Projectors... and Projector Mods.

Discuss about cameras, projectors, calibration panels, turntables etc.
mading
Posts: 307
Joined: 31 Jan 2017, 13:09

Re: Projectors... and Projector Mods.

Post by mading »

220 mm panels.
On-the-fly test

(will modify my rig: too low angles, and 12 mm still to tele for unmod Acer K132)
calib.jpg
2018-01-11_13-03-20.png
2018-01-11_13-03-18.png
some noise around:
2018-01-11_13-09-25.png
0.05.png
0.1.png
0.2.png
0.3.png
LG PF50, LG PF1500, RangeVision DIY: 2x DahengMer630, 2X12 and 2X16 mm 5Mp ZK lenses, RV turntable
bigbomber
Posts: 114
Joined: 14 Dec 2017, 18:08

Re: Projectors... and Projector Mods.

Post by bigbomber »

mading wrote: 11 Jan 2018, 12:22 220 mm panels.
On-the-fly test

(will modify my rig: too low angles, and 12 mm still to tele for unmod Acer K132)
calib.jpg
Thank you mading.
as you can see jagged edges are allover. so calibration is so off.
Is calib panel made by yourself? I'm not sure if the source of problem is your calip panel.
K132? Is it from HP/David?

16 deg is not so bad. for internal bore scanning I use 12~15 deg with good results.
Capture.JPG
bigbomber
Posts: 114
Joined: 14 Dec 2017, 18:08

Re: Projectors... and Projector Mods.

Post by bigbomber »

mading wrote: 11 Jan 2018, 11:37 Well, I realised I have some room for improvements.. definitely more than expected! :lol:
(I'm competing for the most weird results)
A fast try (cams with different angles):
-wood 110 mm panel with photographic ink-jet printed paper glued with spray contact glue
-acer K132 (unmod)
-a couple of DMK 23UX236, at 1920*1080-60fps

calibration :
60.jpg

Various parameters:


cam screenshots:


I got severe wave patterns, still looking for an improvement on it. Fine-tuning fps of projector and cams did not produced desidered improvements.

oh, I see this previous post after the last.

No desktop-printer can create those accurate markers on their correct position.
I think I should create a new thread for "Diy calibration Panel". It seems simple and easy but actually it is a horrible job to make and inspect and adjust a near-to-perfect panel.
so first try on a better calib panel. I can say with closed eyes that if you measure marker-to-marker distance on your current panel by a simple ruler (measure distance between each four markers in arbitrary direction), you can see a difference about 0.5mm or more for measurement.
mading
Posts: 307
Joined: 31 Jan 2017, 13:09

Re: Projectors... and Projector Mods.

Post by mading »

Yes, I did both panels.
110 is simply a photographic paper printed with my canon mx420, then glued with spray contact glue to white melaminic wood particleboard.
220 is printed directly to the wood panels.
K132 is unmod: original projector

Sorry Bigbomber for the off-topic on panels. And thanks to all for the patience.
I hope projector mod will solve wave patterns too.

->@Micro: That's true for the 110mm panel. Also the 220 mm has differences of 0.5 mm (and more): and it was shop-printed!!
I guess that david panels will be soon on the nearby. Nice to have an evaluation of differences.
I could cnc-mill dots on the same kind melaminic wood panel and paint them black. A 0.3 mm of depth would be a problem? Flatness and Perperndicularity on that setup are not as ugly as dot position.
LG PF50, LG PF1500, RangeVision DIY: 2x DahengMer630, 2X12 and 2X16 mm 5Mp ZK lenses, RV turntable
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Micr0
Posts: 586
Joined: 15 Nov 2016, 15:20
Location: New York City

Re: Projectors... and Projector Mods.

Post by Micr0 »

bigbomber wrote: 11 Jan 2018, 13:09
No desktop-printer can create those accurate markers on their correct position.
I think I should create a new thread for "Diy calibration Panel". It seems simple and easy but actually it is a horrible job to make and inspect and adjust a near-to-perfect panel.
so first try on a better calib panel. I can say with closed eyes that if you measure marker-to-marker distance on your current panel by a simple ruler (measure distance between each four markers in arbitrary direction), you can see a difference about 0.5mm or more for measurement.
This could be a good new thread. I'm curious as to why you think this. We regularly use laser printed (HP Laserjet 5550) patterns for silks screening very fine photo etched trace patterns. Never found the deviation to be more than a few µ out. I've been using laser printed patterns for <200mm with excellent results. I've never measured the accuracy of the plotter I use for >250mm patterns but again I never suspected them. I have always suspected that my errors were in the optics when my calibrations appear to be good.

FWIW I usually print all my panels as a single sheet (left and right) then mount them as one, and cut to separate. Even the 3D printed panel holders are good to +-.1mm, my CNC ones to +_.03mm.
µ
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Micr0
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Location: New York City

Re: Projectors... and Projector Mods.

Post by Micr0 »

bigbomber wrote: 11 Jan 2018, 12:54
Thank you mading.
as you can see jagged edges are allover. so calibration is so off.
Is calib panel made by yourself? I'm not sure if the source of problem is your calip panel.
K132? Is it from HP/David?

16 deg is not so bad. for internal bore scanning I use 12~15 deg with good results.
Capture.JPG
The jagged edges are more of a function of the DLP and projector resolution than proper calibration. I chose MY LG projector because it used square pixels and not the diamond shape that are common in low cost projectors, and when my projector is on the same horizontal plane as my calibration panels I get nice smooth lines. However if the vertices where the checker squares are not in the exact center of the calibration dots (or circles) then I know the calibration is out, and I need to re-do it. I have a focusing scope for focusing dark room enlargers that allows me to get a very good read on this. One issue that I have always suspected is that there can be slight color fringing on the edges of the black. The LG doesn't have this problem but the Optoma I had prior did slightly. Both of these projectors are LED and don't have a color-wheel to take out so I don't know what the best fix for this would be.
µ
erapip
Posts: 56
Joined: 16 Dec 2016, 07:16

Re: Projectors... and Projector Mods.

Post by erapip »

@bigbomber
I try to optimize and test with single camera with a positive calibration board. Scale is 120mm and Total angle is 24deg. See attache results. Its better than with dual camera. What do you think?
I have to ask about the FlexScan that you use before, was it better than David? Did you compare some scans? What about your experience with uEye camera?

@Micr0
What type of Optoma did you use before? Can you show some setup (triangulation angles) when you dont have jagged edges? I can not use the HDMI signial of my projector to investigate for the influence off the resolution. My question is: if calibration is off (jaged edges or the white and black cros is not in the center of the circles) and we have good scann quality (even with some aligment difficulty), WHAT DOES THAT MEAN?! Are these data OK for RE?

Thanks
Attachments
2018-01-11_15-46-15.png
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bigbomber
Posts: 114
Joined: 14 Dec 2017, 18:08

Re: Projectors... and Projector Mods.

Post by bigbomber »

Micr0 wrote: 11 Jan 2018, 15:54 This could be a good new thread. I'm curious as to why you think this. We regularly use laser printed (HP Laserjet 5550) patterns for silks screening very fine photo etched trace patterns. Never found the deviation to be more than a few µ out. I've been using laser printed patterns for <200mm with excellent results. I've never measured the accuracy of the plotter I use for >250mm patterns but again I never suspected them. I have always suspected that my errors were in the optics when my calibrations appear to be good.

FWIW I usually print all my panels as a single sheet (left and right) then mount them as one, and cut to separate. Even the 3D printed panel holders are good to +-.1mm, my CNC ones to +_.03mm.
On calib panel we need a very accurate positioning. All desktop printer just use rollers to feed paper. Rollers are suspended by springs. You can image what I'm talking about.
For silk printing, I'm familiar with this method. I always print my PCB board myself with negatives printed by my own desktop laser printer. Even for very small SMD parts. Desktop printers will shrink photos. But in small scales, shrinkage as a percentage of scale has a very small value. So for near components on PCB for example there is no difference between 1mm to 1.005mm (0.5% error on scale). But on 100mm the error is 0.5mm.
bigbomber
Posts: 114
Joined: 14 Dec 2017, 18:08

Re: Projectors... and Projector Mods.

Post by bigbomber »

Micr0 wrote: 11 Jan 2018, 16:05
bigbomber wrote: 11 Jan 2018, 12:54
Thank you mading.
as you can see jagged edges are allover. so calibration is so off.
Is calib panel made by yourself? I'm not sure if the source of problem is your calip panel.
K132? Is it from HP/David?

16 deg is not so bad. for internal bore scanning I use 12~15 deg with good results.
Capture.JPG
The jagged edges are more of a function of the DLP and projector resolution than proper calibration. I chose MY LG projector because it used square pixels and not the diamond shape that are common in low cost projectors, and when my projector is on the same horizontal plane as my calibration panels I get nice smooth lines. However if the vertices where the checker squares are not in the exact center of the calibration dots (or circles) then I know the calibration is out, and I need to re-do it. I have a focusing scope for focusing dark room enlargers that allows me to get a very good read on this. One issue that I have always suspected is that there can be slight color fringing on the edges of the black. The LG doesn't have this problem but the Optoma I had prior did slightly. Both of these projectors are LED and don't have a color-wheel to take out so I don't know what the best fix for this would be.
about diamond pixel: which projectors have this type of pixels? I've never seen. I think it is used in old DMD chips and because of its horrible effects on image, it is extinct. All projector which I've saw used square pixels.
Center-Test-Pattern-Comparison-Diamond-Pixel.png
but as you can see in following photo, even by square pixel can be occurred due to projector incompatibility (disabling my modification temporary).
photo_2018-01-12_02-39-09.jpg
and after thinking a little more and observation on my panel, I found a new thing: how to distinct Jagged edges are from incompatible projector or from not-accurately-made calib panel:
answer:
- if vertexes of projected squares aren't lied exactly on the center of circles but you see jagged edges, this is the result of incompatible projector (or can be caused if cameras can't see calib panel correctly (Dark Image, Not enough contrast & Brightness, unfocused lens & etc)).

- if vertexes of projected squares are lied exactly on center of circles but you see jagged edges, this is the result of not-accurately-made calib panel.

In brief, software try to project squares vertexes to centers of circles, even if they are not in their correct position. but if software can not calibrate projector correctly, efforts will be failed and vertexes deviated from centers.
this is my idea. what do you think.
I'm going to create a test on my idea. can you guess the method? it is simple.

Meanwhile, It is very nice to see the forum come to live again. thanks to all friends.
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Micr0
Posts: 586
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Location: New York City

Re: Projectors... and Projector Mods.

Post by Micr0 »

bigbomber wrote: 11 Jan 2018, 23:33

about diamond pixel: which projectors have this type of pixels? I've never seen. I think it is used in old DMD chips and because of its horrible effects on image, it is extinct. All projector which I've saw used square pixels.
Center-Test-Pattern-Comparison-Diamond-Pixel.png
Most of the older, lower resolution (WXGA and below), inexpensive projectors (<$900 or so) I have seen have had diamond pixels. My two previous were the Optoma Ml550 and an Acer K330 which both had that type of DLP. The Optoma did produce very good scans though. When I say diamond I mean that they were square but turned 45deg from horizontal. This produced fuzzy vertical and horizontal edges.

http://www.kguttag.com/2012/02/09/ti-dlp-diamond-pixel/

FWIW I think the Acer K132 that David uses has a Diamond pixel DLP.
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