我写了一个计算图像焦点值的代码。但要花5秒以上才能完成。将循环转换为并行循环
public double GetFValue(Image image)
{
Bitmap source = new Bitmap(image);
int count = 0;
double total = 0;
double totalVariance = 0;
double FM = 0;
Bitmap bm = new Bitmap(source.Width, source.Height);
Rectangle rect = new Rectangle(0,0,source.Width,source.Height);
Bitmap targetRect = new Bitmap(rect.Width, rect.Height);
// converting to grayscale
for (int y = 0; y < source.Height; y++)
{
for (int x = 0; x < source.Width; x++)
{
count++;
Color c = source.GetPixel(x, y);
int luma = (int)(c.R * 0.3 + c.G * 0.59 + c.B * 0.11);
source.SetPixel(x, y, Color.FromArgb(luma, luma, luma)); // the image is now gray scaled
var pixelval = source.GetPixel(x, y);
// targetRect.Save(@"C:\Users\payam\Desktop\frame-42-rectangle.png", System.Drawing.Imaging.ImageFormat.Png);
int pixelValue = pixelval.G;
total += pixelValue;
double avg = total/count;
totalVariance += Math.Pow(pixelValue - avg, 2);
double stDV = Math.Sqrt(totalVariance/count); // the standard deviation, which is also the focus value
FM = Math.Round(stDV, 2);
}
}
return FM;
}
我想将此代码转换为并行计算。我最终得到的错误是我无法将他们的头围绕在他们身上。任何建议?
public double CalculateFvalue (Image image)
{
Bitmap myimage = new Bitmap(image);
int count = 0;
int total = 0;
double totalVariance = 0;
double FM = 0;
Parallel.For(0, image.Height, y =>
{
for (int x = 0; x < myimage.Width; x++)
{
count++;
Color c = myimage.GetPixel(x, y);
int luma = (int)(c.R * 0.3 + c.G * 0.59 + c.B * 0.11);
myimage.SetPixel(x, y, Color.FromArgb(luma, luma, luma)); // the image is now gray scaled
var pixelval = myimage.GetPixel(x, y);
int pixelValue = pixelval.G;
total += pixelValue;
double avg = total/count;
totalVariance += Math.Pow(pixelValue - avg, 2);
double stDV = Math.Sqrt(totalVariance/count); // the standard deviation, which is also the focus value
FM = Math.Round(stDV, 2);
}
});
return Math.Round(FM,2);
}
你看到的错误是什么? –
是的,你有一个线程安全问题的整个负载。但无论如何,getpixel是非常缓慢的,而不是锁定位而不是 – Steve
你在不同的线程上同时更新'count','total'和'FM'。您应该让每个循环迭代计算这些值的本地值,然后在最后将它们组合在一起。 – Lee