117 lines
5.7 KiB
C
117 lines
5.7 KiB
C
/*
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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 _SSIM_H_
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#define _SSIM_H_
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#include "convolve.h"
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/*
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* Circular-symmetric Gaussian weighting.
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* h(x,y) = hg(x,y)/SUM(SUM(hg)) , for normalization to 1.0
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* hg(x,y) = e^( -0.5*( (x^2+y^2)/sigma^2 ) ) , where sigma was 1.5
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*/
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#define GAUSSIAN_LEN 11
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static const float g_gaussian_window[GAUSSIAN_LEN][GAUSSIAN_LEN] = {
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{0.000001f, 0.000008f, 0.000037f, 0.000112f, 0.000219f, 0.000274f, 0.000219f, 0.000112f, 0.000037f, 0.000008f, 0.000001f},
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{0.000008f, 0.000058f, 0.000274f, 0.000831f, 0.001619f, 0.002021f, 0.001619f, 0.000831f, 0.000274f, 0.000058f, 0.000008f},
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{0.000037f, 0.000274f, 0.001296f, 0.003937f, 0.007668f, 0.009577f, 0.007668f, 0.003937f, 0.001296f, 0.000274f, 0.000037f},
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{0.000112f, 0.000831f, 0.003937f, 0.011960f, 0.023294f, 0.029091f, 0.023294f, 0.011960f, 0.003937f, 0.000831f, 0.000112f},
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{0.000219f, 0.001619f, 0.007668f, 0.023294f, 0.045371f, 0.056662f, 0.045371f, 0.023294f, 0.007668f, 0.001619f, 0.000219f},
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{0.000274f, 0.002021f, 0.009577f, 0.029091f, 0.056662f, 0.070762f, 0.056662f, 0.029091f, 0.009577f, 0.002021f, 0.000274f},
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{0.000219f, 0.001619f, 0.007668f, 0.023294f, 0.045371f, 0.056662f, 0.045371f, 0.023294f, 0.007668f, 0.001619f, 0.000219f},
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{0.000112f, 0.000831f, 0.003937f, 0.011960f, 0.023294f, 0.029091f, 0.023294f, 0.011960f, 0.003937f, 0.000831f, 0.000112f},
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{0.000037f, 0.000274f, 0.001296f, 0.003937f, 0.007668f, 0.009577f, 0.007668f, 0.003937f, 0.001296f, 0.000274f, 0.000037f},
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{0.000008f, 0.000058f, 0.000274f, 0.000831f, 0.001619f, 0.002021f, 0.001619f, 0.000831f, 0.000274f, 0.000058f, 0.000008f},
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{0.000001f, 0.000008f, 0.000037f, 0.000112f, 0.000219f, 0.000274f, 0.000219f, 0.000112f, 0.000037f, 0.000008f, 0.000001f},
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};
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/*
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* Equal weight square window.
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* Each pixel is equally weighted (1/64) so that SUM(x) = 1.0
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*/
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#define SQUARE_LEN 8
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static const float g_square_window[SQUARE_LEN][SQUARE_LEN] = {
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{0.015625f, 0.015625f, 0.015625f, 0.015625f, 0.015625f, 0.015625f, 0.015625f, 0.015625f},
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{0.015625f, 0.015625f, 0.015625f, 0.015625f, 0.015625f, 0.015625f, 0.015625f, 0.015625f},
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{0.015625f, 0.015625f, 0.015625f, 0.015625f, 0.015625f, 0.015625f, 0.015625f, 0.015625f},
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{0.015625f, 0.015625f, 0.015625f, 0.015625f, 0.015625f, 0.015625f, 0.015625f, 0.015625f},
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{0.015625f, 0.015625f, 0.015625f, 0.015625f, 0.015625f, 0.015625f, 0.015625f, 0.015625f},
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{0.015625f, 0.015625f, 0.015625f, 0.015625f, 0.015625f, 0.015625f, 0.015625f, 0.015625f},
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{0.015625f, 0.015625f, 0.015625f, 0.015625f, 0.015625f, 0.015625f, 0.015625f, 0.015625f},
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{0.015625f, 0.015625f, 0.015625f, 0.015625f, 0.015625f, 0.015625f, 0.015625f, 0.015625f},
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};
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/* Holds intermediate SSIM values for map-reduce operation. */
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struct _ssim_int {
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double l;
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double c;
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double s;
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};
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/* Defines the pointers to the map-reduce functions. */
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typedef int (*_map)(const struct _ssim_int *, void *);
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typedef float (*_reduce)(int, int, void *);
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/* Arguments for map-reduce. The 'context' is user-defined. */
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struct _map_reduce {
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_map map;
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_reduce reduce;
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void *context;
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};
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/**
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* Private method that calculates the SSIM value on a pre-processed image.
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*
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* The input images must have stride==width. This method does not scale.
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*
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* @note Image buffers are modified.
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*
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* Map-reduce is used for doing the final SSIM calculation. The map function is
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* called for every pixel, and the reduce is called at the end. The context is
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* caller-defined and *not* modified by this method.
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*
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* @param ref Original reference image
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* @param cmp Distorted image
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* @param w Width of the images
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* @param h Height of the images
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* @param k The kernel used as the window function
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* @param mr Optional map-reduce functions to use to calculate SSIM. Required
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* if 'args' is not null. Ignored if 'args' is null.
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* @param args Optional SSIM arguments for fine control of the algorithm. 0 for defaults.
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* Defaults are a=b=g=1.0, L=255, K1=0.01, K2=0.03
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* @return The mean SSIM over the entire image (MSSIM), or INFINITY if error.
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*/
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float _iqa_ssim(float *ref, float *cmp, int w, int h, const struct _kernel *k, const struct _map_reduce *mr, const struct iqa_ssim_args *args);
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#endif /* _SSIM_H_ */
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