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tesseract/classify/mfoutline.cpp

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/******************************************************************************
** Filename: mfoutline.c
** Purpose: Interface to outline struct used for extracting features
** Author: Dan Johnson
** History: Thu May 17 08:14:18 1990, 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 "clusttool.h" //If remove you get cought in a loop somewhere
#include "emalloc.h"
#include "mfoutline.h"
#include "blobs.h"
#include "const.h"
#include "mfx.h"
#include "params.h"
#include "classify.h"
#include <math.h>
#include <stdio.h>
/*----------------------------------------------------------------------------
Public Code
----------------------------------------------------------------------------*/
/*---------------------------------------------------------------------------*/
/** Convert a blob into a list of MFOUTLINEs (float-based microfeature format).
*/
LIST ConvertBlob(TBLOB *blob) {
LIST outlines = NIL_LIST;
return (blob == NULL)
? NIL_LIST
: ConvertOutlines(blob->outlines, outlines, outer);
}
/*---------------------------------------------------------------------------*/
/** Convert a TESSLINE into the float-based MFOUTLINE micro-feature format. */
MFOUTLINE ConvertOutline(TESSLINE *outline) {
MFEDGEPT *NewPoint;
MFOUTLINE MFOutline = NIL_LIST;
EDGEPT *EdgePoint;
EDGEPT *StartPoint;
EDGEPT *NextPoint;
if (outline == NULL || outline->loop == NULL)
return MFOutline;
StartPoint = outline->loop;
EdgePoint = StartPoint;
do {
NextPoint = EdgePoint->next;
/* filter out duplicate points */
if (EdgePoint->pos.x != NextPoint->pos.x ||
EdgePoint->pos.y != NextPoint->pos.y) {
NewPoint = NewEdgePoint();
ClearMark(NewPoint);
NewPoint->Hidden = EdgePoint->IsHidden();
NewPoint->Point.x = EdgePoint->pos.x;
NewPoint->Point.y = EdgePoint->pos.y;
MFOutline = push(MFOutline, NewPoint);
}
EdgePoint = NextPoint;
} while (EdgePoint != StartPoint);
if (MFOutline != NULL)
MakeOutlineCircular(MFOutline);
return MFOutline;
}
/*---------------------------------------------------------------------------*/
/**
* Convert a tree of outlines to a list of MFOUTLINEs (lists of MFEDGEPTs).
*
* @param outline first outline to be converted
* @param mf_outlines list to add converted outlines to
* @param outline_type are the outlines outer or holes?
*/
LIST ConvertOutlines(TESSLINE *outline,
LIST mf_outlines,
OUTLINETYPE outline_type) {
MFOUTLINE mf_outline;
while (outline != NULL) {
mf_outline = ConvertOutline(outline);
if (mf_outline != NULL)
mf_outlines = push(mf_outlines, mf_outline);
outline = outline->next;
}
return mf_outlines;
}
/*---------------------------------------------------------------------------*/
/**
* This routine searches through the specified outline, computes
* a slope for each vector in the outline, and marks each
* vector as having one of the following directions:
* N, S, E, W, NE, NW, SE, SW
* This information is then stored in the outline and the
* outline is returned.
* @param Outline micro-feature outline to analyze
* @param MinSlope controls "snapping" of segments to horizontal
* @param MaxSlope controls "snapping" of segments to vertical
* @return none
* @note Exceptions: none
* @note History: 7/21/89, DSJ, Created.
*/
void FindDirectionChanges(MFOUTLINE Outline,
FLOAT32 MinSlope,
FLOAT32 MaxSlope) {
MFEDGEPT *Current;
MFEDGEPT *Last;
MFOUTLINE EdgePoint;
if (DegenerateOutline (Outline))
return;
Last = PointAt (Outline);
Outline = NextPointAfter (Outline);
EdgePoint = Outline;
do {
Current = PointAt (EdgePoint);
ComputeDirection(Last, Current, MinSlope, MaxSlope);
Last = Current;
EdgePoint = NextPointAfter (EdgePoint);
}
while (EdgePoint != Outline);
} /* FindDirectionChanges */
/*---------------------------------------------------------------------------*/
/**
* This routine deallocates all of the memory consumed by
* a micro-feature outline.
* @param arg micro-feature outline to be freed
* @return none
* @note Exceptions: none
* @note History: 7/27/89, DSJ, Created.
*/
void FreeMFOutline(void *arg) { //MFOUTLINE Outline)
MFOUTLINE Start;
MFOUTLINE Outline = (MFOUTLINE) arg;
/* break the circular outline so we can use std. techniques to deallocate */
Start = list_rest (Outline);
set_rest(Outline, NIL_LIST);
while (Start != NULL) {
free_struct (first_node (Start), sizeof (MFEDGEPT), "MFEDGEPT");
Start = pop (Start);
}
} /* FreeMFOutline */
/*---------------------------------------------------------------------------*/
/**
* Release all memory consumed by the specified list
* of outlines.
* @param Outlines list of mf-outlines to be freed
* @return none
* @note Exceptions: none
* @note History: Thu Dec 13 16:14:50 1990, DSJ, Created.
*/
void FreeOutlines(LIST Outlines) {
destroy_nodes(Outlines, FreeMFOutline);
} /* FreeOutlines */
/*---------------------------------------------------------------------------*/
/**
* This routine searches through the specified outline and finds
* the points at which the outline changes direction. These
* points are then marked as "extremities". This routine is
* used as an alternative to FindExtremities(). It forces the
* endpoints of the microfeatures to be at the direction
* changes rather than at the midpoint between direction
* changes.
* @param Outline micro-feature outline to analyze
* @return none
* @note Globals: none
* @note Exceptions: none
* @note History: 6/29/90, DSJ, Created.
*/
void MarkDirectionChanges(MFOUTLINE Outline) {
MFOUTLINE Current;
MFOUTLINE Last;
MFOUTLINE First;
if (DegenerateOutline (Outline))
return;
First = NextDirectionChange (Outline);
Last = First;
do {
Current = NextDirectionChange (Last);
MarkPoint (PointAt (Current));
Last = Current;
}
while (Last != First);
} /* MarkDirectionChanges */
/*---------------------------------------------------------------------------*/
/** Return a new edge point for a micro-feature outline. */
MFEDGEPT *NewEdgePoint() {
return ((MFEDGEPT *) alloc_struct(sizeof(MFEDGEPT), "MFEDGEPT"));
}
/*---------------------------------------------------------------------------*/
/**
* This routine returns the next point in the micro-feature
* outline that is an extremity. The search starts after
* EdgePoint. The routine assumes that the outline being
* searched is not a degenerate outline (i.e. it must have
* 2 or more edge points).
* @param EdgePoint start search from this point
* @return Next extremity in the outline after EdgePoint.
* @note Globals: none
* @note Exceptions: none
* @note History: 7/26/89, DSJ, Created.
*/
MFOUTLINE NextExtremity(MFOUTLINE EdgePoint) {
EdgePoint = NextPointAfter(EdgePoint);
while (!PointAt(EdgePoint)->ExtremityMark)
EdgePoint = NextPointAfter(EdgePoint);
return (EdgePoint);
} /* NextExtremity */
/*---------------------------------------------------------------------------*/
/**
* This routine normalizes the coordinates of the specified
* outline so that the outline is deskewed down to the
* baseline, translated so that x=0 is at XOrigin, and scaled
* so that the height of a character cell from descender to
* ascender is 1. Of this height, 0.25 is for the descender,
* 0.25 for the ascender, and 0.5 for the x-height. The
* y coordinate of the baseline is 0.
* @param Outline outline to be normalized
* @param XOrigin x-origin of text
* @return none
* @note Globals: none
* @note Exceptions: none
* @note History: 8/2/89, DSJ, Created.
*/
void NormalizeOutline(MFOUTLINE Outline,
FLOAT32 XOrigin) {
if (Outline == NIL_LIST)
return;
MFOUTLINE EdgePoint = Outline;
do {
MFEDGEPT *Current = PointAt(EdgePoint);
Current->Point.y = MF_SCALE_FACTOR *
(Current->Point.y - kBlnBaselineOffset);
Current->Point.x = MF_SCALE_FACTOR * (Current->Point.x - XOrigin);
EdgePoint = NextPointAfter(EdgePoint);
} while (EdgePoint != Outline);
} /* NormalizeOutline */
/*---------------------------------------------------------------------------*/
namespace tesseract {
/**
* This routine normalizes every outline in Outlines
* according to the currently selected normalization method.
* It also returns the scale factors that it used to do this
* scaling. The scale factors returned represent the x and
* y sizes in the normalized coordinate system that correspond
* to 1 pixel in the original coordinate system.
*
* Globals:
* - classify_norm_method method being used for normalization
* - classify_char_norm_range map radius of gyration to this value
* @param Outlines list of outlines to be normalized
* @param XScale x-direction scale factor used by routine
* @param YScale y-direction scale factor used by routine
* @return none (Outlines are changed and XScale and YScale are updated)
* @note Exceptions: none
* @note History: Fri Dec 14 08:14:55 1990, DSJ, Created.
*/
void Classify::NormalizeOutlines(LIST Outlines,
FLOAT32 *XScale,
FLOAT32 *YScale) {
MFOUTLINE Outline;
switch (classify_norm_method) {
case character:
ASSERT_HOST(!"How did NormalizeOutlines get called in character mode?");
break;
case baseline:
iterate(Outlines) {
Outline = (MFOUTLINE) first_node(Outlines);
NormalizeOutline(Outline, 0.0);
}
*XScale = *YScale = MF_SCALE_FACTOR;
break;
}
} /* NormalizeOutlines */
} // namespace tesseract
/*----------------------------------------------------------------------------
Private Code
----------------------------------------------------------------------------*/
/**
* Change the direction of every vector in the specified
* outline segment to Direction. The segment to be changed
* starts at Start and ends at End. Note that the previous
* direction of End must also be changed to reflect the
* change in direction of the point before it.
* @param Start, End defines segment of outline to be modified
* @param Direction new direction to assign to segment
* @return none
* @note Globals: none
* @note Exceptions: none
* @note History: Fri May 4 10:42:04 1990, DSJ, Created.
*/
void ChangeDirection(MFOUTLINE Start, MFOUTLINE End, DIRECTION Direction) {
MFOUTLINE Current;
for (Current = Start; Current != End; Current = NextPointAfter (Current))
PointAt (Current)->Direction = Direction;
PointAt (End)->PreviousDirection = Direction;
} /* ChangeDirection */
/**
* This routine normalizes each point in Outline by
* translating it to the specified center and scaling it
* anisotropically according to the given scale factors.
* @param Outline outline to be character normalized
* @param cn_denorm
* @return none
* @note Globals: none
* @note Exceptions: none
* @note History: Fri Dec 14 10:27:11 1990, DSJ, Created.
*/
void CharNormalizeOutline(MFOUTLINE Outline, const DENORM& cn_denorm) {
MFOUTLINE First, Current;
MFEDGEPT *CurrentPoint;
if (Outline == NIL_LIST)
return;
First = Outline;
Current = First;
do {
CurrentPoint = PointAt(Current);
FCOORD pos(CurrentPoint->Point.x, CurrentPoint->Point.y);
cn_denorm.LocalNormTransform(pos, &pos);
CurrentPoint->Point.x = (pos.x() - MAX_UINT8 / 2) * MF_SCALE_FACTOR;
CurrentPoint->Point.y = (pos.y() - MAX_UINT8 / 2) * MF_SCALE_FACTOR;
Current = NextPointAfter(Current);
}
while (Current != First);
} /* CharNormalizeOutline */
/**
* This routine computes the slope from Start to Finish and
* and then computes the approximate direction of the line
* segment from Start to Finish. The direction is quantized
* into 8 buckets:
* N, S, E, W, NE, NW, SE, SW
* Both the slope and the direction are then stored into
* the appropriate fields of the Start edge point. The
* direction is also stored into the PreviousDirection field
* of the Finish edge point.
* @param Start starting point to compute direction from
* @param Finish finishing point to compute direction to
* @param MinSlope slope below which lines are horizontal
* @param MaxSlope slope above which lines are vertical
* @return none
* @note Globals: none
* @note Exceptions: none
* @note History: 7/25/89, DSJ, Created.
*/
void ComputeDirection(MFEDGEPT *Start,
MFEDGEPT *Finish,
FLOAT32 MinSlope,
FLOAT32 MaxSlope) {
FVECTOR Delta;
Delta.x = Finish->Point.x - Start->Point.x;
Delta.y = Finish->Point.y - Start->Point.y;
if (Delta.x == 0)
if (Delta.y < 0) {
Start->Slope = -MAX_FLOAT32;
Start->Direction = south;
}
else {
Start->Slope = MAX_FLOAT32;
Start->Direction = north;
}
else {
Start->Slope = Delta.y / Delta.x;
if (Delta.x > 0)
if (Delta.y > 0)
if (Start->Slope > MinSlope)
if (Start->Slope < MaxSlope)
Start->Direction = northeast;
else
Start->Direction = north;
else
Start->Direction = east;
else if (Start->Slope < -MinSlope)
if (Start->Slope > -MaxSlope)
Start->Direction = southeast;
else
Start->Direction = south;
else
Start->Direction = east;
else if (Delta.y > 0)
if (Start->Slope < -MinSlope)
if (Start->Slope > -MaxSlope)
Start->Direction = northwest;
else
Start->Direction = north;
else
Start->Direction = west;
else if (Start->Slope > MinSlope)
if (Start->Slope < MaxSlope)
Start->Direction = southwest;
else
Start->Direction = south;
else
Start->Direction = west;
}
Finish->PreviousDirection = Start->Direction;
}
/**
* This routine returns the next point in the micro-feature
* outline that has a direction different than EdgePoint. The
* routine assumes that the outline being searched is not a
* degenerate outline (i.e. it must have 2 or more edge points).
* @param EdgePoint start search from this point
* @return Point of next direction change in micro-feature outline.
* @note Globals: none
* @note Exceptions: none
* @note History: 7/25/89, DSJ, Created.
*/
MFOUTLINE NextDirectionChange(MFOUTLINE EdgePoint) {
DIRECTION InitialDirection;
InitialDirection = PointAt (EdgePoint)->Direction;
MFOUTLINE next_pt = NULL;
do {
EdgePoint = NextPointAfter(EdgePoint);
next_pt = NextPointAfter(EdgePoint);
} while (PointAt(EdgePoint)->Direction == InitialDirection &&
!PointAt(EdgePoint)->Hidden &&
next_pt != NULL && !PointAt(next_pt)->Hidden);
return (EdgePoint);
}
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