My Window Rig Prototype

[eliscio]

Well, I had some scrap wood and an afternoon to kill so I decided it was time to try a "window rig" and see if I could get this to scan.

So, attached is a quick image of the rig...it's very basic and I didn't do as much planning as I should have, but it is more fun that way and I have a better idea of what I need for the next version.

I have some general questions and am hoping some of you can respond:

I have recently received the Logitech 9000 camera and overall it is a better quality camera. However, I am finding that the scanning process is slower and not as responsive as my logitech Quickcam. I believe the resolution is one factor since it is now 800x600 instead of 640x480, but it also seems that it's not as sensitive and it could be I am simply not familiar with the settings.

Does the relative size of the object being scanned have impact on scan performance?

Any suggestions as how to best setup the camera exposure, gain and such so that you avoid unecessary noise? (I have been trying to make it so all that I can see in the view is the laser beam and nothing else).

Also, when I start DLS, the window that shows the camera's image is huge and goes off the screen. How can I get this back to a more normal window size with correct aspect ratio?

I was also curious about those who have a the Pro 9000 camera and how they control the resolution...do you go to the Logitech control panel to change this or do you give all the control to David to control?

The good news is that it worked and I have a lot more things to scan and build!

Cheers,

Eugene

[MagWeb]

Hi,

nice construction, thanks for sharing.

well, I´m working for two years with the PRO 9000 - and sometimes find settings being chanced or being not saved switching between the different needs - but I can not find some rule.

First: (if you do not need the cam- or Logitech's videoconference Vid) Install only the driver. To do this: In the installation options: disable Vid installation, disable cam software. Now you can choose: instal driver only.
(If you need the cam for other things too, the logitech cam software pops up too if DAVID calls the cam. Close this software)

DAVID 2.4.3 opened the cam at 1600x1200 by default. Now with 2.4.4 Sven set that default setting to VGA 640x480. You can change the resolution of the cam in the calibration step before calibrating. Do not forget to set a higher framerate in this dialog too!! When you close DAVID and restart it, the cam should be at the set res again (if this was the last used cam).

At 640x480 you should get around 30fps, at 800x600 the framerate should be around 20fps, at 960x720 around 15fps, at 1600x1200 only 5 fps.
To get this framerate, you have to do two things:
Set the framerate to the highest value possible in the resolution dialog on DAVID's calibration step
AND:
Pay attention on the exposure time in the cam settings (third tab) - it is rather logical: if you set this value to 1/8 sec, you will get only 8 frames per second, for 8*1/8= 1

@ Saving the exposure settings:
The Pro 9000 driver makes it possible to set many exposure times, but saves only in 8 grades. Values between this grades fall back to the next longer exposure time:
e.g: If you set 1/20sec for scanning, close the driver dialog, switch to another setting (maybe the texture settings ) and back to the scanning settings you will find the exposure at 1/16. So use only settings on the exposure 1/8, 1/16, 1/32,1/64..... otherwise you will get wired...

@RightLight
Logitech ships with a automatic RightLight setting function. Disable this function on the third tab (since driver version 11)

There are to many things you´ve to consider setting the cam to give ideal values. Color and surface quality and profile of the object, ambient light....
Hints for the scanning settings: I always set the longest saveable exposure possible (e.g 1/16 for a scan at 15fps or 1/32 for scans at 30 or 20 fps) and saturation on zero. That's the basis I adjust brightness, contrast and sensitivity on...

Another hint on ambient light:
With a green laser you can scan in some darker, but normal ambient light. But beware of neon light!! Its flickering together with the rolling shutter may create moving zones of brightness in the cam picture.

Hope that helps
Gunter

[eliscio]

Gunter,

Very good points! I chose not to install the Logitech Vid software, but I do have the other software because I use this as a webcam too. The problem is that if you do not give DLS the controls, then you lose the ability to set some options through DLS and you have to go to the Logitech software.

I should have paid closer attention to the exposure settings. I will see what I can do there to improve the scanning performance. I scan by hand at the moment and when it gets really "choppy" it's not so much fun and takes a lot of work to get a clean scan.

As I develop more scans on this rig and move onto a more professional looking rig, I'll keep everyone posted.

Thanks,

Eugene

[hal]

Hi eliscio,

Hey cool Rig! I'm courious to see your new scan results.
Keep up your great work,
Mattia

[eliscio]

Gunter,

I went back last night and started to adjust the setting some more. The exposure was in fact what was giving me most of my issues. Now that it is better matched, the scan is much faster and "filled".

Thanks,

Eugene

[eliscio]

Here are the fruits of my labour...I scanned a footprint in the sand...I had to "turn on" the points behind the panels to True so that I could get as much of the scan completed at once. Otherwise, it would only scan what was in front of the panels (i.e. where the panels were removed.) I am quite happy with the results, but I need to look at the next prototype and make improvements.

[eliscio]

Ok, I think I am starting to get the hang of this. The effort was well worth the results!

I know I can do better, but I think I want to start looking at a projector instead of a laser.

Regards,

Eugene