[joe12south]

I've always understood, and used, the term "screen-door" to refer to the visual artifact caused by the amount of dead space "between" pixels. That is to say, the greater the fill-factor, the less the appearance of screen-door.


More and more it seems that this term is being used to describe plain old pixelation ... i.e. the fact that all things being equal and 800x600 projector will show more pixelation than an 1024x768 projector.


To me the distinction is important, because for instance an WXGA LCD projector like the Sanyo PLV-60 has a higher resolution and less pixelation than a WSVGA DLP projector like the inFocus LS110 ... BUT ... the LS110 has significantly less screen-door.


I'm not sure what my point is, other than there are two different digital artifacts that need evaluated, and thus, shouldn't we use two distinct terms to describe them? Is there industry accepted terminology?

 

[scottyb]

You hit the nail on the head Joe. People just need to know the difference.


When one of the masters here has time they should put together a glossary. It would save newbies from asking questions that have been covered many times. No, I'm not the candidate to do it. I own a restaurant so my time is pretty well taken up between that and the Mrs.


Maybe someone could start it and people could add as necessary. I'm sure this has been proposed before, but....

 

[QQQ]

I appreciate your point but I believe you are creating a distinction that doesn't exist. Screen door is the ability to see pixels, WHICH HAPPEN to be more visible when there is a lower fill factor. Screen door does not = fill factor, screen door = the ability to see distinct pixels, regardless of the reason (low resolution or poor fill factor).


If I see pixels on a 10' screen with an 800 x 600 DLP projector do I say "that's pixelization", but if I see it on 10' screen with a 1365 x 768 LCD projector say "that's screen door"? If I then change to a 2000 x 1500 projector with the same fill factor (as the 1365 x 768) and can't see pixels does the (the 1365 x 768) suddenly become pixelization instead of screen door? When any picture is blown up large enough and/or you get close enough you can see the pixels. You can't say "now I see the pixels because there aren't enough of them so I'll call it pixelization" or "now I see the pixels because of poor fill factor so I'll call it screen door". In fact, you are always seeing them because of a combination of both factors!


I think I've said the same thing about 5 different ways now - sorry!


Note for new members: pixelization is also often used to describe "motion pixelization", which is not what we are discussing here.

 

[joe12south]

QQQ,

I have to dissagree. The two respective issues *do* yield different visual artifacts, behave differently with different projectors, and therefore benefit from being discuss separately and labeled individually.


For instance:

Many high resolution LCD's, even when viewed from a distance from which individual pixels are not visible, suffer from a less than "solid" image because the percentage of area devoted to image vs the percentage of area that is dead border space is substantial.


Given that the fill factor on a typical DLP projector is much higher, at the same resolution, screen size, and viewing distance the DLP picture will appear more "solid."


Of course, the phosphors of a CRT yield no screen door at all, even if the display resolution is very low.