Re: Parralex Inversion Fix???
Posted: Sun Mar 25, 2012 8:57 am
Hi N,
Things are not looking good:
Well I thought that last trick would do something good but too bad I only tested it on my CRT because when I tested on my DLP, I could see that the PJ compensates for that adjustment so it doesn't have the desired effect. Yes, you did it right and it would have been a good trick if it had worked but the technology is just not the same as a CRT. It looks like it memorizes the image and displays it at the next vertical sync pulse and so that cancels out any fine tuning of the timing of the image between pulses. At this point, I could recommend some other things but the situation doesn't look good right now. I'm starting to think your PJ has an unresolvable(?) color mismatch issue and I would like you to test that in a weird way but first some things that probably won't work.
Use one of Windows' "Restore Points" to restore things back to before you had this problem. That would be some time before March 5th.
Use the Reset function under your projector's help menu.
Change video timing standard - choices are General, Discrete Monitor, Coordinated Video, or Fixed Aspect Ratio Timing (FART). I tried these on my DLP with no effect as expected. Don't bother with this.
Change video signal timing manually - it turns out that changing vertical backporch and frontporch do something similar to what you just tried by moving the image down but it can also squash or stretch the image. This shouldn't help. Don't bother with this. Now for some "fun"...
The spinning-pen test:
( I'll put this in it's own thread later but right now I'll just give you a brief version here. )
This may seem weird but please try it. It will help you and me figure out exactly what is going on with your PJ's colorwheel and it's a technique that you can use with any future DLP PJ or TV you may get.
Step 1. Get a white pen with a clip on it and tie it to about 8 inches of string or rubberbands.
Step 2. set up your eDim dongle and eDim glasses for use with your setup (original TH2Go setup is fine)
Step 3. Start up your PJ and switch to 60 Hz Presentation mode
Step 4. Make the screen all white with a maximized empty text window or bitmap.
Step 5. get edim glasses shuttering with Activator but don't put them on yet.
Step 6. twirl the pen in a circle in the beam of the projector. Don't look at the screen through the twirling pen because it's harder to see the colors that way. See the colors better by offset viewing against a dark background. Now you see the colors of your colorwheel. It should look something like this:
Notice that it's made up of continuous bands of colors probably in this order: red, green, white, blue (RGWB), but how can you tell that red is the first color of a frame? That's next.
Step 7. Repeat step 6 with the glasses on and one eye closed. You will see dark segments where colors are missing. Try to adjust the twirling speed to steady the image but I know it's hard. You should see 12 colors between the dark regions because your PJ has a 4-color wheel and it's speed is 3x so that it spins three times for each frame. Instead of counting 12 colors, just note the first and last colors (expect red first, then blue last) and count 3 blue bands in each sweep of colors. Just to be clear, I expect this pattern: darkness,RGWB,RGWB,RGWB,darkness with a possible thin red band on the end since that's what I see with my old PJ. The purpose of step seven is to get you familiar with the PJ's "normal" colorwheel operation. That's why you're at 60 Hz and you're in Presentation mode because it shows the white band better. For brighter viewing, look and twirl in a direction perpendicular to the beam while standing closer to the PJ. Now you see the standard colorwheel operation. I suspect a different behavior at higher freqs so let's test it. First here's an image of how it would look if your colorwheel only spun once per frame. My old PJ shows 8 colored bands between the dark regions instead of 4, and that proves that it spins twice per frame (if it has 4 colors per cycle). Yours is different.
A shuttered view of a hypothetical 1-color-cycle per frame projector using a 4 segment color wheel (RGWB). Light from every second frame gets blocked creating the dark zones. Now you know that the red band comes first in the color cycle assuming you spin the pen clockwise. Step 8. de-Activate glasses, change freq to 75 Hz, Activate glasses, repeat step 7. Notice differences between each eye-view. I expect the two views to have different patterns. Try to note the first and last color for each view. From this info, we can tell exactly what the PJs are doing and where the red ghost is coming from. It just takes some analysis.
This all may seem tedious and complicated but I think it's fun so try and have it be fun for you too. I bet you never expected this when I started to "help" you.
awaiting your results,
--- iondrive ---
PS: if you do alot of twirling, rubberbands may be softer on your skin so you don't get a raw patch. I guess you could use yarn or gloves. jeez.
And don't let the pen fly off into someone's eye.
Things are not looking good:
Well I thought that last trick would do something good but too bad I only tested it on my CRT because when I tested on my DLP, I could see that the PJ compensates for that adjustment so it doesn't have the desired effect. Yes, you did it right and it would have been a good trick if it had worked but the technology is just not the same as a CRT. It looks like it memorizes the image and displays it at the next vertical sync pulse and so that cancels out any fine tuning of the timing of the image between pulses. At this point, I could recommend some other things but the situation doesn't look good right now. I'm starting to think your PJ has an unresolvable(?) color mismatch issue and I would like you to test that in a weird way but first some things that probably won't work.
Use one of Windows' "Restore Points" to restore things back to before you had this problem. That would be some time before March 5th.
Use the Reset function under your projector's help menu.
Change video timing standard - choices are General, Discrete Monitor, Coordinated Video, or Fixed Aspect Ratio Timing (FART). I tried these on my DLP with no effect as expected. Don't bother with this.
Change video signal timing manually - it turns out that changing vertical backporch and frontporch do something similar to what you just tried by moving the image down but it can also squash or stretch the image. This shouldn't help. Don't bother with this. Now for some "fun"...
The spinning-pen test:
( I'll put this in it's own thread later but right now I'll just give you a brief version here. )
This may seem weird but please try it. It will help you and me figure out exactly what is going on with your PJ's colorwheel and it's a technique that you can use with any future DLP PJ or TV you may get.
Step 1. Get a white pen with a clip on it and tie it to about 8 inches of string or rubberbands.
Step 2. set up your eDim dongle and eDim glasses for use with your setup (original TH2Go setup is fine)
Step 3. Start up your PJ and switch to 60 Hz Presentation mode
Step 4. Make the screen all white with a maximized empty text window or bitmap.
Step 5. get edim glasses shuttering with Activator but don't put them on yet.
Step 6. twirl the pen in a circle in the beam of the projector. Don't look at the screen through the twirling pen because it's harder to see the colors that way. See the colors better by offset viewing against a dark background. Now you see the colors of your colorwheel. It should look something like this:
Notice that it's made up of continuous bands of colors probably in this order: red, green, white, blue (RGWB), but how can you tell that red is the first color of a frame? That's next.
Step 7. Repeat step 6 with the glasses on and one eye closed. You will see dark segments where colors are missing. Try to adjust the twirling speed to steady the image but I know it's hard. You should see 12 colors between the dark regions because your PJ has a 4-color wheel and it's speed is 3x so that it spins three times for each frame. Instead of counting 12 colors, just note the first and last colors (expect red first, then blue last) and count 3 blue bands in each sweep of colors. Just to be clear, I expect this pattern: darkness,RGWB,RGWB,RGWB,darkness with a possible thin red band on the end since that's what I see with my old PJ. The purpose of step seven is to get you familiar with the PJ's "normal" colorwheel operation. That's why you're at 60 Hz and you're in Presentation mode because it shows the white band better. For brighter viewing, look and twirl in a direction perpendicular to the beam while standing closer to the PJ. Now you see the standard colorwheel operation. I suspect a different behavior at higher freqs so let's test it. First here's an image of how it would look if your colorwheel only spun once per frame. My old PJ shows 8 colored bands between the dark regions instead of 4, and that proves that it spins twice per frame (if it has 4 colors per cycle). Yours is different.
A shuttered view of a hypothetical 1-color-cycle per frame projector using a 4 segment color wheel (RGWB). Light from every second frame gets blocked creating the dark zones. Now you know that the red band comes first in the color cycle assuming you spin the pen clockwise. Step 8. de-Activate glasses, change freq to 75 Hz, Activate glasses, repeat step 7. Notice differences between each eye-view. I expect the two views to have different patterns. Try to note the first and last color for each view. From this info, we can tell exactly what the PJs are doing and where the red ghost is coming from. It just takes some analysis.
This all may seem tedious and complicated but I think it's fun so try and have it be fun for you too. I bet you never expected this when I started to "help" you.
awaiting your results,
--- iondrive ---
PS: if you do alot of twirling, rubberbands may be softer on your skin so you don't get a raw patch. I guess you could use yarn or gloves. jeez.
And don't let the pen fly off into someone's eye.