我正在处理由视频摄像机拍摄的1000万像素图像。
目标是将每个像素的灰度值在一个矩阵(一个二维数组)中进行注册。
我最初使用了GetPixel,但需要25秒才能完成。现在我使用Lockbits但仍需要10秒,如果不保存结果到文本文件中则只需要3秒。
我的导师说他们不需要注册结果,但3秒仍然太慢了。那么我的程序有什么问题吗?或者有没有比Lockbits更快的方法适用于我的应用程序?
这是我的代码:
public void ExtractMatrix()
{
Bitmap bmpPicture = new Bitmap(nameNumber + ".bmp");
int[,] GRAY = new int[3840, 2748]; //Matrix with "grayscales" in INTeger values
unsafe
{
//create an empty bitmap the same size as original
Bitmap bmp = new Bitmap(bmpPicture.Width, bmpPicture.Height);
//lock the original bitmap in memory
BitmapData originalData = bmpPicture.LockBits(
new Rectangle(0, 0, bmpPicture.Width, bmpPicture.Height),
ImageLockMode.ReadOnly, PixelFormat.Format24bppRgb);
//lock the new bitmap in memory
BitmapData newData = bmp.LockBits(
new Rectangle(0, 0, bmpPicture.Width, bmpPicture.Height),
ImageLockMode.WriteOnly, PixelFormat.Format24bppRgb);
//set the number of bytes per pixel
// here is set to 3 because I use an Image with 24bpp
int pixelSize = 3;
for (int y = 0; y < bmpPicture.Height; y++)
{
//get the data from the original image
byte* oRow = (byte*)originalData.Scan0 + (y * originalData.Stride);
//get the data from the new image
byte* nRow = (byte*)newData.Scan0 + (y * newData.Stride);
for (int x = 0; x < bmpPicture.Width; x++)
{
//create the grayscale version
byte grayScale =
(byte)((oRow[x * pixelSize] * .114) + //B
(oRow[x * pixelSize + 1] * .587) + //G
(oRow[x * pixelSize + 2] * .299)); //R
//set the new image's pixel to the grayscale version
// nRow[x * pixelSize] = grayScale; //B
// nRow[x * pixelSize + 1] = grayScale; //G
// nRow[x * pixelSize + 2] = grayScale; //R
GRAY[x, y] = (int)grayScale;
}
}