Find areas of interest in an image

[Andi34]

Is there a special command to get areas of interest (e. g. by finding clusters of high contrast) in ImageMagick?
I imagine a command like this

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convert -interest 3 image

where -interest is the maximum number of areas with the highest interest to be found, the output would be a crop geometry.

[snibgo]

We can readily find the contrast, eg with "-statistic StandardDeviation". I show some other methods at Details, details. This can give us an image that is black-gray-white: light where the contrast is high, and dark where the contrast is low.

Finding clusters is less simple, and less well defined. For example, a group of 100 light pixels distant from another similar group is two clusters, but they might virtually merge, and we might want to call that one cluster.

Methods shown on K-clustering may be useful, to partition the black-gray-white image. Or we could threshold the black-gray-white image and use connected-components.

[Andi34]

Yes, this is what I tested some hours ago:

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convert ... -colorspace Gray -auto-gamma -sharpen 2x1 -statistic StandardDeviation

Your post is very helpful to find a performant solution, thank you for sharing!

[kraftydevil]

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convert ... -colorspace Gray -auto-gamma -sharpen 2x1 -statistic StandardDeviation

I've tried this but I'm getting:

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convert: option requires an argument `-statistic' @ error/convert.c/ConvertImageCommand/2880.

Why would StandardDeviation not be found as an option?

[snibgo]

What is your complete command?

You have three dots where IM expects an input image.

You have no output image.

You have a type but no geometry for "-statistic". See http://www.imagemagick.org/script/comma ... #statistic

[Andi34]

To complete my command - example:

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convert inputimg -colorspace Gray -auto-gamma -sharpen 2x1 -statistic StandardDeviation 3x3 outputimg

It's useful to append -contrast-stretch 0x0 or -normalize after -statistic ..., else the highest luminance will be very low for smaller geometries.

[fmw42]

You need to specify a region size (geometry) after -statistic StandardDeviation, such as 3x3. See https://imagemagick.org/script/command- ... #statistic