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https://github.com/tesseract-ocr/tesseract.git
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git-svn-id: https://tesseract-ocr.googlecode.com/svn/trunk@873 d0cd1f9f-072b-0410-8dd7-cf729c803f20
215 lines
8.5 KiB
C++
215 lines
8.5 KiB
C++
/******************************************************************************
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** Filename: mfx.c
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** Purpose: Micro feature extraction routines
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** Author: Dan Johnson
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** History: 7/21/89, DSJ, Created.
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**
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** (c) Copyright Hewlett-Packard Company, 1988.
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** Licensed under the Apache License, Version 2.0 (the "License");
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** you may not use this file except in compliance with the License.
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** You may obtain a copy of the License at
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** http://www.apache.org/licenses/LICENSE-2.0
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** Unless required by applicable law or agreed to in writing, software
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** distributed under the License is distributed on an "AS IS" BASIS,
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** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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** See the License for the specific language governing permissions and
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** limitations under the License.
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******************************************************************************/
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/**----------------------------------------------------------------------------
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Include Files and Type Defines
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----------------------------------------------------------------------------**/
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#include "mfdefs.h"
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#include "mfoutline.h"
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#include "clusttool.h" //NEEDED
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#include "const.h"
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#include "intfx.h"
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#include "normalis.h"
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#include "params.h"
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#include <math.h>
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/**----------------------------------------------------------------------------
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Variables
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----------------------------------------------------------------------------**/
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/* old numbers corresponded to 10.0 degrees and 80.0 degrees */
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double_VAR(classify_min_slope, 0.414213562,
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"Slope below which lines are called horizontal");
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double_VAR(classify_max_slope, 2.414213562,
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"Slope above which lines are called vertical");
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/**----------------------------------------------------------------------------
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Macros
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----------------------------------------------------------------------------**/
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/* miscellaneous macros */
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#define NormalizeAngle(A) ( (((A)<0)?((A)+2*PI):(A)) / (2*PI) )
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/*----------------------------------------------------------------------------
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Private Function Prototypes
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-----------------------------------------------------------------------------*/
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FLOAT32 ComputeOrientation(MFEDGEPT *Start, MFEDGEPT *End);
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MICROFEATURES ConvertToMicroFeatures(MFOUTLINE Outline,
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MICROFEATURES MicroFeatures);
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MICROFEATURE ExtractMicroFeature(MFOUTLINE Start, MFOUTLINE End);
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/**----------------------------------------------------------------------------
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Public Code
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----------------------------------------------------------------------------**/
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/*---------------------------------------------------------------------------*/
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CHAR_FEATURES BlobMicroFeatures(TBLOB *Blob, const DENORM& bl_denorm,
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const DENORM& cn_denorm,
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const INT_FX_RESULT_STRUCT& fx_info) {
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/*
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** Parameters:
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** Blob blob to extract micro-features from
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** denorm control parameter to feature extractor
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** Operation:
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** This routine extracts micro-features from the specified
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** blob and returns a list of the micro-features. All
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** micro-features are normalized according to the specified
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** line statistics.
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** Return: List of micro-features extracted from the blob.
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** Exceptions: none
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** History: 7/21/89, DSJ, Created.
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*/
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MICROFEATURES MicroFeatures = NIL_LIST;
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LIST Outlines;
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LIST RemainingOutlines;
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MFOUTLINE Outline;
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if (Blob != NULL) {
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Outlines = ConvertBlob(Blob);
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RemainingOutlines = Outlines;
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iterate(RemainingOutlines) {
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Outline = (MFOUTLINE) first_node (RemainingOutlines);
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CharNormalizeOutline(Outline, cn_denorm);
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}
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RemainingOutlines = Outlines;
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iterate(RemainingOutlines) {
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Outline = (MFOUTLINE) first_node(RemainingOutlines);
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FindDirectionChanges(Outline, classify_min_slope, classify_max_slope);
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MarkDirectionChanges(Outline);
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MicroFeatures = ConvertToMicroFeatures(Outline, MicroFeatures);
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}
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FreeOutlines(Outlines);
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}
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return ((CHAR_FEATURES) MicroFeatures);
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} /* BlobMicroFeatures */
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/*---------------------------------------------------------------------------
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Private Code
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---------------------------------------------------------------------------*/
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/*---------------------------------------------------------------------------*/
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FLOAT32 ComputeOrientation(MFEDGEPT *Start, MFEDGEPT *End) {
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/*
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** Parameters:
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** Start starting edge point of micro-feature
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** End ending edge point of micro-feature
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** Globals: none
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** Operation:
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** This routine computes the orientation parameter of the
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** specified micro-feature. The orientation is the angle of
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** the vector from Start to End. It is normalized to a number
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** between 0 and 1 where 0 corresponds to 0 degrees and 1
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** corresponds to 360 degrees. The actual range is [0,1), i.e.
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** 1 is excluded from the range (since it is actual the
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** same orientation as 0). This routine assumes that Start
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** and End are not the same point.
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** Return: Orientation parameter for the specified micro-feature.
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** Exceptions: none
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** History: 7/27/89, DSJ, Created.
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*/
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FLOAT32 Orientation;
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Orientation = NormalizeAngle (AngleFrom (Start->Point, End->Point));
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/* ensure that round-off errors do not put circular param out of range */
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if ((Orientation < 0) || (Orientation >= 1))
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Orientation = 0;
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return (Orientation);
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} /* ComputeOrientation */
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/*---------------------------------------------------------------------------*/
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MICROFEATURES ConvertToMicroFeatures(MFOUTLINE Outline,
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MICROFEATURES MicroFeatures) {
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/*
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** Parameters:
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** Outline outline to extract micro-features from
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** MicroFeatures list of micro-features to add to
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** Globals: none
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** Operation:
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** This routine
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** Return: List of micro-features with new features added to front.
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** Exceptions: none
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** History: 7/26/89, DSJ, Created.
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*/
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MFOUTLINE Current;
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MFOUTLINE Last;
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MFOUTLINE First;
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MICROFEATURE NewFeature;
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if (DegenerateOutline (Outline))
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return (MicroFeatures);
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First = NextExtremity (Outline);
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Last = First;
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do {
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Current = NextExtremity (Last);
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if (!PointAt(Current)->Hidden) {
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NewFeature = ExtractMicroFeature (Last, Current);
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if (NewFeature != NULL)
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MicroFeatures = push (MicroFeatures, NewFeature);
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}
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Last = Current;
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}
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while (Last != First);
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return (MicroFeatures);
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} /* ConvertToMicroFeatures */
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/*---------------------------------------------------------------------------*/
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MICROFEATURE ExtractMicroFeature(MFOUTLINE Start, MFOUTLINE End) {
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/*
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** Parameters:
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** Start starting point of micro-feature
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** End ending point of micro-feature
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** Globals: none
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** Operation:
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** This routine computes the feature parameters which describe
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** the micro-feature that starts and Start and ends at End.
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** A new micro-feature is allocated, filled with the feature
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** parameters, and returned. The routine assumes that
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** Start and End are not the same point. If they are the
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** same point, NULL is returned, a warning message is
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** printed, and the current outline is dumped to stdout.
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** Return: New micro-feature or NULL if the feature was rejected.
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** Exceptions: none
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** History: 7/26/89, DSJ, Created.
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** 11/17/89, DSJ, Added handling for Start and End same point.
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*/
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MICROFEATURE NewFeature;
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MFEDGEPT *P1, *P2;
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P1 = PointAt(Start);
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P2 = PointAt(End);
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NewFeature = NewMicroFeature ();
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NewFeature[XPOSITION] = AverageOf(P1->Point.x, P2->Point.x);
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NewFeature[YPOSITION] = AverageOf(P1->Point.y, P2->Point.y);
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NewFeature[MFLENGTH] = DistanceBetween(P1->Point, P2->Point);
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NewFeature[ORIENTATION] = NormalizedAngleFrom(&P1->Point, &P2->Point, 1.0);
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NewFeature[FIRSTBULGE] = 0.0f; // deprecated
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NewFeature[SECONDBULGE] = 0.0f; // deprecated
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return NewFeature;
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} /* ExtractMicroFeature */
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