如何创造棕褐色调？

What are the basic operations needed to create a sepia tone? My reference point is the perl imagemagick library, so I can easily use any basic operation. I've tried to quantize (making it grayscale), colorize, and then enhance the image but it's still a bit blurry.

创建棕褐色调需要什么基本操作?我的参考点是perl imagemagick库,所以我可以轻松使用任何基本操作。我试图量化(使其灰度),着色,然后增强图像,但它仍然有点模糊。

4 个解决方案

#1

Sample code of a sepia converter in C# is available in my answer here: What is wrong with this sepia tone conversion algorithm?

我在这里的答案中提供了C#中的棕褐色转换器的示例代码:这种棕褐色调转换算法有什么问题?

The algorithm comes from this page, each input pixel color is transformed in the following way:

该算法来自此页面,每个输入像素颜色按以下方式转换:

outputRed = (inputRed * .393) + (inputGreen *.769) + (inputBlue * .189)
outputGreen = (inputRed * .349) + (inputGreen *.686) + (inputBlue * .168)
outputBlue = (inputRed * .272) + (inputGreen *.534) + (inputBlue * .131)

If any of these output values is greater than 255, you simply set it to 255. These specific values are the values for sepia tone that are recommended by Microsoft.

如果这些输出值中的任何一个大于255,则只需将其设置为255.这些特定值是Microsoft推荐的棕褐色调值。

#2

This is in C#, however, the basic concepts are the same. You will likely be able to convert this into perl.

这是在C#中,但基本概念是相同的。您可能会将其转换为perl。

  private void SepiaBitmap(Bitmap bmp)
{
    Rectangle rect = new Rectangle(0, 0, bmp.Width, bmp.Height);
    System.Drawing.Imaging.BitmapData bmpData = bmp.LockBits(rect, System.Drawing.Imaging.ImageLockMode.ReadWrite,
        System.Drawing.Imaging.PixelFormat.Format32bppRgb);

    IntPtr ptr = bmpData.Scan0;

    int numPixels = bmpData.Width * bmp.Height;
    int numBytes = numPixels * 4;
    byte[] rgbValues = new byte[numBytes];

    System.Runtime.InteropServices.Marshal.Copy(ptr, rgbValues, 0, numBytes);
    for (int i = 0; i < rgbValues.Length; i += 4)
    {
        rgbValues[i + 2] = (byte)Math.Min((.393 * red) + (.769 * green) + (.189 * (blue)), 255.0); //red
        rgbValues[i + 1] = (byte)Math.Min((.349 * red) + (.686 * green) + (.168 * (blue)), 255.0); //green
        rgbValues[i + 0] = (byte)Math.Min((.272 * red) + (.534 * green) + (.131 * (blue)), 255.0); //blue
        if ((rgbValues[i + 2]) > 255)
        {
            rgbValues[i + 2] = 255; 
        }

        if ((rgbValues[i + 1]) > 255)
        {
            rgbValues[i + 1] = 255;
        }
        if ((rgbValues[i + 0]) > 255)
        {
            rgbValues[i + 0] = 255;
        }
    }

    System.Runtime.InteropServices.Marshal.Copy(rgbValues, 0, ptr, numBytes);
    this.Invalidate();
    bmp.UnlockBits(bmpData);

}

#3

It's easy if you use the imagemagic command line.

如果你使用imagemagic命令行很容易。

http://www.imagemagick.org/script/convert.php

Use the "-sepia-tone threshold" argument when converting.

转换时使用“-sepia-tone threshold”参数。

Strangely enough, the PerlMagick API doesn't seem to include a method for doing this directly:

奇怪的是,PerlMagick API似乎没有包含直接执行此操作的方法:

http://www.imagemagick.org/script/perl-magick.php

...and no reference to any Sepia method.

......并没有提到任何深褐色方法。

#4

Take a look at how it's implemented in the AForge.NET library, the C# code is here.

看看它是如何在AForge.NET库中实现的,C#代码就在这里。

The basics seem to be

基本似乎是

transform it to the YIQ color space

将其转换为YIQ颜色空间

modify it
transform back to RGB

转换回RGB

The full alrogithm is in the source code, plus the RGB -> YIQ and YIQ -> RGB transformations are explained.

完整的alrogithm在源代码中,加上RGB - > YIQ和YIQ - > RGB转换。

#1