on the software correction for CA idea...
I know this is a bit old, but thought of this thread when I read it on the panamorph site:
"Unfortunately, LCA in the horizontal stretch case is so visible that some type of color correction is mandatory and all of today's popular HE lenses require extra lens elements to compensate for this (which is why HE lenses are so much more expensive than VC lenses). However, we have another trick we can play as well. LCA can be imagined as slight geometric scaling of each color component making up the image relative to some base color such as, for example, green. If the projector (or external scaler) can slightly vary the stretch of each color to compensate for the optical stretch on the screen, the remaining color aberration can be neutralized to within one half of a pixel. This patented technology has already been demonstrated. However, actual implementation into projectors and scalers is something only the market can decide. While the minor residual LCA of current vertical compression lenses is not enough to warrant this capability, it is possible that growth in the demand of a low-cost, high performance HE lens may provide enough motivation to develop it."
I know this is a bit old, but thought of this thread when I read it on the panamorph site:
"Unfortunately, LCA in the horizontal stretch case is so visible that some type of color correction is mandatory and all of today's popular HE lenses require extra lens elements to compensate for this (which is why HE lenses are so much more expensive than VC lenses). However, we have another trick we can play as well. LCA can be imagined as slight geometric scaling of each color component making up the image relative to some base color such as, for example, green. If the projector (or external scaler) can slightly vary the stretch of each color to compensate for the optical stretch on the screen, the remaining color aberration can be neutralized to within one half of a pixel. This patented technology has already been demonstrated. However, actual implementation into projectors and scalers is something only the market can decide. While the minor residual LCA of current vertical compression lenses is not enough to warrant this capability, it is possible that growth in the demand of a low-cost, high performance HE lens may provide enough motivation to develop it."
A fair comment. It should noted that CA is a progressive abberation and not fixed to multiples of a pixel as well as it also bi-directional. This means it could be 1/10 of a pixel at 25% in from the edges and 2.6 pixels at the edges. Will S/W have that kind of flexibility?
I honestly belive that this can not be fixed electronically with the current projector technology.
Also, what happens if the user wants to move the lens for 16:9? Suddenly the screen is full of misconverged colours.
I honestly belive that this can not be fixed electronically with the current projector technology.
Also, what happens if the user wants to move the lens for 16:9? Suddenly the screen is full of misconverged colours.
software could have that kind of flexibility... as long as the phenomena is well understood and consitent, i see it as no different than any other kind of image processing... in fact, it is easier than some. edge enhancement is very dynamic and requires user selectable parameters... certainly not a static pixel contrast displacement across the image (i.e. depends on where the high contrast edges are). same goes for algorithms to smooth motion. I think it can certainly be done, but the place for it to happen is in the image processing chip of the PJ, not externally. That way, when you select vertical stretching, the same logic that triggers the anamorphic lens moving into place in some systems will trigger a reconfiguration of the image processing much in the same way you have different calibration sets for different sources. I think panamorph is correct here (at least as far as they are concerned holding the patent); the market desire for such a solution (or lack thereof) will determine whether or not we will see it.
Reminds me of some technology I saw from a small company that sells stereoscopic machine vision systems (security systems, factory automation, etc.)... they had all the processing usually done on workstations on a dedicated chip... very complex algorithms to map stereoscopic images to a 3D model in high resolution/high update rate... they found a market for it, so putting on a chip became the better business model for them. The problem here, is that such a solution would likely be short lived, for if sufficient market existed to justify investment, we'd see 64:27 projectors shortly thereafter given the competitiveness of that marketplace.
Reminds me of some technology I saw from a small company that sells stereoscopic machine vision systems (security systems, factory automation, etc.)... they had all the processing usually done on workstations on a dedicated chip... very complex algorithms to map stereoscopic images to a 3D model in high resolution/high update rate... they found a market for it, so putting on a chip became the better business model for them. The problem here, is that such a solution would likely be short lived, for if sufficient market existed to justify investment, we'd see 64:27 projectors shortly thereafter given the competitiveness of that marketplace.
hi``i am sduting zemax, and try to design a astro telescope, the software you are using now is also zemax?
Nice meet u!
you could add me or email me:
skype: yuki_hanxue
email: yuki.optic@gmail.com
Nice meet u!
you could add me or email me:
skype: yuki_hanxue
email: yuki.optic@gmail.com
I recently upgraded to a 1080p optima DLP (HD20) projector from a Benq 720p. My 720p projector had its hdmi port stop working a year out of waranty. I sold the old one on ebay and advertized it as working except for the hdmi port. A guy purchased it and I got the 1080p.
Anyway had been looking at anamorphic but I only paid $1000 for my projector with extended warranty (3 years and one bulb replacesment for $600 and I am happy with it. Great picture quality for my use and the huge screen does not have the LCD screen door. Even a $1000 anamorphic lense would not make sense. I picked up two big glass prisims and I have to say I am impressed by just holding them up in front of it. Box is coming soon and I got the wood for it today.
When reading the boards I looked at some of the sites that sell them. I read about some sort of astigmatism correction piece. It looks like it makes the picture sharper. What is this and is there a DIY option to put one of these on.
Thanks
Anyway had been looking at anamorphic but I only paid $1000 for my projector with extended warranty (3 years and one bulb replacesment for $600 and I am happy with it. Great picture quality for my use and the huge screen does not have the LCD screen door. Even a $1000 anamorphic lense would not make sense. I picked up two big glass prisims and I have to say I am impressed by just holding them up in front of it. Box is coming soon and I got the wood for it today.
When reading the boards I looked at some of the sites that sell them. I read about some sort of astigmatism correction piece. It looks like it makes the picture sharper. What is this and is there a DIY option to put one of these on.
Thanks
Update, this thread seems dead but I will at least post what I have found so far in my build. The prisms I got are huge compared to some I have seen used here. I built a make shift box for figuring out the angles and distance. Instead of gluing the plexi to the tops and bottoms of the prisms I chose to use velcro. This would allow me to easily remove it and ajust things if I needed. So far I am impressed with that as well. I held it up to the projector tonight and seemed to get a pretty good picture from what I could tell from my spot under the projector. I dont see any of the reflections people have griped about or the pronounced problems with the edges. Then it occured to me... since I got wedges that are pretty much huge it probably fixes the reflection problem. Or at lease the noticable reflection because the light coming out of the ends is going well off screen. Also with the prisms being huge they are also thich which helps lower the angle that the light is going through them (I hope I used the right term) kind of like using two prisms stacked on each other. I am going to mess with this more tomorrow and will soon get to building a slead.
Oh one odd problem though, the whole image seems to shift down on the wall about 2-3 inches with the box in front. I dont know if the prism are completely alligned but I guess I will figure it out tomorrow. It is a painted screen so worse comes to worse I will make the screen a little bigger at the bottom for when I use the slead. I know it will not have the crisp black boarder but at this point I have not really noticed any problems.
Oh one odd problem though, the whole image seems to shift down on the wall about 2-3 inches with the box in front. I dont know if the prism are completely alligned but I guess I will figure it out tomorrow. It is a painted screen so worse comes to worse I will make the screen a little bigger at the bottom for when I use the slead. I know it will not have the crisp black boarder but at this point I have not really noticed any problems.
Another source of Prism lenses
A web site that sells optical quality plastic (not glass and no anti-reflective coating) is Bernell.com
Prisms
Just thought this may help.
With the prism technique, you are shining light onto a glass or plastic surface and such a oblique angle that you are guaranteed to have light reflect off of it and this occurs twice (at each interface between air and prism). This will cause a loss of illumination so i would think you would need to increase the brightness using this method. I have only tested this with simple lenses and a light source but not with a projector.
This is why i'm trying to come up with a way to make an cylinder anamorphic lens with materials that anyone can get. Just trying to figure out how to do it well.
With cylinder anamorphic lenses the light will not be hitting the glass and an angle and therefor you should get only 1% reflection and 99% transmission.
hope this helps
pete
A web site that sells optical quality plastic (not glass and no anti-reflective coating) is Bernell.com
Prisms
Just thought this may help.
With the prism technique, you are shining light onto a glass or plastic surface and such a oblique angle that you are guaranteed to have light reflect off of it and this occurs twice (at each interface between air and prism). This will cause a loss of illumination so i would think you would need to increase the brightness using this method. I have only tested this with simple lenses and a light source but not with a projector.
This is why i'm trying to come up with a way to make an cylinder anamorphic lens with materials that anyone can get. Just trying to figure out how to do it well.
With cylinder anamorphic lenses the light will not be hitting the glass and an angle and therefor you should get only 1% reflection and 99% transmission.
hope this helps
pete
I have not posted in a while. The only way I see DIY'er making their own cylindrical lenses is to pay for glass and make the case.
The DIY part will be the case and the mechanics used to move one (or more) lenses to adjust astigmatism correction, the alignment and final adjustment once the lens in installed. CA correction will be handled in the glass itself. The level of precision we need for this is out side the realms of virtually any DIY'er, so even if someone actually was able to do it, they would be the only one and the project would not be duplicated by others.
You'll get losses from all glass types, even coated glass so you will not get 99% transmission.
The DIY part will be the case and the mechanics used to move one (or more) lenses to adjust astigmatism correction, the alignment and final adjustment once the lens in installed. CA correction will be handled in the glass itself. The level of precision we need for this is out side the realms of virtually any DIY'er, so even if someone actually was able to do it, they would be the only one and the project would not be duplicated by others.
You'll get losses from all glass types, even coated glass so you will not get 99% transmission.
I have Infocus IN82 projector. Reading through this tread, I am keen to make Anomrophic Lens.
I found this in UK web site. Is this any good for Anomrophic Lens?
5 Inch Guardian Optical Crystal Wedge Award : Classic Crystal Awards Collection @ PerfectlyEngraved.co.uk
When I phone this Company lady on the phone did said some of the people did buy for other use then Award.
They have 5", 6", 7" three sizes, which one is best for my projector.
Any help will be apreciated.
I found this in UK web site. Is this any good for Anomrophic Lens?
5 Inch Guardian Optical Crystal Wedge Award : Classic Crystal Awards Collection @ PerfectlyEngraved.co.uk
When I phone this Company lady on the phone did said some of the people did buy for other use then Award.
They have 5", 6", 7" three sizes, which one is best for my projector.
Any help will be apreciated.
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