内存法通过把图像储存在内存中进行处理,效率大大高于GetPixel方法,安全性高于指针法。
笔者当初写图像处理的时候发现网上多是用GetPixel方法实现,提到内存法的时候也没有具体实现,所以笔者在这里具体实现一下- -,望指正。
首先讲一下用到的一些方法。
1.LockBits和UnlockBits:使用 LockBits 方法,可在系统内存中锁定现有的位图,以便通过编程方式进行更改,每调用LockBits之后都应该调用一次UnlockBits。
2.Scan0:图像的第一个字节地址。
3.Stride:步幅,扫描宽度,形象的说就是一行的长度。
4.PixelFormat:数据的实际像素格式。
给出原图:
一、灰度
对每个像素点进行加权平均,(方法不唯一)。
/// <summary>/// 灰化实现方法/// </summary>void Image_Ashing(){if (pbshowbox.Image != null){int Height = this.pbshowbox.Image.Height;int Width = this.pbshowbox.Image.Width;Bitmap bitmap = new Bitmap(Width, Height, PixelFormat.Format24bppRgb);Bitmap MyBitmap = (Bitmap)this.pbshowbox.Image;BitmapData oldData = MyBitmap.LockBits(new Rectangle(0, 0, Width, Height), ImageLockMode.ReadOnly, PixelFormat.Format24bppRgb);BitmapData newData = bitmap.LockBits(new Rectangle(0, 0, Width, Height), ImageLockMode.ReadWrite, PixelFormat.Format24bppRgb);unsafe{byte* pin = (byte*)(oldData.Scan0.ToPointer());byte* pout = (byte*)(newData.Scan0.ToPointer());for (int y = 0; y < oldData.Height; y++){for (int x = 0; x < oldData.Width; x++){byte Result = (byte)(pin[0] * 0.1 + pin[1] * 0.2 + pin[2] * 0.7);//加权平均实现灰化pout[0] = (byte)(Result);pout[1] = (byte)(Result);pout[2] = (byte)(Result);pin = pin + 3;pout = pout + 3;}pin += oldData.Stride - oldData.Width * 3;pout += newData.Stride - newData.Width * 3;}bitmap.UnlockBits(newData);MyBitmap.UnlockBits(oldData);this.pbshowbox.Image = bitmap;}}else{MessageBox.Show("请先打开一张图片!");}}
二、柔化
像素点与周围像素点差别较大时取平均值。
/// <summary>/// 柔化实现方法/// </summary>void Image_Soften(){if (pbshowbox.Image != null){int Height = this.pbshowbox.Image.Height;int Width = this.pbshowbox.Image.Width;Bitmap bitmap = new Bitmap(Width, Height, PixelFormat.Format32bppRgb);Bitmap MyBitmap = (Bitmap)this.pbshowbox.Image;BitmapData oldData = MyBitmap.LockBits(new Rectangle(0, 0, Width, Height), ImageLockMode.ReadOnly, PixelFormat.Format32bppRgb);BitmapData newData = bitmap.LockBits(new Rectangle(0, 0, Width, Height), ImageLockMode.ReadWrite, PixelFormat.Format32bppRgb);unsafe{byte* pin = (byte*)(oldData.Scan0.ToPointer());byte* pout = (byte*)(newData.Scan0.ToPointer());//高斯模板int[] Gauss = { 1, 2, 1, 2, 4, 2, 1, 2, 1 };for (int i = 1; i < Width - 1; i++){for (int j = 1; j < Height - 1; j++){int r = 0, g = 0, b = 0;int Index = 0;for (int col = -1; col <= 1; col++){for (int row = -1; row <= 1; row++){int off = ((j + row) * (Width) + (i + col)) * 4;r += pin[off + 0] * Gauss[Index];g += pin[off + 1] * Gauss[Index];b += pin[off + 2] * Gauss[Index];Index++;}}r /= 16;g /= 16;b /= 16;//处理颜色值溢出if (r < 0) r = 0;if (r > 255) r = 255;if (g < 0) g = 0;if (g > 255) g = 255;if (b < 0) b = 0;if (b > 255) b = 255;int off2 = (j * Width + i) * 4;pout[off2 + 0] = (byte)r;pout[off2 + 1] = (byte)g;pout[off2 + 2] = (byte)b;}}bitmap.UnlockBits(newData);MyBitmap.UnlockBits(oldData);this.pbshowbox.Image = bitmap;}}else{MessageBox.Show("请先打开一张图片!");}}
三、锐化
突出显示颜色值大的像素点。
/// <summary>/// 锐化实现方法,显示数值最大像素点/// </summary>void Image_Sharpen(){if (this.pbshowbox.Image != null){int Height = this.pbshowbox.Image.Height;int Width = this.pbshowbox.Image.Width;Bitmap bitmap = new Bitmap(Width, Height, PixelFormat.Format32bppRgb);Bitmap MyBitmap = (Bitmap)this.pbshowbox.Image;BitmapData oldData = MyBitmap.LockBits(new Rectangle(0, 0, Width, Height), ImageLockMode.ReadOnly, PixelFormat.Format32bppRgb);BitmapData newData = bitmap.LockBits(new Rectangle(0, 0, Width, Height), ImageLockMode.ReadWrite, PixelFormat.Format32bppRgb);unsafe{byte* pin = (byte*)(oldData.Scan0.ToPointer());byte* pout = (byte*)(newData.Scan0.ToPointer());//拉普拉斯模板int[] Laplacian = { -1, -1, -1, -1, 9, -1, -1, -1, -1 };for (int i = 1; i < Width - 1; i++){for (int j = 1; j < Height - 1; j++){int r = 0, g = 0, b = 0;int Index = 0;for (int col = -1; col <= 1; col++){for (int row = -1; row <= 1; row++){int off = ((j + row) * (Width) + (i + col)) * 4;r += pin[off + 0] * Laplacian[Index];g += pin[off + 1] * Laplacian[Index];b += pin[off + 2] * Laplacian[Index];Index++;}}if (r < 0) r = 0;if (r > 255) r = 255;if (g < 0) g = 0;if (g > 255) g = 255;if (b < 0) b = 0;if (b > 255) b = 255;int off2 = (j * Width + i) * 4;pout[off2 + 0] = (byte)r;pout[off2 + 1] = (byte)g;pout[off2 + 2] = (byte)b;}}bitmap.UnlockBits(newData);MyBitmap.UnlockBits(oldData);this.pbshowbox.Image = bitmap;}}else{MessageBox.Show("请先打开一张图片!");}}
四、浮雕
对图像像素点的像素值分别与相邻像素点的像素值相减后加上128, 然后将其作为新的像素点的值。
/// <summary>/// 浮雕实现方法/// </summary>void Image_Relief(){if (this.pbshowbox.Image != null){int Height = this.pbshowbox.Image.Height;int Width = this.pbshowbox.Image.Width;Bitmap bitmap = new Bitmap(Width, Height, PixelFormat.Format24bppRgb);Bitmap MyBitmap = (Bitmap)this.pbshowbox.Image;BitmapData oldData = MyBitmap.LockBits(new Rectangle(0, 0, Width, Height), ImageLockMode.ReadOnly, PixelFormat.Format24bppRgb);BitmapData newData = bitmap.LockBits(new Rectangle(0, 0, Width, Height), ImageLockMode.ReadWrite, PixelFormat.Format24bppRgb);unsafe{byte* pin_1 = (byte*)(oldData.Scan0.ToPointer());byte* pin_2 = pin_1 + (oldData.Stride); byte* pout = (byte*)(newData.Scan0.ToPointer());for (int y = 0; y < oldData.Height - 1; y++){for (int x = 0; x < oldData.Width; x++){ int b = (int)pin_1[0] - (int)pin_2[0] + 128;int g = (int)pin_1[1] - (int)pin_2[1] + 128;int r = (int)pin_1[2] - (int)pin_2[2] + 128;if (r < 0) r = 0;if (r > 255) r = 255;if (g < 0) g = 0;if (g > 255) g = 255;if (b < 0) b = 0;if (b > 255) b = 255;pout[0] = (byte)(b);pout[1] = (byte)(g);pout[2] = (byte)(r);pin_1 = pin_1 + 3;pin_2 = pin_2 + 3;pout = pout + 3; }pin_1 += oldData.Stride - oldData.Width * 3;pin_2 += oldData.Stride - oldData.Width * 3;pout += newData.Stride - newData.Width * 3;}bitmap.UnlockBits(newData);MyBitmap.UnlockBits(oldData);this.pbshowbox.Image = bitmap;}}else{MessageBox.Show("请先打开一张图片!");}}
五、底片
颜色值取反。
/// <summary>/// 底片实现方法/// </summary>void Image_Negative(){if (pbshowbox.Image != null){int Height = this.pbshowbox.Image.Height;int Width = this.pbshowbox.Image.Width;Bitmap bitmap = new Bitmap(Width, Height, PixelFormat.Format24bppRgb);Bitmap MyBitmap = (Bitmap)this.pbshowbox.Image;BitmapData oldData = MyBitmap.LockBits(new Rectangle(0, 0, Width, Height), ImageLockMode.ReadOnly, PixelFormat.Format24bppRgb);BitmapData newData = bitmap.LockBits(new Rectangle(0, 0, Width, Height), ImageLockMode.ReadWrite, PixelFormat.Format24bppRgb);unsafe{byte* pin = (byte*)(oldData.Scan0.ToPointer());byte* pout = (byte*)(newData.Scan0.ToPointer());for (int y = 0; y < oldData.Height; y++){for (int x = 0; x < oldData.Width; x++){pout[0] = (byte)(255 - pin[0]);pout[1] = (byte)(255 - pin[1]);pout[2] = (byte)(255 - pin[2]);pin = pin + 3;pout = pout + 3;}pin += oldData.Stride - oldData.Width * 3;pout += newData.Stride - newData.Width * 3;}bitmap.UnlockBits(newData);MyBitmap.UnlockBits(oldData);this.pbshowbox.Image = bitmap;}}else{MessageBox.Show("请先打开一张图片!");}}
六、积木
低像素置0,高像素置255。
/// <summary>/// 积木实现方法/// </summary>private void Image_Block(){if (this.pbshowbox.Image != null){int Height = this.pbshowbox.Image.Height;int Width = this.pbshowbox.Image.Width;Bitmap bitmap = new Bitmap(Width, Height);Bitmap Mybitmap = (Bitmap)this.pbshowbox.Image;BitmapData oldData = Mybitmap.LockBits(new Rectangle(0, 0, Width, Height), ImageLockMode.ReadOnly, PixelFormat.Format24bppRgb);BitmapData newData = bitmap.LockBits(new Rectangle(0, 0, Width, Height), ImageLockMode.ReadWrite, PixelFormat.Format24bppRgb);unsafe{byte* pin = (byte*)(oldData.Scan0.ToPointer());byte* pout = (byte*)(newData.Scan0.ToPointer());for (int y = 0; y < oldData.Height; y++){for (int x = 0; x < oldData.Width; x++){int avg = (pin[0] + pin[1] + pin[2]) / 3;if (avg > 128){pout[0] = 255;pout[1] = 255;pout[2] = 255;}else{pout[0] = 0;pout[1] = 0;pout[2] = 0;}pin = pin + 3;pout = pout + 3;}pin = pin + oldData.Stride - oldData.Width * 3;pout = pout + newData.Stride - newData.Width * 3;}bitmap.UnlockBits(newData);Mybitmap.UnlockBits(oldData);this.pbshowbox.Image = bitmap;}}else{MessageBox.Show("请先打开一张图片!");}}
有些图片效果看起来不明显是因为笔者把图缩小了,其实效果挺明显的- -。