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Tesseract
3.02
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Tesseract
3.02
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#include <beam_search.h>
Public Member Functions | |
| BeamSearch (CubeRecoContext *cntxt, bool word_mode=true) | |
| ~BeamSearch () | |
| WordAltList * | Search (SearchObject *srch_obj, LangModel *lang_mod=NULL) |
| SearchNode * | BestNode () const |
| char_32 * | Alt (int alt) const |
| CharSamp ** | BackTrack (SearchObject *srch_obj, int node_index, int *char_cnt, char_32 **str32, Boxa **char_boxes) const |
| CharSamp ** | BackTrack (SearchObject *srch_obj, SearchNode *node, int *char_cnt, char_32 **str32, Boxa **char_boxes) const |
| int | SizeCost (SearchObject *srch_obj, SearchNode *node, char_32 **str32=NULL) const |
| int | WordUnigramCost (char_32 *str32, WordUnigrams *word_unigrams) const |
| int | ColCnt () const |
| SearchColumn * | Column (int col_idx) const |
| int | BestPresortedNodeIndex () const |
Definition at line 44 of file beam_search.h.
| tesseract::BeamSearch::BeamSearch | ( | CubeRecoContext * | cntxt, |
| bool | word_mode = true |
||
| ) | [explicit] |
Definition at line 27 of file beam_search.cpp.
{
cntxt_ = cntxt;
seg_pt_cnt_ = 0;
col_cnt_ = 1;
col_ = NULL;
word_mode_ = word_mode;
}
| tesseract::BeamSearch::~BeamSearch | ( | ) |
Definition at line 47 of file beam_search.cpp.
{
Cleanup();
}
| char_32 * tesseract::BeamSearch::Alt | ( | int | alt | ) | const |
Definition at line 298 of file beam_search.cpp.
{
// get the last column of the lattice
if (col_cnt_ <= 0)
return NULL;
SearchColumn *srch_col = col_[col_cnt_ - 1];
if (!srch_col)
return NULL;
// point to the last node in the selected path
if (alt >= srch_col->NodeCount() || srch_col->Nodes() == NULL) {
return NULL;
}
SearchNode *srch_node = srch_col->Nodes()[alt];
if (!srch_node)
return NULL;
// get string
char_32 *str32 = srch_node->PathString();
if (!str32)
return NULL;
return str32;
}
| CharSamp ** tesseract::BeamSearch::BackTrack | ( | SearchObject * | srch_obj, |
| int | node_index, | ||
| int * | char_cnt, | ||
| char_32 ** | str32, | ||
| Boxa ** | char_boxes | ||
| ) | const |
Definition at line 328 of file beam_search.cpp.
{
// get the last column of the lattice
if (col_cnt_ <= 0)
return NULL;
SearchColumn *srch_col = col_[col_cnt_ - 1];
if (!srch_col)
return NULL;
// point to the last node in the selected path
if (node_index >= srch_col->NodeCount() || !srch_col->Nodes())
return NULL;
SearchNode *srch_node = srch_col->Nodes()[node_index];
if (!srch_node)
return NULL;
return BackTrack(srch_obj, srch_node, char_cnt, str32, char_boxes);
}
| CharSamp ** tesseract::BeamSearch::BackTrack | ( | SearchObject * | srch_obj, |
| SearchNode * | node, | ||
| int * | char_cnt, | ||
| char_32 ** | str32, | ||
| Boxa ** | char_boxes | ||
| ) | const |
Definition at line 352 of file beam_search.cpp.
{
if (!srch_node)
return NULL;
if (str32) {
if (*str32)
delete [](*str32); // clear existing value
*str32 = srch_node->PathString();
if (!*str32)
return NULL;
}
if (char_boxes && *char_boxes) {
boxaDestroy(char_boxes); // clear existing value
}
CharSamp **chars;
chars = SplitByNode(srch_obj, srch_node, char_cnt, char_boxes);
if (!chars && str32)
delete []*str32;
return chars;
}
| SearchNode * tesseract::BeamSearch::BestNode | ( | ) | const |
Definition at line 286 of file beam_search.cpp.
| int tesseract::BeamSearch::BestPresortedNodeIndex | ( | ) | const [inline] |
Definition at line 81 of file beam_search.h.
{
return best_presorted_node_idx_;
};
| int tesseract::BeamSearch::ColCnt | ( | ) | const [inline] |
Definition at line 76 of file beam_search.h.
{ return col_cnt_; }
| SearchColumn * tesseract::BeamSearch::Column | ( | int | col_idx | ) | const |
Definition at line 279 of file beam_search.cpp.
{
if (col < 0 || col >= col_cnt_ || !col_)
return NULL;
return col_[col];
}
| WordAltList * tesseract::BeamSearch::Search | ( | SearchObject * | srch_obj, |
| LangModel * | lang_mod = NULL |
||
| ) |
Definition at line 98 of file beam_search.cpp.
{
// verifications
if (!lang_mod)
lang_mod = cntxt_->LangMod();
if (!lang_mod) {
fprintf(stderr, "Cube ERROR (BeamSearch::Search): could not construct "
"LangModel\n");
return NULL;
}
// free existing state
Cleanup();
// get seg pt count
seg_pt_cnt_ = srch_obj->SegPtCnt();
if (seg_pt_cnt_ < 0) {
return NULL;
}
col_cnt_ = seg_pt_cnt_ + 1;
// disregard suspicious cases
if (seg_pt_cnt_ > 128) {
fprintf(stderr, "Cube ERROR (BeamSearch::Search): segment point count is "
"suspiciously high; bailing out\n");
return NULL;
}
// alloc memory for columns
col_ = new SearchColumn *[col_cnt_];
if (!col_) {
fprintf(stderr, "Cube ERROR (BeamSearch::Search): could not construct "
"SearchColumn array\n");
return NULL;
}
memset(col_, 0, col_cnt_ * sizeof(*col_));
// for all possible segments
for (int end_seg = 1; end_seg <= (seg_pt_cnt_ + 1); end_seg++) {
// create a search column
col_[end_seg - 1] = new SearchColumn(end_seg - 1,
cntxt_->Params()->BeamWidth());
if (!col_[end_seg - 1]) {
fprintf(stderr, "Cube ERROR (BeamSearch::Search): could not construct "
"SearchColumn for column %d\n", end_seg - 1);
return NULL;
}
// for all possible start segments
int init_seg = MAX(0, end_seg - cntxt_->Params()->MaxSegPerChar());
for (int strt_seg = init_seg; strt_seg < end_seg; strt_seg++) {
int parent_nodes_cnt;
SearchNode **parent_nodes;
// for the root segment, we do not have a parent
if (strt_seg == 0) {
parent_nodes_cnt = 1;
parent_nodes = NULL;
} else {
// for all the existing nodes in the starting column
parent_nodes_cnt = col_[strt_seg - 1]->NodeCount();
parent_nodes = col_[strt_seg - 1]->Nodes();
}
// run the shape recognizer
CharAltList *char_alt_list = srch_obj->RecognizeSegment(strt_seg - 1,
end_seg - 1);
// for all the possible parents
for (int parent_idx = 0; parent_idx < parent_nodes_cnt; parent_idx++) {
// point to the parent node
SearchNode *parent_node = !parent_nodes ? NULL
: parent_nodes[parent_idx];
LangModEdge *lm_parent_edge = !parent_node ? lang_mod->Root()
: parent_node->LangModelEdge();
// compute the cost of not having spaces within the segment range
int contig_cost = srch_obj->NoSpaceCost(strt_seg - 1, end_seg - 1);
// In phrase mode, compute the cost of not having a space before
// this character
int no_space_cost = 0;
if (!word_mode_ && strt_seg > 0) {
no_space_cost = srch_obj->NoSpaceCost(strt_seg - 1);
}
// if the no space cost is low enough
if ((contig_cost + no_space_cost) < MIN_PROB_COST) {
// Add the children nodes
CreateChildren(col_[end_seg - 1], lang_mod, parent_node,
lm_parent_edge, char_alt_list,
contig_cost + no_space_cost);
}
// In phrase mode and if not starting at the root
if (!word_mode_ && strt_seg > 0) { // parent_node must be non-NULL
// consider starting a new word for nodes that are valid EOW
if (parent_node->LangModelEdge()->IsEOW()) {
// get the space cost
int space_cost = srch_obj->SpaceCost(strt_seg - 1);
// if the space cost is low enough
if ((contig_cost + space_cost) < MIN_PROB_COST) {
// Restart the language model and add nodes as children to the
// space node.
CreateChildren(col_[end_seg - 1], lang_mod, parent_node, NULL,
char_alt_list, contig_cost + space_cost);
}
}
}
} // parent
} // strt_seg
// prune the column nodes
col_[end_seg - 1]->Prune();
// Free the column hash table. No longer needed
col_[end_seg - 1]->FreeHashTable();
} // end_seg
WordAltList *alt_list = CreateWordAltList(srch_obj);
return alt_list;
}
| int tesseract::BeamSearch::SizeCost | ( | SearchObject * | srch_obj, |
| SearchNode * | node, | ||
| char_32 ** | str32 = NULL |
||
| ) | const |
Definition at line 472 of file beam_search.cpp.
{
CharSamp **chars = NULL;
int char_cnt = 0;
if (!node)
return 0;
// Backtrack to get string and character segmentation
chars = BackTrack(srch_obj, node, &char_cnt, str32, NULL);
if (!chars)
return WORST_COST;
int size_cost = (cntxt_->SizeModel() == NULL) ? 0 :
cntxt_->SizeModel()->Cost(chars, char_cnt);
delete []chars;
return size_cost;
}
| int tesseract::BeamSearch::WordUnigramCost | ( | char_32 * | str32, |
| WordUnigrams * | word_unigrams | ||
| ) | const |
1.7.5.1