/**
* Set up the data object with empty UltrasoundPoint%s representing the points
* that need to be scanned.
*
* This is analagous to setting up the view frustum in traditional 3D graphics.
*/
private void EstablishScanningPlane(ref UltrasoundScanData data)
{
OnionLogger.globalLog.PushInfoLayer("Pre-populating data");
UltrasoundProbeConfiguration config = data.GetProbeConfig();
// nearZ and farZ represent near and far clipping "planes" (they're really arcs)
float nearZ = config.GetMinScanDistance();
float farZ = config.GetMaxScanDistance();
float arcSizeDegrees = config.GetArcSizeInDegrees();
int scanlines = config.GetNumberOfScanlines();
int pointsPerScanline = config.GetPointsPerScanline();
for (int i = 0; i < scanlines; ++i)
{
UltrasoundScanline scanline = new UltrasoundScanline(config.GetPosition());
float angleInDegrees = -(arcSizeDegrees / 2) + i * arcSizeDegrees / (scanlines - 1);
float angleInRadians = Mathf.Deg2Rad * angleInDegrees;
Vector2 trajectory = new Vector2(Mathf.Sin(angleInRadians), Mathf.Cos(angleInRadians));
for (int j = 0; j < pointsPerScanline; ++j)
{
float d = nearZ + j * (farZ - nearZ) / (pointsPerScanline - 1);
Vector2 positionOnPlane = d * trajectory;
Vector3 positionInWorldSpace = WorldSpaceFromProjectedPosition(positionOnPlane, config);
UltrasoundPoint point = new UltrasoundPoint(positionInWorldSpace, positionOnPlane);
scanline.AddUltrasoundPoint(point);
}
data.AddScanline(scanline);
}
OnionLogger.globalLog.PopInfoLayer();
}
/**
* Since the pulse will lose energy after interacting with tissue at a point, we will
* need to recalculate the pulse intensity after processing each UltrasoundPoint.
*
* @param previousPulseIntensity The intensity of the pulse that hit this point.
* @param previousOrgan The properties of the organ at this point.
* @param config The probe configuration. (Used for normalizing energy loss for higher res display)
*
* @return The new intensity to use for the next UltrasoundPoint.
*/
private float PulseIntensityAfterPoint(float previousPulseIntensity,
HorayMaterialProperties previousOrgan,
UltrasoundProbeConfiguration config)
{
// When calculating energy lost, we need to normalize for the number of points in the display.
float resolutionCoefficient = config.GetPointsPerScanline();
float energyLost = (previousOrgan.echogenicity + previousOrgan.attenuation) / resolutionCoefficient;
float newIntensity = previousPulseIntensity - energyLost;
return(newIntensity);
}
/**
* Copy constructor to instantiate a new UltrasoundProbeConfiguration from another.
*
* @param config The other UltrasoundProbeConfiguration object.
* @throw ArgumentNullException
*/
public UltrasoundProbeConfiguration(UltrasoundProbeConfiguration config)
{
UltrasoundDebug.Assert(null != config,
"Null UltrasoundProbeConfiguration used for copy constructor.",
this);
this.SetPosition(config.GetPosition());
this.SetRotation(config.GetRotation());
this.maxDistance = config.GetMaxScanDistance();
this.minDistance = config.GetMinScanDistance();
this.arcSizeInDegrees = config.GetArcSizeInDegrees();
this.pointsPerScanline = config.GetPointsPerScanline();
this.numberOfScanlines = config.GetNumberOfScanlines();
this.gain = config.GetGain();
}
