/// <summary>
/// Get the quality in one of the components(Y/Cb/Cr)
/// </summary>
/// <param name="valueRef">component value of reference image</param>
/// <param name="valueDis">component value of distorted image</param>
/// <returns>quality</returns>
private double GetComponentQuality(double[,] valueRef, double[,] valueDis)
{
double quality = 1;
for (int scaleLevel = 1; scaleLevel <= MaxScaleLevel; scaleLevel++)
{
if (scaleLevel != 1)
{
valueRef = Downscaler.DownscaleByFactor(valueRef, 2);
valueDis = Downscaler.DownscaleByFactor(valueDis, 2);
}
SsimParameters ssimParams = new SsimParameters(WindowWidth, WindowHeight, C1, C2, C3, Alpha[scaleLevel], Beta[scaleLevel], Gamma[scaleLevel]);
quality *= new SsimCalculator(ssimParams).CalcMeanSsim(valueRef, valueDis);
}
return(quality);
}
/// <summary>
/// Get the quality in one of the component(Y/Cb/Cr)
/// </summary>
/// <param name="valueRef">component value of reference image</param>
/// <param name="valueDis">component value of distorted image</param>
/// <returns>quality</returns>
private double GetComponentQuality(double[,] valueRef, double[,] valueDis)
{
double quality = 1;
for (int scaleLevel = 1; scaleLevel <= MaxScaleLevel; scaleLevel++)
{
if (scaleLevel != 1)
{
valueRef = Downscaler.DownscaleByFactor(valueRef, 2);
valueDis = Downscaler.DownscaleByFactor(valueDis, 2);
}
SsimParameters ssimParams = new SsimParameters(WindowWidth, WindowHeight, C1, C2, C3, Alphas[scaleLevel], Betas[scaleLevel], Gammas[scaleLevel]);
double intermediateQuality = new SsimCalculator(ssimParams).CalcMeanSsim(valueRef, valueDis);
// make sure when the image is downscaled to less then 8x8 it can get a meaningful result.
if (!Double.Equals(intermediateQuality, 0.0))
{
quality *= intermediateQuality;
}
}
return(quality);
}
/// <summary>
/// Assess Mean MS-SSIM of a distorted bitmap with the reference bitmap
/// </summary>
/// <param name="reference">Reference bitmap</param>
/// <param name="distorted">Distorted bitmap</param>
/// <param name="component">Specify which components will be assessed, multiple components can be set by using bitwise-or</param>
/// <exception cref="ArgumentNullException">Thrown when at least one param is null</exception>
/// <exception cref="ArgumentException">Thrown when the size of the two bitmaps are not illegal for assessment (Sizes are not same, Size too small, etc.)</exception>
/// <returns>A new AssessResult object indicates the assess results in every specified component.</returns>
public override AssessResult Assess(Bitmap reference, Bitmap distorted, UseComponent component)
{
InitBitmaps(reference, distorted);
LumaReference = Downscaler.DownscaleByKeepMinLength(LumaReference, ScaleMinLength);
LumaDistorted = Downscaler.DownscaleByKeepMinLength(LumaDistorted, ScaleMinLength);
AssessResult res = new AssessResult();
if (component.HasFlag(UseComponent.Luma))
{
res.Luma = GetComponentQuality(LumaReference, LumaDistorted);
}
if (component.HasFlag(UseComponent.Cb))
{
res.Cb = GetComponentQuality(CbReference, CbDistorted);
}
if (component.HasFlag(UseComponent.Cr))
{
res.Cr = GetComponentQuality(CrReference, CrDistorted);
}
return(res);
}
/// <summary>
/// Assess Mean G-SSIM of a distorted bitmap with the reference bitmap
/// </summary>
/// <param name="reference">Reference bitmap</param>
/// <param name="distorted">Distorted bitmap</param>
/// <param name="component">Specify which components will be assessed, multiple components can be set by using bitwise-or</param>
/// <exception cref="ArgumentNullException">Thrown when at least one param is null</exception>
/// <exception cref="ArgumentException">Thrown when the size of the two bitmaps are not illegal for assessment (Sizes are not same, Size too small, etc.)</exception>
/// <returns>A new AssessResult object indicates the assess results in every specified component.</returns>
public override AssessResult Assess(Bitmap reference, Bitmap distorted, UseComponent component)
{
InitBitmaps(reference, distorted);
LumaReference = Downscaler.DownscaleByKeepMinLength(LumaReference, ScaleMinLength);
LumaDistorted = Downscaler.DownscaleByKeepMinLength(LumaDistorted, ScaleMinLength);
SsimParameters gssimParams = new SsimParameters(WindowWidth, WindowHeight, C1, C2, C3);
GssimCalculator gssimCalc = new GssimCalculator(gssimParams);
AssessResult res = new AssessResult();
if (component.HasFlag(UseComponent.Luma))
{
res.Luma = gssimCalc.CalcMeanGssim(LumaReference, LumaDistorted);
}
if (component.HasFlag(UseComponent.Cb))
{
res.Cb = gssimCalc.CalcMeanGssim(CbReference, CbDistorted);
}
if (component.HasFlag(UseComponent.Cr))
{
res.Cr = gssimCalc.CalcMeanGssim(CrReference, CrDistorted);
}
return(res);
}
