Morphological Filtering

[[Ja...]]

Can someone explain what Morphological Filtering is? When and how do I use it? Does this simulate mechanical filtering? The only thing Google turned up was some type of image processing, and the help/users manual is useless. Any and all info welcomed. Thanks.

[[Er...]]

Yes you are right. It simulates the acting of a mechanical filter. Its often described as a circle of a given diameter that drags on a surfaces. The diameter is big, so it wont catch all the dips. And a value is calculated from en center of the circle. So you are only filtrering out negative peaks. In to the material.

[[Ja...]]

Thanks Eric. So how does it filter out the high spots (noise)? Is the noise included in the calculations?

[[Me...]]

There are some good pictures on page 5.

-JG

[[Ja...]]

Thanks Joseph. I better understand how it works now. Calypso shuts off the UPR and lambda cutoff because those are basically taken out of the picture because of the mechanical filter effect. The outlier and pre-filters are still active and adjustable. Still not understanding the "Opening" and "Closing" options though.

[[Me...]]

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not quite, the mechanical filtering is totally separate from the filtering provided through calypso.

the mechanical or morphological filtering is dependent on the stylus diameter being used in the measurement.

[[Ja...]]

I apologize if I didn't state it clearly. From what I see the morphological filtering does essentially the same thing as mechanical filtering, it just does it in the software. But what I still don't understand is the "Opening" and "Closing" option.

[[Me...]]

are you referring to a 2d curve? where you can select an open or closed contour?
If so, I don't have a clear answer, but I would imagine that it affects the filtering/outliers in some way.

[[Ja...]]

No, it doesn't matter what kind of feature. When you select Morphological Filtering you are given a choice of Filter Type. The two options you're given are "Opening" and "Closing", and of course the radius size. I'd like to know how the Filter Type affects the filtering.

[[Me...]]

Jack i think were missing each other here...

would you mind snipping a picture on where you are tuning on morphological filtering, and where the opening and closing options are?

[[Ja...]]

Does this help?

Morphological.JPG

[[Me...]]

ahhh no wonder I couldn't find it, I always filter on the feature side not the characteristic side lol...
this option is only available on the characteristic filter section.

i just did a quick F1 on that section. attached is the description i found.

looks like it simulates how your stylus diameter filterers the data at a set radius.
still not much info on what its actually doing but does state "reduces higher-order deviations"

i like how it says "According to ISO" 🤣

morphological filtering.JPG

[[Ja...]]

Yes, I found that too. That's why I was hoping somebody could shed some light. Anyone else familiar with this?

[[Ja...]]

Bump. Does anyone know what the "Opening" and "Closing" are for?

[[Ba...]]

I think this article would help you.

https://guide.digitalsurf.com/en/guide- ... iques.html

[[Ja...]]

Thanks Baishuo. That helped. Although I still have questions, it gives me a starting point.

[[To...]]

This is the first time I've ever seen anything on this topic. Maybe I missed something. Do you have an uncommon option configured on your Calypso?

[[Ja...]]

No. Morphological filtering comes standard in 6.6.

[[To...]]

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Well, I'll be darned. Thank you. From what I could find on Google, it appears that it might apply more to vision type inspection.

https://www.youtube.com/watch?v=u0nCv5cCeiY

[[Er...]]

Tom is right, this is to be used with optical measurements. Not tactile.

Open is defined by: O(A,B)=D[E(A,B),B]
Closed means: C(A,B)=E[D(A,B),B]
The difference is the sequence order of when dilatation and erosion is applied.

So in a understandable language,

Open applies erosion first, then dilatation, while closed does the opposite. So the difference you'll get between them is. Open will smooth convex corners, while closed will smooth concave corners.

But at nice handmade picture says more than thousand words.

How ever, intended use is with optical stuff.

[[Ja...]]

That makes a lot more sense now. Thanks Eric. I don't understand the DEABB thing but your illustration makes the erosion/dilation part a lot more understandable. Because I didn't have a clear understanding of what it was and how it worked I haven't used it at all on our current CMMs (tactile). However, I'm thinking within the next year we'll be adding an O-Inspect so I'll have to learn more about it then.