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intfeaturespace.cpp
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1 // Copyright 2010 Google Inc. All Rights Reserved.
2 // Author: rays@google.com (Ray Smith)
4 // File: intfeaturespace.cpp
5 // Description: Indexed feature space based on INT_FEATURE_STRUCT.
6 // Created: Wed Mar 24 11:21:27 PDT 2010
7 //
8 // Licensed under the Apache License, Version 2.0 (the "License");
9 // you may not use this file except in compliance with the License.
10 // You may obtain a copy of the License at
11 // http://www.apache.org/licenses/LICENSE-2.0
12 // Unless required by applicable law or agreed to in writing, software
13 // distributed under the License is distributed on an "AS IS" BASIS,
14 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15 // See the License for the specific language governing permissions and
16 // limitations under the License.
17 //
19
20 #include "intfeaturespace.h"
21 #include "intfx.h"
22
23 namespace tesseract {
24
25 IntFeatureSpace::IntFeatureSpace()
26 : x_buckets_(0), y_buckets_(0), theta_buckets_(0) {
27 }
28
29 void IntFeatureSpace::Init(uinT8 xbuckets, uinT8 ybuckets, uinT8 thetabuckets) {
30 x_buckets_ = xbuckets;
31 y_buckets_ = ybuckets;
32 theta_buckets_ = thetabuckets;
33 }
34
35 // Serializes the feature space definition to the given file.
36 // Returns false on error.
37 bool IntFeatureSpace::Serialize(FILE* fp) const {
38 if (fwrite(&x_buckets_, sizeof(x_buckets_), 1, fp) != 1)
39 return false;
40 if (fwrite(&y_buckets_, sizeof(y_buckets_), 1, fp) != 1)
41 return false;
42 if (fwrite(&theta_buckets_, sizeof(theta_buckets_), 1, fp) != 1)
43 return false;
44 return true;
45 }
46
47 // DeSerializes the feature space definition from the given file.
48 // If swap is true, the data is big/little-endian swapped.
49 // Returns false on error.
50 bool IntFeatureSpace::DeSerialize(bool swap, FILE* fp) {
51 if (fread(&x_buckets_, sizeof(x_buckets_), 1, fp) != 1)
52 return false;
53 if (fread(&y_buckets_, sizeof(y_buckets_), 1, fp) != 1)
54 return false;
55 if (fread(&theta_buckets_, sizeof(theta_buckets_), 1, fp) != 1)
56 return false;
57 return true;
58 }
59
60 // Returns an INT_FEATURE_STRUCT corresponding to the given index.
61 // This is the inverse of the Index member.
62 INT_FEATURE_STRUCT IntFeatureSpace::PositionFromIndex(int index) const {
63 return PositionFromBuckets(index / (y_buckets_ * theta_buckets_),
64 index / theta_buckets_ % y_buckets_,
65 index % theta_buckets_);
66 }
67
68 // Bulk calls to Index. Maps the given array of features to a vector of
69 // inT32 indices in the same order as the input.
70 void IntFeatureSpace::IndexFeatures(const INT_FEATURE_STRUCT* features,
71 int num_features,
72 GenericVector<int>* mapped_features) const {
73 mapped_features->truncate(0);
74 for (int f = 0; f < num_features; ++f)
75 mapped_features->push_back(Index(features[f]));
76 }
77
78 // Bulk calls to Index. Maps the given array of features to a vector of
79 // sorted inT32 indices.
80 void IntFeatureSpace::IndexAndSortFeatures(
81 const INT_FEATURE_STRUCT* features, int num_features,
82 GenericVector<int>* sorted_features) const {
83 sorted_features->truncate(0);
84 for (int f = 0; f < num_features; ++f)
85 sorted_features->push_back(Index(features[f]));
86 sorted_features->sort();
87 }
88
89 // Returns a feature space index for the given x,y position in a display
90 // window, or -1 if the feature is a miss.
91 int IntFeatureSpace::XYToFeatureIndex(int x, int y) const {
92 // Round the x,y position to a feature. Search for a valid theta.
93 INT_FEATURE_STRUCT feature = {static_cast< uinT8 >(x), static_cast<uinT8>(y),
94 0, 0};
95 int index = -1;
96 for (int theta = 0; theta <= MAX_UINT8 && index < 0; ++theta) {
97 feature.Theta = theta;
98 index = Index(feature);
99 }
100 if (index < 0) {
101 tprintf("(%d,%d) does not exist in feature space!\n", x, y);
102 return -1;
103 }
104 feature = PositionFromIndex(index);
105 tprintf("Click at (%d, %d) ->(%d, %d), ->(%d, %d)\n",
106 x, y, feature.X, feature.Y, x - feature.X, y - feature.Y);
107 // Get the relative position of x,y from the rounded feature.
108 x -= feature.X;
109 y -= feature.Y;
110 if (x != 0 || y != 0) {
111 double angle = atan2(static_cast<double>(y), static_cast<double>(x)) + PI;
112 angle *= kIntFeatureExtent / (2.0 * PI);
113 feature.Theta = static_cast< uinT8 >(angle + 0.5);
114 index = Index(feature);
115 if (index < 0) {
116 tprintf("Feature failed to map to a valid index:");
117 feature.print();
118 return -1;
119 }
120 feature = PositionFromIndex(index);
121 }
122 feature.print();
123 return index;
124 }
125
126 // Returns an INT_FEATURE_STRUCT corresponding to the given bucket coords.
127 INT_FEATURE_STRUCT IntFeatureSpace::PositionFromBuckets(int x,
128 int y,
129 int theta) const {
130 INT_FEATURE_STRUCT pos = {
131 static_cast< uinT8 >(ClipToRange(
132 (x * kIntFeatureExtent + kIntFeatureExtent / 2) / x_buckets_,
133 0, MAX_UINT8)),
134 static_cast<uinT8>(ClipToRange(
135 (y * kIntFeatureExtent + kIntFeatureExtent / 2) / y_buckets_,
136 0, MAX_UINT8)),
137 static_cast<uinT8>(ClipToRange(
138 DivRounded(theta * kIntFeatureExtent, theta_buckets_),
139 0, MAX_UINT8))};
140 return pos;
141 }
142
143 } // namespace tesseract.