As for the 3D factor, given the way the Curiosity can move, can't it just snap one image, move slightly to the side and snap it again for stereo LR?
Mars rover camera project manager explains 2MP camera choice
81–89 of 89 posts
Re: Mars rover camera project manager explains 2MP camera choice
#82It would be neat if one day they send rovers in modules - one nuclear power supply to last dozens if not a hundred years, then a mini-robot sent to replace the modular camera with a 15MP one after they upgrade the bandwidth from 2mpbs to 10mbps and then one day 100mbps. That 15-30 minute pingtime is a problem that cannot be overcome unless they find a faster than light wave that can be used for transmission - or a wa…
I think the problem is that, if you are going to make a second launch, it's nearly always better to land some place different. We will accumulate a bunch of data on Gale Crater over the next several years, but we have essentially zero data on a whole bunch of very interesting parts of Mars.
With enough supplementary shipments, and enough patience, a rover could stroll all over the planet.
Re: Mars rover camera project manager explains 2MP camera choice
#83They should eventually release a series of regular-quality images taken sequentially as the camera pans left and right, and have a competition to see who can squeeze the most resolution out of them using image enhancement and fusion techniques. There are lots of interesting stochastic methods out there (e.g. "compressed sensing") that have application for this kind of thing. It would make a great academic competition…
During one of the press conferences Ravine mentioned they had hundreds of images of a single spot on the ground taken by MARDI, the descent camera, after it had landed and that a member of his team was working on using those to build a super-resolution image of the surface. I like the idea of a competition though.
Re: Mars rover camera project manager explains 2MP camera choice
#84Earlier quoted context omitted.
The sensor is black and white. This lets them collect the most accurate information about how much light hits each part of the sensor. To take a color image they put a color filter in front of the lens, then they can recolor the black and white image according to the color of the filter. If they take multiple pictures with different filters, they can reconstruct a color image. http://areo.info/mer/
Actually, the MastCams on Curiosity are bayer-pattern color sensors.
Wow, I had no idea. Thanks for the info. http://www.nasa.gov/mission_pages/msl/multimedia/pia15109.ht...
Re: Mars rover camera project manager explains 2MP camera choice
#85We'll just have to settle for the next mission to include 50MP cameras.
Re: Mars rover camera project manager explains 2MP camera choice
#86Earlier quoted context omitted.
I can understand their choice of a tested technology, but I don't understand the bandwidth argument. Is the processor so underpowered that it couldn't crop the image when needed?
(Sometimes I despair) If you crop 2MP out of a 4MP image, you might as well have started out with a 2MP camera in the first place. Except that if your 4MP CCD is the same size as your 2MP CCD, the light gathering area per pixel is significantly less -- you capture fewer photons, hence less information about what you're pointing the camera at! Raw pixel count is not a good measure of the imaging accuracy of a digital…
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Re: Mars rover camera project manager explains 2MP camera choice
#87Earlier quoted context omitted.
I can understand their choice of a tested technology, but I don't understand the bandwidth argument. Is the processor so underpowered that it couldn't crop the image when needed?
(Sometimes I despair) If you crop 2MP out of a 4MP image, you might as well have started out with a 2MP camera in the first place. Except that if your 4MP CCD is the same size as your 2MP CCD, the light gathering area per pixel is significantly less -- you capture fewer photons, hence less information about what you're pointing the camera at! Raw pixel count is not a good measure of the imaging accuracy of a digital…
That's why I stated "when needed". I thought I didn't have to explain it in more detail, but it seems I do. You obviously have an interest in these things and rightfully have issues with pure MP arguments. In this case you read something into my comment that wasn't there. That's my despair, and one of the reasons why I try to avoid commenting on technical posts.
Note that I also stated that I did understand that there were other technical reasons. My comment was limited to the question of bandwidth only.
My original question that you didn't reply to still remains. From a pure bandwidth point of view, they could crop the image when they need a high transfer rate so that they can have a higher resolution when they have enough available bandwidth.
If they chose 2MP for other reasons, that's fair enough.
Re: Mars rover camera project manager explains 2MP camera choice
#88Earlier quoted context omitted.
(Sometimes I despair) If you crop 2MP out of a 4MP image, you might as well have started out with a 2MP camera in the first place. Except that if your 4MP CCD is the same size as your 2MP CCD, the light gathering area per pixel is significantly less -- you capture fewer photons, hence less information about what you're pointing the camera at! Raw pixel count is not a good measure of the imaging accuracy of a digital…
That's why I stated "when needed". I thought I didn't have to explain it in more detail, but it seems I do. You obviously have an interest in these things and rightfully have issues with pure MP arguments. In this case you read something into my comment that wasn't there. That's my despair, and one of the reasons why I try to avoid commenting on technical posts. Note that I also stated that I did understand that ther…
I don't think you quite understand the difference between cropping and compression. Cropping an image is the equivalent of choosing which part of the image Facebook displays as your profile picture. While this method could reduce the size of the image to transmit down to '2MP', there's really no purpose in taking photos that are essentially cut in half.
Re: Mars rover camera project manager explains 2MP camera choice
#89Can anyone explain what the key limits on bandwidth are when communicating from Mars? Is it just a matter of higher bandwidth requiring higher energy consumption?
It's wireless transmission. Your bandwidth is a function of the frequency of your communication channel, and long-distance transmission generally uses low-frequency signals (and as a result, low speed).
The one way to get around this is to use a multi-channel link, that is to say you communicate over several frequencies simultaneously. This is more difficult, both technically and because you must find unused frequencies.