Curiosity cameras - why such low res?

[Syntarsus]

I read in the NASA landing briefing that Curiosity's cameras were only 2megapixels. I think you can even get more than that on some mobile phones these days and that would be really low for typical consumer camera. My camera is 16mp which is pretty average. Curiosity's cameras can also shoot HD video but only 720p. So I was wondering why they haven't opted for the highest res they can get. Bandwidth limitations or what? I'd have thought that even if they didn't use the full resolution all the time it would have been good to have the option available. I'm a bit disappointed we won't have some really high res pictures though I guess they can stitch multiple images together but why not just get a better CCD?

[Earl]

They mosaic the images.

the camera may only be 2mp however it will be built to a much higher standard than normal cameras.

[Stephen]

I'd wager a small amount that a mobile phone camera wouldn't survive the journey to Mars but the Hazcams are designed to do so

The Hazcams are also engineering cameras, Curiosity isn't there to take pretty pictures

[FarSide]

My dad asked the same quwstion this morning. Curiosity isn't there to take pictures, as Stephen said, it's there to perform experiments. The cameras are there simply for guiding.

[Stephen]

More info here : http://www.nasa.gov/mission_pages/msl/news/msl20120803.html

[Naz]

My dad asked the same quwstion this morning. Curiosity isn't there to take pictures, as Stephen said, it's there to perform experiments. The cameras are there simply for guiding.

and to give the general public something they can relate too

[Syntarsus]

Seems weird though. The cost for better images is negligible so why take deliberately lower quality images? That's what I don't understand. You might well see some detail on a better quality image that a lower res shot will miss. I can only guess that the reason is something like bandwidth limits but I don't really know.

[Ainsley]

The pics came from the hazard cameras that just look at the wheels. I think that because the antenna is not yet up the signal is sent via one of the two orbiting satalites and then sent from them to us. So band width right now is an issue, until the big antenna is up. Also for just checking the wheels are OK and not stuck you dont need more res.

[Stephen]

Seems weird though. The cost for better images is negligible so why take deliberately lower quality images? That's what I don't understand. You might well see some detail on a better quality image that a lower res shot will miss. I can only guess that the reason is something like bandwidth limits but I don't really know.

An Atik 314L+ is only 1.45 megapixels .... OMG SHOCKINGLY POOR ... not

It's designed for a purpose, and it does that purpose well.

As covered above, the HAZard CAMeras have NOTHING to do with seeing, or detail, or images.

They are there for an engineering reason.

[kirkster501]

Seems weird though. The cost for better images is negligible so why take deliberately lower quality images? That's what I don't understand. You might well see some detail on a better quality image that a lower res shot will miss. I can only guess that the reason is something like bandwidth limits but I don't really know.

Bandwidth to upload the pictures. CPU to process them and memory to store them. Remember, although its true your camera on your iphone is 8 MegPixels nowadays, Curoisity was designed, debugged and tested several years ago. They are not going to say, just before launch, "Oh, lets put an higher res camera on there" ! What they will do is create a mozaic of images to give nice visuals so the US public can relate to their 2.5 billion dollar investment.

[Astro-Nova]

you wait till you see the panorama images with the main camera, id say that be way better quality

[riklaunim]

And Curiosity CPU is slower than iPhone CPU... but it can sustain radiation (imaging sensors too - like e2v testing one of their sensor up to 200 Krads), lower temperatures, and they must work for few years - they "cannot" break Also you don't get fast data transfer from and to Mars.

[Zakalwe]

Seems weird though. The cost for better images is negligible so why take deliberately lower quality images? That's what I don't understand. You might well see some detail on a better quality image that a lower res shot will miss. I can only guess that the reason is something like bandwidth limits but I don't really know.

Why does it seem weird, though? I don't want to sound like I am patronising (I am not), but what experience do you have in image data acquisition of this type? It might be more pertinent to ask yourself why you think it is weird and perhaps to research the subject?

As kirkster said, I'd bet a lot has to do with the bandwidth available. If you look at the Lunar Reconnaissance Orbiter, one of the cameras is 1 pixel wide by 5000 long. The second wide-angle camera system has a 1024 x 14 sensor, a 704 x 14 and a 128 x 2. These sensors are atched to the optics and to the available bandwidth. More bandwidth is probably not available. As it stands, by March last year it had delivered nearly 200 TERABYTES of data.....that'll keep the scientists busy for years.

The consumer DSLR marketing departments have the general public convinced that more megapixels = better quality. Do you really think that a mobile phone camera at 8 megapixels can really take better images than a 9 year old Canon 10d (6 megapixels) fitted with quality L lenses?

[Dazzyd]

The main camera mast hasn't been deployed yet, neither has the one on the long arm that can actually look back at Curiosity, those get deployed over the next week or two. The Images so far are from the Hazcams which are only used for hazard avoidance stuff. These became enabled as soon as the rover landed because they are fixed and they didn't need to be moved into place. Once the main cameras (all 17 of em) are up and running we should get some pretty decent images. As has been said, they could have probably put 5MP or higher sensors in but it was a trade off between quality and bandwidth. I'm sure I heard at one of the briefings that the data rate is around 2Mbit/sec (around 250kByte/sec) and then you have error correction etc on top of that as well as telemetry, scientific data etc and you can see how impractical higher MP sensors would have been.

We're going to see some amazing images over the coming months, the scientific teams need them as well as us so they can see where to drive to next (in case they see something interesting). Just like waiting for our clear skies, we just need to be patient

[SamAndrew]

Bandwidth isn't an issue, It says in Sky at Night that relay rate is 250Mbps

The resolution will be 3 times that of any previous landscape camera. so it will be able to put great mosaics together. I'm sure there's a reason they chose the cameras they did.

you must have an old phone if it's only 2 Megapixel I think there's a new Nokia that has 41Megapixels

[rory]

The main camera mast hasn't been deployed yet, neither has the one on the long arm that can actually look back at Curiosity, those get deployed over the next week or two. The Images so far are from the Hazcams which are only used for hazard avoidance stuff. These became enabled as soon as the rover landed because they are fixed and they didn't need to be moved into place. Once the main cameras (all 17 of em) are up and running we should get some pretty decent images. As has been said, they could have probably put 5MP or higher sensors in but it was a trade off between quality and bandwidth. I'm sure I heard at one of the briefings that the data rate is around 2Mbit/sec (around 250kByte/sec) and then you have error correction etc on top of that as well as telemetry, scientific data etc and you can see how impractical higher MP sensors would have been.

We're going to see some amazing images over the coming months, the scientific teams need them as well as us so they can see where to drive to next (in case they see something interesting). Just like waiting for our clear skies, we just need to be patient

spot on, patience is the word. all will be revealed as and when.

[Bluey]

I think the low resolution is so that when we find old Martian cities, the pictures will be grainy enough to cast doubt on what we are seeing

[E621Keith]

More megapixel means more computationally intensive. If the camera is used for machine vision, too many megapixels can significantly slows the frame rate, and by the time the computer finished processing that multi mega pixel image, the rover could have driven over a cliff.

Plus they won't want to waste too much data bandwidth to transmit images just to wow the public. Those data needs to travel from the rover to one of the orbiting satellite which relays the signal to some radio telescope on earth. Those two relay satellites orbiting Mars also have their own science mission and their own science data to beam back.

[barkis]

Oh I think we'll be happy with the quality that will no doubt come later.

Lots of systems appraisals to be carried out before the serious work begins.

We'll be Wowing into our Cornflakes before too long .

Ron.

[johninderby]

It was mentioned that the images were taken with the protective lens covers on the hazard cams still on just so they would have something to show. Hence the murky poor quality images. Once they've gotten things up and running properly then you'll see some proper images.

John

[tony4563]

Just getting ANY image from the surface of Mars is an amazing feat.

Having watched the animated sequences again, I still cant believe it landed so perfectly, the way it did.

Amazing stuff

[umadog]

I suspect the lower pixel count is because the CCD, like other electronics in these space probes, is radiation hardened. If you look at the computing hardware in space probes and vehicles you will see that it's always many generations behind what you can buy commercially. This is because it has to be extra robust and radiation hardened. So larger transistors, etc. Larger transistors probably translate into larger pixels. I'm just guessing here, mind you.

Also a greater pixel count isn't always better. Marketers like to push pixel count in commercial digital cameras but in practice there are applications where a greater pixel density is a drawback. Astrophotography is one such situation. Small pixels are not good for low light situations because the photon count per pixel is low and the read noise (Google it) becomes a problem. It's possible that a similar situations exist in a space probe camera, where radiation adds noise.

[ggreene1]

Bandwidth to upload the pictures. CPU to process them and memory to store them. Remember, although its true your camera on your iphone is 8 MegPixels nowadays, Curoisity was designed, debugged and tested several years ago. They are not going to say, just before launch, "Oh, lets put an higher res camera on there" ! What they will do is create a mozaic of images to give nice visuals so the US public can relate to their 2.5 billion dollar investment.

I agree with some of the posts above, that the early photos were of an engineering variety. On a side note... Being a taxpayer from the US, I'm good with a mission spanning 8 years that costs $2.5 Billion... (A mission that is worthwhile, in my opinion) $2.5 Billion is a lot of money, granted, but realizing that Americans spend almost 7 Billion dollars a year on potato chips. It doesn't seem like quite as much. I'm just saying.

[neil phillips]

When the panorama comes i think we are all going to be speechless. In the meantime heres a low res image of mount sharp. i messed with it a little to sharpen the image. Yes its noisey. I could have smoothed it. But prefer the sharper affect on the gravel than the Nasa smooth image.

Exciting times for us all. with this new science lab

[cotterless45]

Lovely, 3 mile high Mount Sharp in the background. Start rolling!

Nick.