Author Topic: Correct aspect of projection?  (Read 7473 times)

Offline Wiweeyum

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on: December 11, 2008, 10:21:48 PM
The issue I have with projecting the screen onto a desk is that the perspective is all screwed up. If you were to take a rectangle and trace it onto the screen, the object will appear to be the correct shape, but if that image were saved and looked at later on the computer screen, the rectangle would be a trapezoid; larger at the top because of the projected angle. While this isn't an issue when using it for office or presentations, using it for more precise applications such as photo manipulation etc would cause problems.


The simplest fix would be to use the perspective adjustments built into the projector to correct the issue, but not all projectors (and especially not the low end ones) have this feature built in.

I want to be able to calibrate the screen display coming from the computer to only display in a portion of the projected area. The screen would be the correct aspect and ratio on the surface it's projected onto, but skewed on the computer display. This would reduce the resolution of the tangible area, but even using the Wiimote Whiteboard, I'm usually only taking advantage of about 20 to 30 percent of the tracking resolution. It doesn't seem that it would bee to big of an issue.


Though I'm not confident in my writing eloquence, I hope the images help to illustrate my concerns and ideas.

Is there anything created that could do this already? I know Johnny Lee has the automatic surface tracking system, but I don't need anything that powerful. Just a one time calibration is all that would be necessary.


~"Any intelligent fool can make things bigger, more complex, and more violent. It takes a touch of genius -- and a lot of courage -- to move in the opposite direction."~
- EF Schumacher


Offline InTheater

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Reply #1 on: February 26, 2009, 01:34:54 AM
I add myself to the list of persons looking for that kind of solution,
the software should exist in some form, most of the media players have today rotating and video effects for "playing" purposes, it should not be so difficult to implement something like that.



Offline boonjin

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Reply #2 on: February 26, 2009, 02:43:42 AM
Hi,

If you are using a nvidia based graphics card, you may try this Software based Keystone correction.
http://www.nvidia.com/object/feature_nvkeystone.html


Regards,
Boon Jin

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Offline Wiweeyum

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Reply #3 on: February 26, 2009, 11:05:59 PM
Yeah, I tried that, but my nvidia card is older than what they built the program for. I've done a lot of looking since I posted this thread originally a few months ago, but There doesn't seem to be much available.


~"Any intelligent fool can make things bigger, more complex, and more violent. It takes a touch of genius -- and a lot of courage -- to move in the opposite direction."~
- EF Schumacher