mfx.cpp

一ＯＣＲ的相关资料。．希望对研究ＯＣＲ的朋友有所帮助．

 **      Parameters:
 **              Start           starting point of micro-feature
 **              End             ending point of micro-feature
 **              MicroFeature    micro-feature whose bulges are to be computed
 **      Globals: none
 **      Operation:
 **              This routine computes the size of the "bulges" of the
 **              specified micro-feature.  The bulges are the deviations
 **              of the micro-features from a straight line at the 1/3
 **              and 2/3 points along the straight line approximation of
 **              the micro-feature.  The size of each bulge is normalized
 **              to the range -0.5 to 0.5.  A positive bulge indicates a
 **              deviation in the counterclockwise direction and vice versa.
 **              A size of 0.5 (+ or -) corresponds to the largest bulge that
 **              could ever occur for the given feature independent of
 **              orientation.  This routine assumes that Start
 **              and End are not the same point.  It also assumes that the
 **              orientation and length parameters of the micro-feature
 **              have already been computed.
 **      Return: none
 **      Exceptions: none
 **      History: 7/27/89, DSJ, Created.
 */
  MATRIX_2D Matrix;
  MFEDGEPT *Origin;
  MFOUTLINE SegmentStart, SegmentEnd;
  FPOINT CurrentPoint, LastPoint;
  FLOAT32 BulgePosition;

  /* check for simple case */
  if (End == NextPointAfter (Start))
    FirstBulgeOf (MicroFeature) = SecondBulgeOf (MicroFeature) = 0;
  else {
    Origin = PointAt (Start);

    InitMatrix(&Matrix);
    RotateMatrix (&Matrix, OrientationOf (MicroFeature) * -2.0 * PI);
    TranslateMatrix (&Matrix, -XPositionOf (Origin), -YPositionOf (Origin));

    SegmentEnd = Start;
    FillPoint (CurrentPoint, 0, 0);
    BulgePosition = LengthOf (MicroFeature) / 3;
    CopyPoint(CurrentPoint, LastPoint);
    while (Xof (CurrentPoint) < BulgePosition) {
      SegmentStart = SegmentEnd;
      SegmentEnd = NextPointAfter (SegmentStart);
      CopyPoint(CurrentPoint, LastPoint);
      MapPoint (&Matrix, PositionOf (PointAt (SegmentEnd)), CurrentPoint);
    }
    FirstBulgeOf (MicroFeature) =
      XIntersectionOf(LastPoint, CurrentPoint, BulgePosition);

    BulgePosition *= 2;

    // Prevents from copying the points before computing the bulge if
    // CurrentPoint will not change. (Which would cause to output nan
    // for the SecondBulge.)
    if (Xof (CurrentPoint) < BulgePosition)
      CopyPoint(CurrentPoint, LastPoint);
    while (Xof (CurrentPoint) < BulgePosition) {
      SegmentStart = SegmentEnd;
      SegmentEnd = NextPointAfter (SegmentStart);
      CopyPoint(CurrentPoint, LastPoint);
      MapPoint (&Matrix, PositionOf (PointAt (SegmentEnd)), CurrentPoint);
    }
    SecondBulgeOf (MicroFeature) =
      XIntersectionOf(LastPoint, CurrentPoint, BulgePosition);

    FirstBulgeOf (MicroFeature) /= BULGENORMALIZER *
      LengthOf(MicroFeature);
    SecondBulgeOf (MicroFeature) /= BULGENORMALIZER *
      LengthOf(MicroFeature);
  }
}                                /* ComputeBulges */


/*---------------------------------------------------------------------------*/
FLOAT32 ComputeOrientation(MFEDGEPT *Start, MFEDGEPT *End) {
/*
 **      Parameters:
 **              Start           starting edge point of micro-feature
 **              End             ending edge point of micro-feature
 **      Globals: none
 **      Operation:
 **              This routine computes the orientation parameter of the
 **              specified micro-feature.  The orientation is the angle of
 **              the vector from Start to End.  It is normalized to a number
 **              between 0 and 1 where 0 corresponds to 0 degrees and 1
 **              corresponds to 360 degrees.  The actual range is [0,1), i.e.
 **              1 is excluded from the range (since it is actual the
 **              same orientation as 0).  This routine assumes that Start
 **              and End are not the same point.
 **      Return: Orientation parameter for the specified micro-feature.
 **      Exceptions: none
 **      History: 7/27/89, DSJ, Created.
 */
  FLOAT32 Orientation;

  Orientation = NormalizeAngle (AngleFrom (PositionOf (Start),
    PositionOf (End)));

  /* ensure that round-off errors do not put circular param out of range */
  if ((Orientation < 0) || (Orientation >= 1))
    Orientation = 0;
  return (Orientation);
}                                /* ComputeOrientation */


/*---------------------------------------------------------------------------*/
MICROFEATURES ConvertToMicroFeatures(MFOUTLINE Outline,
                                     MICROFEATURES MicroFeatures) {
/*
 **      Parameters:
 **              Outline         outline to extract micro-features from
 **              MicroFeatures   list of micro-features to add to
 **      Globals: none
 **      Operation:
 **              This routine
 **      Return: List of micro-features with new features added to front.
 **      Exceptions: none
 **      History: 7/26/89, DSJ, Created.
 */
  MFOUTLINE Current;
  MFOUTLINE Last;
  MFOUTLINE First;
  MICROFEATURE NewFeature;

  if (DegenerateOutline (Outline))
    return (MicroFeatures);

  First = NextExtremity (Outline);
  Last = First;
  do {
    Current = NextExtremity (Last);
    NewFeature = ExtractMicroFeature (Last, Current);
    if (NewFeature != NULL)
      MicroFeatures = push (MicroFeatures, NewFeature);
    Last = Current;
  }
  while (Last != First);

  return (MicroFeatures);
}                                /* ConvertToMicroFeatures */


/*---------------------------------------------------------------------------*/
MICROFEATURE ExtractMicroFeature(MFOUTLINE Start, MFOUTLINE End) {
/*
 **      Parameters:
 **              Start           starting point of micro-feature
 **              End             ending point of micro-feature
 **      Globals: none
 **      Operation:
 **              This routine computes the feature parameters which describe
 **              the micro-feature that starts and Start and ends at End.
 **              A new micro-feature is allocated, filled with the feature
 **              parameters, and returned.  The routine assumes that
 **              Start and End are not the same point.  If they are the
 **              same point, NULL is returned, a warning message is
 **              printed, and the current outline is dumped to stdout.
 **      Return: New micro-feature or NULL if the feature was rejected.
 **      Exceptions: none
 **      History: 7/26/89, DSJ, Created.
 **              11/17/89, DSJ, Added handling for Start and End same point.
 */
  MICROFEATURE NewFeature;
  MFEDGEPT *P1, *P2;

  P1 = PointAt (Start);
  P2 = PointAt (End);

  NewFeature = NewMicroFeature ();
  CenterX (NewFeature) = AverageOf (XPositionOf (P1), XPositionOf (P2));
  CenterY (NewFeature) = AverageOf (YPositionOf (P1), YPositionOf (P2));
  LengthOf (NewFeature) = DistanceBetween (PositionOf (P1), PositionOf (P2));
  OrientationOf (NewFeature) =
    NormalizedAngleFrom (&(PositionOf (P1)), &(PositionOf (P2)), 1.0);
  ComputeBulges(Start, End, NewFeature);
  return (NewFeature);
}                                /* ExtractMicroFeature */


/*---------------------------------------------------------------------------*/
void SmearBulges(MICROFEATURES MicroFeatures, FLOAT32 XScale, FLOAT32 YScale) {
/*
 **      Parameters:
 **              MicroFeatures   features to be smeared
 **		XScale		# of normalized units per pixel in x dir
 **		YScale		# of normalized units per pixel in y dir
 **      Globals: none
 **      Operation: Add a random amount to each bulge parameter of each
 **              feature.  The amount added is between -0.5 pixels and
 **              0.5 pixels.  This is done to prevent the prototypes
 **              generated in training from being unrealistically tight.
 **      Return: none
 **      Exceptions: none
 **      History: Thu Jun 28 18:03:38 1990, DSJ, Created.
 */
  MICROFEATURE MicroFeature;
  FLOAT32 MinSmear;
  FLOAT32 MaxSmear;
  FLOAT32 Cos, Sin;
  FLOAT32 Scale;

  iterate(MicroFeatures) {
    MicroFeature = NextFeatureOf (MicroFeatures);

    Cos = fabs (cos (2.0 * PI * OrientationOf (MicroFeature)));
    Sin = fabs (sin (2.0 * PI * OrientationOf (MicroFeature)));
    Scale = YScale * Cos + XScale * Sin;

    MinSmear = -0.5 * Scale / (BULGENORMALIZER * LengthOf (MicroFeature));
    MaxSmear = 0.5 * Scale / (BULGENORMALIZER * LengthOf (MicroFeature));

    FirstBulgeOf (MicroFeature) += UniformRandomNumber (MinSmear, MaxSmear);
    SecondBulgeOf (MicroFeature) += UniformRandomNumber (MinSmear, MaxSmear);
  }
}                                /* SmearBulges */