multi-galvo system for 'virtual' increase in point rate

[drlava]

drlava: Scary- that was your 666th post I think!

Hmm I almost don't want to post again.. oh well

I think the splitting of a single frame data destined for multiple scanners was mentioned a while back in order to accomodate the heavy point count in the game Star Wars for the original LaserMame. I currently only have one EasyLase, but I will have a sound card DAC soon with a little luck.

yeah it would be great for games and 3d-generated graphics!

Lastly, aren't a lot of DAC's out there limited to the number of PPS they support anyway? If that is the case, the DACs will need to catch up, or something like this is bound to happen.
Cool topic!
-Mike

YES a lot of DACs are limited to 30 or 35 kpps, but that's not a big issue to overcome. Audio DACs natively do 48kpps and some 96kpps. But this would work best if computed before the DAC, IF there is a DAC. It would work great with an ILDA digital projector interface standard, too.

Yes, LOBO has done this as part of their "Tri Dome" product. I am not sure if their LACON takes it any further for the more general case.

In fact, this could be done with our software, albiet using what I might call a "semi-automatic" approach rather than fully automatic. This is in fact, one of the key reasons why Projection Zones were developed. The semi-automatic approach places the division of imagery among available scanners in the hands of the artist rather than the computer, so that consistent results could always be counted on. The fully-automatic approach will lead to inconsistent results, not to mention a stronger requirement for perfect geometric correction.

Bill

If the projection zones are static in position then a complex figure would have to span two zones to have any gain in scan speed. If the complex figure moved mostly into one of the projection zones during some effect then the scan speed would be slowed. If the projectors are tied to sprites or segment groups manually or as they appear then that should work well.

[heroic]

Why not use a cheap webcam and a little image processing to automatically compute the parallax for different parts of the target zone?

[drlava]

I love to see people adding to this.

Interesting idea, cheap webcams are typically 640x480 native resolution but to hit 0.2mrad alignment you would need 3,000 pixels for a 35 degree field. The resolution requirement could be halved by sub-pixel scanning and detecting peaks but it's still pretty high.

In the y direction a 640x480 webcam with sub-pixel scanning technique could get you about 0.62mrad if the scanning field filled the frame.

a more expensive 1024x768 native camera could get you 0.3x0.4mrad which is probably close to acceptable.

EDIT: the above calculations assume black and white mode on the camera if the bayer pixel arrangement of the camera starts to play a role then things get much worse.

[Zoof]

Yep, but for stability purposes and like Steve said the galvos are getting cheaper so it might make a lot of sense to build a single high speed projector.

Cost, I figured that is why you should avoid adding the cost of a pair(!) of PCAOMs. For overlapping projection, both projectors need half the power minus pcoam losses compared to a single high power one.

Another benefit is that you could switch the projector 'mode' from high speed graphics to wide scan angle beams by not overlapping the projected area of the galvos.

Didn;t I just say that???

[drlava]

Cost, I figured that is why you should avoid adding the cost of a pair(!) of PCAOMs. For overlapping projection, both projectors need half the power minus pcoam losses compared to a single high power one.

well you were suggesting separate projectors which would need double lasers anyway so PCAOMs aren't needed. At this point it just depends on usage. If someone expects to use the high speed or wide angle projector most of the time it makes sense to have it all built into one. But if not, then the flexibility of two makes sense.

Didn;t I just say that???

Hmm re-reading it yep!

[Pangolin]

If the projection zones are static in position then a complex figure would have to span two zones to have any gain in scan speed. If the complex figure moved mostly into one of the projection zones during some effect then the scan speed would be slowed. If the projectors are tied to sprites or segment groups manually or as they appear then that should work well.

You misunderstand the concept of zones, as implemented by our system. Understandable since you don't have one of our systems... The latter part of your statement is closer to how zones work in our system. But anyway, you will figure out all of this, plus the limitations soon enough...

Bill

[mixedgas]

Borrow from the eye and put the camera on a piezo or two, shift it 1,2 , or 1/2 pixel.

Digital saccadic motion :-)

You have a precision position sensor in the galvos, and gratings create known images. Think about it...

Steve