stopper.cpp

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/******************************************************************************
 **	Filename:    stopper.c
 **	Purpose:     Stopping criteria for word classifier.
 **	Author:      Dan Johnson
 **	History:     Mon Apr 29 14:56:49 1991, DSJ, 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 "stopper.h"
#include "emalloc.h"
#include "matchdefs.h"
#include "debug.h"
#include "callcpp.h"
#include "permute.h"
#include "context.h"
#include "permnum.h"
#include "danerror.h"
#include "const.h"
#include "freelist.h"
#include "efio.h"
#include "globals.h"
#include "scanutils.h"

#include <stdio.h>
#include <string.h>
#include <ctype.h>
#include <math.h>
#ifdef __UNIX__
#include <assert.h>
#endif

/* these are kludges - add appropriate .h file later */
extern float CertaintyScale;     /* from subfeat.h */

#define MAX_WERD_SIZE   100
#define MAX_AMBIG_SIZE    3
#define DANGEROUS_AMBIGS  "tessdata/DangAmbigs"

typedef LIST AMBIG_TABLE;

typedef struct
{
  UINT8 Class;
  UINT16 NumChunks;
  float Certainty;
}


CHAR_CHOICE;

typedef struct
{
  float Rating;
  float Certainty;
  FLOAT32 AdjustFactor;
  int Length;
  CHAR_CHOICE Blob[1];
} VIABLE_CHOICE_STRUCT;
typedef VIABLE_CHOICE_STRUCT *VIABLE_CHOICE;

typedef struct
{
  VIABLE_CHOICE Choice;
  float ChunkCertainty[MAX_NUM_CHUNKS];
  UINT8 ChunkClass[MAX_NUM_CHUNKS];
}


EXPANDED_CHOICE;

/**----------------------------------------------------------------------------
          Macros
----------------------------------------------------------------------------**/
#define BestCertainty(Choices)  (((VIABLE_CHOICE) first (Choices))->Certainty)
#define BestRating(Choices) (((VIABLE_CHOICE) first (Choices))->Rating)
#define BestFactor(Choices) (((VIABLE_CHOICE) first (Choices))->AdjustFactor)

#define AmbigThreshold(F1,F2)	(((F2) - (F1)) * AmbigThresholdGain - \
				AmbigThresholdOffset)

/*---------------------------------------------------------------------------
          Private Function Prototoypes
----------------------------------------------------------------------------*/
void AddNewChunk(VIABLE_CHOICE Choice, int Blob);

int AmbigsFound(char *Word,
                char *CurrentChar,
                const char *Tail,
                LIST Ambigs,
                DANGERR *fixpt);

int ChoiceSameAs(A_CHOICE *Choice, VIABLE_CHOICE ViableChoice);

int CmpChoiceRatings(void *arg1,   //VIABLE_CHOICE         Choice1,
                     void *arg2);  //VIABLE_CHOICE         Choice2);

void ExpandChoice(VIABLE_CHOICE Choice, EXPANDED_CHOICE *ExpandedChoice);

AMBIG_TABLE *FillAmbigTable();

int FreeBadChoice(void *item1,   //VIABLE_CHOICE                 Choice,
                  void *item2);  //EXPANDED_CHOICE                       *BestChoice);

int LengthOfShortestAlphaRun(register char *Word);

VIABLE_CHOICE NewViableChoice (A_CHOICE * Choice,
FLOAT32 AdjustFactor, float Certainties[]);

void PrintViableChoice(FILE *File, const char *Label, VIABLE_CHOICE Choice);

void ReplaceDuplicateChoice (VIABLE_CHOICE OldChoice,
A_CHOICE * NewChoice,
FLOAT32 AdjustFactor, float Certainties[]);

int StringSameAs(const char *String, VIABLE_CHOICE ViableChoice);

int UniformCertainties(CHOICES_LIST Choices, A_CHOICE *BestChoice);

/**----------------------------------------------------------------------------
        Global Data Definitions and Declarations
----------------------------------------------------------------------------**/
/* Name of file containing potentially dangerous ambiguities */
static const char *DangerousAmbigs = DANGEROUS_AMBIGS;

/* Word for which stopper debug information should be printed to stdout */
static char *WordToDebug = NULL;

/* flag used to disable accumulation of word choices during compound word
  permutation */
BOOL8 KeepWordChoices = TRUE;

/* additional certainty padding allowed before a word is rejected */
static FLOAT32 RejectOffset = 0.0;

/* structures to keep track of viable word choices */
static VIABLE_CHOICE BestRawChoice = NULL;
static LIST BestChoices = NIL;
static PIECES_STATE CurrentSegmentation;

make_float_var (NonDictCertainty, -2.50, MakeNonDictCertainty,
17, 2, SetNonDictCertainty,
"Certainty threshold for non-dict words");

make_float_var (RejectCertaintyOffset, 1.0, MakeRejectCertaintyOffset,
17, 3, SetRejectCertaintyOffset, "Reject certainty offset");

make_int_var (SmallWordSize, 2, MakeSmallWordSize,
17, 4, SetSmallWordSize,
"Size of dict word to be treated as non-dict word");

make_float_var (CertaintyPerChar, -0.50, MakeCertaintyPerChar,
17, 5, SetCertaintyPerChar,
"Certainty to add for each dict char above SmallWordSize");

make_float_var (CertaintyVariation, 3.0, MakeCertaintyVariation,
17, 6, SetCertaintyVariation,
"Max certaintly variation allowed in a word (in sigma)");

make_int_var (StopperDebugLevel, 0, MakeStopperDebugLevel,
17, 7, SetStopperDebugLevel, "Stopper debug level");

make_float_var (AmbigThresholdGain, 8.0, MakeAmbigThresholdGain,
17, 8, SetAmbigThresholdGain,
"Gain factor for ambiguity threshold");

make_float_var (AmbigThresholdOffset, 1.5, MakeAmbigThresholdOffset,
17, 9, SetAmbigThresholdOffset,
"Certainty offset for ambiguity threshold");

//extern char *demodir;
extern int first_pass;
INT_VAR (tessedit_truncate_wordchoice_log, 10, "Max words to keep in list");

/**----------------------------------------------------------------------------
              Public Code
----------------------------------------------------------------------------**/
/*---------------------------------------------------------------------------*/
int AcceptableChoice(CHOICES_LIST Choices,
                     A_CHOICE *BestChoice,
                     A_CHOICE *RawChoice,
                     DANGERR *fixpt) {
/*
 **	Parameters:
 **		Choices		choices for current segmentation
 **		BestChoice	best choice for current segmentation
 **		RawChoice	best raw choice for current segmentation
 **	Globals:
 **		NonDictCertainty	certainty for a non-dict word
 **		SmallWordSize		size of word to be treated as non-word
 **		CertaintyPerChar	certainty to add for each dict char
 **	Operation: Return TRUE if the results from this segmentation are
 **		good enough to stop.  Otherwise return FALSE.
 **	Return: TRUE or FALSE.
 **	Exceptions: none
 **	History: Mon Apr 29 14:57:32 1991, DSJ, Created.
 */
  float CertaintyThreshold = NonDictCertainty;
  int WordSize;

  if (fixpt != NULL)
    fixpt->index = -1;
  if ((BestChoice == NULL) || (class_string (BestChoice) == NULL))
    return (FALSE);

  if (StopperDebugLevel >= 1)
    cprintf ("\nStopper:  %s (word=%c, case=%c, punct=%c)\n",
      class_string (BestChoice),
      (valid_word (class_string (BestChoice)) ? 'y' : 'n'),
    (case_ok (class_string (BestChoice)) ? 'y' : 'n'),
    ((punctuation_ok (class_string (BestChoice)) !=
    -1) ? 'y' : 'n'));

  if (valid_word (class_string (BestChoice)) &&
    case_ok (class_string (BestChoice)) &&
  punctuation_ok (class_string (BestChoice)) != -1) {
    WordSize = LengthOfShortestAlphaRun (class_string (BestChoice));
    WordSize -= SmallWordSize;
    if (WordSize < 0)
      WordSize = 0;
    CertaintyThreshold += WordSize * CertaintyPerChar;
  }
  else if (stopper_numbers_on && valid_number (class_string (BestChoice))) {
    CertaintyThreshold += stopper_numbers_on * CertaintyPerChar;
  }

  if (StopperDebugLevel >= 1)
    cprintf ("Stopper:  Certainty = %4.1f, Threshold = %4.1f\n",
      class_certainty (BestChoice), CertaintyThreshold);

  if (NoDangerousAmbig (class_string (BestChoice), fixpt)
    && class_certainty (BestChoice) > CertaintyThreshold &&
    UniformCertainties (Choices, BestChoice))
    return (TRUE);
  else
    return (FALSE);

}                                /* AcceptableChoice */


/*---------------------------------------------------------------------------*/
int AcceptableResult(A_CHOICE *BestChoice, A_CHOICE *RawChoice) {
/*
 **	Parameters:
 **		BestChoice	best choice for current word
 **		RawChoice	best raw choice for current word
 **	Globals:
 **		NonDictCertainty	certainty for a non-dict word
 **		SmallWordSize		size of word to be treated as non-word
 **		CertaintyPerChar	certainty to add for each dict char
 **		BestChoices		list of all good choices found
 **		RejectOffset		allowed offset before a word is rejected
 **	Operation: Return FALSE if the best choice for the current word
 **		is questionable and should be tried again on the second
 **		pass or should be flagged to the user.
 **	Return: TRUE or FALSE.
 **	Exceptions: none
 **	History: Thu May  9 14:05:05 1991, DSJ, Created.
 */
  float CertaintyThreshold = NonDictCertainty - RejectOffset;
  int WordSize;

  if (StopperDebugLevel >= 1)
    cprintf ("\nRejecter: %s (word=%c, case=%c, punct=%c, unambig=%c)\n",
      class_string (BestChoice),
      (valid_word (class_string (BestChoice)) ? 'y' : 'n'),
    (case_ok (class_string (BestChoice)) ? 'y' : 'n'),
    ((punctuation_ok (class_string (BestChoice)) != -1) ? 'y' : 'n'),
    ((rest (BestChoices) != NIL) ? 'n' : 'y'));

  if ((BestChoice == NULL) ||
    (class_string (BestChoice) == NULL) || CurrentWordAmbig ())
    return (FALSE);

  if (valid_word (class_string (BestChoice)) &&
    case_ok (class_string (BestChoice)) &&
  punctuation_ok (class_string (BestChoice)) != -1) {
    WordSize = LengthOfShortestAlphaRun (class_string (BestChoice));
    WordSize -= SmallWordSize;
    if (WordSize < 0)
      WordSize = 0;
    CertaintyThreshold += WordSize * CertaintyPerChar;
  }

  if (StopperDebugLevel >= 1)
    cprintf ("Rejecter: Certainty = %4.1f, Threshold = %4.1f   ",
      class_certainty (BestChoice), CertaintyThreshold);

  if (class_certainty (BestChoice) > CertaintyThreshold) {
    if (StopperDebugLevel >= 1)
      cprintf ("ACCEPTED\n");
    return (TRUE);
  }
  else {
    if (StopperDebugLevel >= 1)
      cprintf ("REJECTED\n");
    return (FALSE);
  }
}                                /* AcceptableResult */


/*---------------------------------------------------------------------------*/
int AlternativeChoicesWorseThan(FLOAT32 Threshold) {
/*
 **	Parameters:
 **		Threshold	minimum adjust factor for alternative choices
 **	Globals:
 **		BestChoices	alternative choices for current word
 **	Operation: This routine returns TRUE if there are no alternative
 **		choices for the current word OR if all alternatives have
 **		an adjust factor worse than Threshold.
 **	Return: TRUE or FALSE.
 **	Exceptions: none
 **	History: Mon Jun  3 09:36:31 1991, DSJ, Created.
 */
  LIST Alternatives;
  VIABLE_CHOICE Choice;

  Alternatives = rest (BestChoices);
  iterate(Alternatives) {
    Choice = (VIABLE_CHOICE) first (Alternatives);
    if (Choice->AdjustFactor <= Threshold)
      return (FALSE);
  }

  return (TRUE);

}                                /* AlternativeChoicesWorseThan */


/*---------------------------------------------------------------------------*/
int CurrentBestChoiceIs(const char *Word) {
/*
 **	Parameters:
 **		Word	string to compare to current best choice
 **	Globals:
 **		BestChoices	set of best choices for current word
 **	Operation: Returns TRUE if Word is the same as the current best
 **		choice, FALSE otherwise.
 **	Return: TRUE or FALSE
 **	Exceptions: none
 **	History: Thu May 30 14:44:22 1991, DSJ, Created.
 */
  return (BestChoices != NIL &&
    StringSameAs (Word, (VIABLE_CHOICE) first (BestChoices)));

}                                /* CurrentBestChoiceIs */


/*---------------------------------------------------------------------------*/
FLOAT32 CurrentBestChoiceAdjustFactor() {
/*
 **	Parameters: none
 **	Globals:
 **		BestChoices	set of best choices for current word
 **	Operation: Return the adjustment factor for the best choice for
 **		the current word.
 **	Return: Adjust factor for current best choice.
 **	Exceptions: none
 **	History: Thu May 30 14:48:24 1991, DSJ, Created.
 */
  VIABLE_CHOICE BestChoice;

  if (BestChoices == NIL)
    return (MAX_FLOAT32);

  BestChoice = (VIABLE_CHOICE) first (BestChoices);
  return (BestChoice->AdjustFactor);

}                                /* CurrentBestChoiceAdjustFactor */


/*---------------------------------------------------------------------------*/
int CurrentWordAmbig() {
/*
 **	Parameters: none
 **	Globals:
 **		BestChoices	set of best choices for current word
 **	Operation: This routine returns TRUE if there are multiple good
 **		choices for the current word and FALSE otherwise.
 **	Return: TRUE or FALSE
 **	Exceptions: none
 **	History: Wed May 22 15:38:38 1991, DSJ, Created.
 */
  return (rest (BestChoices) != NIL);

}                                /* CurrentWordAmbig */


/*---------------------------------------------------------------------------*/
void DebugWordChoices() {
/*
 **	Parameters: none
 **	Globals:
 **		BestRawChoice
 **		BestChoices
 **	Operation: Print the current choices for this word to stdout.
 **	Return: none
 **	Exceptions: none
 **	History: Wed May 15 13:52:08 1991, DSJ, Created.
 */
  LIST Choices;
  int i;
  char LabelString[80];

  if (StopperDebugLevel >= 1 ||
    WordToDebug && BestChoices &&
  StringSameAs (WordToDebug, (VIABLE_CHOICE) first (BestChoices))) {
    if (BestRawChoice)
      PrintViableChoice (stdout, "\nBest Raw Choice:   ", BestRawChoice);

    i = 1;
    Choices = BestChoices;
    if (Choices)
      cprintf ("\nBest Cooked Choices:\n");
    iterate(Choices) {
      sprintf (LabelString, "Cooked Choice #%d:  ", i);
      PrintViableChoice (stdout, LabelString,
        (VIABLE_CHOICE) first (Choices));
      i++;
    }
  }
}                                /* DebugWordChoices */


/*---------------------------------------------------------------------------*/
void FilterWordChoices() {
/*
 **	Parameters: none
 **	Globals:
 **		BestChoices	set of choices for current word
 **	Operation: This routine removes from BestChoices all choices which
 **		are not within a reasonable range of the best choice.
 **	Return: none
 **	Exceptions: none
 **	History: Wed May 15 13:08:24 1991, DSJ, Created.
 */
  EXPANDED_CHOICE BestChoice;

  if (BestChoices == NIL || second (BestChoices) == NIL)
    return;

  /* compute certainties and class for each chunk in best choice */