picofeat.cpp

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/******************************************************************************
 ** Filename:    picofeat.c
 ** Purpose:     Definition of pico-features.
 ** Author:      Dan Johnson
 **
 ** (c) Copyright Hewlett-Packard Company, 1988.
 ** Licensed under the Apache License, Version 2.0 (the "License");
 ** you may not use this file except in compliance with the License.
 ** You may obtain a copy of the License at
 ** http://www.apache.org/licenses/LICENSE-2.0
 ** Unless required by applicable law or agreed to in writing, software
 ** distributed under the License is distributed on an "AS IS" BASIS,
 ** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 ** See the License for the specific language governing permissions and
 ** limitations under the License.
 ******************************************************************************/
/*----------------------------------------------------------------------------
          Include Files and Type Defines
----------------------------------------------------------------------------*/
#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>

/*---------------------------------------------------------------------------
          Variables
----------------------------------------------------------------------------*/

double_VAR(classify_pico_feature_length, 0.05, "Pico Feature Length");

/*---------------------------------------------------------------------------
          Private Function Prototypes
----------------------------------------------------------------------------*/
void ConvertSegmentToPicoFeat(FPOINT *Start,
                              FPOINT *End,
                              FEATURE_SET FeatureSet);

void ConvertToPicoFeatures2(MFOUTLINE Outline, FEATURE_SET FeatureSet);

void NormalizePicoX(FEATURE_SET FeatureSet);

/*----------------------------------------------------------------------------
              Public Code
----------------------------------------------------------------------------*/
/*---------------------------------------------------------------------------*/
namespace tesseract {
FEATURE_SET Classify::ExtractPicoFeatures(TBLOB *Blob) {
  LIST Outlines;
  LIST RemainingOutlines;
  MFOUTLINE Outline;
  FEATURE_SET FeatureSet;
  float XScale, YScale;

  FeatureSet = NewFeatureSet(MAX_PICO_FEATURES);
  Outlines = ConvertBlob(Blob);
  NormalizeOutlines(Outlines, &XScale, &YScale);
  RemainingOutlines = Outlines;
  iterate(RemainingOutlines) {
    Outline = static_cast<MFOUTLINE>first_node (RemainingOutlines);
    ConvertToPicoFeatures2(Outline, FeatureSet);
  }
  if (classify_norm_method == baseline)
    NormalizePicoX(FeatureSet);
  FreeOutlines(Outlines);
  return (FeatureSet);

}                                /* ExtractPicoFeatures */
}  // namespace tesseract

/*----------------------------------------------------------------------------
              Private Code
----------------------------------------------------------------------------*/
/*---------------------------------------------------------------------------*/
void ConvertSegmentToPicoFeat(FPOINT *Start,
                              FPOINT *End,
                              FEATURE_SET FeatureSet) {
  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 = static_cast<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 */


/*---------------------------------------------------------------------------*/
void ConvertToPicoFeatures2(MFOUTLINE Outline, FEATURE_SET FeatureSet) {
  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 */


/*---------------------------------------------------------------------------*/
void NormalizePicoX(FEATURE_SET FeatureSet) {
  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 */

namespace tesseract {
/*---------------------------------------------------------------------------*/
FEATURE_SET Classify::ExtractIntCNFeatures(
    const TBLOB& blob, const INT_FX_RESULT_STRUCT& fx_info) {
  INT_FX_RESULT_STRUCT local_fx_info(fx_info);
  GenericVector<INT_FEATURE_STRUCT> bl_features;
  tesseract::TrainingSample* sample = tesseract::BlobToTrainingSample(
      blob, false, &local_fx_info, &bl_features);
  if (sample == nullptr) return nullptr;

  uint32_t num_features = sample->num_features();
  const INT_FEATURE_STRUCT* features = sample->features();
  FEATURE_SET feature_set = NewFeatureSet(num_features);
  for (uint32_t f = 0; f < num_features; ++f) {
    FEATURE feature = NewFeature(&IntFeatDesc);

    feature->Params[IntX] = features[f].X;
    feature->Params[IntY] = features[f].Y;
    feature->Params[IntDir] = features[f].Theta;
    AddFeature(feature_set, feature);
  }
  delete sample;

  return feature_set;
}                                /* ExtractIntCNFeatures */

/*---------------------------------------------------------------------------*/
FEATURE_SET Classify::ExtractIntGeoFeatures(
    const TBLOB& blob, const INT_FX_RESULT_STRUCT& fx_info) {
  INT_FX_RESULT_STRUCT local_fx_info(fx_info);
  GenericVector<INT_FEATURE_STRUCT> bl_features;
  tesseract::TrainingSample* sample = tesseract::BlobToTrainingSample(
      blob, false, &local_fx_info, &bl_features);
  if (sample == nullptr) return nullptr;

  FEATURE_SET feature_set = NewFeatureSet(1);
  FEATURE feature = NewFeature(&IntFeatDesc);

  feature->Params[GeoBottom] = sample->geo_feature(GeoBottom);
  feature->Params[GeoTop] = sample->geo_feature(GeoTop);
  feature->Params[GeoWidth] = sample->geo_feature(GeoWidth);
  AddFeature(feature_set, feature);
  delete sample;

  return feature_set;
}                                /* ExtractIntGeoFeatures */

}  // namespace tesseract.