Image Quality Assessment (IQA)是一个快速，精确，可靠的测量视频/图像质量的基于C的库。
它实现了很多流行的算法比如 MS-SSIM, SIMM, MSE 和 PSNR。
其提供的方法在iqa.h中，如下所示：
/*
* Copyright (c) 2011, Tom Distler (http://tdistler.com)
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* The BSD License
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#ifndef _IQA_H_
#define _IQA_H_
#include "iqa_os.h"
/**
* Allows fine-grain control of the SSIM algorithm.
*/
struct iqa_ssim_args {
float alpha; /**< luminance exponent */
float beta; /**< contrast exponent */
float gamma; /**< structure exponent */
int L; /**< dynamic range (2^8 - 1)*/
float K1; /**< stabilization constant 1 */
float K2; /**< stabilization constant 2 */
int f; /**< scale factor. 0=default scaling, 1=no scaling */
};
/**
* Allows fine-grain control of the MS-SSIM algorithm.
*/
struct iqa_ms_ssim_args {
int wang; /**< 1=original algorithm by Wang, et al. 0=MS-SSIM* by Rouse/Hemami (default). */
int gaussian; /**< 1=11x11 Gaussian window (default). 0=8x8 linear window. */
int scales; /**< Number of scaled images to use. Default is 5. */
const float *alphas; /**< Pointer to array of alpha values for each scale. Required if 'scales' isn't 5. */
const float *betas; /**< Pointer to array of beta values for each scale. Required if 'scales' isn't 5. */
const float *gammas; /**< Pointer to array of gamma values for each scale. Required if 'scales' isn't 5. */
};
/**
* Calculates the Mean Squared Error between 2 equal-sized 8-bit images.
* @note The images must have the same width, height, and stride.
* @param ref Original reference image
* @param cmp Distorted image
* @param w Width of the images
* @param h Height of the images
* @param stride The length (in bytes) of each horizontal line in the image.
* This may be different from the image width.
* @return The MSE.
*/
float iqa_mse(const unsigned char *ref, const unsigned char *cmp, int w, int h, int stride);
/**
* Calculates the Peak Signal-to-Noise-Ratio between 2 equal-sized 8-bit
* images.
* @note The images must have the same width, height, and stride.
* @param ref Original reference image
* @param cmp Distorted image
* @param w Width of the images
* @param h Height of the images
* @param stride The length (in bytes) of each horizontal line in the image.
* This may be different from the image width.
* @return The PSNR.
*/
float iqa_psnr(const unsigned char *ref, const unsigned char *cmp, int w, int h, int stride);
/**
* Calculates the Structural SIMilarity between 2 equal-sized 8-bit images.
*
* See https://ece.uwaterloo.ca/~z70wang/publications/ssim.html
* @note The images must have the same width, height, and stride.
* @param ref Original reference image
* @param cmp Distorted image
* @param w Width of the images
* @param h Height of the images
* @param stride The length (in bytes) of each horizontal line in the image.
* This may be different from the image width.
* @param gaussian 0 = 8x8 square window, 1 = 11x11 circular-symmetric Gaussian
* weighting.
* @param args Optional SSIM arguments for fine control of the algorithm. 0 for
* defaults. Defaults are a=b=g=1.0, L=255, K1=0.01, K2=0.03
* @return The mean SSIM over the entire image (MSSIM), or INFINITY if error.
*/
float iqa_ssim(const unsigned char *ref, const unsigned char *cmp, int w, int h, int stride,
int gaussian, const struct iqa_ssim_args *args);
/**
* Calculates the Multi-Scale Structural SIMilarity between 2 equal-sized 8-bit
* images. The default algorithm is MS-SSIM* proposed by Rouse/Hemami 2008.
*
* See https://ece.uwaterloo.ca/~z70wang/publications/msssim.pdf and
* http://foulard.ece.cornell.edu/publications/dmr_hvei2008_paper.pdf
*
* @note 1. The images must have the same width, height, and stride.
* @note 2. The minimum image width or height is 2^(scales-1) * filter, where 'filter' is 11
* if a Gaussian window is being used, or 9 otherwise.
* @param ref Original reference image
* @param cmp Distorted image
* @param w Width of the images.
* @param h Height of the images.
* @param stride The length (in bytes) of each horizontal line in the image.
* This may be different from the image width.
* @param args Optional MS-SSIM arguments for fine control of the algorithm. 0
* for defaults. Defaults are wang=0, scales=5, gaussian=1.
* @return The mean MS-SSIM over the entire image, or INFINITY if error.
*/
float iqa_ms_ssim(const unsigned char *ref, const unsigned char *cmp, int w, int h, int stride,
const struct iqa_ms_ssim_args *args);
#endif /*_IQA_H_*/
源代码下载：http://download.csdn.net/detail/leixiaohua1020/6376741
SourceForge项目页面：http://sourceforge.net/projects/iqa/
项目官方页面：http://tdistler.com/iqa/