Scan Station 2 pattern

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rlasater
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Scan Station 2 pattern

Post by rlasater »

We working with a Scan Station 2 on part of a project for the first time. Can someone with more experience with this scanner tell me if this uneven banding across the face is normal for the unit. Our HD6000 scan points are almost always perfectly spaced, so this look strange to us. (Although we are never at this distance with it of course)

This scan is from aproximately 150m away. The entire building face was scanned at 5cm x 5cm, then the upper portion rescanned at 1cm x 5cm. (btw The noise on the right side is the back face of the bldg.)
Savoy Bands.jpg
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Re: Scan Station 2 pattern

Post by TimBeach »

A Quick thought.

Have you imported all the data?

If you right click on the Database - Re-Import Scans

You should see this window
Capture.JPG
If it reads 100% then all the data has been imported, (It will also tell you what the current percentage of data is imported if it isnt 100%) otherwise the scanworld may only contain 1/4, 1/9 or less of the data. (I.e there could be more that 8 extra lines of data between the displayed ones!)

If you select 100% at the top, then import, it should bring the additional info into the database. However if it was a large amount high resolution scan, it might be best to do it during a quiet period when it can just be left alone for a while!

Hopefully that might explain the streaks.

Apologies if that is teaching you to suck eggs!

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Re: Scan Station 2 pattern

Post by stevenramsey »

I think there is 2 things happening here. 1 there may have been a typo making the vertical spacing look much more different to the vertical. 2 the slight changes in the spacing in the horizontal is the effect of the compensator working probably . remember at that range the vertical lines are not truly vertical as the scanner is rotating while scanning so you may see a slight change in the horizontal spacing.
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Re: Scan Station 2 pattern

Post by Luminous Group »

Hi Richard,

I've had similar issues when using our scan station 2. I find that if you are not scanning square on to something as the laser hits the wall at an increasing angle you get wider and wider vertical spacing. If an even point density is required then I now scan everything from both left and right angles so in effect each wall pretty much gets scanned twice.

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Re: Scan Station 2 pattern

Post by rlasater »

We were pretty much square to this face, so its not a fall off issue. Could it be that the sun was above the building at about where the streaks are? Here are a few more images:
SavoyBanding2.jpg
SavoyBanding3.jpg
SavoyBanding4.jpg
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Re: Scan Station 2 pattern

Post by stevenramsey »

really looks like it was scanned at 5cm by 5mm rather than the 5cm by 5cm you state.
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Re: Scan Station 2 pattern

Post by cpw006 »

We were loaned a scan station 2 so we could complete a project on a dam. We were scanning from around 600 feet and did not have any issues. I scanned at a much more dense level than you did with no spacing issues like the ones you were showing. We did this early in the day so the sun was behind the trees and the winds were calm. I have seen similar issues with a scan station when the sun was very intense and shining on the object being scanned from my back. Also was it windy that day as I have seen uneven spacing due to wind, usually on my target faces.
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Re: Scan Station 2 pattern

Post by Phil Marsh »

stevenramsey wrote:really looks like it was scanned at 5cm by 5mm rather than the 5cm by 5cm you state.
Steven,

Is there any log file that records this information so you can double check what it was actually scanned at?

Thanks
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Re: Scan Station 2 pattern

Post by stevenramsey »

good question Phil. I have never seen one but that doesn't mean it doesn't exist. All the setting should be in the diag files but might take a bit of working out.

bcx ::Sending cyclone scanner type 3
bcy ::Scan params: 5086 7404, -6.142217 0.756107 100.000000 0.292774 0.426091
bcy ::Prescan tilt 0.000855 -0.001802
bcy ::Scanning with front window preference
bcy ::Scan fits in top window
bcy ::Cyclone top: 5086x7404 pts, -6.288604:-5.995830 az, 0.543061:0.969153 el
bcy ::Top scan before: 5086 7404 -6.142217 0.756107 0.292774 0.426091
bcy ::Top scan after: 5086 7404 0.246412 0.028112 0.292774 0.426091
bcy ::SingleScan starting

This is from a random diag file which looks like it shows the number of points which might help.
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Re: Scan Station 2 pattern

Post by rlasater »

stevenramsey wrote:really looks like it was scanned at 5cm by 5mm rather than the 5cm by 5cm you state.
Steven,

I believe you are right about the settings on the higher density scans, they were 5cm x 5mm. The issue though is not the spacing so much as it is the change in spacing, which is also seen in the lower density scan which was at 5cm x 5cm. I had a chance to talk to Mike Harvey about it and says he has seen it due to mechanical, wind, and sun problems. Since the pattern shows up in roughly the same place across three scans done ten minutes apart, mechanical and wind can pretty much be ruled out.

The sun was bright that day and low in the sky over the building. On the other side we had to shade the scanner to keep the sun from causing a flare when taking the images. I think the same thing was happening here. We are out on a similar size structure today, I'll let you know how it goes.

Thanks for everyone's help.
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