112 lines
5 KiB
C
112 lines
5 KiB
C
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/*
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* Copyright (c) 2011, Tom Distler (http://tdistler.com)
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* All rights reserved.
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*
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* The BSD License
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* - Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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*
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* - Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* - Neither the name of the tdistler.com nor the names of its contributors may
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* be used to endorse or promote products derived from this software without
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* specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#ifndef _CONVOLVE_H_
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#define _CONVOLVE_H_
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typedef float (*_iqa_get_pixel)(const float *img, int w, int h, int x, int y, float bnd_const);
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/** Out-of-bounds array values are a mirrored reflection of the border values*/
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float KBND_SYMMETRIC(const float *img, int w, int h, int x, int y, float bnd_const);
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/** Out-of-bounds array values are set to the nearest border value */
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float KBND_REPLICATE(const float *img, int w, int h, int x, int y, float bnd_const);
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/** Out-of-bounds array values are set to 'bnd_const' */
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float KBND_CONSTANT(const float *img, int w, int h, int x, int y, float bnd_const);
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/** Defines a convolution kernel */
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struct _kernel {
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float *kernel; /**< Pointer to the kernel values */
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int w; /**< The kernel width */
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int h; /**< The kernel height */
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int normalized; /**< 1 if the kernel values add up to 1. 0 otherwise */
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_iqa_get_pixel bnd_opt; /**< Defines how out-of-bounds image values are handled */
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float bnd_const; /**< If 'bnd_opt' is KBND_CONSTANT, this specifies the out-of-bounds value */
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};
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/**
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* @brief Applies the specified kernel to the image.
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* The kernel will be applied to all areas where it fits completely within
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* the image. The resulting image will be smaller by half the kernel width
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* and height (w - kw/2 and h - kh/2).
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*
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* @param img Image to modify
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* @param w Image width
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* @param h Image height
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* @param k The kernel to apply
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* @param result Buffer to hold the resulting image ((w-kw)*(h-kh), where kw
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* and kh are the kernel width and height). If 0, the result
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* will be written to the original image buffer.
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* @param rw Optional. The width of the resulting image will be stored here.
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* @param rh Optional. The height of the resulting image will be stored here.
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*/
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void _iqa_convolve(float *img, int w, int h, const struct _kernel *k, float *result, int *rw, int *rh);
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/**
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* The same as _iqa_convolve() except the kernel is applied to the entire image.
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* In other words, the kernel is applied to all areas where the top-left corner
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* of the kernel is in the image. Out-of-bound pixel value (off the right and
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* bottom edges) are chosen based on the 'bnd_opt' and 'bnd_const' members of
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* the kernel structure. The resulting array is the same size as the input
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* image.
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*
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* @param img Image to modify
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* @param w Image width
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* @param h Image height
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* @param k The kernel to apply
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* @param result Buffer to hold the resulting image ((w-kw)*(h-kh), where kw
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* and kh are the kernel width and height). If 0, the result
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* will be written to the original image buffer.
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* @return 0 if successful. Non-zero otherwise.
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*/
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int _iqa_img_filter(float *img, int w, int h, const struct _kernel *k, float *result);
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/**
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* Returns the filtered version of the specified pixel. If no kernel is given,
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* the raw pixel value is returned.
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*
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* @param img Source image
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* @param w Image width
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* @param h Image height
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* @param x The x location of the pixel to filter
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* @param y The y location of the pixel to filter
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* @param k Optional. The convolution kernel to apply to the pixel.
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* @param kscale The scale of the kernel (for normalization). 1 for normalized
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* kernels. Required if 'k' is not null.
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* @return The filtered pixel value.
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*/
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float _iqa_filter_pixel(const float *img, int w, int h, int x, int y, const struct _kernel *k, const float kscale);
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#endif /*_CONVOLVE_H_*/
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