快速将彩色照片变成黑白照片(仅适用于jpg格式)
上篇文章写了将彩色图片变成黑白照片的一个方法,该方法遍历图片色素,然后通过公式将彩色变成黑白,效率十分低下。
今天做了下修改,效率大概提高了1000倍吧
测试图如下:
![](https://www.cnblogs.com/images/cnblogs_com/jillzhang/sdzzzzzzzzzz.JPG)
214452542是上个方法的执行时间
250169是本次方法执行时间
图如本次方法生成图效果
更改了公式为:Y=0.299*R+0.114*G+0.587B
代码:
特别感谢:YaoTong
ahnan
沐枫
三位兄弟在上篇文章对我的帮助!
今天做了下修改,效率大概提高了1000倍吧
测试图如下:
214452542是上个方法的执行时间
250169是本次方法执行时间
图如本次方法生成图效果
更改了公式为:Y=0.299*R+0.114*G+0.587B
代码:
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/// <summary>
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/// 快速的将彩色图像变成黑白图像-目前仅适用于jpg格式的图像
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/// </summary>
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/// <param name="filePath">彩色图像地址</param>
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/// <returns>返回的黑白图像</returns>
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public static Bitmap QuickWhiteAndBlack(string filePath)
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{
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// 从文件创建Bitmap对象
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Bitmap bmp = new Bitmap(filePath);
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// 将Bitmap锁定到系统内存中
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Rectangle rect = new Rectangle(0, 0, bmp.Width, bmp.Height);
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// 获得BitmapData
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System.Drawing.Imaging.BitmapData bmpData =
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bmp.LockBits(rect, System.Drawing.Imaging.ImageLockMode.ReadWrite,
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bmp.PixelFormat);
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// 位图中第一个像素数据的地址。它也可以看成是位图中的第一个扫描行
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IntPtr ptr = bmpData.Scan0;
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// 将Bitmap对象的信息存放到byte数组中
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// 假设位图中一个像素包含3byte,也就是24bit
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int bytes = bmp.Width * bmp.Height * 3;
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byte[] rgbValues = new byte[bytes];
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//复制GRB信息到byte数组
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System.Runtime.InteropServices.Marshal.Copy(ptr, rgbValues, 0, bytes);
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// 根据Y=0.299*R+0.114*G+0.587B,Y为亮度
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for (int counter = 0; counter < rgbValues.Length; counter += 3)
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{
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byte value = (byte)(rgbValues[counter] * 0.299 + rgbValues[counter + 2] * 0.114 + rgbValues[counter + 1] * 0.587);
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rgbValues[counter] = value;
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rgbValues[counter + 1] = value;
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rgbValues[counter + 2] = value;
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}
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//将更改过的byte[]拷贝到原位图
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System.Runtime.InteropServices.Marshal.Copy(rgbValues, 0, ptr, bytes);
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// 解锁位图
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bmp.UnlockBits(bmpData);
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return bmp;
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}
上篇地址:http://www.cnblogs.com/jillzhang/archive/2006/10/09/524571.html![](https://www.cnblogs.com/Images/OutliningIndicators/ExpandedBlockStart.gif)
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特别感谢:YaoTong
ahnan
沐枫
三位兄弟在上篇文章对我的帮助!
作者:jillzhang
出处:http://jillzhang.cnblogs.com/
本文版权归作者和博客园共有,欢迎转载,但未经作者同意必须保留此段声明,且在文章页面明显位置给出原文连接,否则保留追究法律责任的权利。
出处:http://jillzhang.cnblogs.com/
本文版权归作者和博客园共有,欢迎转载,但未经作者同意必须保留此段声明,且在文章页面明显位置给出原文连接,否则保留追究法律责任的权利。