ccmain/fixxht.cpp

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#include "mfcpch.h"
#include          <string.h>
#include          <ctype.h>
#include          "varable.h"
#include          "tessvars.h"
#include          "control.h"
#include          "reject.h"
#include          "fixxht.h"
#include          "secname.h"
#ifdef TEXT_VERBOSE
#include    "callcpp.h"
#endif

#define EXTERN

EXTERN double_VAR (x_ht_fraction_of_caps_ht, 0.7,
"Fract of cps ht est of xht");
EXTERN double_VAR (x_ht_variation, 0.35,
"Err band as fract of caps/xht dist");
EXTERN double_VAR (x_ht_sub_variation, 0.5,
"Err band as fract of caps/xht dist");
EXTERN BOOL_VAR (rej_trial_ambigs, TRUE,
"reject x-ht ambigs when under trial");
EXTERN BOOL_VAR (x_ht_conservative_ambigs, FALSE,
"Dont rely on ambigs + maxht");
EXTERN BOOL_VAR (x_ht_check_est, TRUE, "Cross check estimates");
EXTERN BOOL_VAR (x_ht_case_flip, FALSE, "Flip or reject suspect case");
EXTERN BOOL_VAR (x_ht_include_dodgy_blobs, TRUE,
"Include blobs with possible noise?");
EXTERN BOOL_VAR (x_ht_limit_flip_trials, TRUE,
"Dont do trial flips when ambigs are close to xht?");
EXTERN BOOL_VAR (rej_use_check_block_occ, TRUE,
"Analyse rejection behaviour");

EXTERN STRING_VAR (chs_non_ambig_caps_ht,
"!#$%&()/12346789?ABDEFGHIKLNQRT[]\\bdfhkl",
"Reliable ascenders");
EXTERN STRING_VAR (chs_x_ht, "acegmnopqrsuvwxyz", "X height chars");
EXTERN STRING_VAR (chs_non_ambig_x_ht, "aenqr", "reliable X height chars");
EXTERN STRING_VAR (chs_ambig_caps_x, "cCmMoO05sSuUvVwWxXzZ",
"X ht or caps ht chars");
EXTERN STRING_VAR (chs_bl_ambig_caps_x, "pPyY", " Caps or descender ambigs");

/* The following arent used in this module but are used in applybox.c */
EXTERN STRING_VAR (chs_caps_ht,
"!#$%&()/0123456789?ABCDEFGHIJKLMNOPQRSTUVWXYZ[]\\bdfhkl{|}",
"Ascender chars");
EXTERN STRING_VAR (chs_desc, "gjpqy", "Descender chars");
EXTERN STRING_VAR (chs_non_ambig_bl,
"!#$%&01246789?ABCDEFGHIKLMNORSTUVWXYZabcdehiklmnorstuvwxz",
"Reliable baseline chars");
EXTERN STRING_VAR (chs_odd_top, "ijt", "Chars with funny ascender region");
EXTERN STRING_VAR (chs_odd_bot, "()35JQ[]\\/{}|", "Chars with funny base");

/* The following arent used but are defined for completeness */
EXTERN STRING_VAR (chs_bl,
"!#$%&()/01246789?ABCDEFGHIJKLMNOPRSTUVWXYZ[]\\abcdefhiklmnorstuvwxz{}",
"Baseline chars");
EXTERN STRING_VAR (chs_non_ambig_desc, "gq", "Reliable descender chars");
void re_estimate_x_ht(                     //improve for 1 word
                      WERD_RES *word_res,  //word to do
                      float *trial_x_ht    //new match value
                     ) {
  PBLOB_IT blob_it;
  INT16 blob_ht_above_baseline;

  const char *word_str;
  INT16 i;

  STATS all_blobs_ht (0, 300);   //every blob in word
  STATS x_ht (0, 300);           //confirmed pts in wd
  STATS caps_ht (0, 300);        //confirmed pts in wd
  STATS case_ambig (0, 300);     //lower case ambigs

  INT16 rej_blobs_count = 0;
  INT16 rej_blobs_max_height = 0;
  INT32 rej_blobs_max_area = 0;
  float x_ht_ok_variation;
  float max_blob_ht;
  float marginally_above_x_ht;

  BOX blob_box;                  //blob bounding box
  float est_x_ht = 0.0;          //word estimate
  float est_caps_ht = 0.0;       //word estimate
                                 //based on hard data?
  BOOL8 est_caps_ht_certain = FALSE;
  BOOL8 est_x_ht_certain = FALSE;//based on hard data?
  BOOL8 trial = FALSE;           //Sepeculative values?
  BOOL8 no_comment = FALSE;      //No change in xht
  float ambig_lc_x_est;
  float ambig_uc_caps_est;
  INT16 x_ht_ambigs = 0;
  INT16 caps_ht_ambigs = 0;

#ifdef TEXT_VERBOSE
  // gets a 'h', see ccmain/tesseractmain.dox
  cprintf("h");
#endif
  /* Calculate default variation of blob x_ht from bln x_ht for bln word */
  x_ht_ok_variation =
    (bln_x_height / x_ht_fraction_of_caps_ht - bln_x_height) * x_ht_variation;

  word_str = word_res->best_choice->string ().string ();
  /*
    Cycle blobs, allocating to one of the stats sets when possible.
  */
  blob_it.set_to_list (word_res->outword->blob_list ());
  for (blob_it.mark_cycle_pt (), i = 0;
  !blob_it.cycled_list (); blob_it.forward (), i++) {
    if (!dodgy_blob (blob_it.data ())) {
      blob_box = blob_it.data ()->bounding_box ();
      blob_ht_above_baseline = blob_box.top () - bln_baseline_offset;
      all_blobs_ht.add (blob_ht_above_baseline, 1);

      if (word_res->reject_map[i].rejected ()) {
        rej_blobs_count++;
        if (blob_box.height () > rej_blobs_max_height)
          rej_blobs_max_height = blob_box.height ();
        if (blob_box.area () > rej_blobs_max_area)
          rej_blobs_max_area = blob_box.area ();
      }
      else {
        if (STRING (chs_non_ambig_x_ht).contains (word_str[i]))
          x_ht.add (blob_ht_above_baseline, 1);

        if (STRING (chs_non_ambig_caps_ht).contains (word_str[i]))
          caps_ht.add (blob_ht_above_baseline, 1);

        if (STRING (chs_ambig_caps_x).contains (word_str[i])) {
          case_ambig.add (blob_ht_above_baseline, 1);
          if (STRING (chs_x_ht).contains (word_str[i]))
            x_ht_ambigs++;
          else
            caps_ht_ambigs++;
        }

        if (STRING (chs_bl_ambig_caps_x).contains (word_str[i])) {
          if (STRING (chs_x_ht).contains (word_str[i])) {
            /* confirm x_height provided > 15% total height below baseline */
            if ((bln_baseline_offset - blob_box.bottom ()) /
              (float) blob_box.height () > 0.15)
              x_ht.add (blob_ht_above_baseline, 1);
          }
          else {
            /* confirm caps_height provided < 5% total height below baseline */
            if ((bln_baseline_offset - blob_box.bottom ()) /
              (float) blob_box.height () < 0.05)
              caps_ht.add (blob_ht_above_baseline, 1);
          }
        }
      }
    }
  }
  est_caps_ht = estimate_from_stats (caps_ht);
  est_x_ht = estimate_from_stats (x_ht);
  est_ambigs(word_res, case_ambig, &ambig_lc_x_est, &ambig_uc_caps_est); 
  max_blob_ht = all_blobs_ht.ile (0.9999);

  #ifndef SECURE_NAMES
  if (debug_x_ht_level >= 20) {
    tprintf ("Mode20:A: %s ", word_str);
    word_res->reject_map.print (debug_fp);
    tprintf (" XHT:%f CAP:%f MAX:%f AMBIG X:%f CAP:%f\n",
      est_x_ht, est_caps_ht, max_blob_ht,
      ambig_lc_x_est, ambig_uc_caps_est);
  }
  #endif
  if (!x_ht_conservative_ambigs &&
    (ambig_lc_x_est > 0) &&
    (ambig_lc_x_est == ambig_uc_caps_est) &&
  (max_blob_ht > ambig_lc_x_est + x_ht_ok_variation)) {
                                 //may be zero but believe xht
    ambig_uc_caps_est = est_caps_ht;
    #ifndef SECURE_NAMES
    if (debug_x_ht_level >= 20)
      tprintf ("Mode20:B: Fiddle ambig_uc_caps_est to %f\n",
        ambig_lc_x_est);
    #endif
  }

  /* Now make some estimates */

  if ((est_x_ht > 0) ||
    (est_caps_ht > 0) ||
  ((ambig_lc_x_est > 0) && (ambig_lc_x_est != ambig_uc_caps_est))) {
    /* There is some sensible data to go on so make the most of it. */
    #ifndef SECURE_NAMES
    if (debug_x_ht_level >= 20)
      tprintf ("Mode20:C: Sensible Data\n", ambig_lc_x_est);
    #endif
    if (est_x_ht > 0) {
      est_x_ht_certain = TRUE;
      if (est_caps_ht == 0) {
        if ((ambig_uc_caps_est > ambig_lc_x_est) &&
          (ambig_uc_caps_est > est_x_ht + x_ht_ok_variation))
          est_caps_ht = ambig_uc_caps_est;
        else
          est_caps_ht = est_x_ht / x_ht_fraction_of_caps_ht;
      }
      if (case_ambig.get_total () > 0)
        improve_estimate(word_res, est_x_ht, est_caps_ht, x_ht, caps_ht); 
      est_caps_ht_certain = caps_ht.get_total () > 0;
      #ifndef SECURE_NAMES
      if (debug_x_ht_level >= 20)
        tprintf ("Mode20:D: Est from xht XHT:%f CAP:%f\n",
          est_x_ht, est_caps_ht);
      #endif
    }
    else if (est_caps_ht > 0) {
      est_caps_ht_certain = TRUE;
      if ((ambig_lc_x_est > 0) &&
        (ambig_lc_x_est < est_caps_ht - x_ht_ok_variation))
        est_x_ht = ambig_lc_x_est;
      else
        est_x_ht = est_caps_ht * x_ht_fraction_of_caps_ht;
      if (ambig_lc_x_est + ambig_uc_caps_est > 0)
        improve_estimate(word_res, est_x_ht, est_caps_ht, x_ht, caps_ht); 
      est_x_ht_certain = x_ht.get_total () > 0;
      #ifndef SECURE_NAMES
      if (debug_x_ht_level >= 20)
        tprintf ("Mode20:E: Est from caps XHT:%f CAP:%f\n",
          est_x_ht, est_caps_ht);
      #endif
    }
    else {
      /*
     Do something based on case ambig chars alone - we have
     guessed that the ambigs are lower case.
     */
      est_x_ht = ambig_lc_x_est;
      est_x_ht_certain = TRUE;
      if (ambig_uc_caps_est > ambig_lc_x_est) {
        est_caps_ht = ambig_uc_caps_est;
        est_caps_ht_certain = TRUE;
      }
      else
        est_caps_ht = est_x_ht / x_ht_fraction_of_caps_ht;

      #ifndef SECURE_NAMES
      if (debug_x_ht_level >= 20)
        tprintf ("Mode20:F: Est from ambigs XHT:%f CAP:%f\n",
          est_x_ht, est_caps_ht);
      #endif
    }
    /*
     Check for sane interpretation of evidence:
      Try shifting caps ht if min certain caps ht is not significantly greater
      than the estimated x ht or the max certain x ht is not significantly less
      than the estimated caps ht.
    */
    if (x_ht_check_est) {
      if ((caps_ht.get_total () > 0) &&
      (est_x_ht + x_ht_ok_variation >= caps_ht.ile (0.0001))) {
        trial = TRUE;
        est_caps_ht = est_x_ht;
        est_x_ht = x_ht_fraction_of_caps_ht * est_caps_ht;

        #ifndef SECURE_NAMES
        if (debug_x_ht_level >= 20)
          tprintf ("Mode20:G: Trial XHT:%f CAP:%f\n",
            est_x_ht, est_caps_ht);
        #endif
      }
      else if ((x_ht.get_total () > 0) &&
      (est_caps_ht - x_ht_ok_variation <= x_ht.ile (0.9999))) {
        trial = TRUE;
        est_x_ht = est_caps_ht;
        est_caps_ht = est_x_ht / x_ht_fraction_of_caps_ht;
        #ifndef SECURE_NAMES
        if (debug_x_ht_level >= 20)
          tprintf ("Mode20:H: Trial XHT:%f CAP:%f\n",
            est_x_ht, est_caps_ht);
        #endif
      }
    }
  }

  else {
    /* There is no sensible data so we're in the dark. */
    marginally_above_x_ht = bln_x_height +
      x_ht_ok_variation * x_ht_sub_variation;
    /*
     If there are no rejects, or the only rejects have a narrow height,
     or have a small area compared to a normal char, then estimate the x-height
     as the original one. (I.e dont fiddle about if the only rejects look like
      punctuation) - we use max height as mean or median will be too low if
      there are only two blobs - Eg "F."
    */

    #ifndef SECURE_NAMES
    if (debug_x_ht_level >= 20)
      tprintf ("Mode20:I: In the dark\n");
    #endif

    if ((rej_blobs_count == 0) ||
      (rej_blobs_max_height < 0.3 * max_blob_ht) ||
    (rej_blobs_max_area < 0.3 * max_blob_ht * max_blob_ht)) {
      no_comment = TRUE;
      #ifndef SECURE_NAMES
      if (debug_x_ht_level >= 20)
        tprintf ("Mode20:J: No comment due to no rejects\n");
     #endif
    }
    else if (x_ht_limit_flip_trials &&
      ((max_blob_ht < marginally_above_x_ht) ||
      ((ambig_lc_x_est > 0) &&
      (ambig_lc_x_est == ambig_uc_caps_est) &&
    (ambig_lc_x_est < marginally_above_x_ht)))) {
      no_comment = TRUE;
      #ifndef SECURE_NAMES
      if (debug_x_ht_level >= 20)
        tprintf ("Mode20:K: No comment as close to xht %f < %f\n",
          ambig_lc_x_est, marginally_above_x_ht);
     #endif
    }
    else if (x_ht_conservative_ambigs && (ambig_uc_caps_est > 0)) {
      trial = TRUE;
      est_caps_ht = ambig_lc_x_est;
      est_x_ht = x_ht_fraction_of_caps_ht * est_caps_ht;

      #ifndef SECURE_NAMES
      if (debug_x_ht_level >= 20)
        tprintf ("Mode20:L: Trial XHT:%f CAP:%f\n",
          est_x_ht, est_caps_ht);
      #endif
    }
    /*
   If the top of the word is nowhere near where we expect ascenders to be
     \(less than half the x_ht \-> caps_ht distance\)
     
     That is, suspect an all caps word at the x-ht & estimate x-ht
     accordingly, but only as a TRIAL!

      NOTE we do NOT check location of baseline. Commas can descend as much as
      real descenders so we would need to do something to make sure that any
      disqualifying descenders were not at the end.
    */
    else {
      if (max_blob_ht <
      (bln_x_height + bln_x_height / x_ht_fraction_of_caps_ht) / 2.0) {
        trial = TRUE;
        est_x_ht = x_ht_fraction_of_caps_ht * max_blob_ht;
        est_caps_ht = max_blob_ht;

        #ifndef SECURE_NAMES
        if (debug_x_ht_level >= 20)
          tprintf ("Mode20:M: Trial XHT:%f CAP:%f\n",
            est_x_ht, est_caps_ht);
        #endif
      }
      else {
        no_comment = TRUE;
        if (debug_x_ht_level >= 20)
          tprintf ("Mode20:N: No comment as nothing else matched\n");
      }
    }
  }

  /* Sanity check - reject word if fails */
  if (!no_comment &&
    ((est_x_ht > 2 * bln_x_height) ||
    (est_x_ht / word_res->denorm.scale () <= min_sane_x_ht_pixels) ||
  (est_caps_ht <= est_x_ht) || (est_caps_ht >= 2.5 * est_x_ht))) {
    no_comment = TRUE;
    if (!trial && rej_use_xht) {
      if (debug_x_ht_level >= 2) {
        tprintf ("Sanity check rejecting %s ", word_str);
        word_res->reject_map.print (debug_fp);
        tprintf ("\n");
      }
      word_res->reject_map.rej_word_xht_fixup ();

    }
    if (debug_x_ht_level >= 20)
      tprintf ("Mode20:O: No comment as nothing else matched\n");
  }

  if (no_comment || trial) {
    word_res->x_height = bln_x_height / word_res->denorm.scale ();
    word_res->guessed_x_ht = TRUE;
    word_res->caps_height = (bln_x_height / x_ht_fraction_of_caps_ht) /
      word_res->denorm.scale ();
    word_res->guessed_caps_ht = TRUE;
    /*
       Reject ambigs in the current word if we are uncertain and:
       \li there are rejects OR
       \li there is only one char which is an ambig OR
       \li there is conflict between the case of the ambigs even though there is
       \li no height separation Eg "Ms" recognised from "MS"
    */
    if (rej_trial_ambigs &&
      ((word_res->reject_map.reject_count () > 0) ||
      (word_res->reject_map.length () == 1) ||
    ((x_ht_ambigs > 0) && (caps_ht_ambigs > 0)))) {
      #ifndef SECURE_NAMES
      if (debug_x_ht_level >= 2) {
        tprintf ("TRIAL Rej Ambigs %s ", word_str);
        word_res->reject_map.print (debug_fp);
      }
      #endif
      reject_ambigs(word_res); 
      if (debug_x_ht_level >= 2) {
        tprintf (" ");
        word_res->reject_map.print (debug_fp);
        tprintf ("\n");
      }
    }
  }
  else {
    word_res->x_height = est_x_ht / word_res->denorm.scale ();
    word_res->guessed_x_ht = !est_x_ht_certain;
    word_res->caps_height = est_caps_ht / word_res->denorm.scale ();
    word_res->guessed_caps_ht = !est_caps_ht_certain;
  }

  if (!no_comment && (fabs (est_x_ht - bln_x_height) > x_ht_ok_variation))
    *trial_x_ht = est_x_ht / word_res->denorm.scale ();
  else
    *trial_x_ht = 0.0;

  #ifndef SECURE_NAMES
  if (((*trial_x_ht > 0) && (debug_x_ht_level >= 3)) ||
  (debug_x_ht_level >= 5)) {
    tprintf ("%s ", word_str);
    word_res->reject_map.print (debug_fp);
    tprintf
      (" X:%0.2f Cps:%0.2f Mxht:%0.2f RJ MxHt:%d MxAr:%d Rematch:%c\n",
      est_x_ht, est_caps_ht, max_blob_ht, rej_blobs_max_height,
      rej_blobs_max_area, *trial_x_ht > 0 ? '*' : ' ');
  }
  #endif

}

void check_block_occ(WERD_RES *word_res) { 
  PBLOB_IT blob_it;
  STRING new_string;
  REJMAP new_map = word_res->reject_map;
  WERD_CHOICE *new_choice;

  const char *word_str = word_res->best_choice->string ().string ();
  INT16 i;
  INT16 reject_count = 0;
  char confirmed_char;
  float x_ht;
  float caps_ht;

  if (word_res->x_height > 0)
    x_ht = word_res->x_height * word_res->denorm.scale ();
  else
    x_ht = bln_x_height;

  if (word_res->caps_height > 0)
    caps_ht = word_res->caps_height * word_res->denorm.scale ();
  else
    caps_ht = x_ht / x_ht_fraction_of_caps_ht;

  blob_it.set_to_list (word_res->outword->blob_list ());

  for (blob_it.mark_cycle_pt (), i = 0;
  !blob_it.cycled_list (); blob_it.forward (), i++) {
    new_string += word_str[i];   //default copy
    if (word_res->reject_map[i].accepted ()) {
      confirmed_char = check_blob_occ (word_str[i],
        blob_it.data ()->bounding_box ().
        top () - bln_baseline_offset, x_ht,
        caps_ht);

      if (confirmed_char == '\0') {
        if (rej_use_check_block_occ) {
          new_map[i].setrej_xht_fixup ();
          reject_count++;
        }
      }
      else
        new_string[i] = confirmed_char;
    }
  }
  if ((reject_count > 0) || (new_string != word_str)) {
    if (debug_x_ht_level >= 2) {
      tprintf ("Shape Verification: %s ", word_str);
      word_res->reject_map.print (debug_fp);
      tprintf (" -> %s ", new_string.string ());
      new_map.print (debug_fp);
      tprintf ("\n");
    }
    new_choice = new WERD_CHOICE (new_string.string (),
      word_res->best_choice->rating (),
      word_res->best_choice->certainty (),
      word_res->best_choice->permuter ());
    delete word_res->best_choice;
    word_res->best_choice = new_choice;
    word_res->reject_map = new_map;
  }
}


char check_blob_occ(char proposed_char,
                    INT16 blob_ht_above_baseline,
                    float x_ht,
                    float caps_ht) {
  BOOL8 blob_definite_x_ht;
  BOOL8 blob_definite_caps_ht;
  float acceptable_variation;

  acceptable_variation = (caps_ht - x_ht) * x_ht_variation;
  /*
  REJECT if:
  \li expected descender and nothing significantly below BL
  \li expected ascender and nothing significantly above x-ht 
  */

  /*
    IF AMBIG_CAPS_X_CHS
      IF blob is definitely an ascender ( > xht + xht err )AND
        char is an x-ht char
      THEN
        flip case
      IF blob is defintiely an x-ht ( <= xht + xht err ) AND
        char is an ascender char
      THEN
        flip case
  */
  blob_definite_x_ht = blob_ht_above_baseline <= x_ht + acceptable_variation;
  blob_definite_caps_ht = blob_ht_above_baseline >=
    caps_ht - acceptable_variation;

  if (STRING (chs_ambig_caps_x).contains (proposed_char)) {
    if ((!blob_definite_x_ht && !blob_definite_caps_ht) ||
      (proposed_char == '0' && !blob_definite_caps_ht) ||
      (proposed_char == 'o' && !blob_definite_x_ht))
      return '\0';

    else if (blob_definite_caps_ht &&
    STRING (chs_x_ht).contains (proposed_char)) {
      if (x_ht_case_flip)
                                 //flip to upper case
        return (char) toupper (proposed_char);
      else
        return '\0';
    }

    else if (blob_definite_x_ht &&
    !STRING (chs_x_ht).contains (proposed_char)) {
      if (x_ht_case_flip)
                                 //flip to lower case
        return (char) tolower (proposed_char);
      else
        return '\0';
    }
  }
  else
  if ((STRING (chs_non_ambig_x_ht).contains (proposed_char)
    && !blob_definite_x_ht)
    || (STRING (chs_non_ambig_caps_ht).contains (proposed_char)
    && !blob_definite_caps_ht))
    return '\0';
  return proposed_char;
}


float estimate_from_stats(STATS &stats) { 
  if (stats.get_total () <= 0)
    return 0.0;
  else if (stats.get_total () >= 3)
    return stats.ile (0.5);      //median
  else
    return stats.mean ();
}


void improve_estimate(WERD_RES *word_res,
                      float &est_x_ht,
                      float &est_caps_ht,
                      STATS &x_ht,
                      STATS &caps_ht) {
  PBLOB_IT blob_it;
  INT16 blob_ht_above_baseline;

  const char *word_str;
  INT16 i;
  BOX blob_box;                  //blob bounding box
  char confirmed_char;
  float new_val;

  blob_it.set_to_list (word_res->outword->blob_list ());
  word_str = word_res->best_choice->string ().string ();
  for (blob_it.mark_cycle_pt (), i = 0;
  !blob_it.cycled_list (); blob_it.forward (), i++) {
    if ((STRING (chs_ambig_caps_x).contains (word_str[i])) &&
    (!dodgy_blob (blob_it.data ()))) {
      blob_box = blob_it.data ()->bounding_box ();
      blob_ht_above_baseline = blob_box.top () - bln_baseline_offset;
      confirmed_char = check_blob_occ (word_str[i],
        blob_ht_above_baseline,
        est_x_ht, est_caps_ht);
      if (confirmed_char != '\0')
        if (STRING (chs_x_ht).contains (confirmed_char))
          x_ht.add (blob_ht_above_baseline, 1);
      else
        caps_ht.add (blob_ht_above_baseline, 1);
    }
  }
  new_val = estimate_from_stats (x_ht);
  if (new_val > 0)
    est_x_ht = new_val;
  new_val = estimate_from_stats (caps_ht);
  if (new_val > 0)
    est_caps_ht = new_val;
}

void reject_ambigs(
                   WERD_RES *word) {
  const char *word_str;
  int i = 0;

  word_str = word->best_choice->string ().string ();
  while (*word_str != '\0') {
    if (STRING (chs_ambig_caps_x).contains (*word_str))
      word->reject_map[i].setrej_xht_fixup ();
    word_str++;
    i++;
  }
}


void est_ambigs(
                WERD_RES *word_res,
                STATS &stats,
                float *ambig_lc_x_est,    //xht est
                float *ambig_uc_caps_est  //caps est
               ) {
  float x_ht_ok_variation;
  STATS short_ambigs (0, 300);
  STATS tall_ambigs (0, 300);
  PBLOB_IT blob_it;
  BOX blob_box;                  //blob bounding box
  INT16 blob_ht_above_baseline;

  const char *word_str;
  INT16 i;
  float min;                     //min ambig ch ht
  float max;                     //max ambig ch ht
  float short_limit;             // for lower case
  float tall_limit;              // for upper case

  x_ht_ok_variation =
    (bln_x_height / x_ht_fraction_of_caps_ht - bln_x_height) * x_ht_variation;

  if (stats.get_total () == 0) {
    *ambig_lc_x_est = 0;
    *ambig_uc_caps_est = 0;
  }
  else {
    min = stats.ile (0.0);
    max = stats.ile (0.99999);
    if ((max - min) < x_ht_ok_variation) {
      *ambig_lc_x_est = *ambig_uc_caps_est = stats.mean ();
      //close enough
    }
    else {
    /* Try reclustering into lower and upper case chars */
      short_limit = min + (max - min) * x_ht_variation;
      tall_limit = max - (max - min) * x_ht_variation;
      word_str = word_res->best_choice->string ().string ();
      blob_it.set_to_list (word_res->outword->blob_list ());
      for (blob_it.mark_cycle_pt (), i = 0;
      !blob_it.cycled_list (); blob_it.forward (), i++) {
        if (word_res->reject_map[i].accepted () &&
          STRING (chs_ambig_caps_x).contains (word_str[i]) &&
        (!dodgy_blob (blob_it.data ()))) {
          blob_box = blob_it.data ()->bounding_box ();
          blob_ht_above_baseline =
            blob_box.top () - bln_baseline_offset;
          if (blob_ht_above_baseline <= short_limit)
            short_ambigs.add (blob_ht_above_baseline, 1);
          else if (blob_ht_above_baseline >= tall_limit)
            tall_ambigs.add (blob_ht_above_baseline, 1);
        }
      }
      *ambig_lc_x_est = short_ambigs.mean ();
      *ambig_uc_caps_est = tall_ambigs.mean ();
      /* Cop out if we havent got sensible clusters. */
      if (*ambig_uc_caps_est - *ambig_lc_x_est <= x_ht_ok_variation)
        *ambig_lc_x_est = *ambig_uc_caps_est = stats.mean ();
      //close enough
    }
  }
}


BOOL8 dodgy_blob(PBLOB *blob) { 
  OUTLINE_IT outline_it = blob->out_list ();
  INT16 highest_bottom = -MAX_INT16;
  INT16 lowest_top = MAX_INT16;
  BOX outline_box;

  if (x_ht_include_dodgy_blobs)
    return FALSE;                //no blob is ever dodgy
  for (outline_it.mark_cycle_pt ();
  !outline_it.cycled_list (); outline_it.forward ()) {
    outline_box = outline_it.data ()->bounding_box ();
    if (lowest_top > outline_box.top ())
      lowest_top = outline_box.top ();
    if (highest_bottom < outline_box.bottom ())
      highest_bottom = outline_box.bottom ();
  }
  return highest_bottom >= lowest_top;
}

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