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stridsvognen
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| Posted: Sat Jun 16, 2012 7:01 pm Post subject: |
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| macgyver655 wrote: | | stridsvognen wrote: |
Ahh im not sure its that simple. How would you adjust the panel if your just off in the borders / corners.?
could just as well be the optics that distort the convergence a bit. |
Why would the borders or corners just be off and not the center if the signal is not being manipulated? The digital signal is the digital signal. Unless a panel is warped or damaged.
If it were the optics,(which is very minimal for the actual image) then it would be a flaw and all projectors would suffer the same.
And who's to say that those borders and edges couldn't be correctly from the tilt option?
Hey, I',m not saying it would be perfect either but it's way better then grossly manipulating the signal.
More ammunition for my clip.......  |
Well i'm just looking my own JVC X7 and its like the geometry is a bit off between the panels, and its spot on in the center..
Gets worse the closer you get to the corners. So look like i should bend the panels to get it right.
So your idea will just help make the convergence right in the center of the image, which is no problem on my machine.
I still don't understand how its possible to adjust 1/16 pixel with scaling on a fixed pixel panel.. 
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macgyver655
Joined: 22 Aug 2007
Posts: 8508
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| Posted: Sat Jun 16, 2012 7:21 pm Post subject: |
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Then I guess they are just crap like I always said......
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stridsvognen
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| Posted: Sat Jun 16, 2012 7:24 pm Post subject: |
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| macgyver655 wrote: | | Then I guess they are just crap like I always said...... |
Guess why i recently ended up with a 9500LC
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HogPilot
Joined: 21 Jan 2010
Posts: 2383
TV/Projector: Vizio P702ui-B3, Pioneer Elite Pro-151FD & 111FD
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| Posted: Sat Jun 16, 2012 7:37 pm Post subject: |
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Panel alignment is obviously very sensitive - you're talking about 3 chips that are, at most, 1", and in the case of LCoS, only 0.6" or 0.7" diagonal. At that point whole pixels are 1/10,000th of an inch wide, so you need to be able to adjust in 1/100,000th inch increments minimum. A full set of panel adjustments would have to allow 1) translation up, down, left, right, front, and back, and 2) rotation in the pitch, roll, and yaw axes. As you can imagine, the kind of mechanism that could allow this would have incredibly tight tolerances. This is why the large majority of digital projectors have the alignment adjusted at the factory, with the chips secured in place permanently. Projectors that do have the ability to have their convergence adjusted physically are very expensive - Art Sonneborn's HT5000 is one example of such a projector.
The multi-zone processing is a much cheaper way of accomplishing this, even though it does have its own set of drawbacks. I personally am not a fan because of the artifacts it can induce, but I'm self-admittedly a stickler for maintaining image fidelity and not adding processing unless it is necessary. Given that the projectors that I've owned have had very good convergence, I'd just as soon deal with a 1/4 or even 1/2 pixel misconvergence on the edges - which is essentially unnoticeable on almost any material - than use processing. But that's just me.
_________________
| ecrabb wrote: | | Curt Palme wrote: | | Interesting, Mac isn't returning my emails. Go figure. |
He's mad at us for making Hog a moderator. He took his ball and went home.
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CIR Engineering
Joined: 25 Aug 2008
Posts: 4269
Location: Chicago USA & Berlin Germany
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| Posted: Sat Jun 16, 2012 9:41 pm Post subject: |
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| HogPilot wrote: |
The multi-zone processing is a much cheaper way of accomplishing this, even though it does have its own set of drawbacks. I personally am not a fan because of the artifacts it can induce, but I'm self-admittedly a stickler for maintaining image fidelity and not adding processing unless it is necessary. Given that the projectors that I've owned have had very good convergence, I'd just as soon deal with a 1/4 or even 1/2 pixel misconvergence on the edges - which is essentially unnoticeable on almost any material - than use processing. But that's just me. |
Exactly what I tell my clients. Just live with a little misconvergence because it is better than the artifacts and loss of resolution.
craigr
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garyfritz
Joined: 08 Apr 2006
Posts: 12088
Location: Fort Collins, CO
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| Posted: Sat Jun 16, 2012 11:16 pm Post subject: |
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Yeah, I would think a simple mechanical mirror adjustment would be better than dicking with the video signal and the 1:1 mapping. The mirror is reflecting a perfectly rectangular pixel array, so there's no reason to do screen zones. Just line up one rectangular reflection with the others and you should be good.
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stefuel
Joined: 07 Mar 2006
Posts: 3353
Location: Green Harbor MA USA
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| Posted: Sun Jun 17, 2012 4:37 am Post subject: |
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| mp20748 wrote: | Everything is now being done in "Image Processing" these day, or at least that I what they have been doing in the Commercial AV industries upper end projectors. This same technology allows similar to CRT technology Geometry adjustments. Which is how they are able to use digitals in the Simulators and other unusual screen applications.
Image processing allows them to make various geometry/linearity and other changes in the electronics without ever making any changes to the physical optical path.
I have two Barco projector here that has these options. I'm thinking JVC may be using something very similar.
Barco calls theirs Warping.
Christie also has Image Processing for Blending and Stacking that is software based:
http://www.youtube.com/watch?v=tn9C8nbADMw
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I have a scaler/processor with "warp" processing. You can project off center and onto irregular shapes. It's kinda cool if your into that sort of thing.
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A Barco is only a AmPro with training wheels
Card carrying member of the AVS chain gang.
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HogPilot
Joined: 21 Jan 2010
Posts: 2383
TV/Projector: Vizio P702ui-B3, Pioneer Elite Pro-151FD & 111FD
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| Posted: Sun Jun 17, 2012 5:21 am Post subject: |
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| garyfritz wrote: | | Yeah, I would think a simple mechanical mirror adjustment would be better than dicking with the video signal and the 1:1 mapping. The mirror is reflecting a perfectly rectangular pixel array, so there's no reason to do screen zones. Just line up one rectangular reflection with the others and you should be good. |
As I outlined above, the mechanisms required to make sub-pixel adjustments to chip alignment have to be VERY precise and have VERY tight tolerances - 1/4 of a pixel would equal about 1/25,000th of an inch movement. It doesn't really matter what those mechanisms are attached to, they're still quite expensive to implement. Plus I'd have to imagine that having 3 mirrors inside a light engine would be a nightmare for trying to minimize stray light, and that the negative effect on CR would easily negate the convergence benefits. It's more efficient to just manipulate the chips themselves.
_________________
| ecrabb wrote: | | Curt Palme wrote: | | Interesting, Mac isn't returning my emails. Go figure. |
He's mad at us for making Hog a moderator. He took his ball and went home.
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stridsvognen
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| Posted: Sun Jun 17, 2012 11:36 am Post subject: |
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| ecrabb wrote: | Kal,
I saw the RS55 at CEDIA, and I think it's definitely a worthwhile upgrade over the RS45. If I had the cash to throw at it, I'd definitely have gone that route, as it would be especially beneficial with my large viewing angle. I can occasionally see pixels and with the e-shift, it really does make it hard to see pixels from any normal viewing position. The convergence ability is nice, too. My machine is one pixel out on the red channel on the left third of the screen. It's perfect in the center and on the right (I have no idea how that happens). Fortunately, It's really not even visible on anything but small white details like stars, and not really from my seating position.
I could see myself selling the RS45 and picking up an RS55 either if they fire-sale them around CEDIA or next spring or something (as a year-old model), or used if somebody got reasonable on a used price. If you're leaning that way, and you can cost-justify it, go for it.
So busy with work right now, and have to travel next week, but I can't wait to get this thing on the ceiling... It's so small and quiet... And black... Once it's up there, and I get my light-weight "hush box" up there (just for appearance/protection/heat removal), you'll barely notice the projector!
SC |
Just a experiment i'm playing with.
Try put up the focus menu on your RS 45, and push the key pad down to adjust it out of focus. keep an eye on the text, and stop before the color bleed get to bad, the convergence will change a bit, but i think it looks more natural, like CRT when the pixels bleed a little together and not generating the over hard focus edge to everything.
The pixel flicker from Digital is still there, but you can eliminate the grid between the pixels, and the hard square pixels.
I feel more natural dept to a 2D movie. and its more relaxing to my eyes looking a hole movie.
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macgyver655
Joined: 22 Aug 2007
Posts: 8508
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| Posted: Sun Jun 17, 2012 1:51 pm Post subject: |
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| HogPilot wrote: |
As I outlined above, the mechanisms required to make sub-pixel adjustments to chip alignment have to be VERY precise and have VERY tight tolerances - 1/4 of a pixel would equal about 1/25,000th of an inch movement. It doesn't really matter what those mechanisms are attached to, they're still quite expensive to implement. |
Why would you believe this would be so difficult and expensive?
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macgyver655
Joined: 22 Aug 2007
Posts: 8508
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| Posted: Sun Jun 17, 2012 2:01 pm Post subject: |
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| garyfritz wrote: | | Yeah, I would think a simple mechanical mirror adjustment would be better than dicking with the video signal and the 1:1 mapping. The mirror is reflecting a perfectly rectangular pixel array, so there's no reason to do screen zones. Just line up one rectangular reflection with the others and you should be good. |
Gary, I think your are thinking like I was at first. If it's just a panel alignment then fixing it should be fairly simple. But after some of these posts indicating the center is fine but the outer edges of the images are not then it wouldn't be alignment. And like you, also thinking that being digital, each panel should be displaying the exact same and proper geometric shape.
My conclusion is that the final prism must be distorting the shape of the images as they are combined back into 1 image. So it would not be fixable by any possible way other then manipulating the image on the panel itself to the opposite affect of the distortion.
This would be my assumption.
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Curt Palme
CRT Tech
Joined: 08 Mar 2006
Posts: 24396
Location: Langley, BC
TV/Projector: All of them!
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| Posted: Sun Jun 17, 2012 2:18 pm Post subject: |
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I've seen that too, from the Barco 3 DLP that I posted about a while back in the theatre, to the Sony Rubys that I saw at the Sony Store here in LAngley. Pixel misalignment was not consistent throughout the screen.
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HogPilot
Joined: 21 Jan 2010
Posts: 2383
TV/Projector: Vizio P702ui-B3, Pioneer Elite Pro-151FD & 111FD
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| Posted: Sun Jun 17, 2012 2:22 pm Post subject: |
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| macgyver655 wrote: | | HogPilot wrote: |
As I outlined above, the mechanisms required to make sub-pixel adjustments to chip alignment have to be VERY precise and have VERY tight tolerances - 1/4 of a pixel would equal about 1/25,000th of an inch movement. It doesn't really matter what those mechanisms are attached to, they're still quite expensive to implement. |
Why would you believe this would be so difficult and expensive? |
It's not belief, it's simply fact. Designing a mechanism that can move on those tiny scales in by translating and rotating in all three axes would not be simple. It also has to be designed so as not to drift over time. There's a reason it doesn't appear on all but some of the most expensive projectors.
| macgyver655 wrote: | | garyfritz wrote: | | Yeah, I would think a simple mechanical mirror adjustment would be better than dicking with the video signal and the 1:1 mapping. The mirror is reflecting a perfectly rectangular pixel array, so there's no reason to do screen zones. Just line up one rectangular reflection with the others and you should be good. |
Gary, I think your are thinking like I was at first. If it's just a panel alignment then fixing it should be fairly simple. But after some of these posts indicating the center is fine but the outer edges of the images are not then it wouldn't be alignment. And like you, also thinking that being digital, each panel should be displaying the exact same and proper geometric shape.
My conclusion is that the final prism must be distorting the shape of the images as they are combined back into 1 image. So it would not be fixable by any possible way other then manipulating the image on the panel itself to the opposite affect of the distortion.
This would be my assumption. |
Actually, it's most likely panel alignment rather than optics. It's very easy to produce an orientation where all three panels match in the center of the screen but not the edges. This can be caused by even the smallest difference in their angular relation to one another. The optics that combine all three chip images into one are fairly simple with flat surfaces - it's getting all three chips aligned properly with respect to the optics that's the challenge.
None of this is new or that complex, and the problems are well understood. What's difficult is finding a simple, inexpensive solution that can be used in the mass production of these machines.
_________________
| ecrabb wrote: | | Curt Palme wrote: | | Interesting, Mac isn't returning my emails. Go figure. |
He's mad at us for making Hog a moderator. He took his ball and went home.
SC |
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macgyver655
Joined: 22 Aug 2007
Posts: 8508
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| Posted: Sun Jun 17, 2012 2:56 pm Post subject: |
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| HogPilot wrote: | | macgyver655 wrote: | | HogPilot wrote: |
As I outlined above, the mechanisms required to make sub-pixel adjustments to chip alignment have to be VERY precise and have VERY tight tolerances - 1/4 of a pixel would equal about 1/25,000th of an inch movement. It doesn't really matter what those mechanisms are attached to, they're still quite expensive to implement. |
Why would you believe this would be so difficult and expensive? |
It's not belief, it's simply fact. Designing a mechanism that can move on those tiny scales in by translating and rotating in all three axes would not be simple. It also has to be designed so as not to drift over time. There's a reason it doesn't appear on all but some of the most expensive projectors.
| macgyver655 wrote: | | garyfritz wrote: | | Yeah, I would think a simple mechanical mirror adjustment would be better than dicking with the video signal and the 1:1 mapping. The mirror is reflecting a perfectly rectangular pixel array, so there's no reason to do screen zones. Just line up one rectangular reflection with the others and you should be good. |
Gary, I think your are thinking like I was at first. If it's just a panel alignment then fixing it should be fairly simple. But after some of these posts indicating the center is fine but the outer edges of the images are not then it wouldn't be alignment. And like you, also thinking that being digital, each panel should be displaying the exact same and proper geometric shape.
My conclusion is that the final prism must be distorting the shape of the images as they are combined back into 1 image. So it would not be fixable by any possible way other then manipulating the image on the panel itself to the opposite affect of the distortion.
This would be my assumption. |
Actually, it's most likely panel alignment rather than optics. It's very easy to produce an orientation where all three panels match in the center of the screen but not the edges. This can be caused by even the smallest difference in their angular relation to one another. The optics that combine all three chip images into one are fairly simple with flat surfaces - it's getting all three chips aligned properly with respect to the optics that's the challenge.
None of this is new or that complex, and the problems are well understood. What's difficult is finding a simple, inexpensive solution that can be used in the mass production of these machines. |
Well your 1/125000th is 1 micron, correct?
Last edited by macgyver655 on Sun Jun 17, 2012 3:01 pm; edited 1 time in total
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macgyver655
Joined: 22 Aug 2007
Posts: 8508
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| Posted: Sun Jun 17, 2012 3:00 pm Post subject: |
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| HogPilot wrote: |
Actually, it's most likely panel alignment rather than optics. It's very easy to produce an orientation where all three panels match in the center of the screen but not the edges. This can be caused by even the smallest difference in their angular relation to one another. The optics that combine all three chip images into one are fairly simple with flat surfaces - it's getting all three chips aligned properly with respect to the optics that's the challenge.
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I have no problem agreeing with the fact that a panel misalignment can be correct in the center but off on an outer edges but this would be more of a poor quality issue. I've worked on many of LCD projectors and have never seen an image with these characteristics.
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macgyver655
Joined: 22 Aug 2007
Posts: 8508
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| Posted: Sun Jun 17, 2012 3:16 pm Post subject: |
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| stridsvognen wrote: |
Well i'm just looking my own JVC X7 and its like the geometry is a bit off between the panels, and its spot on in the center..
Gets worse the closer you get to the corners. So look like i should bend the panels to get it right.
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Can you describe just how the grid is off on these outer edges or post a pic?
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HogPilot
Joined: 21 Jan 2010
Posts: 2383
TV/Projector: Vizio P702ui-B3, Pioneer Elite Pro-151FD & 111FD
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| Posted: Sun Jun 17, 2012 6:03 pm Post subject: |
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| macgyver655 wrote: | | Well your 1/125000th is 1 micron, correct? |
It's 1/25,000th - so one order of magnitude (roughly) larger than a micron.
| macgyver655 wrote: | | HogPilot wrote: |
Actually, it's most likely panel alignment rather than optics. It's very easy to produce an orientation where all three panels match in the center of the screen but not the edges. This can be caused by even the smallest difference in their angular relation to one another. The optics that combine all three chip images into one are fairly simple with flat surfaces - it's getting all three chips aligned properly with respect to the optics that's the challenge.
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I have no problem agreeing with the fact that a panel misalignment can be correct in the center but off on an outer edges but this would be more of a poor quality issue. I've worked on many of LCD projectors and have never seen an image with these characteristics. |
I don't know what LCDs you've worked on, but like I said this issue is very well documented and understood within the digital community. Frankly the attention it's getting here is far more than it's worth; it makes for an acceptable academic discussion at best. In terms of real-world impact on image quality, it's generally unnoticeable with most material. We're talking an average of at most 1/2 pixel misconvergence at the edges (at least on projectors of decent quality). Different manufacturers are known for different levels of QC. Epson had a streak of poor QC for a while that led to rather egregious levels of misconvergence (multiple pixel widths). The worst I've seen on any of my JVCs was my Pioneer RS2 clone (FPJ1), and that was off by one whole pixel of red around the perimeter, which was noticeable for me. Every other JVC I've had maxed out around 1/2 pixel MC at the edges, and my current one has even less.
_________________
| ecrabb wrote: | | Curt Palme wrote: | | Interesting, Mac isn't returning my emails. Go figure. |
He's mad at us for making Hog a moderator. He took his ball and went home.
SC |
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stridsvognen
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| Posted: Sun Jun 17, 2012 6:08 pm Post subject: |
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| macgyver655 wrote: | | stridsvognen wrote: |
Well i'm just looking my own JVC X7 and its like the geometry is a bit off between the panels, and its spot on in the center..
Gets worse the closer you get to the corners. So look like i should bend the panels to get it right.
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Can you describe just how the grid is off on these outer edges or post a pic? |
2 top corners and center
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macgyver655
Joined: 22 Aug 2007
Posts: 8508
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| Posted: Sun Jun 17, 2012 6:42 pm Post subject: |
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| HogPilot wrote: | | macgyver655 wrote: | | Well your 1/125000th is 1 micron, correct? |
It's 1/25,000th - so one order of magnitude (roughly) larger than a micron.
| macgyver655 wrote: | | HogPilot wrote: |
Actually, it's most likely panel alignment rather than optics. It's very easy to produce an orientation where all three panels match in the center of the screen but not the edges. This can be caused by even the smallest difference in their angular relation to one another. The optics that combine all three chip images into one are fairly simple with flat surfaces - it's getting all three chips aligned properly with respect to the optics that's the challenge.
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I have no problem agreeing with the fact that a panel misalignment can be correct in the center but off on an outer edges but this would be more of a poor quality issue. I've worked on many of LCD projectors and have never seen an image with these characteristics. |
I don't know what LCDs you've worked on, but like I said this issue is very well documented and understood within the digital community. Frankly the attention it's getting here is far more than it's worth; it makes for an acceptable academic discussion at best. In terms of real-world impact on image quality, it's generally unnoticeable with most material. We're talking an average of at most 1/2 pixel misconvergence at the edges (at least on projectors of decent quality). Different manufacturers are known for different levels of QC. Epson had a streak of poor QC for a while that led to rather egregious levels of misconvergence (multiple pixel widths). The worst I've seen on any of my JVCs was my Pioneer RS2 clone (FPJ1), and that was off by one whole pixel of red around the perimeter, which was noticeable for me. Every other JVC I've had maxed out around 1/2 pixel MC at the edges, and my current one has even less. |
A DVD mechanism moves to within .74 micron and a blu ray to .32 micron for tracking. Very simple build and very accurate with very little cost and have been proven for over 20 years. So it's giving way more finer adjustment then you indicated to be required.
I agree on that the conversation is not even worth discussing any further. I'm just gathering ammo..... I guess the true cause doesn't even matter. It's a problem and that's pretty much all there is to it.
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macgyver655
Joined: 22 Aug 2007
Posts: 8508
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| Posted: Sun Jun 17, 2012 6:44 pm Post subject: |
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| stridsvognen wrote: | | macgyver655 wrote: | | stridsvognen wrote: |
Well i'm just looking my own JVC X7 and its like the geometry is a bit off between the panels, and its spot on in the center..
Gets worse the closer you get to the corners. So look like i should bend the panels to get it right.
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Can you describe just how the grid is off on these outer edges or post a pic? |
2 top corners and center |
I can't really see it that well and I would ask some more questions for a better determination but i guess we are just going to bail on the subject. Like I just said in the other post, it's a problem and what ever is causing it is not relevant.....
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