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/*
* Copyright (c) 2021, Alliance for Open Media. All rights reserved
*
* This source code is subject to the terms of the BSD 3-Clause Clear License
* and the Alliance for Open Media Patent License 1.0. If the BSD 3-Clause Clear
* License was not distributed with this source code in the LICENSE file, you
* can obtain it at aomedia.org/license/software-license/bsd-3-c-c/. If the
* Alliance for Open Media Patent License 1.0 was not distributed with this
* source code in the PATENTS file, you can obtain it at
* aomedia.org/license/patent-license/.
*/
#ifndef AOM_AOM_DSP_NOISE_UTIL_H_
#define AOM_AOM_DSP_NOISE_UTIL_H_
#ifdef __cplusplus
extern "C" {
#endif // __cplusplus
// aom_noise_tx_t is an abstraction of a transform that is used for denoising.
// It is meant to be lightweight and does hold the transformed data (as
// the user should not be manipulating the transformed data directly).
struct aom_noise_tx_t;
// Allocates and returns a aom_noise_tx_t useful for denoising the given
// block_size. The resulting aom_noise_tx_t should be free'd with
// aom_noise_tx_free.
struct aom_noise_tx_t *aom_noise_tx_malloc(int block_size);
void aom_noise_tx_free(struct aom_noise_tx_t *aom_noise_tx);
// Transforms the internal data and holds it in the aom_noise_tx's internal
// buffer. For compatibility with existing SIMD implementations, "data" must
// be 32-byte aligned.
void aom_noise_tx_forward(struct aom_noise_tx_t *aom_noise_tx,
const float *data);
// Filters aom_noise_tx's internal data using the provided noise power spectral
// density. The PSD must be at least block_size * block_size and should be
// populated with a constant or via estimates taken from
// aom_noise_tx_add_energy.
void aom_noise_tx_filter(struct aom_noise_tx_t *aom_noise_tx, const float *psd);
// Performs an inverse transform using the internal transform data.
// For compatibility with existing SIMD implementations, "data" must be 32-byte
// aligned.
void aom_noise_tx_inverse(struct aom_noise_tx_t *aom_noise_tx, float *data);
// Aggregates the power of the buffered transform data into the psd buffer.
void aom_noise_tx_add_energy(const struct aom_noise_tx_t *aom_noise_tx,
float *psd);
// Returns a default value suitable for denosing a transform of the given
// block_size. The noise "factor" determines the strength of the noise to
// be removed. A value of about 2.5 can be used for moderate denoising,
// where a value of 5.0 can be used for a high level of denoising.
float aom_noise_psd_get_default_value(int block_size, float factor);
// Computes normalized cross correlation of two vectors a and b of length n.
double aom_normalized_cross_correlation(const double *a, const double *b,
int n);
// Validates the correlated noise in the data buffer of size (w, h).
int aom_noise_data_validate(const double *data, int w, int h);
#ifdef __cplusplus
} // extern "C"
#endif // __cplusplus
#endif // AOM_AOM_DSP_NOISE_UTIL_H_