static void Compare(string bmp1, string bmp2, byte threshold = 5)
{
//get the full path of the images
string image1Path = Path.Combine(sampleImagesFolder.FullName, bmp1);
string image2Path = Path.Combine(sampleImagesFolder.FullName, bmp2);
//compare the two
Console.Write("Comparing: " + bmp1 + " and " + bmp2 + ", with a threshold of " + threshold);
Bitmap firstBmp = (Bitmap)Image.FromFile(image1Path);
Bitmap secondBmp = (Bitmap)Image.FromFile(image2Path);
//get the difference as a bitmap
firstBmp.GetDifferenceImage(secondBmp,true)
.Save(image1Path + "_diff.png");
Console.WriteLine(string.Format("Difference: {0:0.0} %", firstBmp.PercentageDifference(secondBmp, threshold) * 100));
//Console.WriteLine("ENTER see histogram for " + bmp1);
//Console.ReadLine();
Console.WriteLine();
Console.WriteLine("Creating histogram for " + bmp1);
Histogram hist = new Histogram(firstBmp);
// hist.Visualize().Save(image1Path + "_hist.png");
Console.WriteLine(hist.ToString());
Console.WriteLine("ENTER to continue...");
Console.ReadLine();
}
/// <summary>
/// Gets the variance between two histograms (http://en.wikipedia.org/wiki/Variance) as a percentage of the maximum possible variance: 256 (for a white image compared to a black image)
/// </summary>
/// <param name="histogram">the histogram to compare this one to</param>
/// <returns>A percentage which tells how different the two histograms are</returns>
public float GetVariance(Histogram histogram)
{
//
double diffRed = 0, diffGreen = 0, diffBlue = 0;
for (int i = 0; i < 256; i++)
{
diffRed += Math.Pow(Red[i] - histogram.Red[i], 2);
diffGreen += Math.Pow(Green[i] - histogram.Green[i], 2);
diffBlue += Math.Pow(Blue[i] - histogram.Blue[i], 2);
}
diffRed /= 256;
diffGreen /= 256;
diffBlue /= 256;
const double maxDiff = 512;
return (float)(diffRed / maxDiff + diffGreen / maxDiff + diffBlue / maxDiff) / 3;
}
