350 Megapixel Camera

Remy Hathaway writes "Ars Technica just posted an article on the "MegaCam", a 350 megapixel camera. The original story is from the Honolulu Advertiser."

Comments

Filesize of the pictures

[neur0maniak]

Just imagine how big they'll be.. 350Mb(yes, megabits!) x 24bpp = 8.4Gb (Gigabits) = 1.05GB (Gigabytes). And that's without compression. How long would that take to compress, too?

Re:Filesize of the pictures

[p4ul13]

I'm not sure about compression, but there is an X10 joke in here somewhere...

Looking through the links I saw pleanty of images of the camera itself, but no actual images from the camera. Yes, yes, I know they're not going to put the +-1GB image on a site, but a largely scaled down and compressed sample for the gee-whiz factor would be nice.

Re:Filesize of the pictures

[lfourrier]

I think we need some breakthrough in technology. I've heard about some technic using a silver based substrat. The file is written in parallel, using some light encoding. Total writing of the file can take as little as 1/1000 second. Calculate the througput, it is very impressing. Compression is lossy, and it is more similar to cd-r than to cd-rw, and long term stability is not guaranted. But give it a few years, and I'm sure we will have a solution derived from this principle.

Re:Filesize of the pictures

[Idarubicin]

Not only that, but it could readily be made compatible with a large installed base of legacy technology.

Re:Filesize of the pictures

[faxafloi]

From the project description at CEA:

Each exposure will produce about 770 MB of data; the mosaic will be read out in about 20 seconds which means that Megacam will produce approximately 100 images (science fields and calibration) per night, ie 77 GB of data each night or about 1 TB of data for an average observing run.

So it will likely be 16bpp, not 24. Astronomical images are usually FITS, not JPEG.

Large images like this are becoming the norm in astronomy. Double the dimensions of a CCD and you quadruple the file size. With mosaiced chips like this one, you can easily get monster images. Then there's the processing, where you're usually juggling several similar-sized images. Looks like CEA is addressing this.

Incidentally, if they did want to compress these, some lossy algorithms (wavelets, Starck) do well on astronomical images. Most of what you lose in those cases is the sky noise, as long as you don't select too high a compression factor. The DSS did very well with 10x wavelet compression.

Re:oops

[mdielmann]

Actally, if you follow the link to megaprime from ARS, you'll find that the camera is called MegaCam, from the MegaPrime project...
http://www-dapnia.cea.fr/Phys/Sap/Acti vites/Projet s/Megacam/index.html

Re:oh my...

[jzs9783]

but then those pictures of Britney Spears having sex with a donkey while spanking Natalie Portman's ass will actually be clear!!!

Additional info on their website...

[stienman]

For those too busy to go to their website:

The imager is made up of 40 silicon imagers, each of which has two imaging surfaces on it, for a total of 80 channels of about 4.3 megapixels each. There are gaps between the silicon imagers. Images they make have black borders around them so that the image spatially is like looking through a window with bars. The imagers are rectangular, and are set up in a pattern somewhat like this

.HHHHHHHHH
HHHHHHHHHHH
HHHHHHHHHHH
.HHHHHHHHH
The periods are due to slashdot's inability to do & nbsp;, & #160;, etc. The #'s I was going to use in place of H caused the lameness filter to spew "Too many junk characters." I guess I didn't realize I had a junk character account, nevermind that it is apparently overdrawn!

It takes a full ten seconds to get the data from the sensors, and there is a rotating shutter above it. The time to take the image and then copy it off the array is long enough that they can only obtain about 1TB of data on a typical veiwing night.

-Adam

Re:god...

[_pruegel_]

Quote from their camera pictures page:

Cryogenic The cooling is done using a "pulse tube", a closed-cycle cooler with no moving part, therefore no vibrations. The cold capacity is used to keep the CCD mosaic cold during the installation of the instrument at the prime focus.

So yes, it is cooled.

Megaprime

[Strange Ranger]

So Optimus Prime can take pictures during battle?

350 megapixels really is More Than Meets The Eye.

CCD mosaic

[Anonymous Coward]

they actually use CCD mosaic. There are 38 CCD chips of which 36 are usable, each 9 Mega pixel.
Total resolution is about 18000x18000. At 0.2" visibility (the best you get anywhere on earth), this gives 1 degree FOV. It is large in total pixels, but each chip is not. Largest single CCD ever made is about 63 Mega pixel. Largest in 35 mm digital cameras are 16 mega pixels. Mosaics are suitable in astronomy where they don't mind a line here and there not exposed.

The most important characteristic of astronomy CCD chip is back illumination which gives ultra high efficiency and extremely low noise.

I believe, there is another project where they plan more than giga pixel mosaic. But forgot the project name or link.

how many LOCs?

[snot whistle]

how many LOCs per cubic hectare per fortnight is that? imagine a beowulf cluster of THESE babys! what a great day for pr0n! in soviet russia, they take pictures of you!! all of your pixel are belong to us! (this post is just a lameness filter test)