ImageHelper.cs
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using System;
using System.Collections.Generic;
using System.Drawing;
using System.Drawing.Imaging;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading.Tasks;
namespace CodeLibrary
{
public class ImageHelper
{ /// <summary>
/// 图像灰度化
/// </summary>
/// <param name="bmp"></param>
/// <returns></returns>
public static Bitmap ToGray(Bitmap bmp)
{
for (int i = 0; i < bmp.Width; i++)
{
for (int j = 0; j < bmp.Height; j++)
{
//获取该点的像素的RGB的颜色
Color color = bmp.GetPixel(i, j);
//利用公式计算灰度值
int gray = (int)(color.R * 0.3 + color.G * 0.59 + color.B * 0.11);
Color newColor = Color.FromArgb(gray, gray, gray);
bmp.SetPixel(i, j, newColor);
}
}
return bmp;
}
/// <summary>
/// 图像灰度反转
/// </summary>
/// <param name="bmp"></param>
/// <returns></returns>
public static Bitmap GrayReverse(Bitmap bmp)
{
for (int i = 0; i < bmp.Width; i++)
{
for (int j = 0; j < bmp.Height; j++)
{
//获取该点的像素的RGB的颜色
Color color = bmp.GetPixel(i, j);
Color newColor = Color.FromArgb(255 - color.R, 255 - color.G, 255 - color.B);
bmp.SetPixel(i, j, newColor);
}
}
return bmp;
}
/// <summary>
/// 图像二值化1：取图片的平均灰度作为阈值，低于该值的全都为0，高于该值的全都为255
/// </summary>
/// <param name="bmp"></param>
/// <returns></returns>
public static Bitmap ConvertTo1Bpp1(Bitmap bmp)
{
int average = 0;
for (int i = 0; i < bmp.Width; i++)
{
for (int j = 0; j < bmp.Height; j++)
{
Color color = bmp.GetPixel(i, j);
average += color.B;
}
}
average = (int)average / (bmp.Width * bmp.Height);
for (int i = 0; i < bmp.Width; i++)
{
for (int j = 0; j < bmp.Height; j++)
{
//获取该点的像素的RGB的颜色
Color color = bmp.GetPixel(i, j);
int value = 255 - color.B;
Color newColor = value > average ? Color.FromArgb(0, 0, 0) : Color.FromArgb(255, 255, 255);
bmp.SetPixel(i, j, newColor);
}
}
return bmp;
}
/// <summary>
/// 图像二值化2
/// </summary>
/// <param name="img"></param>
/// <returns></returns>
public static Bitmap ConvertTo1Bpp2(Bitmap img)
{
int w = img.Width;
int h = img.Height;
Bitmap bmp = new Bitmap(w, h, PixelFormat.Format1bppIndexed);
BitmapData data = bmp.LockBits(new Rectangle(0, 0, w, h), ImageLockMode.ReadWrite, PixelFormat.Format1bppIndexed);
for (int y = 0; y < h; y++)
{
byte[] scan = new byte[(w + 7) / 8];
for (int x = 0; x < w; x++)
{
Color c = img.GetPixel(x, y);
if (c.GetBrightness() >= 0.5) scan[x / 8] |= (byte)(0x80 >> (x % 8));
}
Marshal.Copy(scan, 0, (IntPtr)((int)data.Scan0 + data.Stride * y), scan.Length);
}
return bmp;
}
/// <summary>
/// 图像明暗调整
/// </summary>
/// <param name="b">原始图</param>
/// <param name="degree">亮度[-255, 255]</param>
/// <returns></returns>
public static Bitmap KiLighten(Bitmap b, int degree)
{
if (b == null)
{
return null;
}
if (degree < -255) degree = -255;
if (degree > 255) degree = 255;
try
{
int width = b.Width;
int height = b.Height;
int pix = 0;
BitmapData data = b.LockBits(new Rectangle(0, 0, width, height), ImageLockMode.ReadWrite, PixelFormat.Format24bppRgb);
unsafe
{
byte* p = (byte*)data.Scan0;
int offset = data.Stride - width * 3;
for (int y = 0; y < height; y++)
{
for (int x = 0; x < width; x++)
{
// 处理指定位置像素的亮度
for (int i = 0; i < 3; i++)
{
pix = p[i] + degree;
if (degree < 0) p[i] = (byte)Math.Max(0, pix);
if (degree > 0) p[i] = (byte)Math.Min(255, pix);
} // i
p += 3;
} // x
p += offset;
} // y
}
b.UnlockBits(data);
return b;
}
catch
{
return null;
}
} // end of Lighten
}
}