picofeat.cpp File Reference

#include "picofeat.h"
#include "classify.h"
#include "featdefs.h"
#include "fpoint.h"
#include "mfoutline.h"
#include "ocrfeatures.h"
#include "params.h"
#include "trainingsample.h"
#include <cmath>
#include <cstdio>

Go to the source code of this file.

Namespaces
	tesseract

Functions
void	ConvertSegmentToPicoFeat (FPOINT *Start, FPOINT *End, FEATURE_SET FeatureSet)
void	ConvertToPicoFeatures2 (MFOUTLINE Outline, FEATURE_SET FeatureSet)
void	NormalizePicoX (FEATURE_SET FeatureSet)

Variables
double	classify_pico_feature_length = 0.05

Function Documentation

ConvertSegmentToPicoFeat()

void ConvertSegmentToPicoFeat	(	FPOINT *	Start,
		FPOINT *	End,
		FEATURE_SET	FeatureSet
	)

This routine converts an entire segment of an outline into a set of pico features which are added to FeatureSet. The length of the segment is rounded to the nearest whole number of pico-features. The pico-features are spaced evenly over the entire segment. Globals:

• classify_pico_feature_length length of a single pico-feature

  Parameters

  Start	starting point of pico-feature
  End	ending point of pico-feature
  FeatureSet	set to add pico-feature to

  Returns

  none (results are placed in FeatureSet)

Definition at line 104 of file picofeat.cpp.

                                                      {
  FEATURE Feature;
  float Angle;
  float Length;
  int NumFeatures;
  FPOINT Center;
  FPOINT Delta;
  int i;

  Angle = NormalizedAngleFrom (Start, End, 1.0);
  Length = DistanceBetween (*Start, *End);
  NumFeatures = (int) floor (Length / classify_pico_feature_length + 0.5);
  if (NumFeatures < 1)
    NumFeatures = 1;

  /* compute vector for one pico feature */
  Delta.x = XDelta (*Start, *End) / NumFeatures;
  Delta.y = YDelta (*Start, *End) / NumFeatures;

  /* compute position of first pico feature */
  Center.x = Start->x + Delta.x / 2.0;
  Center.y = Start->y + Delta.y / 2.0;

  /* compute each pico feature in segment and add to feature set */
  for (i = 0; i < NumFeatures; i++) {
    Feature = NewFeature (&PicoFeatDesc);
    Feature->Params[PicoFeatDir] = Angle;
    Feature->Params[PicoFeatX] = Center.x;
    Feature->Params[PicoFeatY] = Center.y;
    AddFeature(FeatureSet, Feature);

    Center.x += Delta.x;
    Center.y += Delta.y;
  }
}                                /* ConvertSegmentToPicoFeat */

ConvertToPicoFeatures2()

void ConvertToPicoFeatures2	(	MFOUTLINE	Outline,
		FEATURE_SET	FeatureSet
	)

This routine steps through the specified outline and cuts it up into pieces of equal length. These pieces become the desired pico-features. Each segment in the outline is converted into an integral number of pico-features.

Globals:

• classify_pico_feature_length length of features to be extracted

  Parameters

  Outline	outline to extract micro-features from
  FeatureSet	set of features to add pico-features to

  Returns

  none (results are returned in FeatureSet)

Definition at line 156 of file picofeat.cpp.

                                                                       {
  MFOUTLINE Next;
  MFOUTLINE First;
  MFOUTLINE Current;

  if (DegenerateOutline(Outline))
    return;

  First = Outline;
  Current = First;
  Next = NextPointAfter(Current);
  do {
    /* note that an edge is hidden if the ending point of the edge is
       marked as hidden.  This situation happens because the order of
       the outlines is reversed when they are converted from the old
       format.  In the old format, a hidden edge is marked by the
       starting point for that edge. */
    if (!(PointAt(Next)->Hidden))
      ConvertSegmentToPicoFeat (&(PointAt(Current)->Point),
        &(PointAt(Next)->Point), FeatureSet);

    Current = Next;
    Next = NextPointAfter(Current);
  }
  while (Current != First);

}                                /* ConvertToPicoFeatures2 */

NormalizePicoX()

void NormalizePicoX

(

FEATURE_SET

FeatureSet

)

This routine computes the average x position over all of the pico-features in FeatureSet and then renormalizes the pico-features to force this average to be the x origin (i.e. x=0).

Parameters

FeatureSet

pico-features to be normalized

Returns

none (FeatureSet is changed)

Note

Globals: none

Definition at line 195 of file picofeat.cpp.

                                            {
  int i;
  FEATURE Feature;
  float Origin = 0.0;

  for (i = 0; i < FeatureSet->NumFeatures; i++) {
    Feature = FeatureSet->Features[i];
    Origin += Feature->Params[PicoFeatX];
  }
  Origin /= FeatureSet->NumFeatures;

  for (i = 0; i < FeatureSet->NumFeatures; i++) {
    Feature = FeatureSet->Features[i];
    Feature->Params[PicoFeatX] -= Origin;
  }
}                                /* NormalizePicoX */

Variable Documentation

classify_pico_feature_length

double classify_pico_feature_length = 0.05

"Pico Feature Length"

Definition at line 38 of file picofeat.cpp.