((image_orientation_patient[0] == +1) &&
+ (image_orientation_patient[5] == +1))
+ patient_slice_orientation = prone_feetfirst_coronal;
+ return patient_slice_orientation;
+}
+#else
+
+-------------------------------------------------------------------------*/
+
+} // end namespace gdcm