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https://github.com/tesseract-ocr/tesseract.git
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53fc4456cc
Eliminated the flexfx scheme for calling global feature extractor functions through an array of function pointers. Deleted dead code I found as a by-product. This CL does not change BlobToTrainingSample or ExtractFeatures to be full members of Classify (the eventual goal) as that would make it even bigger, since there are a lot of callers to these functions. When ExtractFeatures and BlobToTrainingSample are members of Classify they will be able to access control parameters in Classify, which will greatly simplify developing variations to the feature extraction process.
213 lines
8.4 KiB
C++
213 lines
8.4 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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MICROFEATURES BlobMicroFeatures(TBLOB* Blob, const DENORM& cn_denorm) {
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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 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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