Waves/Ripples with DavidScan SLS-2

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LaserJack
Posts: 5
Joined: 16 Sep 2021, 14:37

Waves/Ripples with DavidScan SLS-2

Post by LaserJack »

Trying to get some help here since HP killed the David forums and that's where my original scanner vendor referred me to for help..

Battling these ripples or waves! It has not always done this, when I first got it, results were pretty good. I am not a frequent user, I bought this in probably 2015 or so but it sits in a Pelican case sometimes for years on end..I brought it out for a quick project a couple years ago but had this problem but didn't have a lot of time to put in to it at that point. Anyway, I have another project now but..this is a problem! I can't really use it like this.

Shown is just the calibration board..no object even necessary. I've tried two different versions of the David 4 software (the latest before 5 came around, and whatever version was on the dongle when it shipped, don't recall the versions). I've fiddled with projector settings, brightness settings, frame rate, camera resolution, ambient light and lackthereof, under/overexposure, focus, camera/projector position, tried a different computer...some things have altered how they look, but nothing has fixed/improved it with the exception of running way out of focus, which then gives a highly 'textured' result.

Any help or ideas appreciated! About ready to try replacing hardware, or maybe just accepting that I have a $4000 brick...
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OBNRacerMan
Posts: 306
Joined: 12 Aug 2019, 09:46
Location: Obninsk, Russia

Re: Waves/Ripples with DavidScan SLS-2

Post by OBNRacerMan »

Still, I got the impression that your shutter speed is incorrectly set (or the projector is giving out the wrong frequency).
Here is an example where with one camera at 15.000ms, which corresponds to 1/67 "(green), there are stripes, and on the second camera, with the correct 16.667ms or 1/60" (blue), everything is fine.
Compare 1/67" vs 1/60" exposure
Compare 1/67" vs 1/60" exposure
Soft: RangeVision DIY, Calibration panel/Rotary tables - RangeVision, Prj: LG PF1500G, Cam: Daheng Mercury MER-630-60U3M-L (USB3.0, monochrome) x2, Obj: ZLKC HM1628MP10 (F2.8, 10Mp, 16mm) x2 & Azure 3518M3M (F1.8, 3Mp, 35mm).
LaserJack
Posts: 5
Joined: 16 Sep 2021, 14:37

Re: Waves/Ripples with DavidScan SLS-2

Post by LaserJack »

Hi thanks for the reply!

My exposure setting is at 1/60s - I actually cannot seem to adjust it shorter than that, at least not in the menus I have found. I have tried 1/30s as well, which is the next longer setting that is available. It sounds like you have adjustments I do not; what software are you using?
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OBNRacerMan
Posts: 306
Joined: 12 Aug 2019, 09:46
Location: Obninsk, Russia

Re: Waves/Ripples with DavidScan SLS-2

Post by OBNRacerMan »

I am using custom hardware and software listed in the signature. But it is also compatible with HP3DScan. And yes, when working at HP, my cameras have the ability to fine-tune the frequency.
Soft: RangeVision DIY, Calibration panel/Rotary tables - RangeVision, Prj: LG PF1500G, Cam: Daheng Mercury MER-630-60U3M-L (USB3.0, monochrome) x2, Obj: ZLKC HM1628MP10 (F2.8, 10Mp, 16mm) x2 & Azure 3518M3M (F1.8, 3Mp, 35mm).
LaserJack
Posts: 5
Joined: 16 Sep 2021, 14:37

Re: Waves/Ripples with DavidScan SLS-2

Post by LaserJack »

Do you think this is possible to correct without custom software, etc? The more I think about it I am not sure I want to invest more money in to this setup, for the number of projects I don't mind fiddling with it a bit but it may be best for me to sell and just hire a service for the scanning component of my projects. Thanks again..
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OBNRacerMan
Posts: 306
Joined: 12 Aug 2019, 09:46
Location: Obninsk, Russia

Re: Waves/Ripples with DavidScan SLS-2

Post by OBNRacerMan »

I just can't figure out why the original hardware is not working properly. I have already said that I have never had the opportunity to "hold in my hands" these original components, I do not even know which shutter is used in these cameras (rolling or global shutter).
Usually in such cases (when I used simple cameras) I increased their shutter speed and / or decreased the frequency of the projector (from 60 to 50Hz), this often helped me.
Soft: RangeVision DIY, Calibration panel/Rotary tables - RangeVision, Prj: LG PF1500G, Cam: Daheng Mercury MER-630-60U3M-L (USB3.0, monochrome) x2, Obj: ZLKC HM1628MP10 (F2.8, 10Mp, 16mm) x2 & Azure 3518M3M (F1.8, 3Mp, 35mm).
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Micr0
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Joined: 15 Nov 2016, 15:20
Location: New York City

Re: Waves/Ripples with DavidScan SLS-2

Post by Micr0 »

OBNRacerMan wrote: 21 Sep 2021, 13:53 I just can't figure out why the original hardware is not working properly. I have already said that I have never had the opportunity to "hold in my hands" these original components, I do not even know which shutter is used in these cameras (rolling or global shutter).
Usually in such cases (when I used simple cameras) I increased their shutter speed and / or decreased the frequency of the projector (from 60 to 50Hz), this often helped me.
In the camera setting reset everything to the defaults. If you haven't, install the latest drivers for your graphics card. Depending on the card, nVidia and AMD both offer control panels that give you some fairly granular control of things like refresh rate. However, I would start with everything reset to the defaults. Your hardware at the default settings should be fairly good.
µ
LaserJack
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Joined: 16 Sep 2021, 14:37

Re: Waves/Ripples with DavidScan SLS-2

Post by LaserJack »

Everything un/reinstalled and reset to default; GPU driver is now the latest using DDU cleanup (had older version for CAD compatibility), still I am getting the banding. I am seeing ~25 FPS during scanning (laptops were much slower).

If it matters, running W7 Pro, i7 2600, Nvidia K2000 GPU..older, yes, but so is all of the scanning stuff. :) This is the computer I used it on successfully when the setup was all new, only hardware change is a new hard drive after the old one died.
Alonso
Posts: 104
Joined: 05 Dec 2016, 05:55
Location: USA

Re: Waves/Ripples with DavidScan SLS-2

Post by Alonso »

I used hp3dscan with similar pc setup as you-
i5 2500k, k2000, 16gb ram

To get rid of the banding, I had to delay the projector patterns. Basically making each pattern to be projected for longer periods of time to give the cameras a chance to capture the proper images at the right time.

If I tried to do scans at full speed, it just resulted in frustration like you're currently experiencing 🙂
LaserJack
Posts: 5
Joined: 16 Sep 2021, 14:37

Re: Waves/Ripples with DavidScan SLS-2

Post by LaserJack »

This sounds promising! How do you slow down the scans?
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