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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>
#define MIN_INERTIA (0.00001)
/*----------------------------------------------------------------------------
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);
MakeOutlineCircular(MFOutline);
return MFOutline;
}
/*---------------------------------------------------------------------------*/
// Convert a tree of outlines to a list of MFOUTLINEs (lists of MFEDGEPTs).
//
// Parameters:
// outline first outline to be converted
// mf_outlines list to add converted outlines to
// 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);
mf_outlines = push(mf_outlines, mf_outline);
outline = outline->next;
}
return mf_outlines;
}
/*---------------------------------------------------------------------------*/
void ComputeOutlineStats(LIST Outlines, OUTLINE_STATS *OutlineStats) {
/*
** Parameters:
** Outlines list of outlines to compute stats for
** OutlineStats place to put results
** Globals: none
** Operation: This routine computes several statistics about the outlines
** in Outlines. These statistics are usually used to perform
** anistropic normalization of all of the outlines. The
** statistics generated are:
** first moments about x and y axes
** total length of all outlines
** center of mass of all outlines
** second moments about center of mass axes
** radius of gyration about center of mass axes
** Return: none (results are returned in OutlineStats)
** Exceptions: none
** History: Fri Dec 14 08:32:03 1990, DSJ, Created.
*/
MFOUTLINE Outline;
MFOUTLINE EdgePoint;
MFEDGEPT *Current;
MFEDGEPT *Last;
InitOutlineStats(OutlineStats);
iterate(Outlines) {
Outline = (MFOUTLINE) first_node (Outlines);
Last = PointAt (Outline);
Outline = NextPointAfter (Outline);
EdgePoint = Outline;
do {
Current = PointAt (EdgePoint);
UpdateOutlineStats (OutlineStats,
Last->Point.x, Last->Point.y,
Current->Point.x, Current->Point.y);
Last = Current;
EdgePoint = NextPointAfter (EdgePoint);
}
while (EdgePoint != Outline);
}
FinishOutlineStats(OutlineStats);
} /* ComputeOutlineStats */
/*---------------------------------------------------------------------------*/
void FindDirectionChanges(MFOUTLINE Outline,
FLOAT32 MinSlope,
FLOAT32 MaxSlope) {
/*
** Parameters:
** Outline micro-feature outline to analyze
** MinSlope controls "snapping" of segments to horizontal
** MaxSlope controls "snapping" of segments to vertical
** Globals: none
** Operation:
** This routine searches thru 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.
** Return: none
** Exceptions: none
** History: 7/21/89, DSJ, Created.
*/
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 */
/*---------------------------------------------------------------------------*/
void FreeMFOutline(void *arg) { //MFOUTLINE Outline)
/*
** Parameters:
** Outline micro-feature outline to be freed
** Globals: none
** Operation:
** This routine deallocates all of the memory consumed by
** a micro-feature outline.
** Return: none
** Exceptions: none
** History: 7/27/89, DSJ, Created.
*/
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 */
/*---------------------------------------------------------------------------*/
void FreeOutlines(LIST Outlines) {
/*
** Parameters:
** Outlines list of mf-outlines to be freed
** Globals: none
** Operation: Release all memory consumed by the specified list
** of outlines.
** Return: none
** Exceptions: none
** History: Thu Dec 13 16:14:50 1990, DSJ, Created.
*/
destroy_nodes(Outlines, FreeMFOutline);
} /* FreeOutlines */
/*---------------------------------------------------------------------------*/
void MarkDirectionChanges(MFOUTLINE Outline) {
/*
** Parameters:
** Outline micro-feature outline to analyze
** Globals: none
** Operation:
** This routine searches thru 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.
** Return: none
** Exceptions: none
** History: 6/29/90, DSJ, Created.
*/
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"));
}
/*---------------------------------------------------------------------------*/
MFOUTLINE NextExtremity(MFOUTLINE EdgePoint) {
/*
** Parameters:
** EdgePoint start search from this point
** Globals: none
** Operation:
** 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).
** Return: Next extremity in the outline after EdgePoint.
** Exceptions: none
** History: 7/26/89, DSJ, Created.
*/
EdgePoint = NextPointAfter(EdgePoint);
while (!PointAt(EdgePoint)->ExtremityMark)
EdgePoint = NextPointAfter(EdgePoint);
return (EdgePoint);
} /* NextExtremity */
/*---------------------------------------------------------------------------*/
void NormalizeOutline(MFOUTLINE Outline,
FLOAT32 XOrigin) {
/*
** Parameters:
** Outline outline to be normalized
** XOrigin x-origin of text
** Globals: none
** Operation:
** 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.
** Return: none
** Exceptions: none
** History: 8/2/89, DSJ, Created.
*/
if (Outline == NIL_LIST)
return;
MFOUTLINE EdgePoint = Outline;
do {
MFEDGEPT *Current = PointAt(EdgePoint);
Current->Point.y = MF_SCALE_FACTOR * (Current->Point.y - BASELINE_OFFSET);
Current->Point.x = MF_SCALE_FACTOR * (Current->Point.x - XOrigin);
EdgePoint = NextPointAfter(EdgePoint);
} while (EdgePoint != Outline);
} /* NormalizeOutline */
/*---------------------------------------------------------------------------*/
namespace tesseract {
void Classify::NormalizeOutlines(LIST Outlines,
FLOAT32 *XScale,
FLOAT32 *YScale) {
/*
** Parameters:
** Outlines list of outlines to be normalized
** XScale x-direction scale factor used by routine
** YScale y-direction scale factor used by routine
** Globals:
** classify_norm_method method being used for normalization
** classify_char_norm_range map radius of gyration to this value
** Operation: 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.
** Return: none (Outlines are changed and XScale and YScale are updated)
** Exceptions: none
** History: Fri Dec 14 08:14:55 1990, DSJ, Created.
*/
MFOUTLINE Outline;
OUTLINE_STATS OutlineStats;
FLOAT32 BaselineScale;
switch (classify_norm_method) {
case character:
ComputeOutlineStats(Outlines, &OutlineStats);
/* limit scale factor to avoid overscaling small blobs (.,`'),
thin blobs (l1ift), and merged blobs */
*XScale = *YScale = BaselineScale = MF_SCALE_FACTOR;
*XScale *= OutlineStats.Ry;
*YScale *= OutlineStats.Rx;
if (*XScale < classify_min_norm_scale_x)
*XScale = classify_min_norm_scale_x;
if (*YScale < classify_min_norm_scale_y)
*YScale = classify_min_norm_scale_y;
if (*XScale > classify_max_norm_scale_x &&
*YScale <= classify_max_norm_scale_y)
*XScale = classify_max_norm_scale_x;
*XScale = classify_char_norm_range * BaselineScale / *XScale;
*YScale = classify_char_norm_range * BaselineScale / *YScale;
iterate(Outlines) {
Outline = (MFOUTLINE) first_node (Outlines);
CharNormalizeOutline (Outline,
OutlineStats.x, OutlineStats.y,
*XScale, *YScale);
}
break;
case baseline:
iterate(Outlines) {
Outline = (MFOUTLINE) first_node(Outlines);
NormalizeOutline(Outline, 0.0);
}
*XScale = *YScale = MF_SCALE_FACTOR;
break;
}
} /* NormalizeOutlines */
} // namespace tesseract
/*---------------------------------------------------------------------------*/
void SmearExtremities(MFOUTLINE Outline, FLOAT32 XScale, FLOAT32 YScale) {
/*
** Parameters:
** Outline outline whose extremities are to be smeared
** XScale factor used to normalize outline in x dir
** YScale factor used to normalize outline in y dir
** Globals: none
** Operation:
** This routine smears the extremities of the specified outline.
** It does this by adding a random number between
** -0.5 and 0.5 pixels (that is why X/YScale are needed) to
** the x and y position of the point. This is done so that
** the discrete nature of the original scanned image does not
** affect the statistical clustering used during training.
** Return: none
** Exceptions: none
** History: 1/11/90, DSJ, Created.
*/
MFEDGEPT *Current;
MFOUTLINE EdgePoint;
FLOAT32 MinXSmear;
FLOAT32 MaxXSmear;
FLOAT32 MinYSmear;
FLOAT32 MaxYSmear;
if (Outline != NIL_LIST) {
MinXSmear = -0.5 * XScale;
MaxXSmear = 0.5 * XScale;
MinYSmear = -0.5 * YScale;
MaxYSmear = 0.5 * YScale;
EdgePoint = Outline;
do {
Current = PointAt (EdgePoint);
if (Current->ExtremityMark) {
Current->Point.x +=
UniformRandomNumber(MinXSmear, MaxXSmear);
Current->Point.y +=
UniformRandomNumber(MinYSmear, MaxYSmear);
}
EdgePoint = NextPointAfter (EdgePoint);
}
while (EdgePoint != Outline);
}
} /* SmearExtremities */
/**----------------------------------------------------------------------------
Private Code
----------------------------------------------------------------------------**/
/*---------------------------------------------------------------------------*/
void ChangeDirection(MFOUTLINE Start, MFOUTLINE End, DIRECTION Direction) {
/*
** Parameters:
** Start, End defines segment of outline to be modified
** Direction new direction to assign to segment
** Globals: none
** Operation: 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.
** Return: none
** Exceptions: none
** History: Fri May 4 10:42:04 1990, DSJ, Created.
*/
MFOUTLINE Current;
for (Current = Start; Current != End; Current = NextPointAfter (Current))
PointAt (Current)->Direction = Direction;
PointAt (End)->PreviousDirection = Direction;
} /* ChangeDirection */
/*---------------------------------------------------------------------------*/
void CharNormalizeOutline(MFOUTLINE Outline,
FLOAT32 XCenter,
FLOAT32 YCenter,
FLOAT32 XScale,
FLOAT32 YScale) {
/*
** Parameters:
** Outline outline to be character normalized
** XCenter, YCenter center point for normalization
** XScale, YScale scale factors for normalization
** Globals: none
** Operation: This routine normalizes each point in Outline by
** translating it to the specified center and scaling it
** anisotropically according to the given scale factors.
** Return: none
** Exceptions: none
** History: Fri Dec 14 10:27:11 1990, DSJ, Created.
*/
MFOUTLINE First, Current;
MFEDGEPT *CurrentPoint;
if (Outline == NIL_LIST)
return;
First = Outline;
Current = First;
do {
CurrentPoint = PointAt (Current);
CurrentPoint->Point.x =
(CurrentPoint->Point.x - XCenter) * XScale;
CurrentPoint->Point.y =
(CurrentPoint->Point.y - YCenter) * YScale;
Current = NextPointAfter (Current);
}
while (Current != First);
} /* CharNormalizeOutline */
/*---------------------------------------------------------------------------*/
void ComputeDirection(MFEDGEPT *Start,
MFEDGEPT *Finish,
FLOAT32 MinSlope,
FLOAT32 MaxSlope) {
/*
** Parameters:
** Start starting point to compute direction from
** Finish finishing point to compute direction to
** MinSlope slope below which lines are horizontal
** MaxSlope slope above which lines are vertical
** Globals: none
** Operation:
** 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.
** Return: none
** Exceptions: none
** History: 7/25/89, DSJ, Created.
*/
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;
} /* ComputeDirection */
/*---------------------------------------------------------------------------*/
void FinishOutlineStats(register OUTLINE_STATS *OutlineStats) {
/*
** Parameters:
** OutlineStats statistics about a set of outlines
** Globals: none
** Operation: Use the preliminary statistics accumulated in OutlineStats
** to compute the final statistics.
** (see Dan Johnson's Tesseract lab
** notebook #2, pgs. 74-78).
** Return: none
** Exceptions: none
** History: Fri Dec 14 10:13:36 1990, DSJ, Created.
*/
OutlineStats->x = 0.5 * OutlineStats->My / OutlineStats->L;
OutlineStats->y = 0.5 * OutlineStats->Mx / OutlineStats->L;
OutlineStats->Ix = (OutlineStats->Ix / 3.0 -
OutlineStats->y * OutlineStats->Mx +
OutlineStats->y * OutlineStats->y * OutlineStats->L);
OutlineStats->Iy = (OutlineStats->Iy / 3.0 -
OutlineStats->x * OutlineStats->My +
OutlineStats->x * OutlineStats->x * OutlineStats->L);
/* Ix and/or Iy could possibly be negative due to roundoff error */
if (OutlineStats->Ix < 0.0)
OutlineStats->Ix = MIN_INERTIA;
if (OutlineStats->Iy < 0.0)
OutlineStats->Iy = MIN_INERTIA;
OutlineStats->Rx = sqrt (OutlineStats->Ix / OutlineStats->L);
OutlineStats->Ry = sqrt (OutlineStats->Iy / OutlineStats->L);
OutlineStats->Mx *= 0.5;
OutlineStats->My *= 0.5;
} /* FinishOutlineStats */
/*---------------------------------------------------------------------------*/
void InitOutlineStats(OUTLINE_STATS *OutlineStats) {
/*
** Parameters:
** OutlineStats stats data structure to be initialized
** Globals: none
** Operation: Initialize the outline statistics data structure so
** that it is ready to start accumulating statistics.
** Return: none
** Exceptions: none
** History: Fri Dec 14 08:55:22 1990, DSJ, Created.
*/
OutlineStats->Mx = 0.0;
OutlineStats->My = 0.0;
OutlineStats->L = 0.0;
OutlineStats->x = 0.0;
OutlineStats->y = 0.0;
OutlineStats->Ix = 0.0;
OutlineStats->Iy = 0.0;
OutlineStats->Rx = 0.0;
OutlineStats->Ry = 0.0;
} /* InitOutlineStats */
/*---------------------------------------------------------------------------*/
MFOUTLINE NextDirectionChange(MFOUTLINE EdgePoint) {
/*
** Parameters:
** EdgePoint start search from this point
** Globals: none
** Operation:
** 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).
** Return: Point of next direction change in micro-feature outline.
** Exceptions: none
** History: 7/25/89, DSJ, Created.
*/
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);
} /* NextDirectionChange */
/*---------------------------------------------------------------------------*/
void UpdateOutlineStats(register OUTLINE_STATS *OutlineStats,
register FLOAT32 x1,
register FLOAT32 x2,
register FLOAT32 y1,
register FLOAT32 y2) {
/*
** Parameters:
** OutlineStats statistics to add this segment to
** x1, y1, x2, y2 segment to be added to statistics
** Globals: none
** Operation: This routine adds the statistics for the specified
** line segment to OutlineStats. The statistics that are
** kept are:
** sum of length of all segments
** sum of 2*Mx for all segments
** sum of 2*My for all segments
** sum of 2*Mx*(y1+y2) - L*y1*y2 for all segments
** sum of 2*My*(x1+x2) - L*x1*x2 for all segments
** These numbers, once collected can later be used to easily
** compute the center of mass, first and second moments,
** and radii of gyration. (see Dan Johnson's Tesseract lab
** notebook #2, pgs. 74-78).
** Return: none
** Exceptions: none
** History: Fri Dec 14 08:59:17 1990, DSJ, Created.
*/
register FLOAT64 L;
register FLOAT64 Mx2;
register FLOAT64 My2;
/* compute length of segment */
L = sqrt ((x2 - x1) * (x2 - x1) + (y2 - y1) * (y2 - y1));
OutlineStats->L += L;
/* compute 2Mx and 2My components */
Mx2 = L * (y1 + y2);
My2 = L * (x1 + x2);
OutlineStats->Mx += Mx2;
OutlineStats->My += My2;
/* compute second moment component */
OutlineStats->Ix += Mx2 * (y1 + y2) - L * y1 * y2;
OutlineStats->Iy += My2 * (x1 + x2) - L * x1 * x2;
} /* UpdateOutlineStats */
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