Opensource ML embedded evaluation kit21.03

Change-Id: I12e807f19f5cacad7cef82572b6dd48252fd61fd

1 files changed, 101 insertions, 0 deletions

diff --git a/source/use_case/kws_asr/include/Wav2LetterPostprocess.hpp b/source/use_case/kws_asr/include/Wav2LetterPostprocess.hpp
new file mode 100644
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+++ b/source/use_case/kws_asr/include/Wav2LetterPostprocess.hpp
@@ -0,0 +1,101 @@
+/*
+ * Copyright (c) 2021 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 KWS_ASR_WAV2LET_POSTPROC_HPP
+#define KWS_ASR_WAV2LET_POSTPROC_HPP
+
+#include "TensorFlowLiteMicro.hpp" /* TensorFlow headers */
+#include "hal.h"    /* stdout facility */
+
+namespace arm {
+namespace app {
+namespace audio {
+namespace asr {
+
+    /**
+     * @brief   Helper class to manage tensor post-processing for "wav2letter"
+     *          output.
+     */
+    class Postprocess {
+    public:
+        /**
+         * @brief       Constructor
+         * @param[in]   contextLen   Left and right context length for
+         *                           output tensor.
+         * @param[in]   innerLen     This is the length of the section
+         *                           between left and right context.
+         **/
+        Postprocess(uint32_t contextLen,
+                    uint32_t innerLen,
+                    uint32_t blankTokenIdx);
+
+        Postprocess() = delete;
+        ~Postprocess() = default;
+
+        /**
+         * @brief       Erases the required part of the tensor based
+         *              on context lengths set up during initialisation
+         * @param[in]   tensor          Pointer to the tensor
+         * @param[in]   axisIdx         Index of the axis on which erase is
+         *                              performed.
+         * @param[in]   lastIteration   Flag to signal is this is the
+         *                              last iteration in which case
+         *                              the right context is preserved.
+         * @return      true if successful, false otherwise.
+         */
+        bool Invoke(TfLiteTensor*  tensor,
+                    uint32_t axisIdx,
+                    bool lastIteration = false);
+
+    private:
+        uint32_t    _m_contextLen;      /* Lengths of left and right contexts. */
+        uint32_t    _m_innerLen;        /* Length of 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. */
+        /**
+         * @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.
+         */
+        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 asr */
+} /* namespace audio */
+} /* namespace app */
+} /* namespace arm */
+
+#endif /* KWS_ASR_WAV2LET_POSTPROC_HPP */
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