我有一个BitmapFrames数组,需要进行直方图拉伸。我知道这与直方图均衡不同,以及最终结果是什么...但问题是在获取直方图后,我完全不知道该怎么做。
到目前为止,我的代码创建了一个直方图数组,所以我知道每个值有多少像素。但在此之后,我不知道该怎么办。
这是我目前的代码...现在它生成直方图,然后进行直方图均衡...这不是我想要的...我只是想学习更多关于直方图的知识。
到目前为止,我的代码创建了一个直方图数组,所以我知道每个值有多少像素。但在此之后,我不知道该怎么办。
这是我目前的代码...现在它生成直方图,然后进行直方图均衡...这不是我想要的...我只是想学习更多关于直方图的知识。
[Cmdlet(VerbsData.ConvertTo, "HistoStretch")]
public class HistoStretchCmdlet : PSCmdlet
{
private BitmapFrame[] bFrame, outFrame;
private BitmapSource src;
private double pixelsize;
private byte[] pixels, outPixels;
private byte MAX_VAL;
private int[] histogram;
private int cf, start;
[Parameter(ValueFromPipeline = true,
ValueFromPipelineByPropertyName = true), ValidateNotNullOrEmpty]
public BitmapFrame[] Bitmap
{
get
{
return bFrame;
}
set
{
bFrame = value;
}
}
protected override void ProcessRecord()
{
base.ProcessRecord();
Console.Write("Applying a histogram stretch to the image...\n\n");
outFrame = new BitmapFrame[bFrame.Length];
for (int c = 0; c < bFrame.Length; c++)
{
MAX_VAL = (byte)((1 << bFrame[c].Format.BitsPerPixel) - 1);
histogram = new int[MAX_VAL + 1];
for (int i = 0; i <= MAX_VAL; i++)
{
histogram[i] = 0;
}
pixelsize = bFrame[c].PixelWidth * bFrame[c].PixelHeight;
pixels = new byte[(int)pixelsize];
outPixels = new byte[(int)pixelsize];
bFrame[c].CopyPixels(pixels,(int)bFrame[c].Width * (bFrame[c].Format.BitsPerPixel / 8),0);
for (int i = 0; i < pixelsize; i++)
{
histogram[(int)pixels[i]] = histogram[(int)pixels[i]] + 1;
}
for (int i = 0; i <= MAX_VAL; i++)
{
Console.Write("{0}: {1}\n", i, histogram[i]);
}
for (int i = 0; i <= MAX_VAL; i++)
{
if (histogram[i] >= 1)
{
start = i;
break;
}
}
for (int i = 0; i < pixelsize; i++)
{
cf = 0;
for (int g = 0; g <= MAX_VAL; g++)
{
cf += histogram[g];
if (g == pixels[i])
{
break;
}
}
outPixels[i] = (byte)(cf * (MAX_VAL / pixelsize));
}
src = BitmapSource.Create(bFrame[c].PixelWidth, bFrame[c].PixelHeight, bFrame[c].DpiX, bFrame[c].DpiY,
bFrame[c].Format, bFrame[c].Palette, outPixels, (int)(bFrame[c].Width * (bFrame[c].Format.BitsPerPixel / 8)));
outFrame[c] = BitmapFrame.Create(src);
}
WriteObject(outFrame);
}
}
这是我的老师告诉我的直方图应该看起来的样子:
http://www.fileden.com/files/2009/8/18/2547657/histostretch.PNG
我运行了上面的代码...但是得到了一张全黑的图片。以下是我的代码:
outFrame = new BitmapFrame[bFrame.Length];
for (int c = 0; c < bFrame.Length; c++)
{
MAX_VAL = (byte)((1 << bFrame[c].Format.BitsPerPixel) - 1);
histogram = new int[MAX_VAL + 1];
for (int i = 0; i <= MAX_VAL; i++)
{
histogram[i] = 0;
}
pixelsize = bFrame[c].PixelWidth * bFrame[c].PixelHeight;
pixels = new byte[(int)pixelsize];
outPixels = new byte[(int)pixelsize];
bFrame[c].CopyPixels(pixels,(int)bFrame[c].Width * (bFrame[c].Format.BitsPerPixel / 8),0);
max = pixels[0];
min = pixels[0];
for (int i = 0; i < pixelsize; i++)
{
histogram[(int)pixels[i]] = histogram[(int)pixels[i]] + 1;
if((int)pixels[i] > max)
max = pixels[i];
if((int)pixels[i] < min)
min = pixels[i];
}
dynamic = max - min;
for (int i = 0; i < pixelsize; i++)
{
outPixels[i] = (byte)(((pixels[i] - min) / dynamic) * MAX_VAL);
}