classify/mfx.cpp File Reference

#include "mfdefs.h"
#include "mfoutline.h"
#include "clusttool.h"
#include "const.h"
#include "intfx.h"
#include "normalis.h"
#include "params.h"
#include <math.h>

Go to the source code of this file.

Defines
#define	NormalizeAngle(A)   ( (((A)<0)?((A)+2*PI):(A)) / (2*PI) )
Functions
FLOAT32	ComputeOrientation (MFEDGEPT *Start, MFEDGEPT *End)
MICROFEATURES	ConvertToMicroFeatures (MFOUTLINE Outline, MICROFEATURES MicroFeatures)
MICROFEATURE	ExtractMicroFeature (MFOUTLINE Start, MFOUTLINE End)
MICROFEATURES	BlobMicroFeatures (TBLOB *Blob, const DENORM &cn_denorm)
Variables
double	classify_min_slope = 0.414213562
double	classify_max_slope = 2.414213562

---

Define Documentation

#define NormalizeAngle

(

A

)

( (((A)<0)?((A)+2*PI):(A)) / (2*PI) )

Definition at line 45 of file mfx.cpp.

---

Function Documentation

MICROFEATURES BlobMicroFeatures	(	TBLOB *	Blob,
		const DENORM &	cn_denorm
	)

This routine extracts micro-features from the specified blob and returns a list of the micro-features. All micro-features are normalized according to the specified line statistics.

Parameters:

Blob	blob to extract micro-features from
cn_denorm	control parameter to feature extractor

Returns:

List of micro-features extracted from the blob.

Note:

Exceptions: none

History: 7/21/89, DSJ, Created.

Definition at line 72 of file mfx.cpp.

                                                                      {
  MICROFEATURES MicroFeatures = NIL_LIST;
  LIST Outlines;
  LIST RemainingOutlines;
  MFOUTLINE Outline;

  if (Blob != NULL) {
    Outlines = ConvertBlob(Blob);

    RemainingOutlines = Outlines;
    iterate(RemainingOutlines) {
      Outline = (MFOUTLINE) first_node (RemainingOutlines);
      CharNormalizeOutline(Outline, cn_denorm);
    }

    RemainingOutlines = Outlines;
    iterate(RemainingOutlines) {
      Outline = (MFOUTLINE) first_node(RemainingOutlines);
      FindDirectionChanges(Outline, classify_min_slope, classify_max_slope);
      MarkDirectionChanges(Outline);
      MicroFeatures = ConvertToMicroFeatures(Outline, MicroFeatures);
    }
    FreeOutlines(Outlines);
  }
  return MicroFeatures;
}                                /* BlobMicroFeatures */

FLOAT32 ComputeOrientation	(	MFEDGEPT *	Start,
		MFEDGEPT *	End
	)

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.

Parameters:

Start	starting edge point of micro-feature
End	ending edge point of micro-feature

Note:

Globals: none

Returns:

Orientation parameter for the specified micro-feature.

Note:

Exceptions: none

History: 7/27/89, DSJ, Created.

Definition at line 120 of file mfx.cpp.

                                                           {
  FLOAT32 Orientation;

  Orientation = NormalizeAngle (AngleFrom (Start->Point, End->Point));

  /* 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
	)

Convert Outline to MicroFeatures

Parameters:

Outline	outline to extract micro-features from
MicroFeatures	list of micro-features to add to

Returns:

List of micro-features with new features added to front.

Note:

Globals: none

Exceptions: none

History: 7/26/89, DSJ, Created.

Definition at line 141 of file mfx.cpp.

                                                                  {
  MFOUTLINE Current;
  MFOUTLINE Last;
  MFOUTLINE First;
  MICROFEATURE NewFeature;

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

  First = NextExtremity (Outline);
  Last = First;
  do {
    Current = NextExtremity (Last);
    if (!PointAt(Current)->Hidden) {
      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
	)

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.

Parameters:

Start	starting point of micro-feature
End	ending point of micro-feature

Returns:

New micro-feature or NULL if the feature was rejected.

Note:

Globals: none

Exceptions: none

History:

• 7/26/89, DSJ, Created.
• 11/17/89, DSJ, Added handling for Start and End same point.

Definition at line 185 of file mfx.cpp.

                                                                 {
  MICROFEATURE NewFeature;
  MFEDGEPT *P1, *P2;

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

  NewFeature = NewMicroFeature ();
  NewFeature[XPOSITION] = AverageOf(P1->Point.x, P2->Point.x);
  NewFeature[YPOSITION] = AverageOf(P1->Point.y, P2->Point.y);
  NewFeature[MFLENGTH] = DistanceBetween(P1->Point, P2->Point);
  NewFeature[ORIENTATION] = NormalizedAngleFrom(&P1->Point, &P2->Point, 1.0);
  NewFeature[FIRSTBULGE] = 0.0f;  // deprecated
  NewFeature[SECONDBULGE] = 0.0f;  // deprecated

  return NewFeature;
}                                /* ExtractMicroFeature */

---

Variable Documentation

double classify_max_slope = 2.414213562

"Slope above which lines are called vertical"

Definition at line 39 of file mfx.cpp.

double classify_min_slope = 0.414213562

"Slope below which lines are called horizontal"

Definition at line 37 of file mfx.cpp.