P40 scan Pattern issues & Angle of Incidence

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gsisman
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P40 scan Pattern issues & Angle of Incidence

Post by gsisman »

Has anyone seen this problem with P series Leica scanners?
We have our own BLK360 scanner that we've used for Intersection surveys and yesterday we had access to a consultants P40 scanner on a larger intersection that I wanted to experiement with on extended range and control scans (i.e. Dual axis compensated) to use as a base for fill in BLK360 scans.
We got some weird patterns in the scans. We also scanned right after rain which really eliminated the pavement distance because of reflection. Our amgle of incidence with the pavement was pretty oblique because we couldn't get RDP lite on either Android or iPAD to communicate with the scanner even after following detailed Leica manuals on the setup

1. Has anyone an idea what caused the striation?

2. Does the angle of incidence increase the number of returns significantly on wet blacktop or concrete pavement


Import_P40_data_smartalign_on_GEO_Photo_by_time__3_53pm__2020-02-04_1553.png
Imported_and_processed_2020-02-05_0934.png
Striation_in_scanning_P40_2020-02-05_0846.png
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pburrows145
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Re: P40 scan Pattern issues & Angle of Incidence

Post by pburrows145 »

Could the data have been collected in high wind? If yes, then you might be seeing the effects of the data being kept upright using the dual axis comp...

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Re: P40 scan Pattern issues & Angle of Incidence

Post by matu78 »

I agree looks like high wind effect, I have seen similar with ground movements due to heavy plant, compactors or piling occuring nearby too.

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Re: P40 scan Pattern issues & Angle of Incidence

Post by gsisman »

pburrows145 wrote:
Wed Feb 05, 2020 2:40 pm
Could the data have been collected in high wind? If yes, then you might be seeing the effects of the data being kept upright using the dual axis comp...
No I don't think it was windy at all. It had just finished raining and all the pavement was wet that's all. We were at the edge of the corners of a BUSY intersection (North of Washington DC) as you can see in the attached image.
Would the ground vibration possibly from passing traffic cause this?

Busy_ISO_BUNDLE_VIEW_2020-02-05_1020.png
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Re: P40 scan Pattern issues & Angle of Incidence

Post by stevenramsey »

What tripod where you using and yes cars and lorry make a lot of vibrations and wind.
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Re: P40 scan Pattern issues & Angle of Incidence

Post by gsisman »

stevenramsey wrote:
Wed Feb 05, 2020 3:56 pm
What tripod where you using and yes cars and lorry make a lot of vibrations and wind.
This is the tripod at about 6' scanner height above the ground.

https://www.laserscanning-america.com/e ... ng-tripod/

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Re: P40 scan Pattern issues & Angle of Incidence

Post by Scott.Warren »

Also, use gamma Correction to make the scans appear less dark (0.40 as a suggestion)
Under Appearance in the pulldowns

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Re: P40 scan Pattern issues & Angle of Incidence

Post by steves01x »

What does the station look like when you open it only in modelspace?

I have had some data from P40 that looks similar to your example but its either been poorly timed with traffic passing and a crap aluminium tripod that vibrates! :lol:

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Re: P40 scan Pattern issues & Angle of Incidence

Post by gsisman »

steves01x wrote:
Wed Feb 05, 2020 5:56 pm
What does the station look like when you open it only in modelspace?

I have had some data from P40 that looks similar to your example but its either been poorly timed with traffic passing and a crap aluminium tripod that vibrates! :lol:
The more I examine it it looks like it might be vibration or something because it is only really on one of the 4 scans.
Interesting to know.
I have seen wavy scans before- from wind on this same tripod using the BLK360 (only 2kg) and on the carbon fiber tripd with the RTC360, although the latter shocked me in how stable the scans were in VERY windy conditions. When we rented one over a year ago, I had to literally hold the tripod down because of some wind gusts one day that actually triggered the sensors on the RTC several times

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Re: P40 scan Pattern issues & Angle of Incidence

Post by jashby »

What tripod were you using?

I’ve seen this when the P50 was not with a heavy duty enough tripod. A lightweight aluminum one specifically in my case.

Basically it’s the P series scanner culling points that are bad due to vibrations.

J.

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