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Diffstat (limited to 'source/application/api/use_case/asr/include/Wav2LetterPostprocess.hpp')
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1 files changed, 109 insertions, 0 deletions
diff --git a/source/application/api/use_case/asr/include/Wav2LetterPostprocess.hpp b/source/application/api/use_case/asr/include/Wav2LetterPostprocess.hpp new file mode 100644 index 0000000..02738bc --- /dev/null +++ b/source/application/api/use_case/asr/include/Wav2LetterPostprocess.hpp @@ -0,0 +1,109 @@ +/* + * Copyright (c) 2021-2022 Arm Limited. All rights reserved. + * SPDX-License-Identifier: Apache-2.0 + * + * 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 ASR_WAV2LETTER_POSTPROCESS_HPP +#define ASR_WAV2LETTER_POSTPROCESS_HPP + +#include "TensorFlowLiteMicro.hpp" /* TensorFlow headers. */ +#include "BaseProcessing.hpp" +#include "Model.hpp" +#include "AsrClassifier.hpp" +#include "AsrResult.hpp" +#include "log_macros.h" + +namespace arm { +namespace app { + + /** + * @brief Helper class to manage tensor post-processing for "wav2letter" + * output. + */ + class AsrPostProcess : public BasePostProcess { + public: + bool m_lastIteration = false; /* Flag to set if processing the last set of data for a clip. */ + + /** + * @brief Constructor + * @param[in] outputTensor Pointer to the TFLite Micro output Tensor. + * @param[in] classifier Object used to get top N results from classification. + * @param[in] labels Vector of string labels to identify each output of the model. + * @param[in/out] result Vector of classification results to store decoded outputs. + * @param[in] outputContextLen Left/right context length for output tensor. + * @param[in] blankTokenIdx Index in the labels that the "Blank token" takes. + * @param[in] reductionAxis The axis that the logits of each time step is on. + **/ + AsrPostProcess(TfLiteTensor* outputTensor, AsrClassifier& classifier, + const std::vector<std::string>& labels, asr::ResultVec& result, + uint32_t outputContextLen, + uint32_t blankTokenIdx, uint32_t reductionAxis); + + /** + * @brief Should perform post-processing of the result of inference then + * populate ASR result data for any later use. + * @return true if successful, false otherwise. + **/ + bool DoPostProcess() override; + + /** @brief Gets the output inner length for post-processing. */ + static uint32_t GetOutputInnerLen(const TfLiteTensor*, uint32_t outputCtxLen); + + /** @brief Gets the output context length (left/right) for post-processing. */ + static uint32_t GetOutputContextLen(const Model& model, uint32_t inputCtxLen); + + /** @brief Gets the number of feature vectors to be computed. */ + static uint32_t GetNumFeatureVectors(const Model& model); + + private: + AsrClassifier& m_classifier; /* ASR Classifier object. */ + TfLiteTensor* m_outputTensor; /* Model output tensor. */ + const std::vector<std::string>& m_labels; /* ASR Labels. */ + asr::ResultVec & m_results; /* Results vector for a single inference. */ + uint32_t m_outputContextLen; /* lengths of left/right contexts for output. */ + uint32_t m_outputInnerLen; /* Length of output inner context. */ + uint32_t m_totalLen; /* Total length of the required axis. */ + uint32_t m_countIterations; /* Current number of iterations. */ + uint32_t m_blankTokenIdx; /* Index of the labels blank token. */ + uint32_t m_reductionAxisIdx; /* Axis containing output logits for a single step. */ + + /** + * @brief Checks if the tensor and axis index are valid + * inputs to the object - based on how it has been initialised. + * @return true if valid, false otherwise. + */ + bool IsInputValid(TfLiteTensor* tensor, + uint32_t axisIdx) const; + + /** + * @brief Gets the tensor data element size in bytes based + * on the tensor type. + * @return Size in bytes, 0 if not supported. + */ + static uint32_t GetTensorElementSize(TfLiteTensor* tensor); + + /** + * @brief Erases sections from the data assuming row-wise + * arrangement along the context axis. + * @return true if successful, false otherwise. + */ + bool EraseSectionsRowWise(uint8_t* ptrData, + uint32_t strideSzBytes, + bool lastIteration); + }; + +} /* namespace app */ +} /* namespace arm */ + +#endif /* ASR_WAV2LETTER_POSTPROCESS_HPP */
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