params_model.h

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// File:        params_model.h
// Description: Trained feature serialization for language parameter training.
// Author:      David Eger
//
// (C) Copyright 2011, Google Inc.
// 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.
//
 
#ifndef TESSERACT_WORDREC_PARAMS_MODEL_H_
#define TESSERACT_WORDREC_PARAMS_MODEL_H_
 
#include <tesseract/export.h>        // for TESS_API
#include "params_training_featdef.h" // for PTRAIN_NUM_FEATURE_TYPES
 
namespace tesseract {
 
class TFile;
 
// Represents the learned weights for a given language.
class TESS_API ParamsModel {
public:
  // Enum for expressing OCR pass.
  enum PassEnum {
    PTRAIN_PASS1,
    PTRAIN_PASS2,
 
    PTRAIN_NUM_PASSES
  };
 
  ParamsModel() : pass_(PTRAIN_PASS1) {}
  ParamsModel(const char *lang, const std::vector<float> &weights)
      : lang_(lang), pass_(PTRAIN_PASS1) {
    weights_vec_[pass_] = weights;
  }
  inline bool Initialized() {
    return weights_vec_[pass_].size() == PTRAIN_NUM_FEATURE_TYPES;
  }
  // Prints out feature weights.
  void Print();
  // Clears weights for all passes.
  void Clear() {
    for (auto &p : weights_vec_) {
      p.clear();
    }
  }
  // Copies the weights of the given params model.
  void Copy(const ParamsModel &other_model);
  // Applies params model weights to the given features.
  // Assumes that features is an array of size PTRAIN_NUM_FEATURE_TYPES.
  float ComputeCost(const float features[]) const;
  bool Equivalent(const ParamsModel &that) const;
 
  // Returns true on success.
  bool SaveToFile(const char *full_path) const;
 
  // Returns true on success.
  bool LoadFromFp(const char *lang, TFile *fp);
 
  const std::vector<float> &weights() const {
    return weights_vec_[pass_];
  }
  const std::vector<float> &weights_for_pass(PassEnum pass) const {
    return weights_vec_[pass];
  }
  void SetPass(PassEnum pass) {
    pass_ = pass;
  }
 
private:
  bool ParseLine(char *line, char **key, float *val);
 
  std::string lang_;
  // Set to the current pass type and used to determine which set of weights
  // should be used for ComputeCost() and other functions.
  PassEnum pass_;
  // Several sets of weights for various OCR passes (e.g. pass1 with adaption,
  // pass2 without adaption, etc).
  std::vector<float> weights_vec_[PTRAIN_NUM_PASSES];
};
 
} // namespace tesseract
 
#endif // TESSERACT_WORDREC_PARAMS_MODEL_H_