1/8/2004: "Bent" propeller

Undertoad · 01-08-2004, 11:22 AM

This is a simple digital photograph of two windmills. But when the photographer looked at the resulting image, it became a mystery, because the propeller on the one mill is not bent like that at all.

Another image was taken:

...and now not only is the propeller bent, but there's a ghostly floating propeller as well! WTF? Are our digital cameras documenting a new kind of aura??

Nope. It turns out that this can happen with cheap digital cams. Some of them rather slowly "read" the image on their sensor, line by line. If the subject moves at the right speed, especially if the speed is close to the speed of the sensor "reading", the image captured can contain these kinds of artifacts. And so the result is not what was expected.

To show the same principle, a guy turned his flatbed scanner into a camera. It slowly "read" the image it was looking at, line by line. He took a picture of his garage door opening and closing while the image was being "taken", and here's what he got:

Kitsune · 01-08-2004, 11:42 AM

That's excellent!

Any link for these images, UT? I'm curious to know how the scanner was modified. Those things normally don't focus beyond a couple inches off the glass.

I experienced a "slow scan CCD" camera's effects while taking snapshots and driving down the interstate. The result: trees nearest to the road seem to lean in recognition of your speed.

glatt · 01-08-2004, 12:14 PM

The scanner camera guy has a really cool home page with lots of neat stuff:

http://www.sentex.net/~mwandel/index.html

blue · 01-08-2004, 12:30 PM

If you haven't checked out the above web page yet do it NOW...this guy is a freaking evil genius!

SteveDallas · 01-08-2004, 12:30 PM

Fasinating... I wonder what the window of error is that you have to hit in order for it not to be just plain blurry.

tjennings · 01-08-2004, 12:34 PM

The propeller in that top picture looks like it was either by Dali or Burt Rutan.

I just noticed that those are Windchargers. They were made years ago in the little burg that I live in. If I'm not mistaken, they were among the first commercially available wind generators.

xoxoxoBruce · 01-08-2004, 06:13 PM

Hmmm, I smell a new hobby. Kudos, UT.

zippyt · 01-08-2004, 07:06 PM

Quote:

blue58 said If you haven't checked out the above web page yet do it NOW...this guy is a freaking evil genius!

I agree , this dude is SHARP!!!!!! But i question just how he would empty his wasp trap ????

Griff · 01-08-2004, 07:19 PM

I was checking out his Ruins page and found a burnt castle from New Jersey and googled it. That lead me to this. Damn, I love the internet.

That Guy · 01-09-2004, 12:02 PM

Quote:

Originally posted by glatt
The scanner camera guy has a really cool home page with lots of neat stuff:

http://www.sentex.net/~mwandel/index.html

See how much you can get accomplished when you don't have a TV?

And · 01-09-2004, 04:05 PM

Quote:

Originally posted by Griff
I was checking out his Ruins page and found a burnt castle from New Jersey and googled it. That lead me to this. Damn, I love the internet.

Looks similar to this.

Schweet... I want one of those cameras.

Kitsune · 01-09-2004, 04:08 PM

Quote:

Originally posted by And

Looks similar to this.

I love that site. This one, too.

01-08-2004, 11:22 AM	#1
Undertoad Radical Centrist Join Date: Jan 2001 Location: Cottage of Prussia Posts: 31,423	1/8/2004: "Bent" propeller This is a simple digital photograph of two windmills. But when the photographer looked at the resulting image, it became a mystery, because the propeller on the one mill is not bent like that at all. Another image was taken: ...and now not only is the propeller bent, but there's a ghostly floating propeller as well! WTF? Are our digital cameras documenting a new kind of aura?? Nope. It turns out that this can happen with cheap digital cams. Some of them rather slowly "read" the image on their sensor, line by line. If the subject moves at the right speed, especially if the speed is close to the speed of the sensor "reading", the image captured can contain these kinds of artifacts. And so the result is not what was expected. To show the same principle, a guy turned his flatbed scanner into a camera. It slowly "read" the image it was looking at, line by line. He took a picture of his garage door opening and closing while the image was being "taken", and here's what he got:

01-08-2004, 12:30 PM	#4
blue Operations Operative Join Date: Aug 2003 Location: Northern WI Posts: 739	If you haven't checked out the above web page yet do it NOW...this guy is a freaking evil genius! __________________ If you spot a tornado, always remember to point at it, yell "tornado!", and run like hell.

01-08-2004, 12:34 PM	#6
tjennings Belt Conveyor Join Date: Jul 2002 Location: Sioux City, IA Posts: 66	The propeller in that top picture looks like it was either by Dali or Burt Rutan. I just noticed that those are Windchargers. They were made years ago in the little burg that I live in. If I'm not mistaken, they were among the first commercially available wind generators. __________________ No, no, you're not thinking, you're just being logical. Niels Bohr, physicist (1885-1962)

01-08-2004, 07:19 PM	#9
Griff still says videotape Join Date: Feb 2001 Posts: 26,813	I was checking out his Ruins page and found a burnt castle from New Jersey and googled it. That lead me to this. Damn, I love the internet. __________________ If you would only recognize that life is hard, things would be so much easier for you. - Louis D. Brandeis

01-08-2004, 11:42 AM	#2
Kitsune still eats dirt Join Date: Sep 2003 Location: Tampa, FL Posts: 3,031	That's excellent! Any link for these images, UT? I'm curious to know how the scanner was modified. Those things normally don't focus beyond a couple inches off the glass. I experienced a "slow scan CCD" camera's effects while taking snapshots and driving down the interstate. The result: trees nearest to the road seem to lean in recognition of your speed.

01-08-2004, 12:14 PM	#3
glatt ™ Join Date: Jul 2003 Location: Arlington, VA Posts: 27,717	The scanner camera guy has a really cool home page with lots of neat stuff: http://www.sentex.net/~mwandel/index.html

01-08-2004, 12:30 PM	#5
SteveDallas Your Bartender Join Date: Jan 2002 Location: Philly Burbs, PA Posts: 7,651	Fasinating... I wonder what the window of error is that you have to hit in order for it not to be just plain blurry.

01-08-2004, 06:13 PM	#7
xoxoxoBruce The future is unwritten Join Date: Oct 2002 Posts: 71,105	Hmmm, I smell a new hobby. Kudos, UT.

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