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Author Topic: SEUW Value/k-p values  (Read 7748 times)

Mina

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SEUW Value/k-p values
« on: August 24, 2018, 02:12:38 PM »
Hi everyone,

After each Optimization trial, you can find a value for the Standard Error of Unit Weight (SEUW) in the Console window. Can someone explain how this value should be changed during the optimization?
In my case, it stoped somewhere around:
adjusting: xxxxxxxxxxx- 0.306153 -> 0.305069

Thanks!

Best,
Mina

parthbhatt21

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SEUW Value/k-p values
« Reply #1 on: April 05, 2019, 01:05:36 AM »
Can anyone explain me about what are SEUW values are and how do they effect on scale of 0.1-1? Also what are k and p values and what they do?

parthbhatt21

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SEUW
« Reply #2 on: April 20, 2019, 12:21:24 AM »
Can anyone explain me what is SEUW and what does it exactly do in Metashape?

Alexey Pasumansky

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Re: SEUW Value/k-p values
« Reply #3 on: April 20, 2019, 02:07:19 PM »
Hello parthbhatt21,

Can you please provide the screenshot of the values that you are speaking about?

The value that is displayed in the processing log after optimization (adjusting: xxxxxxxxxxx- 0.306153 -> 0.305069) is a Sigma0 value.
Best regards,
Alexey Pasumansky,
Agisoft LLC

parthbhatt21

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Re: SEUW Value/k-p values
« Reply #4 on: April 20, 2019, 08:42:00 PM »
Yes I am talking about that value, after we apply optimization that value improves sometimes.
So my question is what is that value exactly with respect to alignment and how does optimization improves it?

parthbhatt21

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Re: SEUW Value/k-p values
« Reply #5 on: April 20, 2019, 10:29:10 PM »
Also, can you kindly explain to me alexy that when we use a low alignment settings it downscales the image - so how does it overall impact the image and in what way?

parthbhatt21

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Re: SEUW Value/k-p values
« Reply #6 on: June 06, 2019, 10:05:24 AM »
I still don't understand what is SEUW, can you kindly explain it to me briefly in theory?

bgroff

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Re: SEUW Value/k-p values
« Reply #7 on: November 21, 2019, 12:50:18 AM »
Hi. I would like to see this thread continue a bit more with some explanation from Agisoft.

I understand Standard Error of Unit Weight (SEUW) is output in the console after Optimization is performed. The USGS has some very good information on how they use this value:

https://uas.usgs.gov/nupo/otherresources.shtml

If I follow the USGS workflow closely, I can use gradual selection as they suggest and replicate some of their targets or results. What I don't understand is the relationship between tie point tolerance and SEUW. Is it reasonable that raising or lowering tie point tolerance (in a range of 0.1 to 1) should control the amount of error reported on my ground control and check points? In effect, if at a tolerance of 0.1 I don't like the error reported then I can just raise it 0.3 or 0.5 or whatever until I get an error that I accept.

I do note that that lowering the tolerance gets me closer to the SEUW = 1.0, but why is it important to achieve a Sigma0=1? The bigger question in my mind is how do I know the true accuracy of my survey?

3DWinter

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Re: SEUW Value/k-p values
« Reply #8 on: November 27, 2019, 02:24:03 AM »
I am interested in understanding how does Metashape calculate this constant, what some claim is "Standard Error of Unit Weight (SEUW)", but there is no reference to SEUW in the manual!
Thanks

3DWinter

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Re: SEUW Value/k-p values
« Reply #9 on: December 02, 2019, 09:56:07 PM »
I  am interested in understanding how does Metashape calculate this constant, what some claim is "Standard Error of Unit Weight (SEUW)", but there is no reference to SEUW in the manual!
Thanks

3DWinter

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Re: SEUW Value/k-p values
« Reply #10 on: December 05, 2019, 09:22:31 PM »
any update on that?

3DWinter

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Re: SEUW Value/k-p values
« Reply #11 on: December 13, 2019, 11:40:34 PM »
Alexey
is there a intelectual property conerncs for not responding to this question?