Do you need to adjust Scanner Settings? Probably not

User guide and tutorials
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A Liberation user recently emailed me asking about the scanner settings for their particular laser and whether increasing the scan speed would make the output brighter.

It’s a good question, and I thought the answer might be useful to others too.

TL;DR: You usually don’t need to adjust any scanner settings except Scanner Sync (unless you’re doing graphics or other demanding output).

Regarding the overall brightness, one thing that’s worth understanding is that when you make a laser graphic larger, you’re spreading the same amount of laser power over a larger area. A beam concentrated into a small area will always appear brighter than the same beam spread across a large graphic or sheet. This is completely normal and not usually a scanner configuration issue.

It’s also important to understand the difference between point rate and scanner speed.

Unlike most laser software, increasing the point rate (in Advanced Settings, for example from 30kpps to 40kpps) does not make the scanners move faster. In Liberation, the point stream is automatically adjusted to maintain the same scanner movement speed. A higher point rate simply gives the software more temporal resolution to work with, which isn’t usually necessary unless you’re doing a lot of detailed output.

You can use the Speed setting in the laser settings panel to experiment with the actual scanner movement speed. However, making the scanners move faster won’t make the output brighter - it will only make moving content appear less flickery.

Note that the Speed setting should be used with caution. Driving scanners too hard can reduce image quality and, in extreme cases, potentially damage them.

In practice, for the vast majority of users, the only scanner-related setting that needs adjusting is Scanner Sync. That’s the setting used to compensate for timing differences between scanners.

Most people never need to touch any of the other scanner settings. They’re really there for advanced optimisation when doing demanding graphics projections and trying to get the absolute best performance from a particular scanner set.

If you’re primarily doing beam shows and atmospheric effects, I’d strongly recommend leaving the scanner settings completely alone unless you’re experienced and know what you’re doing.

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I would love for someone to make a detailed setup tutorial video, one for quick setup (beamshows) and one with full advanced stuff for graphics…

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Good idea, I’ll add it to the list.

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Every new line drives brightness from the first one so no … i chose “fast” profile in creator nodes only when the picture starts to flicker, or “detail” when corner are not sharp enough. Default is good choice.

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It was a rhetorical question but thanks for the answer :blush:

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I understand, but, why is scanner speed expressed in a percentage? This way I could never know what my scanners can handle right? Is it not possible to have this display the actual kpps output if you know your scanners are good and you do want to display graphics on a surface?

Maybe I’m misinterpreting something here, and I have looked at the advanced scanner speed settings, but I’m not read-in enough to tweak those.

Besides; I’m not really planning on tweaking this, it just stood out to me that it’s a percentage and you could never know when to stop increasing?

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That’s a great question, but it will take some explaining. Here we go!

But before we get into it I just want to reiterate something. With pretty much all traditional laser software, laser cues/ILDA files/whatever are a predetermined point list per frame.

A point list, or point stream is a list of positions and colours that the laser has to “follow” one by one, at the speed of the point rate.

The points could be spread far apart and constantly jumping around the image, in which case the scanners will be working very hard even at a low point rate. Or the points could be close together, and the scanners will be moving relatively slowly even at a high point rate.

If you are running random pre-generated content you literally have no idea what it’s doing to your scanners - you are entirely at the whim of whoever made the frames.

Here’s my hot take: just because your scanners are rated for a particular point rate doesn’t mean every frame can be displayed correctly at that point rate. Scanner ratings are based on a specific test pattern, not arbitrary content.

At least in traditional software.

Liberation does things differently. It generates the point stream in real time as content is sent to the laser, and each laser can use different settings to generate that stream.

But the default settings are conservative and should be fine for cheap scanners. And if you have better scanners, and you need it less flickery, increase the speed setting, or choose a different scanner preset, or customise your own! (With caution :blush:)

So to answer the question :

why is scanner speed expressed in a percentage?

The scanner speed percentage is a relative adjustment for whichever settings you’re using. If the output is too flickery and you think your scanners can handle more, increase it. If the scanners seem to be struggling, reduce it. In my experience you can usually tell if your scanners are struggling to draw something. You’ll get rounded corners and inaccuracies, or they may get noisy.

This way I could never know what my scanners can handle right?

Strictly speaking, the only thing you know your scanners can handle is a specific test pattern[1], at a specific size, at a specific point rate. That’s what the scanner manufacturer’s rating is based on.

Hope this helps, it’s a very confusing thing to try to explain, I hope I’ve done an OK job of it.

Seb

  1. The ILDA Test pattern ↩︎

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Thank you you for the thorough explanantion!
For me it’s not a really relevant topic atm,but i can imagine it would just feel scary to keep increasing the speed until somthing looks ‘good’ without knowing what the limit is, or what might cause long term damage while the scanners can handle it temporarily. But I understand the considirations now, thanks!! :slight_smile:

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Hi @mathijslaser

Yes, I agree that it can be scary!

One of the goals with Liberation is to make it much harder to accidentally overload your scanners. In practice, it’s generally safe to send any Liberation content to your scanners without causing damage, provided you’re not making extreme changes to the settings. Even at 200%, the default settings are usually still quite conservative.

I’ve built a system that estimates scanner load for any given point stream - you can see it in Libera Lab - and I hope to bring that into Liberation soon. [1]

Compared to most software, which will happily send any point stream straight to your scanners with very minor processing and no analysis at all, I think Liberation already does a pretty good job of protecting both the scanners and the quality of the output.

All the best,

Seb

  1. Part of the problem is that all we really have is the ILDA test pattern as a benchmark for scanners, rather than any meaningful engineering data. I’ve experimented with using the load generated by the ILDA test pattern as a baseline, but it’s a difficult problem. ↩︎

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