737 "ElephantAir" build - Image warping with Immersive Display Lite 2

[Flying_Fox]

For image warping and soft blending I use ImmersiveDisplay Lite 2 (version 1.9). This program is amazing for what it does.

As you know already I have Optoma GT720 projectors and Matrox TH2Go Digital Edition. The projector native resolution is 1280 x 800, according to the specs.





I noticed that the projector without the signal has bigger lighted area, compared to its 1280 x 800 picture size. Interestingly enough, the TH2GO Display Properties suggest resolution of 1280 x1024 as default for it.





Here are the projected pictures of unwarped image. I specifically increased gamma/brightness here to show the areas that fall on the black frame around the screen.








Also want to note for the people who never did the warping before, that typical sample warping pictures on actual software sites or in manuals may be confusing misleading.
What shown there as a sample of warped image is not what you see on your projection screen and not what you work with. Here is the picture form Immersive Display site:





The picture they show is the image after warping - how it looks on the FLAT screen, not on curved screen. You almost never see that image unless you move the warped picture on your flat auxiliary monitor, (if you have one). I guess they put these pictures up just because it’s easier to do a screenshot from the PC, then bring the camera and make the actual picture from real projection screen. Sure it’s obvious to the developers, because they know what they are talking about, but may be confusing for the first-time users.

To have the auxiliary monitor in addition to projectors is a really good idea. Since the initially projected image is warped “the wrong way”, it is really difficult to operate with Windows menu bar, since it typically falls onto screen support structure outside the actual screen where it’s hard to see. I have the Windows taskbar moved to the flat monitor and docked there.

So, when you have the projected image like this:




you need to fit that crooked image into your curved screen. You may lose resolution pixels in vertical direction as a result, since both lower and upper image borders are curved, one more than another. Note also, that the pictures I show were done in “projectors on the floor” position.

Obviously, with the projectors on the ceiling the curves of the projected image will be upside down – greater curve on bottom of the image and smaller curve on top. There will be still highlighted areas above/under your screen even after warping – which might not be too bad on the black material. For this light bleeding issue there is a special “Mask” feature in the Immersive Display program that will apply another user-created image, masking those areas so the light just does not go there from the projector.

Before “Mask” feature the only other option was to build a physical mask around the projector lens to block the unwanted light areas.

Here are my current settings for the display properties and Matrox GXM software.







Note “Swap Displays” button in the above picture. Do not try to use it. It is evil. After cycling through it, the Matrox output completely ignored my left projector. While the Windows Desktop was still working, the Immersive Display warping program was starting display from central projector, no matter what settings were. I had to completely reinstall Matrox GXM software to put things back to normal. So if you want to swap projector inputs – just reattach the input cables appropriately.

When starting your warping - do not use the mouse to move the adjustment points. At least until you get the hang on it. It is far more precise and convenient to move adjustment points with arrow keys. Left-Right-Up-Down arrows move from point to point, Ctrl+Left, Ctrl+Right, Ctrl+Up, Ctrl+Down - move the points it the desired direction. For the initial warping you only need to adjust points vertically, and using the mouse you can easily mess the horizontal point position without you noticing it.

Here are the pictures illustrating the warping. I used 6 x 6 points grid. Note that Immersive Display dialog box is not warped along with the actual picture, so you may move it to the screen position where it’s easier to read.

Left screen adjusted, working on central:



Left and central screens adjusted:




All screens adjusted:




I found the most convenient to adjust on the default image with text lines. Then I checked on all other images:













All process including projector images positioning/sizing/alignment, then warping and some edge blending took me about 3 hours. The projection now covers the whole screen with 700 cm arc, which considering the current projectors position, gives 200 degrees field of view. Image overlapping for the edge blending is only 5%. I know it is recommended up to 20% overlapping, but I just do not want to sacrifice that much of the screen estate. Will see.

I also quickly tried the soft edge blending.

–here is the picture without blending:



- and here with some blending applied:




What you adjust for blending is - Overlap % in the first box. When you change this value you will see the overlapping part moving and you must make sure the image in that area matches.

The second box - Fade % adjusts the gradient on the blending area. This requires more tests with both daylight and night pictures in FSX. The trouble is that what might blend perfectly in daylight picture may have highlighted areas around in the night picture. I just did it for All colors – however you may adjust color values separately.

For one blending area you adjust it from both sides, for example Right side on the left projector and Left side on the central projector.

You will also need to additionally adjust the alignment points vertically near the blending area.








Correct blending sure will take more time than warping – you cannot rely only on how it looks in Immersive Display only and will need to check the adjustment in FSX each time.

This was just a quick test; the blending will be finalized after moving the projectors to the ceiling.

Nick

Link to the main build update thread: here

[Sean Nixon]

I think you mentioned earlier that your screen dimensions are based on around a 2 metre (2000mm) radius. Is that correct? It looks bigger in the pictures above.

Sean

[Flying_Fox]

Hi Sean,

Yes, that's correct. The screen radius varies ~ from 195 to 205 cm. The pictures were done with super wide-angle 21 mm lens - that's why it looks bigger. The room is only 4.56 x 3.70 m

Nick

[Sean Nixon]

As I said in the other thread, I'm about to rebuild my screen. My max screen diameter could be 5200mm, but I'd like to reduce it to 4000mm as I've earmarked some space for other use. As you have screen/projector design fresh in your mind, do you have any comments on larger -v- smaller screen size? I'd hate to discover that reducing the screen to 4000mm has a negative effect on the visuals.

Sean

[Flying_Fox]

There is always a trade-off.

Bigger radius:
- less brightness (probably not big impact with modern bright projectors.)
- bigger pixels = less clarity

Smaller screen radius decreases the pixel size and generally increases the image clarity - that's what I took from some other threads where owners described their bigger screens. Of course, the effect also may be individual and depends one one's eyes. I can see pixels from 2 meters only if I really want to.
You might try different projection distances even with flat screen or wall and find the best combination of distance/pixel size that works for you. Also, you should take into consideration that sitting in the captain's seat you will be closer to the left side of screen.

Nick.

[Fritz]

A very good guide. I tried a TripleHead2go with a GForce GTX 580 first but I had
Problems with the TripleHead2Go. Now I use a Radeaon 7970 with Eyefinty. Works better for me but I
couldn't start a FPS limiter with Immersive Display Lite 2.
Do you use an FPS limiter? If so, how did you solve it?

[Flying_Fox]

Hi Fritz,

No, I didn't use external FPS limiter yet, only internal one - I am experimenting with FSX.CFG now and will try extrenal limiter and FPS limiter built-in with NVidia Inspector and latest NVidia drivers.

Nick

[Flying_Fox]

As I said in the other thread, I'm about to rebuild my screen. My max screen diameter could be 5200mm, but I'd like to reduce it to 4000mm as I've earmarked some space for other use. As you have screen/projector design fresh in your mind, do you have any comments on larger -v- smaller screen size? I'd hate to discover that reducing the screen to 4000mm has a negative effect on the visuals.

Sean

Doing a lot of image testing recently, I typically sit somewhat further from the spot where the seats supposed to be in a cockpit. It looks to me that the sweet spot for the screen radius is closer to 2500 mm rather than 2000 mm. From around 2500 mm I don't see screen doors effect at all. However, it's with my eyes. Also, it applies to chosen screen height 4' (~1240 mm) and 3x1280/1024 resolution. With bigger screen height the pixels will be bigger and sweet spot should shift further from the screen.

Nick

[Fritz]

Thanks for the reply. To limit the FPS with the nVidia driver is a better possibility than to limit the FPS in the FSX itself. It is not the optimal solution but flying with this limiter is something more smoth than if the FPS is limited in FSX. However, I have changed to a Radeon.
The d3d_antilag limiter is not compatible with Immersive Display Lite 2. I can also not use FSP_Limiter_0.2, because it starts with parameters the FSX.exe. The wraploader_2 itself launches the FSX.exe.
I haven't found a solution how can I start both programs together. Unfortunately, there are no limiter available in the Radeon driver like in the nVidia driver. Remains for me at the moment no other option than to limit the FPS in FSX.

[Fritz]

Problem resolved. Wraploader2 can launch the external FPS limiter, which starts the FSX. Thanks to Fly Elise-ng for their support.