strange red spot

[p_dutch]

is found a small arplain near the bahama's but whats the red spot in front of the plane??

23 34 30.41N 75 50 26.40W

[GEHER]

Hmm... Very interesting.

Maybe divers from the plane were chumming the water for sharks??

[Munden]

No, the airplane is in flight. That is the 'motion ghost', created by the method the satellite uses to take images. The reddish blur ahead of the aircraft is the color layer which is taken seperately from the 'value' or 'intensity' layer.

When objects are in motion, this effect is created. The greater the speed, the greater the distance between the two images.

Here's another one that makes the effect much clearer.

[SSSALVI]

That is the shadow in shallow water. You can clearly see the sea floor. and the reddish tinge can result due to differential refraction for non-red components through water in upward direction.

Shashi

[Felippo]

I agree with Munden. It's a "Motion Ghost" caused of a moving objekt seen from a multi-spectral camera. It only can bee seen with moving objects and on satellite-images. Sometimes you can see the gost even on cars.

In my placemarker you can find a little collection with "Motion Ghosts" and the shadows of the planes. On some pictures you can see, that the shadows have a "Motion Ghost" too.

Felippo :givebeer:

[GEHER]

Ah yes! I didn't even think of the plane being in flight. I just assumed it was a diving plane out on the reefs.

Makes perfect sense now.

[SSSALVI]

Agreed , provided the MSS acqiusition is not simutaneous for all the bands. In that case the stationary features will be aligned by the software while moving objects will not.

Anyway all the examples show the second moving image in the direction of motion so one can't really disagree.
But then there should be three images for three bands. Any explaination for that.
Each colour has its own value for pixels there in no seperate Value layer.

Shashi

[anmol.geh]

Three bands????

[Ravenfeather]

I'm pretty sure he means that when a satellite scans an object, it scans only in Black-and-White, When it goes back to scan in color, the object has already moved, thus creating the effect of "Ghosting"

[SSSALVI]

I'm pretty sure he means that when a satellite scans an object, it scans only in Black-and-White, When it goes back to scan in color, the object has already moved, thus creating the effect of "Ghosting"

Yes Ravenfeather,

In fact I stumbled upon an old thread yesterday and a little study led to an interesting find.

Just go throgh this thread. : Two Interesting In Dallas ; started by Appletom

Shashi

[jan15]

In some cases, the ghost image is directly ahead of the original image, as though it was shot a fraction of a second later.

But in other cases, the ghost image of both the plane and its vapor trail are also quite a bit to the side of the originals of each. What would cause that shift?

[p_dutch]

thank for the reply