1 // Copyright 2010 Google Inc. All Rights Reserved. 2 // Author: rays@google.com (Ray Smith) 3 /////////////////////////////////////////////////////////////////////// 4 // File: intfeaturespace.h 5 // Description: Indexed feature space based on INT_FEATURE_STRUCT. 6 // 7 // Licensed under the Apache License, Version 2.0 (the "License"); 8 // you may not use this file except in compliance with the License. 9 // You may obtain a copy of the License at 10 // http://www.apache.org/licenses/LICENSE-2.0 11 // Unless required by applicable law or agreed to in writing, software 12 // distributed under the License is distributed on an "AS IS" BASIS, 13 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 // See the License for the specific language governing permissions and 15 // limitations under the License. 16 // 17 /////////////////////////////////////////////////////////////////////// 18 19 #ifndef TESSERACT_CLASSIFY_INTFEATURESPACE_H_ 20 #define TESSERACT_CLASSIFY_INTFEATURESPACE_H_ 21 22 #include "intproto.h" 23 24 // Extent of x,y,theta in the input feature space. [0,255]. 25 const int kIntFeatureExtent = 256; 26 // Extent of x,y,theta dimensions in the quantized feature space. 27 const int kBoostXYBuckets = 16; 28 const int kBoostDirBuckets = 16; 29 30 namespace tesseract { 31 32 class IndexMap; 33 34 // Down-sampling quantization of the INT_FEATURE_STRUCT feature space and 35 // conversion to a single scalar index value, used as a binary feature space. 36 class TESS_API IntFeatureSpace { 37 public: 38 IntFeatureSpace(); 39 // Default copy constructors and assignment OK! 40 41 // Setup the feature space with the given dimensions. 42 void Init(uint8_t xbuckets, uint8_t ybuckets, uint8_t thetabuckets); 43 44 // Serializes the feature space definition to the given file. 45 // Returns false on error. 46 bool Serialize(FILE *fp) const; 47 48 // Returns the total size of the feature space. Size()49 int Size() const { 50 return static_cast<int>(x_buckets_) * y_buckets_ * theta_buckets_; 51 } 52 // Returns an INT_FEATURE_STRUCT corresponding to the given index. 53 // This is the inverse of the Index member. 54 INT_FEATURE_STRUCT PositionFromIndex(int index) const; 55 56 // Returns a 1-dimensional index corresponding to the given feature value. 57 // Range is [0, Size()-1]. Inverse of PositionFromIndex member. Index(const INT_FEATURE_STRUCT & f)58 int Index(const INT_FEATURE_STRUCT &f) const { 59 return (XBucket(f.X) * y_buckets_ + YBucket(f.Y)) * theta_buckets_ + ThetaBucket(f.Theta); 60 } 61 // Bulk calls to Index. Maps the given array of features to a vector of 62 // int32_t indices in the same order as the input. 63 void IndexFeatures(const INT_FEATURE_STRUCT *features, int num_features, 64 std::vector<int> *mapped_features) const; 65 // Bulk calls to Index. Maps the given array of features to a vector of 66 // sorted int32_t indices. 67 void IndexAndSortFeatures(const INT_FEATURE_STRUCT *features, int num_features, 68 std::vector<int> *sorted_features) const; 69 // Returns a feature space index for the given x,y position in a display 70 // window, or -1 if the feature is a miss. 71 int XYToFeatureIndex(int x, int y) const; 72 73 protected: 74 // Converters to generate indices for individual feature dimensions. XBucket(int x)75 int XBucket(int x) const { 76 int bucket = x * x_buckets_ / kIntFeatureExtent; 77 return ClipToRange(bucket, 0, static_cast<int>(x_buckets_) - 1); 78 } YBucket(int y)79 int YBucket(int y) const { 80 int bucket = y * y_buckets_ / kIntFeatureExtent; 81 return ClipToRange(bucket, 0, static_cast<int>(y_buckets_) - 1); 82 } 83 // Use DivRounded for theta so that exactly vertical and horizontal are in 84 // the middle of a bucket. The Modulo takes care of the wrap-around. ThetaBucket(int theta)85 int ThetaBucket(int theta) const { 86 int bucket = DivRounded(theta * theta_buckets_, kIntFeatureExtent); 87 return Modulo(bucket, theta_buckets_); 88 } 89 // Returns an INT_FEATURE_STRUCT corresponding to the given buckets. 90 INT_FEATURE_STRUCT PositionFromBuckets(int x, int y, int theta) const; 91 92 // Feature space definition - serialized. 93 uint8_t x_buckets_; 94 uint8_t y_buckets_; 95 uint8_t theta_buckets_; 96 }; 97 98 } // namespace tesseract. 99 100 #endif // TESSERACT_CLASSIFY_INTFEATURESPACE_H_ 101