Outdoor scanning

[WalterMo]

Hi,
Now I have finished an outdoor scanner for scanning without the background panels.
It can be powered by the 230V mains or by a rechargeable battery with a capacity for a working time of more than two hours.
The clock rate of the stepping motor is quartz oscillator controlled to ensure a very constant speed for the reference scan and later for the object scans.
A built-in up/down counter which can also be illuminated by a external LED indicates the actual position (in motor steps) of the laser.
The mounting unit for camera and motor scanner is made of a square aluminium profil. It's stable and lightweight. By means of wing bolts it can fast and easily be universally adjusted.

Walter

[hal]

Simply perfect!

[RAYA]

Hi Walter

Nice design.


How you can fix camera head to not move during transport ?

raya

[WalterMo]

Hello RAYA,
Of course you are right, the „naked“ Logitech Pro 9000 with its different hinges isn't the ideal cam for a transport just when the reference scan was made.
The photo should only be a demo.
In reality I would build a box or a cage around the cam.

[eliscio]

Hey WalterMo,

That is one clean setup. I have been thinking about starting with David Laser scanner for a very long time, but after seeing your setup, I am now motivated. If I could scan stuff outdoors, that would be incredible.

Would it be possible for you to take another shot or two of your setup from the side?

If you had to do this again, how would you improve it? Also, do you have any samples scans that you have done outside that you can post??

Great job!

[WalterMo]

Hi eliscio,
Up to now I haven't made any outdoor scans with this machine. The reason is quite simple: I don't have a notebook.
But I think in the next weeks we can see some outdoor scans when the scanner is delivered. Then from the results we can decide what should be improved.
A detail photo from the opened motor scanner you can find here:

viewtopic.php?p=5367#p5367

And some specifications regarding the mechanics here:

viewtopic.php?p=5054#p5054

If you need any further info, perhaps for a remake, please let me know.

[eliscio]

This looks like a great little setup and I would like to build one very similar.

Thanks for the photos...I'll send you a PM!

[WalterMo]

Hi,
This is my first outdoor scan. OK, it's not far from the frontdoor, only just in front of it. But what to do without a battery-driven notebook?
So I put my PC on a trolley and pulled the mains cable behind it.

The first reference scan I made inside. But by misadvanture the mains power was interrupted and the initial position of the stepper motor was lost. So I let the tripod with the aluminium frame outside in front of the target and repeated the reference scan on-site.
This has a big advantage because now I first chose the image section, adjusted the focus of the camera and of the laser to the object. Then the tripod head was rotated by about 90° to the left where the calibration corner was standing at circa the same height. After the reference scan the head was pivoted back to start the repetition scan.
It's a special situation to scan outside: Darkness, uneven ground, “invisible“ cables and prying spectators.

Walter

[hal]

WoW, this is great. Compliments Walter, vey well done.
... and very nice home
I want to follow you on this way...
Bye, Mattia

[joecnc2006]

I agree, fantastic.

[Bongobat]

Really nice work!

Thanks,

Greg

[WalterMo]

Thanks for the compliments. But it was nothing exceptional. Only a scan in front of the frontdoor.

Sven told me that the last reference scan will be saved on the harddrive and automatically reloaded when DAVID is started when ever again so that we can just continue with the repetition scan. That means it would be very easy to build camera and motor scanner in one case, do the reference scan once and have a device like the Next Engine Scanner.

Mattia, I wonder what outdoor scan your first will be. Perhaps a Roman statue?
I have just noticed that you have bought a 16mW laser. Is it for the statue?
You see the grey plastic sleeve and the two mini banana jacks will be needed very fast.

Walter

[hal]

Hello Walter,
unfortunately I can't scan a Roman statue (I can't now, but a day... ), but I've in mind to scan something that looks just a little bit more modern: a "thing" with four wheels and a motor inside.
Yes, I've in mind to scan a car. I want to scan it in more than one pieces (really, many pieces) to preserve a good survey of details.

Walter, the gray plastic sleeve is already needed for "indoor" scans. I'm doing some tests indoor, first to go outdoor.
Now I've check that new laser is quite good for get a survey of different surfaces color and material, coated only with a thin layer of talcum powder (removeable only with a breath [I hope that there is no wind the day when I will scan the car!]).

White talcum can be useful , but obviously not the better choise. I'm searching a special spray like used here: http://www.avrsc.com/laser.php (thank you cnc Dave for the link )

About the "indoor" test for materials and surfaces hard to scan, I can see that a 16 mW focusable laser is ok.
As you can see in the attached image, the scan result WITHOUT panels is good... yes, there are many little waves that create a noise in the scans, but the fusion process in ShapeFusion decrease this noise. For the scan result of this circuit, I've moved the laser just a little away the object, around 80 cm of distance, for a better test about laser's power and focus (you can see the line aspect in my "parameters" message, here: viewtopic.php?p=6547#p6547)

I hope that this italian spring become more stable (now the wheater is rainy and sunny, alternately), to start the OutDoor scan test on a big objec, a Volvo 850 car.

Bye,
Mattia

[Bongobat]

Hi Mattia,

A car wow I cant wait to see that.

Your circuit board looks nice too. Im guessing it is a power supply hmmm? More important I notice you have there something Ive noticed scanning similar things. The white lettering on the PCB is raised in the fused result but this should not be. I am guessing the lettering was picked up by the laser easily too so we can not blame interpolation either. I am thinking this is also why I get streaks with a dirty slide. Different intenisity of light maybe. Why does this happen? Anyone know?

Thanks again,

Greg

[Bongobat]

Hi,

Okay thinking about it longer I came up with a theory. If I am correct David looks at the top and bottom edge of a line and tries to find the middle row of pixels. Lets say you have a bright white lettering on a grey flat object. When the laser passes over the lettering the line will become bigger inside the lettering as seen by the camera and David but it will remain thin on the grey parts in the same plane. Perhaps in this case David misjudges where the middle is and If he misjudges the middle only for the lettering he calculates the depth incorectly. Does this make sense?

Err but then again the background corners are usually the whitest part of a scan so im still confused

Greg