Understanding ImageMagic Blur Processing

-blur radius

Q1. You seem to specify the radius and (optional) sigma values, what are the values? How does blurring the image affect it?
(I tried to change the number of arguments, but I didn't know how it was related.)

- blur radius {xsigma}

Q2. What does the following mean?

Radius should be at least twice the Sigma value, through three times
will produce a more accumulate result.

↓Automatic translation

As a guide, Radius should be at least twice the Sigma value, but if it is three times the Sigma value, you can get more accurate results.

imagemagic image-processing

2023-02-02 18:32

1 Answers

When asked why, it becomes a pure math problem. ImageMagic blur is calculated by Gaussian function, so sigma value = standard deviation value is more essential. Gaussian blur (Wikipedia) uses only standard deviation values to indicate differences, and the php official commentary in php function.code> calculates the appropriate value.

Now, the Gaussian function (Gaussian), the standard deviation, and how to apply it to blur are pure mathematics, so I'm not confident that Oira can explain it.In the first place, blurring is likely to take a long time to start.

The answer to this question is - Sigma value is the standard deviation value of Gaussian. - The radius value is how many dots around the point of interest you are trying to calculate should be included in the operation All I can say is that this is the same wording as the previous php manual (same as the questionnaire itself).

See Wikipedia images to see how increasing the sigma value changes.

Even so, if I dare to say it in one word, - Increase Sigma value Beware than = - Too small a radius results in improper behavior as a blur operation - Increasing the radius increases the computation volume and slows it down. So it doesn't make sense if you don't specify the appropriate numbers, and it's up to the operator (you) to decide what's appropriate.

Twice the standard deviation is 2 <3 は, so you can see how wide it is from the diagram of standard deviation."Even if you pick up the surrounding colors from a narrow range, the probability of similar colors is high, so it's hard to become ""blurred."""Even if it's wider than 3 <, it's almost meaningless, so I think I understand.
# Six sigma 6 < in Kaizen also comes from here.

2023-02-02 21:52

If you have any answers or tips

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