diff options
Diffstat (limited to 'third_party/aom/aom_dsp/noise_model.h')
| -rw-r--r-- | third_party/aom/aom_dsp/noise_model.h | 286 |
1 files changed, 286 insertions, 0 deletions
diff --git a/third_party/aom/aom_dsp/noise_model.h b/third_party/aom/aom_dsp/noise_model.h new file mode 100644 index 000000000..dabeacc14 --- /dev/null +++ b/third_party/aom/aom_dsp/noise_model.h @@ -0,0 +1,286 @@ +/* + * Copyright (c) 2017, Alliance for Open Media. All rights reserved + * + * This source code is subject to the terms of the BSD 2 Clause License and + * the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License + * was not distributed with this source code in the LICENSE file, you can + * obtain it at www.aomedia.org/license/software. 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 www.aomedia.org/license/patent. + */ + +#ifndef AOM_DSP_NOISE_MODEL_H_ +#define AOM_DSP_NOISE_MODEL_H_ + +#ifdef __cplusplus +extern "C" { +#endif // __cplusplus + +#include <stdint.h> +#include "aom_dsp/grain_synthesis.h" + +/*!\brief Wrapper of data required to represent linear system of eqns and soln. + */ +typedef struct { + double *A; + double *b; + double *x; + int n; +} aom_equation_system_t; + +/*!\brief Representation of a piecewise linear curve + * + * Holds n points as (x, y) pairs, that store the curve. + */ +typedef struct { + double (*points)[2]; + int num_points; +} aom_noise_strength_lut_t; + +/*!\brief Init the noise strength lut with the given number of points*/ +int aom_noise_strength_lut_init(aom_noise_strength_lut_t *lut, int num_points); + +/*!\brief Frees the noise strength lut. */ +void aom_noise_strength_lut_free(aom_noise_strength_lut_t *lut); + +/*!\brief Evaluate the lut at the point x. + * + * \param[in] lut The lut data. + * \param[in] x The coordinate to evaluate the lut. + */ +double aom_noise_strength_lut_eval(const aom_noise_strength_lut_t *lut, + double x); + +/*!\brief Helper struct to model noise strength as a function of intensity. + * + * Internally, this structure holds a representation of a linear system + * of equations that models noise strength (standard deviation) as a + * function of intensity. The mapping is initially stored using a + * piecewise representation with evenly spaced bins that cover the entire + * domain from [min_intensity, max_intensity]. Each observation (x,y) gives a + * constraint of the form: + * y_{i} (1 - a) + y_{i+1} a = y + * where y_{i} is the value of bin i and x_{i} <= x <= x_{i+1} and + * a = x/(x_{i+1} - x{i}). The equation system holds the corresponding + * normal equations. + * + * As there may be missing data, the solution is regularized to get a + * complete set of values for the bins. A reduced representation after + * solving can be obtained by getting the corresponding noise_strength_lut_t. + */ +typedef struct { + aom_equation_system_t eqns; + double min_intensity; + double max_intensity; + int num_bins; + int num_equations; + double total; +} aom_noise_strength_solver_t; + +/*!\brief Initializes the noise solver with the given number of bins. + * + * Returns 0 if initialization fails. + * + * \param[in] solver The noise solver to be initialized. + * \param[in] num_bins Number of bins to use in the internal representation. + * \param[in] bit_depth The bit depth used to derive {min,max}_intensity. + */ +int aom_noise_strength_solver_init(aom_noise_strength_solver_t *solver, + int num_bins, int bit_depth); +void aom_noise_strength_solver_free(aom_noise_strength_solver_t *solver); + +/*!\brief Gets the x coordinate of bin i. + * + * \param[in] i The bin whose coordinate to query. + */ +double aom_noise_strength_solver_get_center( + const aom_noise_strength_solver_t *solver, int i); + +/*!\brief Add an observation of the block mean intensity to its noise strength. + * + * \param[in] block_mean The average block intensity, + * \param[in] noise_std The observed noise strength. + */ +void aom_noise_strength_solver_add_measurement( + aom_noise_strength_solver_t *solver, double block_mean, double noise_std); + +/*!\brief Solves the current set of equations for the noise strength. */ +int aom_noise_strength_solver_solve(aom_noise_strength_solver_t *solver); + +/*!\brief Fits a reduced piecewise linear lut to the internal solution + * + * \param[in] max_num_points The maximum number of output points + * \param[out] lut The output piecewise linear lut. + */ +int aom_noise_strength_solver_fit_piecewise( + const aom_noise_strength_solver_t *solver, int max_num_points, + aom_noise_strength_lut_t *lut); + +/*!\brief Helper for holding precomputed data for finding flat blocks. + * + * Internally a block is modeled with a low-order polynomial model. A + * planar model would be a bunch of equations like: + * <[y_i x_i 1], [a_1, a_2, a_3]> = b_i + * for each point in the block. The system matrix A with row i as [y_i x_i 1] + * is maintained as is the inverse, inv(A'*A), so that the plane parameters + * can be fit for each block. + */ +typedef struct { + double *AtA_inv; + double *A; + int num_params; // The number of parameters used for internal low-order model + int block_size; // The block size the finder was initialized with + double normalization; // Normalization factor (1 / (2^(bit_depth) - 1)) + int use_highbd; // Whether input data should be interpreted as uint16 +} aom_flat_block_finder_t; + +/*!\brief Init the block_finder with the given block size, bit_depth */ +int aom_flat_block_finder_init(aom_flat_block_finder_t *block_finder, + int block_size, int bit_depth, int use_highbd); +void aom_flat_block_finder_free(aom_flat_block_finder_t *block_finder); + +/*!\brief Helper to extract a block and low order "planar" model. */ +void aom_flat_block_finder_extract_block( + const aom_flat_block_finder_t *block_finder, const uint8_t *const data, + int w, int h, int stride, int offsx, int offsy, double *plane, + double *block); + +/*!\brief Runs the flat block finder on the input data. + * + * Find flat blocks in the input image data. Returns a map of + * flat_blocks, where the value of flat_blocks map will be non-zero + * when a block is determined to be flat. A higher value indicates a bigger + * confidence in the decision. + */ +int aom_flat_block_finder_run(const aom_flat_block_finder_t *block_finder, + const uint8_t *const data, int w, int h, + int stride, uint8_t *flat_blocks); + +// The noise shape indicates the allowed coefficients in the AR model. +typedef enum { + AOM_NOISE_SHAPE_DIAMOND = 0, + AOM_NOISE_SHAPE_SQUARE = 1 +} aom_noise_shape; + +// The parameters of the noise model include the shape type, lag, the +// bit depth of the input images provided, and whether the input images +// will be using uint16 (or uint8) representation. +typedef struct { + aom_noise_shape shape; + int lag; + int bit_depth; + int use_highbd; +} aom_noise_model_params_t; + +/*!\brief State of a noise model estimate for a single channel. + * + * This contains a system of equations that can be used to solve + * for the auto-regressive coefficients as well as a noise strength + * solver that can be used to model noise strength as a function of + * intensity. + */ +typedef struct { + aom_equation_system_t eqns; + aom_noise_strength_solver_t strength_solver; + int num_observations; // The number of observations in the eqn system + double ar_gain; // The gain of the current AR filter +} aom_noise_state_t; + +/*!\brief Complete model of noise for a planar video + * + * This includes a noise model for the latest frame and an aggregated + * estimate over all previous frames that had similar parameters. + */ +typedef struct { + aom_noise_model_params_t params; + aom_noise_state_t combined_state[3]; // Combined state per channel + aom_noise_state_t latest_state[3]; // Latest state per channel + int (*coords)[2]; // Offsets (x,y) of the coefficient samples + int n; // Number of parameters (size of coords) + int bit_depth; +} aom_noise_model_t; + +/*!\brief Result of a noise model update. */ +typedef enum { + AOM_NOISE_STATUS_OK = 0, + AOM_NOISE_STATUS_INVALID_ARGUMENT, + AOM_NOISE_STATUS_INSUFFICIENT_FLAT_BLOCKS, + AOM_NOISE_STATUS_DIFFERENT_NOISE_TYPE, + AOM_NOISE_STATUS_INTERNAL_ERROR, +} aom_noise_status_t; + +/*!\brief Initializes a noise model with the given parameters. + * + * Returns 0 on failure. + */ +int aom_noise_model_init(aom_noise_model_t *model, + const aom_noise_model_params_t params); +void aom_noise_model_free(aom_noise_model_t *model); + +/*!\brief Updates the noise model with a new frame observation. + * + * Updates the noise model with measurements from the given input frame and a + * denoised variant of it. Noise is sampled from flat blocks using the flat + * block map. + * + * Returns a noise_status indicating if the update was successful. If the + * Update was successful, the combined_state is updated with measurements from + * the provided frame. If status is OK or DIFFERENT_NOISE_TYPE, the latest noise + * state will be updated with measurements from the provided frame. + * + * \param[in,out] noise_model The noise model to be updated + * \param[in] data Raw frame data + * \param[in] denoised Denoised frame data. + * \param[in] w Frame width + * \param[in] h Frame height + * \param[in] strides Stride of the planes + * \param[in] chroma_sub_log2 Chroma subsampling for planes != 0. + * \param[in] flat_blocks A map to blocks that have been determined flat + * \param[in] block_size The size of blocks. + */ +aom_noise_status_t aom_noise_model_update( + aom_noise_model_t *const noise_model, const uint8_t *const data[3], + const uint8_t *const denoised[3], int w, int h, int strides[3], + int chroma_sub_log2[2], const uint8_t *const flat_blocks, int block_size); + +/*\brief Save the "latest" estimate into the "combined" estimate. + * + * This is meant to be called when the noise modeling detected a change + * in parameters (or for example, if a user wanted to reset estimation at + * a shot boundary). + */ +void aom_noise_model_save_latest(aom_noise_model_t *noise_model); + +/*!\brief Converts the noise_model parameters to the corresponding + * grain_parameters. + * + * The noise structs in this file are suitable for estimation (e.g., using + * floats), but the grain parameters in the bitstream are quantized. This + * function does the conversion by selecting the correct quantization levels. + */ +int aom_noise_model_get_grain_parameters(aom_noise_model_t *const noise_model, + aom_film_grain_t *film_grain); + +/*!\brief Perform a Wiener filter denoising in 2D using the provided noise psd. + * + * \param[in] data Raw frame data + * \param[out] denoised Denoised frame data + * \param[in] w Frame width + * \param[in] h Frame height + * \param[in] stride Stride of the planes + * \param[in] chroma_sub_log2 Chroma subsampling for planes != 0. + * \param[in] noise_psd The power spectral density of the noise + * \param[in] block_size The size of blocks + * \param[in] bit_depth Bit depth of the image + * \param[in] use_highbd If true, uint8 pointers are interpreted as + * uint16 and stride is measured in uint16. + * This must be true when bit_depth >= 10. + */ +int aom_wiener_denoise_2d(const uint8_t *const data[3], uint8_t *denoised[3], + int w, int h, int stride[3], int chroma_sub_log2[2], + float *noise_psd[3], int block_size, int bit_depth, + int use_highbd); +#ifdef __cplusplus +} // extern "C" +#endif // __cplusplus +#endif // AOM_DSP_NOISE_MODEL_H_ |