include/iqa.h File Reference

#include "iqa_os.h"

Go to the source code of this file.

Data Structures
struct	iqa_ssim_args
struct	iqa_ms_ssim_args
Functions
float	iqa_mse (const unsigned char *ref, const unsigned char *cmp, int w, int h, int stride)
float	iqa_psnr (const unsigned char *ref, const unsigned char *cmp, int w, int h, int stride)
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)
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)

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Function Documentation

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
	)

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.

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.

Parameters:

ref	Original reference image
cmp	Distorted image
w	Width of the images.
h	Height of the images.
stride	The length (in bytes) of each horizontal line in the image. This may be different from the image width.
args	Optional MS-SSIM arguments for fine control of the algorithm. 0 for defaults. Defaults are wang=0, scales=5, gaussian=1.

Returns:

The mean MS-SSIM over the entire image, or INFINITY if error.

Definition at line 129 of file ms_ssim.c.

float iqa_mse	(	const unsigned char *	ref,
		const unsigned char *	cmp,
		int	w,
		int	h,
		int	stride
	)

Calculates the Mean Squared Error between 2 equal-sized 8-bit images.

Note:

The images must have the same width, height, and stride.

Parameters:

ref	Original reference image
cmp	Distorted image
w	Width of the images
h	Height of the images
stride	The length (in bytes) of each horizontal line in the image. This may be different from the image width.

Returns:

The MSE.

Definition at line 37 of file mse.c.

float iqa_psnr	(	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.

Parameters:

ref	Original reference image
cmp	Distorted image
w	Width of the images
h	Height of the images
stride	The length (in bytes) of each horizontal line in the image. This may be different from the image width.

Returns:

The PSNR.

Definition at line 38 of file psnr.c.

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 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.

Parameters:

ref	Original reference image
cmp	Distorted image
w	Width of the images
h	Height of the images
stride	The length (in bytes) of each horizontal line in the image. This may be different from the image width.
gaussian	0 = 8x8 square window, 1 = 11x11 circular-symmetric Gaussian weighting.
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

Returns:

The mean SSIM over the entire image (MSSIM), or INFINITY if error.

Definition at line 59 of file ssim.c.