像Adobe Photoshop一样的OpenCV和锐化蒙版

问题描述：

我正在尝试像在Adobe Photoshop中一样实现不清晰的蒙版.我收集了很多有关Interent的信息，但不确定是否丢失了某些内容.这是代码:

I am trying to implement unsharp masking like it's done in Adobe Photoshop. I gathered a lot of information on the interent but I'm not sure if I'm missing something. Here's the code:

void unsharpMask( cv::Mat* img, double amount, double radius, double threshold ) {

// create blurred img
cv::Mat img32F, imgBlur32F, imgHighContrast32F, imgDiff32F, unsharpMas32F, colDelta32F, compRes, compRes32F, prod;
double r = 1.5;
img->convertTo( img32F, CV_32F );
cv::GaussianBlur( img32F, imgBlur32F, cv::Size(0,0), radius );
cv::subtract( img32F, imgBlur32F, unsharpMas32F );
// increase contrast( original, amount percent ) 
imgHighContrast32F = img32F * amount / 100.0f;
cv::subtract( imgHighContrast32F, img32F, imgDiff32F );
unsharpMas32F /= 255.0f;
cv::multiply( unsharpMas32F, imgDiff32F, colDelta32F );
cv::compare( cv::abs( colDelta32F ), threshold, compRes, cv::CMP_GT );
compRes.convertTo( compRes32F, CV_32F );

cv::multiply( compRes32F, colDelta32F, prod );
cv::add( img32F, prod, img32F );

img32F.convertTo( *img, CV_8U );
}

目前，我正在测试灰度图像.如果我在Photoshop中尝试完全相同的参数，我会得到更好的结果.我自己的代码导致图像嘈杂.我在做什么错了.

At the moment I am testing with a grayscale image. If i try the exact same parameters in Photoshop I get much better result. My own code leads to noisy images. What am I doing wrong.

第二个问题是，如何在RGB图像上应用不清晰的蒙版?我是否需要对3个通道的每个通道进行锐化遮罩，还是在其他颜色空间中更好?这些东西在Photoshop中是如何完成的?

The 2nd question is, how i can apply unsharp masking on RGB images? Do I have to unsharp mask each of the 3 channels or would it be better in another color space? How are these things done in Photoshop?

感谢您的帮助！

答

我也在尝试复制Photoshop的Unsharp Mask. 让我们忽略阈值一秒钟.

I'm trying to replicate Photoshop's Unsharp Mask as well. Let's ignore the Threshold for a second.

我将向您展示如何使用其高斯模糊来复制Photoshop的Unsharp Mask.

I will show you how to replicate Photoshop's Unsharp Mask using its Gaussian Blur.

假设O是原始图像层.

创建一个新层GB，它是应用于O的高斯模糊.
创建一个新的O层-GB(使用应用图像").
通过反转GB-invGB创建新层.
使用Image Apply创建一个新的O + invGB层.
创建一个新层，该层与上一层相反，即inv(O + invGB).
创建一个新层，即O +(O-GB)-inv(O + invGB).

Create a new layer GB which is a Gaussian Blur applied on O.
Create a new layer which is O - GB (Using Apply Image).
Create a new layer by inverting GB - invGB.
Create a new layer which is O + invGB using Image Apply.
Create a new layer which is inversion of the previous layer, namely inv(O + invGB).
Create a new layer which is O + (O - GB) - inv(O + invGB).

在Photoshop中进行此操作时，您将获得Unsharp Mask的完美复制.

When you do that in Photoshop you'll get a perfect reproduction of the Unsharp Mask.

如果做数学运算时回想起inv(L)= 1-L，您将得到锐化蒙版"为 USM(O)= 3O-2B.

If you do the math recalling that inv(L) = 1 - L you will get that the Unsharp Mask is USM(O) = 3O - 2B.

但是当我直接在MATLAB中执行此操作时，我没有得到Photoshop的结果.

Yet when I do that directly in MATLAB I don't get Photoshop's results.

希望有人会知道确切的数学.

Hopefully someone will know the exact math.

好，
我想通了.
在Photoshop中USM(O)= O +(2 *(数量/100)*(O-GB))
GB是O的高斯模糊版本.

OK,
I figured it out.
In Photoshop USM(O) = O + (2 * (Amount / 100) * (O - GB))
Where GB is a Gaussian Blurred version of O.

但是，要复制Photoshop的结果，您必须执行上述步骤，并将每个步骤的结果裁剪为[0，1]，就像在Photoshop中一样.

Yet, in order to replicate Photoshop's results you must do the steps above and clip the result of each step into [0, 1] as done in Photoshop.

像Adobe Photoshop一样的OpenCV和锐化蒙版

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