/****************************************************************************** ** Filename: mfx.c ** Purpose: Micro feature extraction routines ** Author: Dan Johnson ** History: 7/21/89, 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 "mfdefs.h" #include "mfoutline.h" #include "clusttool.h" //NEEDED #include "const.h" #include "intfx.h" #include "normalis.h" #include "params.h" #include /**---------------------------------------------------------------------------- Variables ----------------------------------------------------------------------------**/ /* old numbers corresponded to 10.0 degrees and 80.0 degrees */ double_VAR(classify_min_slope, 0.414213562, "Slope below which lines are called horizontal"); double_VAR(classify_max_slope, 2.414213562, "Slope above which lines are called vertical"); /**---------------------------------------------------------------------------- Macros ----------------------------------------------------------------------------**/ /* miscellaneous macros */ #define NormalizeAngle(A) ( (((A)<0)?((A)+2*PI):(A)) / (2*PI) ) /*---------------------------------------------------------------------------- Private Function Prototypes -----------------------------------------------------------------------------*/ FLOAT32 ComputeOrientation(MFEDGEPT *Start, MFEDGEPT *End); MICROFEATURES ConvertToMicroFeatures(MFOUTLINE Outline, MICROFEATURES MicroFeatures); MICROFEATURE ExtractMicroFeature(MFOUTLINE Start, MFOUTLINE End); /**---------------------------------------------------------------------------- Public Code ----------------------------------------------------------------------------**/ /*---------------------------------------------------------------------------*/ CHAR_FEATURES BlobMicroFeatures(TBLOB *Blob, const DENORM& denorm) { /* ** Parameters: ** Blob blob to extract micro-features from ** denorm control parameter to feature extractor ** Operation: ** This routine extracts micro-features from the specified ** blob and returns a list of the micro-features. All ** micro-features are normalized according to the specified ** line statistics. ** Return: List of micro-features extracted from the blob. ** Exceptions: none ** History: 7/21/89, DSJ, Created. */ MICROFEATURES MicroFeatures = NIL_LIST; FLOAT32 XScale, YScale; LIST Outlines; LIST RemainingOutlines; MFOUTLINE Outline; INT_FEATURE_ARRAY blfeatures; INT_FEATURE_ARRAY cnfeatures; INT_FX_RESULT_STRUCT results; if (Blob != NULL) { Outlines = ConvertBlob (Blob); if (!ExtractIntFeat(Blob, denorm, blfeatures, cnfeatures, &results)) return NULL; XScale = 0.2f / results.Ry; YScale = 0.2f / results.Rx; RemainingOutlines = Outlines; iterate(RemainingOutlines) { Outline = (MFOUTLINE) first_node (RemainingOutlines); CharNormalizeOutline (Outline, results.Xmean, results.Ymean, XScale, YScale); } RemainingOutlines = Outlines; iterate(RemainingOutlines) { Outline = (MFOUTLINE) first_node (RemainingOutlines); FindDirectionChanges(Outline, classify_min_slope, classify_max_slope); MarkDirectionChanges(Outline); MicroFeatures = ConvertToMicroFeatures (Outline, MicroFeatures); } FreeOutlines(Outlines); } return ((CHAR_FEATURES) MicroFeatures); } /* BlobMicroFeatures */ /*--------------------------------------------------------------------------- Private Code ---------------------------------------------------------------------------*/ /*---------------------------------------------------------------------------*/ FLOAT32 ComputeOrientation(MFEDGEPT *Start, MFEDGEPT *End) { /* ** Parameters: ** Start starting edge point of micro-feature ** End ending edge point of micro-feature ** Globals: none ** Operation: ** This routine computes the orientation parameter of the ** specified micro-feature. The orientation is the angle of ** the vector from Start to End. It is normalized to a number ** between 0 and 1 where 0 corresponds to 0 degrees and 1 ** corresponds to 360 degrees. The actual range is [0,1), i.e. ** 1 is excluded from the range (since it is actual the ** same orientation as 0). This routine assumes that Start ** and End are not the same point. ** Return: Orientation parameter for the specified micro-feature. ** Exceptions: none ** History: 7/27/89, DSJ, Created. */ FLOAT32 Orientation; Orientation = NormalizeAngle (AngleFrom (Start->Point, End->Point)); /* ensure that round-off errors do not put circular param out of range */ if ((Orientation < 0) || (Orientation >= 1)) Orientation = 0; return (Orientation); } /* ComputeOrientation */ /*---------------------------------------------------------------------------*/ MICROFEATURES ConvertToMicroFeatures(MFOUTLINE Outline, MICROFEATURES MicroFeatures) { /* ** Parameters: ** Outline outline to extract micro-features from ** MicroFeatures list of micro-features to add to ** Globals: none ** Operation: ** This routine ** Return: List of micro-features with new features added to front. ** Exceptions: none ** History: 7/26/89, DSJ, Created. */ MFOUTLINE Current; MFOUTLINE Last; MFOUTLINE First; MICROFEATURE NewFeature; if (DegenerateOutline (Outline)) return (MicroFeatures); First = NextExtremity (Outline); Last = First; do { Current = NextExtremity (Last); if (!PointAt(Current)->Hidden) { NewFeature = ExtractMicroFeature (Last, Current); if (NewFeature != NULL) MicroFeatures = push (MicroFeatures, NewFeature); } Last = Current; } while (Last != First); return (MicroFeatures); } /* ConvertToMicroFeatures */ /*---------------------------------------------------------------------------*/ MICROFEATURE ExtractMicroFeature(MFOUTLINE Start, MFOUTLINE End) { /* ** Parameters: ** Start starting point of micro-feature ** End ending point of micro-feature ** Globals: none ** Operation: ** This routine computes the feature parameters which describe ** the micro-feature that starts and Start and ends at End. ** A new micro-feature is allocated, filled with the feature ** parameters, and returned. The routine assumes that ** Start and End are not the same point. If they are the ** same point, NULL is returned, a warning message is ** printed, and the current outline is dumped to stdout. ** Return: New micro-feature or NULL if the feature was rejected. ** Exceptions: none ** History: 7/26/89, DSJ, Created. ** 11/17/89, DSJ, Added handling for Start and End same point. */ MICROFEATURE NewFeature; MFEDGEPT *P1, *P2; P1 = PointAt(Start); P2 = PointAt(End); NewFeature = NewMicroFeature (); NewFeature[XPOSITION] = AverageOf(P1->Point.x, P2->Point.x); NewFeature[YPOSITION] = AverageOf(P1->Point.y, P2->Point.y); NewFeature[MFLENGTH] = DistanceBetween(P1->Point, P2->Point); NewFeature[ORIENTATION] = NormalizedAngleFrom(&P1->Point, &P2->Point, 1.0); NewFeature[FIRSTBULGE] = 0.0f; // deprecated NewFeature[SECONDBULGE] = 0.0f; // deprecated return NewFeature; } /* ExtractMicroFeature */