How Can I Convert an Image to Grayscale Using a 16-Bit per Pixel Format?

Grayscale conversion method for 16-bit pixel images

In image processing, grayscale conversion typically sets the red, green, and blue (RGB) components of each pixel to a brightness value. However, there is a way to convert an image to grayscale using a 16-bit-per-pixel format.

Use the PixelFormat constructor

To convert an image to grayscale using this method, you can use the PixelFormat constructor of the Bitmap class. An example is as follows:

<code class="language-c#">Bitmap grayScaleBP = new System.Drawing.Bitmap(2, 2, System.Drawing.Imaging.PixelFormat.Format16bppGrayScale);</code>

This will create a new bitmap with a size of 2x2 pixels and a pixel format of 16 bits per pixel grayscale.

Convert existing image to grayscale

To convert an existing image to grayscale, you can use a loop to loop through the pixels and set them to a grayscale color. An example is as follows:

<code class="language-c#">// 代码片段略，此处需要补充完整代码以实现灰度转换</code>

This code goes through each pixel in the bitmap c and sets the red component to the brightness value and the green and blue components to zero, effectively converting it to grayscale. The resulting bitmap d contains a grayscale version of the original image.

Quick way to use ColorMatrix

Convert grayscale images faster using ColorMatrix:

<code class="language-c#">public static Bitmap MakeGrayscale3(Bitmap original)
{
    // 创建一个与原始图像大小相同的空白位图
    Bitmap newBitmap = new Bitmap(original.Width, original.Height);

    // 从新图像获取图形对象
    using (Graphics g = Graphics.FromImage(newBitmap)) {
        // 创建灰度ColorMatrix
        ColorMatrix colorMatrix = new ColorMatrix(
            new float[][]
            {
                new float[] {.3f, .3f, .3f, 0, 0},
                new float[] {.59f, .59f, .59f, 0, 0},
                new float[] {.11f, .11f, .11f, 0, 0},
                new float[] {0, 0, 0, 1, 0},
                new float[] {0, 0, 0, 0, 1}
            });

        // 创建一些图像属性
        using (ImageAttributes attributes = new ImageAttributes()) {
            // 设置颜色矩阵属性
            attributes.SetColorMatrix(colorMatrix);

            // 使用灰度颜色矩阵在新图像上绘制原始图像
            g.DrawImage(original, new Rectangle(0, 0, original.Width, original.Height),
                        0, 0, original.Width, original.Height, GraphicsUnit.Pixel, attributes);
        }
    }

    // 返回新的位图
    return newBitmap;
}</code>

This method uses a ColorMatrix to perform a grayscale conversion, which is much faster than manually iterating through the pixels.

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