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tesseract/dict/permute.cpp
david.eger@gmail.com 0aadbd0169 Save BLOB_CHOICE s for alternate choices saved during segmentation 
search so we have them when trying to replace words with alternates in
the bigram correction pass.


git-svn-id: https://tesseract-ocr.googlecode.com/svn/trunk@739 d0cd1f9f-072b-0410-8dd7-cf729c803f20
2012-09-01 00:33:46 +00:00

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/* -*-C-*-
********************************************************************************
*
* File: permute.c (Formerly permute.c)
* Description: Choose OCR text given character-probability maps
* for sequences of glyph fragments and a dictionary provided as
* a Dual Acyclic Word Graph.
* In this file, "permute" should be read "combine."
* Author: Mark Seaman, OCR Technology
* Created: Fri Sep 22 14:05:51 1989
* Modified: Thu Jan 3 16:38:46 1991 (Mark Seaman) marks@hpgrlt
* Language: C
* Package: N/A
* Status: Experimental (Do Not Distribute)
*
* (c) Copyright 1989, Hewlett-Packard Company.
** 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.
*
*********************************************************************************/
/*----------------------------------------------------------------------
I n c l u d e s
---------------------------------------------------------------------*/
#ifdef _MSC_VER
#pragma warning(disable:4244) // Conversion warnings
#pragma warning(disable:4800) // int/bool warnings
#endif
#include <assert.h>
#include <math.h>
#include "const.h"
#include "permute.h"
#include "callcpp.h"
#include "ccutil.h"
#include "dict.h"
#include "freelist.h"
#include "helpers.h"
#include "image.h"
#include "globals.h"
#include "ndminx.h"
#include "ratngs.h"
#include "stopper.h"
#include "tprintf.h"
#include "trie.h"
#include "params.h"
#include "unicharset.h"
namespace tesseract {
/*----------------------------------------------------------------------
F u n c t i o n s
----------------------------------------------------------------------*/
/**
* get_best_delete_other
*
* Returns the best of two choices and deletes the other (worse) choice.
* A choice is better if it has a non-empty string and has a lower
* rating than the other choice. If the ratings are the same,
* choice2 is preferred over choice1.
*/
WERD_CHOICE *get_best_delete_other(WERD_CHOICE *choice1,
WERD_CHOICE *choice2) {
if (!choice1) return choice2;
if (!choice2) return choice1;
if (choice1->rating() < choice2->rating() || choice2->length() == 0) {
delete choice2;
return choice1;
} else {
delete choice1;
return choice2;
}
}
/**
* Returns the n-th choice in the given blob_list (top-K choices).
* If n > K, the last choice is returned.
*/
BLOB_CHOICE* get_nth_choice(BLOB_CHOICE_LIST* blob_list, int n) {
BLOB_CHOICE_IT c_it(blob_list);
while (n-- > 0 && !c_it.at_last())
c_it.forward();
return c_it.data();
}
/** Returns the top choice char id. A helper function to make code cleaner. */
UNICHAR_ID get_top_choice_uid(BLOB_CHOICE_LIST *blob_list) {
if (!blob_list) return INVALID_UNICHAR_ID;
BLOB_CHOICE_IT blob_choice_it(blob_list);
return (blob_choice_it.data()) ? blob_choice_it.data()->unichar_id()
: INVALID_UNICHAR_ID;
}
/**
* Returns the rank (starting at 0) of a given unichar ID in the char
* choice list, or -1 if not found.
*/
int find_choice_by_uid(BLOB_CHOICE_LIST *blob_list, UNICHAR_ID target_uid) {
BLOB_CHOICE_IT c_it(blob_list);
int pos = 0;
while (1) {
if (c_it.data()->unichar_id() == target_uid) return pos;
if (c_it.at_last()) break;
c_it.forward();
pos++;
}
return -1;
}
/**
* Returns a WERD formed by taking the specified position (nth choice) string
* from char_choices starting at the given position.
* For example, if start_pos=2, pos_str="0121" will form a word using the
* 1st choice of char 3, 2nd choice of char 4, 3rd choice of char 5, 2nd choice
* of char 6. If n > number of choice, the closest (last) one is used.
*/
WERD_CHOICE* get_choice_from_posstr(const UNICHARSET *unicharset,
const BLOB_CHOICE_LIST_VECTOR &char_choices,
int start_pos,
const char* pos_str,
float *certainties) {
int pos_str_len = strlen(pos_str);
WERD_CHOICE* wchoice = new WERD_CHOICE(unicharset);
if (start_pos + pos_str_len > char_choices.length()) {
wchoice->make_bad();
return wchoice;
}
for (int x = 0; x < pos_str_len; x++) {
int pos = pos_str[x]-'0';
if (pos < 0) pos = 0; // use the top choice by default, eg. '.'
if (pos >= 10)
tprintf("PosStr[%d](%d)=%c %d\n", x, pos_str_len, pos_str[x], pos);
ASSERT_HOST(pos < 10);
BLOB_CHOICE* blob_it = get_nth_choice(char_choices.get(start_pos+x), pos);
wchoice->set_permuter(NO_PERM);
wchoice->append_unichar_id(blob_it->unichar_id(), 1,
blob_it->rating(),
blob_it->certainty());
if (certainties != NULL) certainties[x] = blob_it->certainty();
}
return wchoice;
}
/**
* Given a WERD_CHOICE, find the corresponding position string from
* char_choices. Pos_str must have been allocated already.
* This is the reverse of get_choice_from_posstr.
*/
void get_posstr_from_choice(const BLOB_CHOICE_LIST_VECTOR &char_choices,
WERD_CHOICE* word_choice,
int start_pos,
char* pos_str) {
for (int i = 0; i < word_choice->length(); i++) {
UNICHAR_ID target_id = word_choice->unichar_id(i);
BLOB_CHOICE_LIST* blob_choice_list = char_choices.get(start_pos + i);
int pos = find_choice_by_uid(blob_choice_list, target_id);
if (pos < 0) pos = 0;
pos_str[i] = pos + '0';
}
pos_str[word_choice->length()] = '\0';
}
/**
* Iterate through all the character choices (for a single blob) and
* return the first that matches the given type, which is one of 'aA0px*',
* for lower, upper, digit, punctuation, other, and 'any', respectively.
* If not match is found, a NULL is returned.
*/
BLOB_CHOICE* find_choice_by_type(
BLOB_CHOICE_LIST *blob_choices,
char target_type,
const UNICHARSET &unicharset) {
BLOB_CHOICE_IT c_it(blob_choices);
for (c_it.mark_cycle_pt(); !c_it.cycled_list(); c_it.forward()) {
if (c_it.data() &&
unicharset.get_chartype(c_it.data()->unichar_id()) == target_type)
return c_it.data();
}
return NULL;
}
/**
* Iterate through all the character choices (for a single blob) and
* return the first that matches the target script ID. If backup_sid
* is not 0, then a match on either the target or backup sid is allowed.
* Note that there is no preference between a target or backup sid.
* To search for another sid only if no target_sid matched, use
* secondary_sid.
* So for example, to find first Han or Common char choice, do
* find_choice_by_script(cchoice, han_sid, common_sid, 0);
* To find first Han choice, but allow Common if none is found, do
* find_choice_by_script(cchoice, han_sid, 0, common_sid);
*/
BLOB_CHOICE* find_choice_by_script(
BLOB_CHOICE_LIST *blob_choices,
int target_sid,
int backup_sid,
int secondary_sid) {
BLOB_CHOICE_IT c_it(blob_choices);
for (c_it.mark_cycle_pt(); !c_it.cycled_list(); c_it.forward()) {
bool found = false;
if (c_it.data()->script_id() == 0) continue;
if (c_it.data()->script_id() == target_sid) found = true;
if (backup_sid > 0 && c_it.data()->script_id() == backup_sid) found = true;
if (found) return c_it.data();
}
if (secondary_sid > 0) {
c_it.set_to_list(blob_choices);
for (c_it.mark_cycle_pt(); !c_it.cycled_list(); c_it.forward()) {
if (c_it.data()->script_id() == 0) continue;
if (c_it.data()->script_id() == secondary_sid)
return c_it.data();
}
}
return NULL;
}
PermuterState::PermuterState() {
unicharset_ = NULL;
char_choices_ = NULL;
adjust_factor_ = 1.0f;
allow_collision_ = false;
word_length_ = 0;
debug_ = false;
}
void PermuterState::Init(const BLOB_CHOICE_LIST_VECTOR& char_choices,
const UNICHARSET& unicharset,
float default_bias,
bool debug) {
ASSERT_HOST(char_choices.length() < MAX_PERM_LENGTH);
unicharset_ = &unicharset;
char_choices_ = &char_choices;
word_length_ = char_choices.length();
for (int i = 0; i < word_length_; ++i)
perm_state_[i] = kPosFree;
perm_state_[word_length_] = '\0';
// Skip fragment choice and the mark positions so they remain unchanged.
for (int i = 0; i < word_length_; ++i) {
UNICHAR_ID unichar_id = get_top_choice_uid(char_choices.get(i));
if (unicharset.get_fragment(unichar_id) != NULL)
perm_state_[i] = '1';
}
adjust_factor_ = default_bias;
allow_collision_ = false;
debug_ = debug;
}
// Promote char positions specified in pos_str with given weight.
// For example, AddPreference(5, "234", 0.95f)
// would promote the 3rd, 4th and 5th choice for character 5, 6, 7
// (starting at 0) in the word with a rating adjustment of 0.95.
void PermuterState::AddPreference(int start_pos, char* pos_str, float weight) {
ASSERT_HOST(char_choices_ != NULL);
ASSERT_HOST(start_pos + strlen(pos_str) - 1 < word_length_);
if (debug_) {
tprintf("Copy over %s -> %s @ %d ", pos_str, perm_state_, start_pos);
}
// copy over preferred position without the terminating null
if (!allow_collision_) {
int len = strlen(pos_str);
for (int i = 0; i < len; ++i)
if (position_marked(start_pos + i)) return;
}
strncpy(&perm_state_[start_pos], pos_str, strlen(pos_str));
adjust_factor_ *= weight;
if (debug_) tprintf("==> %s %f\n", perm_state_, adjust_factor_);
}
// Promote the input blob_choice at specified position with given weight.
void PermuterState::AddPreference(int char_pos, BLOB_CHOICE* blob_choice,
float weight) {
ASSERT_HOST(char_choices_ != NULL);
ASSERT_HOST(char_pos < word_length_);
// avoid collision (but this doesn't work if the first choice is favored!
if (!allow_collision_ && position_marked(char_pos)) return;
if (debug_) {
tprintf("Set UID %d -> %s @ %d ",
blob_choice->unichar_id(), perm_state_, char_pos);
}
int pos = find_choice_by_uid(char_choices_->get(char_pos),
blob_choice->unichar_id());
perm_state_[char_pos] = pos + '0';
adjust_factor_ *= weight;
if (debug_) tprintf("==> %s %f\n", perm_state_, adjust_factor_);
}
// Get the best word permutation so far. Caller should destroy WERD_CHOICE.
WERD_CHOICE* PermuterState::GetPermutedWord(float *certainties,
float *adjust_factor) {
ASSERT_HOST(char_choices_ != NULL);
WERD_CHOICE *word_choice = get_choice_from_posstr(
unicharset_, *char_choices_, 0, perm_state_, certainties);
float rating = word_choice->rating() * adjust_factor_;
word_choice->set_rating(rating);
*adjust_factor = adjust_factor_;
return word_choice;
}
/**********************************************************************
* permute_all
*
* Permute all the characters together using all of the different types
* of permuters/selectors available. Each of the characters must have
* a non-NULL choice list.
*
* Note: order of applying permuters does matter, since the latter
* permuter will be recorded if the resulting word ratings are the same.
*
* Note: the function assumes that best_choice and raw_choice are not NULL.
*
* Note: Since permuter_all maybe called recursively (through permuter_
* compound_words), there must be a separate instance of permuter_state
* for each invocation.
**********************************************************************/
WERD_CHOICE *Dict::permute_all(const BLOB_CHOICE_LIST_VECTOR &char_choices,
const WERD_CHOICE *best_choice,
WERD_CHOICE *raw_choice) {
WERD_CHOICE *result1 = NULL;
WERD_CHOICE *result2 = NULL;
BOOL8 any_alpha;
float top_choice_rating_limit = best_choice->rating();
int word_script_id = get_top_word_script(char_choices, getUnicharset());
PermuterState permuter_state;
if (getUnicharset().han_sid() != getUnicharset().null_sid() &&
word_script_id == getUnicharset().han_sid()) {
permuter_state.Init(char_choices, getUnicharset(), 1.0f, permute_debug);
result1 = get_top_choice_word(char_choices);
// Note that we no longer need the returned word from these permuters,
// except to delete the memory. The word choice from all permutations
// is returned by permuter_state.GetpermutedWord() at the end.
if (permute_fixed_length_dawg) {
result2 = permute_fixed_length_words(char_choices, &permuter_state);
delete result2;
}
if (permute_chartype_word) {
result2 = permute_chartype_words(char_choices, &permuter_state);
delete result2;
}
if (permute_script_word) {
result2 = permute_script_words(char_choices, &permuter_state);
delete result2;
}
float certainties[MAX_PERM_LENGTH];
float adjust_factor;
result2 = permuter_state.GetPermutedWord(certainties, &adjust_factor);
LogNewChoice(adjust_factor, certainties, false, result2, char_choices);
result1 = get_best_delete_other(result1, result2);
if (segment_segcost_rating) incorporate_segcost(result1);
} else {
result1 = permute_top_choice(char_choices, &top_choice_rating_limit,
raw_choice, &any_alpha);
if (result1 == NULL)
return (NULL);
if (permute_only_top)
return result1;
if (permute_chartype_word) {
permuter_state.Init(char_choices, getUnicharset(),
segment_penalty_garbage, permute_debug);
result2 = permute_chartype_words(char_choices, &permuter_state);
result1 = get_best_delete_other(result1, result2);
}
// Permute character fragments if necessary.
if (result1 == NULL || result1->fragment_mark()) {
result2 = top_fragments_permute_and_select(char_choices,
top_choice_rating_limit);
result1 = get_best_delete_other(result1, result2);
}
result2 = dawg_permute_and_select(char_choices, best_choice->rating());
result1 = get_best_delete_other(result1, result2);
result2 = permute_compound_words(char_choices, best_choice->rating());
result1 = get_best_delete_other(result1, result2);
}
return result1;
}
/**
* Incorporate segmentation cost into the word rating. This is done
* through a multiplier wordseg_rating_adjust_factor_ which is determined
* in bestfirst.cpp during state evaluation. This is not the cleanest
* way to do this. It would be better to reorganize the SEARCH_STATE
* to keep track of associated states, or do the rating adjustment
* outside the permuter in evalaute_state.
*/
void Dict::incorporate_segcost(WERD_CHOICE *word) {
if (!word || wordseg_rating_adjust_factor_ <= 0) return;
float old_rating = word->rating();
float new_rating = old_rating * wordseg_rating_adjust_factor_;
word->set_rating(new_rating);
if (permute_debug)
tprintf("Permute segadjust %f * %f --> %f\n",
old_rating, wordseg_rating_adjust_factor_, new_rating);
}
/**
* Perform search on fixed-length dictionaries within a word.
* This is used for non-space delimited languages like CJK when a "word"
* corresponds to a "phrase" consisted of multiple short words.
* It iterates over every character position looking for longest matches
* against a set of fixed-length dawgs. Each dictionary hit is rewarded
* with a rating bonus.
* Note: this is very slow as it is performed on every segmentation state.
*/
WERD_CHOICE* Dict::permute_fixed_length_words(
const BLOB_CHOICE_LIST_VECTOR &char_choices,
PermuterState *permuter_state) {
if (permute_debug)
print_char_choices_list("\n\nPermute FixedLength Word",
char_choices, getUnicharset(), false);
WERD_CHOICE* best_choice =
new WERD_CHOICE(&getUnicharset(), char_choices.length());
const int max_dict_len = max_fixed_length_dawgs_wdlen_;
const int min_dict_len = 2;
char posstr[256];
int match_score = 0;
int anchor_pos = 0;
while (anchor_pos < char_choices.length()) {
// search from longest phrase to shortest, stop when we find a match
WERD_CHOICE* part_choice = NULL;
int step = max_dict_len;
while (step >= min_dict_len) {
int end_pos = anchor_pos + step - 1;
if (end_pos < char_choices.length()) {
part_choice = dawg_permute_and_select(char_choices,
200.0, // rate limit
step,
anchor_pos);
if (part_choice->length() == step) {
if (permute_debug)
tprintf("match found at pos=%d len=%d\n%s\n", anchor_pos, step,
part_choice->unichar_string().string());
break;
}
delete part_choice;
part_choice = NULL;
}
step--;
}
if (part_choice && step > 1) { // found lexicon match
get_posstr_from_choice(char_choices, part_choice, anchor_pos, posstr);
float adjust_factor = pow(0.95, 1.0 + step*2.0/char_choices.length());
if (permuter_state)
permuter_state->AddPreference(anchor_pos, posstr, adjust_factor);
match_score += step - 1; // single chars don't count
if (permute_debug)
tprintf("Promote word rating %d-len%d\n%s\n", anchor_pos, step,
part_choice->unichar_string().string());
} else { // no lexicon match
step = 1;
part_choice = get_choice_from_posstr(&getUnicharset(), char_choices,
anchor_pos, "0", NULL);
if (permute_debug)
tprintf("Single char %d %s\n", anchor_pos,
part_choice->unichar_string().string());
}
if (part_choice && part_choice->length() > 0)
(*best_choice) += (*part_choice);
if (part_choice) delete part_choice;
anchor_pos += step;
}
if (match_score > 0) {
float adjust_factor = pow(0.8, // 1.0/segment_penalty_dict_nonword,
match_score * 2.0 / char_choices.length());
float adjusted_score = best_choice->rating() * adjust_factor;
if (permute_debug)
tprintf("Adjusting score %f @ %d -> %f\n",
best_choice->rating(), match_score, adjusted_score);
best_choice->set_rating(adjusted_score);
}
if (permute_debug)
tprintf("Found Best CJK word %f: %s\n",
best_choice->rating(), best_choice->unichar_string().string());
return best_choice;
}
/**********************************************************************
* Returns the dominant chartype for the word. Only the "main" chartype
* of each character is used, and a consistent chartype is defined by
* the majority chartype from non-ambiguous character positions.
* If pos_chartypes is not NULL, then the "main" chartype at each pos
* is also returned. The caller must allocate and deallocate the space.
**********************************************************************/
char Dict::top_word_chartype(const BLOB_CHOICE_LIST_VECTOR &char_choices,
char* pos_chartypes) {
const UNICHARSET &unicharset = getUnicharset();
const int hist_size = 128; // to contain 'A','a','0','x','p'
int chprop[hist_size];
int x;
for (x = 0; x < hist_size; x++) chprop[x] = 0;
for (x = 0; x < char_choices.length(); ++x) {
UNICHAR_ID unichar_id = get_top_choice_uid(char_choices.get(x));
char ctype = unicharset.get_chartype(unichar_id);
if (pos_chartypes) pos_chartypes[x] = ctype;
if (ctype == 0 || ctype == 'p') continue;
if (getUnicharAmbigs().OneToOneDefiniteAmbigs(unichar_id) != NULL) continue;
chprop[ctype]++;
if (x == 0 && ctype == 'A') // first-cap also counts as lower
chprop['a']++;
}
int max_prop = 0;
for (x = 1; x < hist_size; x++)
if (chprop[x] >= chprop[max_prop]) max_prop = x;
return (chprop[max_prop] > 0) ? max_prop : 0;
}
/**********************************************************************
* Promote consistent character type based on neighboring characters.
* For each character position, if the top choice property is inconsistent
* with that of the word or previous character, then its likely
* subsitutions, as defined by DangAmbigs, will be examined and the one
* with a matching property will be selected.
**********************************************************************/
WERD_CHOICE* Dict::permute_chartype_words(
const BLOB_CHOICE_LIST_VECTOR &char_choices,
PermuterState *permuter_state) {
if (char_choices.length() >= MAX_PERM_LENGTH)
return NULL;
// Store main character property of top choice at every position
char pos_chartypes[MAX_PERM_LENGTH];
char word_type = top_word_chartype(char_choices, pos_chartypes);
if (word_type == 0 || word_type == 'p')
return NULL; // skip if word type is punctuation or unknown
if (permute_debug) {
tprintf("\n\nPermuteCharType[%c]\n", word_type);
print_char_choices_list("", char_choices, getUnicharset(), true);
}
WERD_CHOICE *current_word = new WERD_CHOICE(&getUnicharset());
BLOB_CHOICE_IT blob_choice_it;
const UNICHARSET& unicharset = getUnicharset();
bool replaced = false; // has any character choice been replaced
int prev_unambig_type = 0; // the last chartype of an unambiguous char
float certainties[MAX_PERM_LENGTH + 1];
for (int x = 0; x < char_choices.length(); ++x) {
BLOB_CHOICE_LIST* pos_choice = char_choices.get(x);
UNICHAR_ID unichar_id = get_top_choice_uid(pos_choice);
if (unichar_id == 0) {
delete current_word;
return NULL;
}
blob_choice_it.set_to_list(pos_choice);
BLOB_CHOICE *first_choice = blob_choice_it.data();
ASSERT_HOST(first_choice != NULL);
const UnicharIdVector* ambig_uids =
getUnicharAmbigs().OneToOneDefiniteAmbigs(unichar_id);
bool is_ambiguous = (ambig_uids != NULL);
bool is_punct = unicharset.get_ispunctuation(unichar_id);
bool is_consistent = is_punct ||
unicharset.get_chartype(unichar_id) == prev_unambig_type ||
unicharset.get_chartype(unichar_id) == word_type;
bool is_fragment = getUnicharset().get_fragment(unichar_id) != NULL;
if (permute_debug)
tprintf("char[%d]:%s is_ambig %c is_punct %c is_consistent %c\n",
x, unicharset.id_to_unichar(unichar_id),
is_ambiguous?'T':'F', is_punct?'T':'F', is_consistent?'T':'F');
if (is_fragment) {
// Ignore any fragmented characters by skipping them to next choice
// (originally first choice).
first_choice = get_nth_choice(pos_choice, 1);
ASSERT_HOST(first_choice != NULL);
} else if (is_ambiguous && !is_consistent) {
// Check every confusable blob choice where the top choice is inconsistent
// with the character type of the previous unambiguous character.
if (permute_debug) {
tprintf("Checking %s r%g PrevCharType %c\n",
unicharset.id_to_unichar(unichar_id),
first_choice->rating(), prev_unambig_type);
print_ratings_list("\t", pos_choice, getUnicharset());
}
BLOB_CHOICE* c_it = NULL;
if (c_it == NULL) {
c_it = find_choice_by_type(pos_choice, word_type, unicharset);
}
// Prefer a character choice whose type is the same as the previous
// unambiguous character and the confusion appears in the ambig list.
if (c_it == NULL && prev_unambig_type > 0) {
c_it = find_choice_by_type(pos_choice, prev_unambig_type, unicharset);
if (c_it &&
UnicharIdArrayUtils::find_in(*ambig_uids, c_it->unichar_id()) < 0)
c_it = NULL;
}
// Otherwise, perfer a punctuation
if (c_it == NULL) {
c_it = find_choice_by_type(pos_choice, 'p', unicharset);
if (c_it &&
UnicharIdArrayUtils::find_in(*ambig_uids, c_it->unichar_id()) < 0)
c_it = NULL;
}
// save any preference other than the top choice
if (c_it != NULL) {
if (permute_debug) {
tprintf("Replacing %s r%g ==> %s r%g\n",
unicharset.id_to_unichar(unichar_id), first_choice->rating(),
unicharset.id_to_unichar(c_it->unichar_id()), c_it->rating());
tprintf("\n\nPermuteCharType[%c]\n", word_type);
print_char_choices_list("", char_choices, getUnicharset(), false);
}
if (permuter_state)
permuter_state->AddPreference(x, c_it, segment_reward_chartype);
first_choice = c_it;
replaced = true;
}
} else if (!is_ambiguous && !is_punct) {
// keep the last unambiguous character type
prev_unambig_type = pos_chartypes[x];
}
current_word->append_unichar_id(first_choice->unichar_id(), 1,
first_choice->rating(),
first_choice->certainty());
certainties[x] = first_choice->certainty();
}
// All permuter choices should go through adjust_non_word so the choice
// rating would be adjusted on the same scale.
adjust_non_word(current_word, certainties, &char_choices, permute_debug);
if (replaced) {
// Apply a reward multiplier on rating if an chartype permutation is made.
float rating = current_word->rating();
current_word->set_rating(rating * segment_reward_chartype);
if (permute_debug)
current_word->print("<== permute_chartype_word **");
}
return current_word;
}
/**
* Try flipping characters in a word to get better script consistency.
* Similar to how upper/lower case checking is done in top_choice_permuter,
* this permuter tries to suggest a more script-consistent choice AND
* modifies the rating. So it combines both the case_ok check and
* adjust_non_word functionality. However, instead of penalizing an
* inconsistent word with a > 1 multiplier, we reward the script-consistent
* choice with a < 1 multiplier.
*/
WERD_CHOICE* Dict::permute_script_words(
const BLOB_CHOICE_LIST_VECTOR &char_choices,
PermuterState *permuter_state) {
if (char_choices.length() >= MAX_WERD_LENGTH)
return NULL;
int word_sid = get_top_word_script(char_choices, getUnicharset());
if (word_sid == getUnicharset().null_sid())
return NULL;
if (permute_debug) {
tprintf("\n\nPermuteScript %s\n",
getUnicharset().get_script_from_script_id(word_sid));
print_char_choices_list("", char_choices, getUnicharset(),
permute_debug > 1);
}
WERD_CHOICE *current_word = new WERD_CHOICE(&getUnicharset());
BLOB_CHOICE_IT blob_choice_it;
bool replaced = false;
bool prev_is_consistent = false;
float certainties[MAX_PERM_LENGTH + 1];
for (int x = 0; x < char_choices.length(); ++x) {
blob_choice_it.set_to_list(char_choices.get(x));
BLOB_CHOICE *first_choice = blob_choice_it.data();
if (!first_choice) {
delete current_word;
return NULL;
}
UNICHAR_ID unichar_id = first_choice->unichar_id();
if (unichar_id == 0) {
delete current_word;
return NULL;
}
bool sid_consistent = (getUnicharset().get_script(unichar_id) == word_sid);
bool this_is_punct = getUnicharset().get_chartype(unichar_id) == 'p';
bool is_fragment = getUnicharset().get_fragment(unichar_id) != NULL;
if (is_fragment) {
// Ignore any fragmented characters by skipping them to next choice
// (originally first choice).
first_choice = get_nth_choice(char_choices.get(x), 1);
ASSERT_HOST(first_choice != NULL);
} else if (!sid_consistent && !this_is_punct && prev_is_consistent) {
// If the previous char is CJK, we prefer a cjk over non-cjk char
if (permute_debug) {
tprintf("Checking %s r%g\n", getUnicharset().id_to_unichar(unichar_id),
first_choice->rating());
print_ratings_list("\t", char_choices.get(x), getUnicharset());
}
// prefer a script consistent choice
BLOB_CHOICE* c_it = find_choice_by_script(char_choices.get(x),
word_sid, 0, 0);
// otherwise, prefer a punctuation
if (c_it == NULL)
c_it = find_choice_by_type(char_choices.get(x), 'p', getUnicharset());
if (c_it != NULL) {
if (permute_debug)
tprintf("Replacing %s r%g ==> %s r%g\n",
getUnicharset().id_to_unichar(unichar_id),
first_choice->rating(),
getUnicharset().id_to_unichar(c_it->unichar_id()),
c_it->rating());
if (permuter_state)
permuter_state->AddPreference(x, c_it, segment_reward_script);
first_choice = c_it;
replaced = true;
}
}
current_word->append_unichar_id(first_choice->unichar_id(), 1,
first_choice->rating(),
first_choice->certainty());
certainties[x] = first_choice->certainty();
prev_is_consistent = sid_consistent;
}
// All permuter choices should go through adjust_non_word so the choice
// rating would be adjusted on the same scale.
adjust_non_word(current_word, certainties, &char_choices, permute_debug);
if (replaced) {
// Apply a reward multiplier on rating if an script permutation is made.
float rating = current_word->rating();
current_word->set_rating(rating * segment_reward_script);
if (permute_debug)
current_word->print("<== permute_script_word **");
}
return current_word;
}
/**
* permute_characters
*
* Permute these characters together according to each of the different
* permuters that are enabled.
* Returns true if best_choice was updated.
*/
bool Dict::permute_characters(const BLOB_CHOICE_LIST_VECTOR &char_choices,
WERD_CHOICE *best_choice,
WERD_CHOICE *raw_choice) {
if (permute_debug) {
tprintf("\n\n\n##### Permute_Characters #######\n");
print_char_choices_list("\n==> Input CharChoices", char_choices,
getUnicharset(), segment_debug > 1);
tprintf("\n");
}
if (char_choices.length() == 1 &&
get_top_choice_uid(char_choices.get(0)) == 0) return false;
WERD_CHOICE *this_choice = permute_all(char_choices, best_choice, raw_choice);
if (this_choice && this_choice->rating() < best_choice->rating()) {
*best_choice = *this_choice;
if (permute_debug) {
best_choice->print("\n**** Populate BestChoice");
cprintf("populate best_choice\n\t%s\n",
best_choice->debug_string().string());
}
delete this_choice;
return true;
}
delete this_choice;
return false;
}
/**
* permute_compound_words
*
* Return the top choice for each character as the choice for the word.
*/
WERD_CHOICE *Dict::permute_compound_words(
const BLOB_CHOICE_LIST_VECTOR &char_choices,
float rating_limit) {
BLOB_CHOICE *first_choice;
WERD_CHOICE *best_choice = NULL;
WERD_CHOICE current_word(&getUnicharset(), MAX_WERD_LENGTH);
int first_index = 0;
int x;
BLOB_CHOICE_IT blob_choice_it;
if (char_choices.length() > MAX_WERD_LENGTH) {
WERD_CHOICE *bad_word_choice = new WERD_CHOICE(&getUnicharset());
bad_word_choice->make_bad();
return bad_word_choice;
}
UNICHAR_ID slash = getUnicharset().unichar_to_id("/");
UNICHAR_ID dash = getUnicharset().unichar_to_id("-");
for (x = 0; x < char_choices.length(); ++x) {
blob_choice_it.set_to_list(char_choices.get(x));
first_choice = blob_choice_it.data();
if (first_choice->unichar_id() == slash ||
first_choice->unichar_id() == dash) {
if (x > first_index) {
if (segment_debug)
cprintf ("Hyphenated word found\n");
permute_subword(char_choices, rating_limit, first_index,
x - 1, &current_word);
if (current_word.rating() > rating_limit)
break;
}
// Append hyphen/slash separator to current_word.
current_word.append_unichar_id_space_allocated(
first_choice->unichar_id(), 1,
first_choice->rating(), first_choice->certainty());
first_index = x + 1; // update first_index
}
}
if (first_index > 0 && first_index < x &&
current_word.rating() <= rating_limit) {
permute_subword(char_choices, rating_limit, first_index,
x - 1, &current_word);
best_choice = new WERD_CHOICE(current_word);
best_choice->set_permuter(COMPOUND_PERM);
}
return (best_choice);
}
/**
* permute_subword
*
* Permute a part of a compound word this subword is bounded by hyphens
* and the start and end of the word. Call the standard word permute
* function on a set of choices covering only part of the original
* word. When it is done reclaim the memory that was used in the
* exercise.
*/
void Dict::permute_subword(const BLOB_CHOICE_LIST_VECTOR &char_choices,
float rating_limit,
int start,
int end,
WERD_CHOICE *current_word) {
int x;
BLOB_CHOICE_LIST_VECTOR subchoices;
WERD_CHOICE *best_choice = NULL;
WERD_CHOICE raw_choice(&getUnicharset());
raw_choice.make_bad();
DisableChoiceAccum();
for (x = start; x <= end; x++) {
if (char_choices.get(x) != NULL) {
subchoices += char_choices.get(x);
}
}
if (!subchoices.empty()) {
WERD_CHOICE initial_choice(&getUnicharset());
initial_choice.make_bad();
initial_choice.set_rating(rating_limit);
best_choice = permute_all(subchoices, &initial_choice, &raw_choice);
if (best_choice && best_choice->length() > 0) {
*current_word += *best_choice;
} else {
current_word->set_rating(MAX_FLOAT32);
}
} else {
current_word->set_rating(MAX_FLOAT32);
}
if (best_choice)
delete best_choice;
if (segment_debug && current_word->rating() < MAX_FLOAT32) {
cprintf ("Subword permuted = %s, %5.2f, %5.2f\n\n",
current_word->debug_string().string(),
current_word->rating(), current_word->certainty());
}
EnableChoiceAccum();
}
/**
* Return the top choice for each character as the choice for the word.
*/
WERD_CHOICE *Dict::get_top_choice_word(
const BLOB_CHOICE_LIST_VECTOR &char_choices) {
WERD_CHOICE *top_word = new WERD_CHOICE(&getUnicharset(), MAX_PERM_LENGTH);
float certainties[MAX_PERM_LENGTH];
top_word->set_permuter(TOP_CHOICE_PERM);
for (int x = 0; x < char_choices.length(); x++) {
BLOB_CHOICE_IT blob_choice_it;
blob_choice_it.set_to_list(char_choices.get(x));
BLOB_CHOICE *top_choice = blob_choice_it.data();
top_word->append_unichar_id_space_allocated(top_choice->unichar_id(), 1,
top_choice->rating(),
top_choice->certainty());
certainties[x] = top_choice->certainty();
}
LogNewChoice(1.0, certainties, true, top_word, char_choices);
return top_word;
}
/**
* permute_top_choice
*
* Return the top choice for each character as the choice for the word.
* In addition a choice is created for the best lower and upper case
* non-words. In each character position the best lower (or upper) case
* character is substituted for the best overall character.
*/
WERD_CHOICE *Dict::permute_top_choice(
const BLOB_CHOICE_LIST_VECTOR &char_choices,
float* rating_limit,
WERD_CHOICE *raw_choice,
BOOL8 *any_alpha) {
BLOB_CHOICE *first_choice;
const char *first_char; //first choice
const char *second_char; //second choice
const char *third_char; //third choice
char prev_char[UNICHAR_LEN + 1]; //prev in word
const char *next_char = ""; //next in word
const char *next_next_char = ""; //after next next in word
WERD_CHOICE word(&getUnicharset(), MAX_PERM_LENGTH);
word.set_permuter(TOP_CHOICE_PERM);
WERD_CHOICE capital_word(&getUnicharset(), MAX_PERM_LENGTH);
capital_word.set_permuter(UPPER_CASE_PERM);
WERD_CHOICE lower_word(&getUnicharset(), MAX_PERM_LENGTH);
lower_word.set_permuter(LOWER_CASE_PERM);
int x;
BOOL8 char_alpha;
float first_rating = 0;
float certainties[MAX_PERM_LENGTH + 1];
float lower_certainties[MAX_PERM_LENGTH + 1];
float upper_certainties[MAX_PERM_LENGTH + 1];
BLOB_CHOICE_IT blob_choice_it;
UNICHAR_ID temp_id;
UNICHAR_ID unichar_id;
UNICHAR_ID space = getUnicharset().unichar_to_id(" ");
register const char* ch;
register inT8 lower_done;
register inT8 upper_done;
prev_char[0] = '\0';
if (any_alpha != NULL)
*any_alpha = FALSE;
if (char_choices.length() > MAX_PERM_LENGTH) {
return (NULL);
}
for (x = 0; x < char_choices.length(); ++x) {
if (x + 1 < char_choices.length()) {
unichar_id = get_top_choice_uid(char_choices.get(x+1));
next_char = unichar_id != INVALID_UNICHAR_ID ?
getUnicharset().id_to_unichar(unichar_id) : "";
} else {
next_char = "";
}
if (x + 2 < char_choices.length()) {
unichar_id = get_top_choice_uid(char_choices.get(x+2));
next_next_char = unichar_id != INVALID_UNICHAR_ID ?
getUnicharset().id_to_unichar(unichar_id) : "";
} else {
next_next_char = "";
}
blob_choice_it.set_to_list(char_choices.get(x));
ASSERT_HOST(!blob_choice_it.empty());
first_choice = NULL;
for (blob_choice_it.mark_cycle_pt(); !blob_choice_it.cycled_list();
blob_choice_it.forward()) { // find the best non-fragment char choice
temp_id = blob_choice_it.data()->unichar_id();
if (!(getUnicharset().get_fragment(temp_id))) {
first_choice = blob_choice_it.data();
break;
} else if (char_choices.length() > 1) {
word.set_fragment_mark(true);
capital_word.set_fragment_mark(true);
lower_word.set_fragment_mark(true);
}
}
if (first_choice == NULL) {
cprintf("Permuter found only fragments for"
" character at position %d; word=%s\n",
x, word.debug_string().string());
}
ASSERT_HOST(first_choice != NULL);
unichar_id = first_choice->unichar_id() != INVALID_UNICHAR_ID ?
first_choice->unichar_id() : space;
first_char = getUnicharset().id_to_unichar(unichar_id);
first_rating = first_choice->rating();
word.append_unichar_id_space_allocated(
unichar_id, 1, first_choice->rating(), first_choice->certainty());
capital_word.append_unichar_id_space_allocated(
unichar_id, 1, first_choice->rating(), first_choice->certainty());
lower_word.append_unichar_id_space_allocated(
unichar_id, 1, first_choice->rating(), first_choice->certainty());
certainties[x] = first_choice->certainty();
lower_certainties[x] = first_choice->certainty();
upper_certainties[x] = first_choice->certainty();
lower_done = FALSE;
upper_done = FALSE;
char_alpha = FALSE;
second_char = "";
third_char = "";
for (; !blob_choice_it.cycled_list(); blob_choice_it.forward()) {
unichar_id = blob_choice_it.data()->unichar_id();
if (getUnicharset().eq(unichar_id, "l") && !blob_choice_it.at_last() &&
blob_choice_it.data_relative(1)->rating() == first_rating) {
temp_id = blob_choice_it.data_relative(1)->unichar_id();
if (getUnicharset().eq(temp_id, "1") ||
getUnicharset().eq(temp_id, "I")) {
second_char = getUnicharset().id_to_unichar(temp_id);
blob_choice_it.forward();
if (!blob_choice_it.at_last() &&
blob_choice_it.data_relative(1)->rating() == first_rating) {
temp_id = blob_choice_it.data_relative(1)->unichar_id();
if (getUnicharset().eq(temp_id, "1") ||
getUnicharset().eq(temp_id, "I")) {
third_char = getUnicharset().id_to_unichar(temp_id);
blob_choice_it.forward();
}
}
ch = choose_il1 (first_char, second_char, third_char,
prev_char, next_char, next_next_char);
unichar_id = (ch != NULL && *ch != '\0') ?
getUnicharset().unichar_to_id(ch) : INVALID_UNICHAR_ID;
if (strcmp(ch, "l") != 0 &&
getUnicharset().eq(word.unichar_id(x), "l")) {
word.set_unichar_id(unichar_id, x);
lower_word.set_unichar_id(unichar_id, x);
capital_word.set_unichar_id(unichar_id, x);
}
}
}
if (unichar_id != INVALID_UNICHAR_ID) {
/* Find lower case */
if (!lower_done &&
(getUnicharset().get_islower(unichar_id) ||
(getUnicharset().get_isupper(unichar_id) && x == 0))) {
lower_word.set_unichar_id(unichar_id, x);
lower_word.set_rating(lower_word.rating() -
first_choice->rating() + blob_choice_it.data()->rating());
if (blob_choice_it.data()->certainty() < lower_word.certainty()) {
lower_word.set_certainty(blob_choice_it.data()->certainty());
}
lower_certainties[x] = blob_choice_it.data()->certainty();
lower_done = TRUE;
}
/* Find upper case */
if (!upper_done && getUnicharset().get_isupper(unichar_id)) {
capital_word.set_unichar_id(unichar_id, x);
capital_word.set_rating(capital_word.rating() -
first_choice->rating() + blob_choice_it.data()->rating());
if (blob_choice_it.data()->certainty() < capital_word.certainty()) {
capital_word.set_certainty(blob_choice_it.data()->certainty());
}
upper_certainties[x] = blob_choice_it.data()->certainty();
upper_done = TRUE;
}
if (!char_alpha) {
const CHAR_FRAGMENT *fragment =
getUnicharset().get_fragment(unichar_id);
temp_id = !fragment ? unichar_id :
getUnicharset().unichar_to_id(fragment->get_unichar());
if (getUnicharset().get_isalpha(temp_id)) {
char_alpha = TRUE;
}
}
if (lower_done && upper_done)
break;
}
}
if (char_alpha && any_alpha != NULL)
*any_alpha = TRUE;
if (word.rating() > bestrate_pruning_factor * *rating_limit) {
if (permute_debug)
tprintf("\n***** Aborting high-cost word: %g > limit %g\n",
word.rating(), bestrate_pruning_factor * *rating_limit);
return (NULL);
}
*prev_char = '\0';
temp_id = word.unichar_id(word.length()-1);
if (temp_id != INVALID_UNICHAR_ID) {
strcpy(prev_char, getUnicharset().id_to_unichar(temp_id));
}
}
if (raw_choice != NULL && word.rating() < raw_choice->rating()) {
*raw_choice = word;
LogNewChoice(1.0, certainties, true, raw_choice, char_choices);
}
float rating = word.rating();
adjust_non_word(&word, certainties, &char_choices, permute_debug);
float lower_rating = lower_word.rating();
adjust_non_word(&lower_word, lower_certainties, &char_choices,
permute_debug);
float upper_rating = capital_word.rating();
adjust_non_word(&capital_word, upper_certainties, &char_choices,
permute_debug);
WERD_CHOICE *best_choice = &word;
*rating_limit = rating;
if (lower_word.rating() < best_choice->rating()) {
best_choice = &lower_word;
*rating_limit = lower_rating;
}
if (capital_word.rating() < best_choice->rating()) {
best_choice = &capital_word;
*rating_limit = upper_rating;
}
return new WERD_CHOICE(*best_choice);
}
/**
* @name choose_il1
*
* Choose between the candidate il1 chars.
* @param first_char first choice
* @param second_char second choice
* @param third_char third choice
* @param prev_char prev in word
* @param next_char next in word
* @param next_next_char after next next in word
*/
const char* Dict::choose_il1(const char *first_char,
const char *second_char,
const char *third_char,
const char *prev_char,
const char *next_char,
const char *next_next_char) {
inT32 type1; //1/I/l type of first choice
inT32 type2; //1/I/l type of second choice
inT32 type3; //1/I/l type of third choice
int first_char_length = strlen(first_char);
int prev_char_length = strlen(prev_char);
int next_char_length = strlen(next_char);
int next_next_char_length = strlen(next_next_char);
if (*first_char == 'l' && *second_char != '\0') {
if (*second_char == 'I'
&& (((prev_char_length != 0 &&
getUnicharset().get_isupper (prev_char, prev_char_length)) &&
(next_char_length == 0 ||
!getUnicharset().get_islower (next_char, next_char_length)) &&
(next_char_length == 0 ||
!getUnicharset().get_isdigit (next_char, next_char_length))) ||
((next_char_length != 0 &&
getUnicharset().get_isupper (next_char, next_char_length)) &&
(prev_char_length == 0 ||
!getUnicharset().get_islower (prev_char, prev_char_length)) &&
(prev_char_length == 0 ||
!getUnicharset().get_isdigit (prev_char, prev_char_length)))))
first_char = second_char; //override
else if (*second_char == '1' || *third_char == '1') {
if ((next_char_length != 0 &&
getUnicharset().get_isdigit (next_char, next_char_length)) ||
(prev_char_length != 0 &&
getUnicharset().get_isdigit (prev_char, prev_char_length))
|| (*next_char == 'l' &&
(next_next_char_length != 0 &&
getUnicharset().get_isdigit (next_next_char,
next_next_char_length)))) {
first_char = "1";
first_char_length = 1;
}
else if ((prev_char_length == 0 ||
!getUnicharset().get_islower (prev_char, prev_char_length)) &&
((next_char_length == 0 ||
!getUnicharset().get_islower (next_char, next_char_length)) ||
(*next_char == 's' &&
*next_next_char == 't'))) {
if (((*prev_char != '\'' && *prev_char != '`') || *next_char != '\0')
&& ((*next_char != '\'' && *next_char != '`')
|| *prev_char != '\0')) {
first_char = "1";
first_char_length = 1;
}
}
}
if (*first_char == 'l' && *next_char != '\0' &&
(prev_char_length == 0 ||
!getUnicharset().get_isalpha (prev_char, prev_char_length))) {
type1 = 2;
if (*second_char == '1')
type2 = 0;
else if (*second_char == 'I')
type2 = 1;
else if (*second_char == 'l')
type2 = 2;
else
type2 = type1;
if (*third_char == '1')
type3 = 0;
else if (*third_char == 'I')
type3 = 1;
else if (*third_char == 'l')
type3 = 2;
else
type3 = type1;
#if 0
if (bigram_counts[*next_char][type2] >
bigram_counts[*next_char][type1]) {
first_char = second_char;
type1 = type2;
}
if (bigram_counts[*next_char][type3] >
bigram_counts[*next_char][type1]) {
first_char = third_char;
}
#endif
}
}
return first_char;
}
/**
* @name fragment_state
*
* Given the current char choice and information about previously seen
* fragments, determines whether adjacent character fragments are
* present and whether they can be concatenated.
*
* The given prev_char_frag_info contains:
* - fragment: if not NULL contains information about immediately
* preceeding fragmented character choice
* - num_fragments: number of fragments that have been used so far
* to construct a character
* - certainty: certainty of the current choice or minimum
* certainty of all fragments concatenated so far
* - rating: rating of the current choice or sum of fragment
* ratings concatenated so far
*
* The output char_frag_info is filled in as follows:
* - character: is set to be NULL if the choice is a non-matching
* or non-ending fragment piece; is set to unichar of the given choice
* if it represents a regular character or a matching ending fragment
* - fragment,num_fragments,certainty,rating are set as described above
*
* @returns false if a non-matching fragment is discovered, true otherwise.
*/
bool Dict::fragment_state_okay(UNICHAR_ID curr_unichar_id,
float curr_rating, float curr_certainty,
const CHAR_FRAGMENT_INFO *prev_char_frag_info,
const char *debug, int word_ending,
CHAR_FRAGMENT_INFO *char_frag_info) {
const CHAR_FRAGMENT *this_fragment =
getUnicharset().get_fragment(curr_unichar_id);
const CHAR_FRAGMENT *prev_fragment =
prev_char_frag_info != NULL ? prev_char_frag_info->fragment : NULL;
// Print debug info for fragments.
if (debug && (prev_fragment || this_fragment)) {
cprintf("%s check fragments: choice=%s word_ending=%d\n", debug,
getUnicharset().debug_str(curr_unichar_id).string(),
word_ending);
if (prev_fragment) {
cprintf("prev_fragment %s\n", prev_fragment->to_string().string());
}
if (this_fragment) {
cprintf("this_fragment %s\n", this_fragment->to_string().string());
}
}
char_frag_info->unichar_id = curr_unichar_id;
char_frag_info->fragment = this_fragment;
char_frag_info->rating = curr_rating;
char_frag_info->certainty = curr_certainty;
char_frag_info->num_fragments = 1;
if (prev_fragment && !this_fragment) {
if (debug) tprintf("Skip choice with incomplete fragment\n");
return false;
}
if (this_fragment) {
// We are dealing with a fragment.
char_frag_info->unichar_id = INVALID_UNICHAR_ID;
if (prev_fragment) {
if (!this_fragment->is_continuation_of(prev_fragment)) {
if (debug) tprintf("Non-matching fragment piece\n");
return false;
}
if (this_fragment->is_ending()) {
char_frag_info->unichar_id =
getUnicharset().unichar_to_id(this_fragment->get_unichar());
char_frag_info->fragment = NULL;
if (debug) {
tprintf("Built character %s from fragments\n",
getUnicharset().debug_str(
char_frag_info->unichar_id).string());
}
} else {
if (debug) tprintf("Record fragment continuation\n");
char_frag_info->fragment = this_fragment;
}
// Update certainty and rating.
char_frag_info->rating =
prev_char_frag_info->rating + curr_rating;
char_frag_info->num_fragments = prev_char_frag_info->num_fragments + 1;
char_frag_info->certainty =
MIN(curr_certainty, prev_char_frag_info->certainty);
} else {
if (this_fragment->is_beginning()) {
if (debug) cprintf("Record fragment beginning\n");
} else {
if (debug) {
tprintf("Non-starting fragment piece with no prev_fragment\n");
}
return false;
}
}
}
if (word_ending && char_frag_info->fragment) {
if (debug) tprintf("Word can not end with a fragment\n");
return false;
}
return true;
}
/**
* top_fragments_permute_and_select
*
* Creates a copy of character choices list that contain only fragments
* and the best non-fragmented character choice.
* Permutes character in this shortened list, builds characters from
* fragments if possible and returns a better choice if found.
*/
WERD_CHOICE *Dict::top_fragments_permute_and_select(
const BLOB_CHOICE_LIST_VECTOR &char_choices,
float rating_limit) {
if (char_choices.length() <= 1 ||
char_choices.length() > MAX_PERM_LENGTH) {
return NULL;
}
// See it would be possible to benefit from permuting fragments.
int x;
float min_rating = 0.0;
BLOB_CHOICE_IT blob_choice_it;
for (x = 0; x < char_choices.length(); ++x) {
blob_choice_it.set_to_list(char_choices.get(x));
if (blob_choice_it.data()) {
min_rating += blob_choice_it.data()->rating();
}
if (min_rating >= rating_limit) {
return NULL;
}
}
if (fragments_debug > 1) {
tprintf("A choice with fragment beats top choice\n");
tprintf("Running fragment permuter...\n");
}
// Construct a modified choices list that contains (for each position):
// the best choice, all fragments and at least one choice for
// a non-fragmented character.
BLOB_CHOICE_LIST_VECTOR frag_char_choices(char_choices.length());
for (x = 0; x < char_choices.length(); ++x) {
bool need_nonfrag_char = true;
BLOB_CHOICE_LIST *frag_choices = new BLOB_CHOICE_LIST();
BLOB_CHOICE_IT frag_choices_it;
frag_choices_it.set_to_list(frag_choices);
blob_choice_it.set_to_list(char_choices.get(x));
for (blob_choice_it.mark_cycle_pt(); !blob_choice_it.cycled_list();
blob_choice_it.forward()) {
if (getUnicharset().get_fragment(blob_choice_it.data()->unichar_id())) {
frag_choices_it.add_after_then_move(
new BLOB_CHOICE(*(blob_choice_it.data())));
} else if (need_nonfrag_char) {
frag_choices_it.add_after_then_move(
new BLOB_CHOICE(*(blob_choice_it.data())));
need_nonfrag_char = false;
}
}
frag_char_choices += frag_choices;
}
WERD_CHOICE *best_choice = new WERD_CHOICE(&getUnicharset());
best_choice->make_bad();
WERD_CHOICE word(&getUnicharset(), MAX_PERM_LENGTH);
word.set_permuter(TOP_CHOICE_PERM);
float certainties[MAX_PERM_LENGTH];
this->go_deeper_fxn_ = &tesseract::Dict::go_deeper_top_fragments_fxn;
int attempts_left = max_permuter_attempts;
permute_choices((fragments_debug > 1) ? "fragments_debug" : NULL,
frag_char_choices, 0, NULL, &word, certainties,
&rating_limit, best_choice, &attempts_left, NULL);
frag_char_choices.delete_data_pointers();
return best_choice;
}
/**
* permute_choices
*
* Call append_choices() for each BLOB_CHOICE in BLOB_CHOICE_LIST
* with the given char_choice_index in char_choices.
*/
void Dict::permute_choices(
const char *debug,
const BLOB_CHOICE_LIST_VECTOR &char_choices,
int char_choice_index,
const CHAR_FRAGMENT_INFO *prev_char_frag_info,
WERD_CHOICE *word,
float certainties[],
float *limit,
WERD_CHOICE *best_choice,
int *attempts_left,
void *more_args) {
if (debug) {
tprintf("%s permute_choices: char_choice_index=%d"
" limit=%g rating=%g, certainty=%g word=%s\n",
debug, char_choice_index, *limit, word->rating(),
word->certainty(), word->debug_string().string());
}
if (char_choice_index < char_choices.length()) {
BLOB_CHOICE_IT blob_choice_it;
blob_choice_it.set_to_list(char_choices.get(char_choice_index));
for (blob_choice_it.mark_cycle_pt(); !blob_choice_it.cycled_list();
blob_choice_it.forward()) {
(*attempts_left)--;
append_choices(debug, char_choices, *(blob_choice_it.data()),
char_choice_index, prev_char_frag_info, word,
certainties, limit, best_choice, attempts_left, more_args);
if (*attempts_left <= 0) {
if (debug) tprintf("permute_choices(): attempts_left is 0\n");
break;
}
}
}
}
/**
* append_choices
*
* Checks to see whether or not the next choice is worth appending to
* the word being generated. If so then keeps going deeper into the word.
*
* This function assumes that Dict::go_deeper_fxn_ is set.
*/
void Dict::append_choices(
const char *debug,
const BLOB_CHOICE_LIST_VECTOR &char_choices,
const BLOB_CHOICE &blob_choice,
int char_choice_index,
const CHAR_FRAGMENT_INFO *prev_char_frag_info,
WERD_CHOICE *word,
float certainties[],
float *limit,
WERD_CHOICE *best_choice,
int *attempts_left,
void *more_args) {
int word_ending =
(char_choice_index == char_choices.length() - 1) ? true : false;
// Deal with fragments.
CHAR_FRAGMENT_INFO char_frag_info;
if (!fragment_state_okay(blob_choice.unichar_id(), blob_choice.rating(),
blob_choice.certainty(), prev_char_frag_info, debug,
word_ending, &char_frag_info)) {
return; // blob_choice must be an invalid fragment
}
// Search the next letter if this character is a fragment.
if (char_frag_info.unichar_id == INVALID_UNICHAR_ID) {
permute_choices(debug, char_choices, char_choice_index + 1,
&char_frag_info, word, certainties, limit,
best_choice, attempts_left, more_args);
return;
}
// Add the next unichar.
float old_rating = word->rating();
float old_certainty = word->certainty();
uinT8 old_permuter = word->permuter();
certainties[word->length()] = char_frag_info.certainty;
word->append_unichar_id_space_allocated(
char_frag_info.unichar_id, char_frag_info.num_fragments,
char_frag_info.rating, char_frag_info.certainty);
// Explore the next unichar.
(this->*go_deeper_fxn_)(debug, char_choices, char_choice_index,
&char_frag_info, word_ending, word, certainties,
limit, best_choice, attempts_left, more_args);
// Remove the unichar we added to explore other choices in it's place.
word->remove_last_unichar_id();
word->set_rating(old_rating);
word->set_certainty(old_certainty);
word->set_permuter(old_permuter);
}
/**
* go_deeper_top_fragments_fxn
*
* While the choice being composed so far could be better
* than best_choice keeps exploring char_choices.
* If the end of the word is reached and the word is better than
* best_choice, copies word to best_choice and logs the new word choice.
*/
void Dict::go_deeper_top_fragments_fxn(
const char *debug, const BLOB_CHOICE_LIST_VECTOR &char_choices,
int char_choice_index, const CHAR_FRAGMENT_INFO *prev_char_frag_info,
bool word_ending, WERD_CHOICE *word, float certainties[], float *limit,
WERD_CHOICE *best_choice, int *attempts_left, void *more_args) {
if (word->rating() < *limit) {
if (word_ending) {
if (fragments_debug > 1) {
tprintf("fragments_debug new choice = %s\n",
word->debug_string().string());
}
*limit = word->rating();
adjust_non_word(word, certainties, &char_choices, permute_debug);
update_best_choice(*word, best_choice);
} else { // search the next letter
permute_choices(debug, char_choices, char_choice_index + 1,
prev_char_frag_info, word, certainties, limit,
best_choice, attempts_left, more_args);
}
} else {
if (fragments_debug > 1) {
tprintf("fragments_debug pruned word (%s, rating=%4.2f, limit=%4.2f)\n",
word->debug_string().string(), word->rating(), *limit);
}
}
}
} // namespace tesseract
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