Dear DAVID Community,

As you are probably aware, the entire DAVID company, team and product range has been integrated into HP Inc.
This forum is now read-only. Relevant content has been migrated to HP and merged into HP's Support Forums on November 1, 2016.

To start new discussions for 3D Scanning, please register and post your new topic at the HP Support Forums

Increasing the resolution for a cropped scan

The place for all topics related to the 'Shapefusion' tool of DAVID.

Increasing the resolution for a cropped scan

Postby nick_l » Mon Jan 12, 2015 11:54 pm

Hi all,

Apologies if this has already been covered but I didn't find it.

I have a scan of a human head, which has picked up a whole load of background (walls, etc.) several metres behind the head, which means that the head is pretty small within the scan.

So I use the David tool to clean the scan, and do this with other scans, just leaving the head in each scan which is what I want.

Then when I come to use shapefusion I find the maximum setting of the resolution, 4000, gives a vertex spacing of 1.63 mm.

This vertex spacing value was obviously based on the size of the original scan, but 1.63mm spacing on my human head gives a pretty sloppy result.

So is there any way, once you've cropped the scan, of 'resetting' the resolution range, so that David will allow a finer value? Or do I need to use a different method to restrict the scan size in the first place?

I hope that makes sense! Thanks in advance for any help.

Nick
nick_l
 
Posts: 6
Joined: Thu Apr 17, 2014 7:42 pm

Re: Increasing the resolution for a cropped scan

Postby JDM Dyno » Tue Jan 13, 2015 12:11 am

Is your calibration panel alot bigger then your object / head? best to use one that is close to the size of the object.

you can set a maximum distance in advanced settings to stop walls behind getting into the scans that may help
advanced settings.jpg
Camera's: 2 x DFK 42BUC03 Duel Camera,
c615 modified with Computar megapixel lens
lenses: 2 x Pentax 12mm, 2 x Computar 8mm
Optoma ML300 Projector
Turntable

www.jdm-dyno.co.uk
User avatar
JDM Dyno
 
Posts: 185
Joined: Sat May 10, 2014 9:32 pm
Location: England

Re: Increasing the resolution for a cropped scan

Postby nick_l » Tue Jan 13, 2015 9:09 am

I think that the calibration size is fine (120mm panel seems appropriate for the object) but the 'problem' seems to be that the scanner is capable of such an amazing depth of field. Here's an uncropped example, rotated for an isometric view, showing a car I was scanning selected in red, which is at the focus point (the car is 370mm long, focus is about 900mm from the camera), and the scanner has also picked up a box I left on the table, and the wall behind that (note the shadow cast by the box). That's a depth of field of about 2.5 metres! So david sees this scan as being 2.5 metres in size, and sets the vertex spacing in the Fusion resolution appropriately, even after I've cropped all of the junk off.

car.jpg


I'll give your suggested settings a try - they look like just the thing for avoiding unwanted 'noise' like that in the first place. Also I guess scanning closer to a wall or other object might help. And not being so untidy of course. :)

Cheers,

Nick
nick_l
 
Posts: 6
Joined: Thu Apr 17, 2014 7:42 pm


Return to Shape Fusion

Who is online

Users browsing this forum: No registered users and 2 guests

cron