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HI

I just bought a FPV system and we are testing it out.

The Tx is 500mw Rx has a patch 8dbi connected to it We split the out put on the Rx so we can use Goggles and record to a camcorder at the same time. The Camera on the plane is KPS S700B. The Goggles are the I Theater HR With 922,000 pixel resolution.

Here is the problem Too dark and the color is off.

So far we have only made 2 flights one in fun sun the other in full shade. In full sun we did not have a split signal so goggles were the only device in use for FPV. Some dark objects had white borders around them and color was way off. It was like it was compensating to underexposure. This is also true of the second flight. If you would like to see it here is the link http://jonsered-chainsaws.com/fpva.wmv

Is there a way to adjust the camera?

Is there something else that can be done?

Thanks

3R

Just did another test and problem is more with the Goggles than with camera.

Here something interesting Goggles work fine viewing a DVD through a DVD player but color and contrast not very good through Rx but Camcorder is ok.

When goggles were used to view what the camcorder caught was just as bad.

Thanks

3R

Edited by 3rflying

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I don't really understand the problem. Your video looks totally normal to me.

Please note that if you want to split the video signal between 2 devices, to do it properly you need an active video buffer. A Y-cable will only work on some devices, if they are all correctly designed you should end with a dark picture.

About the colors going from "normal" to "overly warm and saturated" back and forth depending on the image, it's THE weak point of the KPC-S700.

Just seen your edit, do you have brightness/contrast adjustments on the goggles? If yes you might want to play with these for example to try and set them to get as close as possible to what you can see with the same video on another screen.

Edited by Kilrah

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I looked at your video and think I know what you're talking about. If you mean that the contrast is too high and the ground looks dark when you're flying towards the sun, this is normal. The AGC in the camera tries to make the best use of the available (but limited dynamic range). Cameras do not have as good dynamic range as our eyes so when you're flying into the bright light, it will try to compensate by lowering the brightness but then the ground becomes dark.

You might be able to get around this if you have a camera with a better dynamic range but I don't think it gets much better than this with what is available cheaply at this point in time. Another thing you can try (besides flying when the sun is higher up in the sky) is to turn off the AGC if you can (some cameras apparently allow this setting but you need to use some software to do it via an I2C or SPI link I think). With the AGC off, you can elect to sacrifice the sky details for ground details. What this means is that when, you're pointed to the light, it blows out all the details, but the ground looks good all the time. That's one way of doing it. Perhaps the easiest way of improving this might be to use a kind of graduated filter. What this is is a filter where the top is darker than the lower part. What this does is that it artificially increases your dynamic range when properly aligned. The problem with this approach is that when you're banking or pointing to the ground it may not work as well. Worth trying though since it's a pretty simple solution. The trick is to find a suitable filter or way to may such a filter. I am thinking of some of the stuff used to tint car windscreens.

Hope this helps and please let us know how the tests go.

Daniel

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I simply position the camera accordingly to compensate for this. Point the camera down a bit, in order to have the horizon at the top 1/4 or 1/3 of the image when flying level, that way the camera will always see more ground and adjust on it. If you have a tilt servo then you can even do that in flight too.

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Another option is to process the video in some kind of software which has the ability to compensate against the AGC. One of my videos had the same problem, it was overcast, the sky was bright grey and the ground looked very dark.

I processed this in Premiere, added an "auto levels" filter, played around a bit with the effects and mixing to get the proper amount of lightness, and that reduced the AGC effect quite a bit.

On the original video you could see the AGC in action on a decent - as you got more and more of the ground in the view. The picture brightened up gradually till you've got full colors.

On the finished product there were no problems like this, these transitions are barely visible.

Take a look:

View in the embedded browser

Or download:

Link to download

Ox.

Edited by oxxyfx

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The only problem with that is that it's not real-time so it won't help when in-flight. As a post processing option, it's good. There are some cameras out there that boast improved dynamic ranges, but I've not seen them in action or read any reports on their real-world performance. In theory though, those cameras should perform better.

Daniel

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I was able to get my hands on a set of Goggles called Cyberman model is GVD510. These are much better. Is there a better model?

They have a brightness and contrast adjustments. We are now able to see a brighter clearer picture. Almost as good as what the camcorder records.

My suggestions is to stay away from goggles that do not have brightness and contrast controls.

Before giving up on the i Theater goggles I bought an amplifier to see if it would help.

The rx output went to the amp and it split to goggles and camcorder. It did improve the image just a little bit on the goggles.

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