/**
* constructor to create a view
*
* @param projection: projection image as Grid2D
* @param radon: radon transformed and derived image as Grid2D
* @param projMatrix: projection matrix as Projection
*/
public View(Grid2D projection, Grid2D radon, Projection projMatrix) {
// Initialize center matrix //
CENTER = new SimpleMatrix(3, 4);
CENTER.setDiagValue(new SimpleVector(1.0, 1.0, 1.0));
// get data out of projection //
this.projectionWidth = projection.getWidth();
this.projectionHeight = projection.getHeight();
// get data out of radon transformed image //
this.radonWidth = radon.getWidth();
this.radonHeight = radon.getHeight();
this.projectionDiag =
Math.sqrt(projectionWidth * projectionWidth + projectionHeight * projectionHeight);
this.lineIncrement = radonWidth / projectionDiag;
this.angleIncrement = radonHeight / Math.PI;
// store radon transformed image //
this.radon = radon;
// get projection matrix P (3x4) //
this.P = SimpleOperators.multiplyMatrixProd(projMatrix.getK(), CENTER);
this.P = SimpleOperators.multiplyMatrixProd(this.P, projMatrix.getRt());
// get source position C (nullspace of the projection) //
DecompositionSVD decoP = new DecompositionSVD(this.P);
this.C = decoP.getV().getCol(3);
// normalize source vectors by last component //
// it is important that the last component is positive to have a positive center
// as it is defined in oriented projective geometry
this.C = this.C.dividedBy(this.C.getElement(3));
}
public Grid2D raytraceScene(PrioritizableScene phantomScene, Projection projection) {
Trajectory geom = Configuration.getGlobalConfiguration().getGeometry();
// Grid2D slice = new Grid2D(geom.getDetectorWidth(), geom.getDetectorHeight());
Grid2D slice =
detector.createDetectorGrid(geom.getDetectorWidth(), geom.getDetectorHeight(), projection);
rayTracer.setScene(phantomScene);
// Second rule of optimization is: Optimize later.
PointND raySource = new PointND(0, 0, 0);
raySource.setCoordinates(projection.computeCameraCenter());
StraightLine castLine = new StraightLine(raySource, new SimpleVector(0, 0, 0));
SimpleVector centerPixDir = null;
if (accurate) {
centerPixDir = projection.computePrincipalAxis();
}
// SimpleVector prinpoint = trajectory.getProjectionMatrix(sliceNumber).getPrincipalPoint();
double xcorr = 0; // trajectory.getDetectorWidth()/2 - prinpoint.getElement(0);
double ycorr = 0; // trajectory.getDetectorHeight()/2 - prinpoint.getElement(1);
double length = trajectory.getSourceToDetectorDistance();
Edge environmentEdge = new Edge(new PointND(0), new PointND(length));
ArrayList<PhysicalObject> fallBackBackground = new ArrayList<PhysicalObject>(1);
SimpleVector pixel = new SimpleVector(0, 0);
boolean negate = false;
for (int y = 0; y < trajectory.getDetectorHeight(); y++) {
for (int x = 0; x < trajectory.getDetectorWidth(); x++) {
pixel.setElementValue(0, x - xcorr);
pixel.setElementValue(1, y - ycorr);
SimpleVector dir = projection.computeRayDirection(pixel);
if ((y == 0) && (x == 0)) {
// Check that ray direction is towards origin.
double max = 0;
int index = 0;
for (int i = 0; i < 3; i++) {
if (Math.abs(dir.getElement(i)) > max) {
max = Math.abs(dir.getElement(i));
index = i;
}
}
double t = -raySource.get(index) / dir.getElement(index);
if (t < 0) negate = true;
}
if (negate) dir.negate();
castLine.setDirection(dir);
ArrayList<PhysicalObject> segments = rayTracer.castRay(castLine);
if (accurate) {
double dirCosine = SimpleOperators.multiplyInnerProd(centerPixDir, dir);
length = trajectory.getSourceToDetectorDistance() / dirCosine;
}
if (segments == null) {
fallBackBackground.clear();
segments = fallBackBackground;
} else {
if (accurate) {
environmentEdge =
new Edge(new PointND(0), new PointND(length - getTotalSegmentsLength(segments)));
}
}
environment.setShape(environmentEdge);
segments.add(environment);
/* old code:
double integral = absorptionModel.evaluateLineIntegral(segments);
slice.putPixelValue(x, y, integral);
*/
detector.writeToDetector(slice, x, y, segments);
}
}
return slice;
}