intfx.cpp

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/******************************************************************************
 **      Filename:    intfx.c
 **      Purpose:     Integer character normalization & feature extraction
 **      Author:      Robert Moss
 **      History:     Tue May 21 15:51:57 MDT 1991, RWM, Created.
 **
 **      (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 "intfx.h"
#include "intmatcher.h"
#include "const.h"
#ifdef __UNIX__
#include <assert.h>
#endif

/**----------------------------------------------------------------------------
          Private Function Prototypes
----------------------------------------------------------------------------**/
int SaveFeature();
uinT8 TableLookup();
uinT8 MySqrt2();
void ClipRadius();

make_int_var (RadiusGyrMinMan, 255, MakeRadiusGyrMinMan,
16, 10, SetRadiusGyrMinMan,
"Minimum Radius of Gyration Mantissa 0-255:        ");

make_int_var (RadiusGyrMinExp, 0, MakeRadiusGyrMinExp,
16, 11, SetRadiusGyrMinExp,
"Minimum Radius of Gyration Exponent 0-255:        ");

make_int_var (RadiusGyrMaxMan, 158, MakeRadiusGyrMaxMan,
16, 12, SetRadiusGyrMaxMan,
"Maximum Radius of Gyration Mantissa 0-255:        ");

make_int_var (RadiusGyrMaxExp, 8, MakeRadiusGyrMaxExp,
16, 13, SetRadiusGyrMaxExp,
"Maximum Radius of Gyration Exponent 0-255:        ");

/**----------------------------------------------------------------------------
        Global Data Definitions and Declarations
----------------------------------------------------------------------------**/
#define  ATAN_TABLE_SIZE    64

static uinT8 AtanTable[ATAN_TABLE_SIZE];

/**----------------------------------------------------------------------------
            Public Code
----------------------------------------------------------------------------**/
/*---------------------------------------------------------------------------*/
void InitIntegerFX() {
  int i;

  for (i = 0; i < ATAN_TABLE_SIZE; i++)
    AtanTable[i] =
      (uinT8) (atan ((i / (float) ATAN_TABLE_SIZE)) * 128.0 / PI + 0.5);

}


/*--------------------------------------------------------------------------*/
int ExtractIntFeat(TBLOB *Blob,
                   INT_FEATURE_ARRAY BLFeat,
                   INT_FEATURE_ARRAY CNFeat,
                   INT_FX_RESULT Results) {

  TESSLINE *OutLine;
  EDGEPT *Loop, *LoopStart, *Segment;
  inT16 LastX, LastY, Xmean, Ymean;
  inT32 NormX, NormY, DeltaX, DeltaY;
  inT32 Xsum, Ysum;
  uinT32 Ix, Iy, LengthSum;
  uinT16 n;
  uinT8 Theta;
  uinT16 NumBLFeatures, NumCNFeatures;
  uinT8 RxInv, RyInv;            /* x.xxxxxxx  *  2^Exp  */
  uinT8 RxExp, RyExp;
                                 /* sxxxxxxxxxxxxxxxxxxxxxxx.xxxxxxxx */
  register inT32 pfX, pfY, dX, dY;
  uinT16 Length;
  register int i;

  Results->Length = 0;
  Results->Xmean = 0;
  Results->Ymean = 0;
  Results->Rx = 0;
  Results->Ry = 0;
  Results->NumBL = 0;
  Results->NumCN = 0;

  /* find Xmean, Ymean */
  NumBLFeatures = 0;
  NumCNFeatures = 0;
  OutLine = Blob->outlines;
  Xsum = 0;
  Ysum = 0;
  LengthSum = 0;
  while (OutLine != NULL) {
    LoopStart = OutLine->loop;
    Loop = LoopStart;
    LastX = Loop->pos.x;
    LastY = Loop->pos.y;
    /* Check for bad loops */
    if ((Loop == NULL) || (Loop->next == NULL) || (Loop->next == LoopStart))
      return FALSE;
    do {
      Segment = Loop;
      Loop = Loop->next;
      NormX = Loop->pos.x;
      NormY = Loop->pos.y;

      n = 1;
      if (!is_hidden_edge (Segment)) {
        DeltaX = NormX - LastX;
        DeltaY = NormY - LastY;
        Length = MySqrt (DeltaX, DeltaY);
        n = ((Length << 2) + Length + 32) >> 6;
        if (n != 0) {
          Xsum += ((LastX << 1) + DeltaX) * (int) Length;
          Ysum += ((LastY << 1) + DeltaY) * (int) Length;
          LengthSum += Length;
        }
      }
      if (n != 0) {              /* Throw away a point that is too close */
        LastX = NormX;
        LastY = NormY;
      }
    }
    while (Loop != LoopStart);
    OutLine = OutLine->next;
  }
  if (LengthSum == 0)
    return FALSE;
  Xmean = (Xsum / (inT32) LengthSum) >> 1;
  Ymean = (Ysum / (inT32) LengthSum) >> 1;

  Results->Length = LengthSum;
  Results->Xmean = Xmean;
  Results->Ymean = Ymean;

  /* extract Baseline normalized features,     */
  /* and find 2nd moments & radius of gyration */
  Ix = 0;
  Iy = 0;
  NumBLFeatures = 0;
  OutLine = Blob->outlines;
  while (OutLine != NULL) {
    LoopStart = OutLine->loop;
    Loop = LoopStart;
    LastX = Loop->pos.x - Xmean;
    LastY = Loop->pos.y;
    /* Check for bad loops */
    if ((Loop == NULL) || (Loop->next == NULL) || (Loop->next == LoopStart))
      return FALSE;
    do {
      Segment = Loop;
      Loop = Loop->next;
      NormX = Loop->pos.x - Xmean;
      NormY = Loop->pos.y;

      n = 1;
      if (!is_hidden_edge (Segment)) {
        DeltaX = NormX - LastX;
        DeltaY = NormY - LastY;
        Length = MySqrt (DeltaX, DeltaY);
        n = ((Length << 2) + Length + 32) >> 6;
        if (n != 0) {
          Theta = TableLookup (DeltaY, DeltaX);
          dX = (DeltaX << 8) / n;
          dY = (DeltaY << 8) / n;
          pfX = (LastX << 8) + (dX >> 1);
          pfY = (LastY << 8) + (dY >> 1);
          Ix += ((pfY >> 8) - Ymean) * ((pfY >> 8) - Ymean);
          Iy += (pfX >> 8) * (pfX >> 8);
          if (SaveFeature (BLFeat, NumBLFeatures, (inT16) (pfX >> 8),
            (inT16) ((pfY >> 8) - 128),
            Theta) == FALSE)
            return FALSE;
          NumBLFeatures++;
          for (i = 1; i < n; i++) {
            pfX += dX;
            pfY += dY;
            Ix += ((pfY >> 8) - Ymean) * ((pfY >> 8) - Ymean);
            Iy += (pfX >> 8) * (pfX >> 8);
            if (SaveFeature
              (BLFeat, NumBLFeatures, (inT16) (pfX >> 8),
              (inT16) ((pfY >> 8) - 128), Theta) == FALSE)
              return FALSE;
            NumBLFeatures++;
          }
        }
      }
      if (n != 0) {              /* Throw away a point that is too close */
        LastX = NormX;
        LastY = NormY;
      }
    }
    while (Loop != LoopStart);
    OutLine = OutLine->next;
  }
  if (Ix == 0)
    Ix = 1;
  if (Iy == 0)
    Iy = 1;
  RxInv = MySqrt2 (NumBLFeatures, Ix, &RxExp);
  RyInv = MySqrt2 (NumBLFeatures, Iy, &RyExp);
  ClipRadius(&RxInv, &RxExp, &RyInv, &RyExp);

  Results->Rx = (inT16) (51.2 / (double) RxInv * pow (2.0, (double) RxExp));
  Results->Ry = (inT16) (51.2 / (double) RyInv * pow (2.0, (double) RyExp));
  Results->NumBL = NumBLFeatures;

  /* extract character normalized features */
  NumCNFeatures = 0;
  OutLine = Blob->outlines;
  while (OutLine != NULL) {
    LoopStart = OutLine->loop;
    Loop = LoopStart;
    LastX = (Loop->pos.x - Xmean) * RyInv;
    LastY = (Loop->pos.y - Ymean) * RxInv;
    LastX >>= (inT8) RyExp;
    LastY >>= (inT8) RxExp;
    /* Check for bad loops */
    if ((Loop == NULL) || (Loop->next == NULL) || (Loop->next == LoopStart))
      return FALSE;
    do {
      Segment = Loop;
      Loop = Loop->next;
      NormX = (Loop->pos.x - Xmean) * RyInv;
      NormY = (Loop->pos.y - Ymean) * RxInv;
      NormX >>= (inT8) RyExp;
      NormY >>= (inT8) RxExp;

      n = 1;
      if (!is_hidden_edge (Segment)) {
        DeltaX = NormX - LastX;
        DeltaY = NormY - LastY;
        Length = MySqrt (DeltaX, DeltaY);
        n = ((Length << 2) + Length + 32) >> 6;
        if (n != 0) {
          Theta = TableLookup (DeltaY, DeltaX);
          dX = (DeltaX << 8) / n;
          dY = (DeltaY << 8) / n;
          pfX = (LastX << 8) + (dX >> 1);
          pfY = (LastY << 8) + (dY >> 1);
          if (SaveFeature (CNFeat, NumCNFeatures, (inT16) (pfX >> 8),
            (inT16) ((pfY >> 8)), Theta) == FALSE)
            return FALSE;
          NumCNFeatures++;
          for (i = 1; i < n; i++) {
            pfX += dX;
            pfY += dY;
            if (SaveFeature
              (CNFeat, NumCNFeatures, (inT16) (pfX >> 8),
              (inT16) ((pfY >> 8)), Theta) == FALSE)
              return FALSE;
            NumCNFeatures++;
          }
        }
      }
      if (n != 0) {              /* Throw away a point that is too close */
        LastX = NormX;
        LastY = NormY;
      }
    }
    while (Loop != LoopStart);
    OutLine = OutLine->next;
  }

  Results->NumCN = NumCNFeatures;
  return TRUE;
}


/*--------------------------------------------------------------------------*/
uinT8 TableLookup(inT32 Y, inT32 X) {
  inT16 Angle;
  uinT16 Ratio;
  uinT32 AbsX, AbsY;

  assert ((X != 0) || (Y != 0));
  if (X < 0)
    AbsX = -X;
  else
    AbsX = X;
  if (Y < 0)
    AbsY = -Y;
  else
    AbsY = Y;
  if (AbsX > AbsY)
    Ratio = AbsY * ATAN_TABLE_SIZE / AbsX;
  else
    Ratio = AbsX * ATAN_TABLE_SIZE / AbsY;