I don't know if it's me or what but the MSL navcam images don't seem to be as good as the MER ones were. Any thoughts anyone ?

As one of the first people to mention that the navcams looked tremendously murky without a lot of processing, I have to say I like the new stretch. Previously, as mhoward has noted, the histograms on the navcam images were all piled up in the dark half the available dynamic range.

As someone who wants to just look at the images and doesn't have an automated pipeline from the website into Photoshop, I'd rather be able to look at and enjoy the images directly, rather than feeling the need to save them and run them through contrast and brightness gamma enhancements just to have a reasonably non-murky image in which my old, tired eyes can actually pick out good details.

That could be just my own reaction, though. As always, YMMV.

-the other Doug

Well, the Navcam image quality on the web improved dramatically for sol 42. The JPEG compression artifacts are gone; in fact I would describe the images as 'pristine', even better than we get from MER, now.

Well yes, dark sand and over exposed rocks ?
http://mars.jpl.nasa.gov/msl-raw-images/pr...NCAM00427M_.JPG

Sorry about that but I have to disagree. Try out to devignetting pictures like this, with so much difference between frames… Maybe it's clearer for people that are just consulting it, but working with that ? Okay, then I think I'm good to some nightMER panoramic adjustments.

I hope that I'm not the only one to have this point of view…

I agree completely. The new stretch makes it so much easier to quickly see if there's anything interesting in the new images. Then we can always compress the histogram back down into the lower 7 bits if we like.

No Fredk. What has been lost, has been lost. If you have black area, or white area, you can't "lower" the contrast to get back some details in these areas

Check this : http://mars.jpl.nasa.gov/msl-raw-images/pr...FHAZ00302M_.JPG

Around the Mastcam shadow, you have a white flat area. There were details inside.

I'm a little bit angry in my words, but for me, it's a total mistake to stretch picture like this. And come one, the previous ones were no so dark…

I think you're right Ant. I study with B/W sonography images and it's all about balancing the need for gain and compression. Once you have captured the image with such settings you can't regain the details by toying around with the histogram

You can reproduce the overall look of the old images. But I agree completely that where the whites are clipped in the new images, you can't recover that. It's the same with MER, but at least there we have Powell's evernote source which appear to be stretched/lut'ed more like the old MSL navcams. I checked and Powell's evernote MSL images changed their stretch today and are providing identical images to the jpl site. So no luck there.

Given that the primary purpose of these images is for people to look at them as they are, without photoshop to stretch them - they have done the right thing.

Many of the previous images were too dark.

http://mars.jpl.nasa.gov/msl/multimedia/ra...0424M_&s=40
http://mars.jpl.nasa.gov/msl-raw-images/pr...NCAM00418M_.JPG
http://mars.jpl.nasa.gov/msl-raw-images/pr...NCAM00302M_.JPG
http://mars.jpl.nasa.gov/msl-raw-images/pr...NCAM00417M_.JPG

These images would be 'better' for people to look at with the newer stretch. Yes - we get clipping at each end as a result, but the image occupies a larger part of the histogram and, combined with lower compression, is far better for people to actually look at.

So, I could think that "people" have some trouble with their screen brightness. Because for me, it's not too dark.

But I guess you're right, and I will continue my battle against windmills.

Hopefully what we're seeing has been temporarily utilized for a specific purpose, but if not...


Aaarg so true.... over or under saturation cannot be recovered, period. But it's the disruption of the gray level relationships that's most lamentable to me because that's where much of the textural subtleties and thus potentially valuable scientific comparatives reside. I'm not a trained geologist, but even from an armchair perspective, for a particular rock or patch of soil, slight differences in the average nominal gray levels is often the key to identifying similar or disparate specimens and helps in theorizing their inherent characteristics and relationships. And of course the extreme halo effect overall will make seamless looking mosaics a nightmare.

If the reasoning behind this is for the usability of the general public as suggested, perhaps some tweaking is part of the plan and we're seeing the first "extreme" test, after which I would hope that "toning down and tuning in" the level adjustment would be the next move. Hopefully there will be someone in the know here soon enough who can explain the rationale or temporal nature of what we're seeing a bit more.

FWIW, my guess is that jpl received masses of emails from the general public saying "these images are too dark". That's why the change. But now that the MSL engineering images look very similar to MER (I'm guessing it's the same algorithm), I doubt very much we'll see further "iterations". It's the masses screaming "too dark" they're reacting too; I'd be surprized if they bent over to tweak the stretching because a few of us complained about clipped whites. Remember that we were also loosing information in the old MSL images, them being effectively around 7 bits instead of 8.
...until the images appear on PDS! It won't be that long...

I'll just comment that I like the change (improved contrast) because now I don't need to process the images to get a decent cross-eyed view anymore. All I need to do is pop open a left navcam or hazcam image in a browser window and place it on the right side of my screen and vice versa. Then, cross eyes and voila!

About 3 months if I'm correct ? Scuse me but, certainly with color pics we will get a hand on it, but on Navcam, I don't think so. I didn't see so much processing of the MER Navcam PDS pictures in the past, and I don't think it will change with those coming from Curiosity. The fact of losing informations between 7 bits and 8 bits is in my opinion less important than losing informations by auto-adjust the histogram.

But I think I can say anything I want, this will not change the fact that now, Navcams will looks like this, I have to deal with it probably. I have sent a feedback via the "feedback" link at the bottom of Curiosity website, who knows ?

Thanksfully, they didn't apply such a processing onto color pictures from Mastcam (general public can fin them too flat, or too red ) !

Definitely not! The "new" ones are really harder to work with and I guess we will see more navcam panoramas with not so good blending now.
Working more than ten years in postproduction on images my opinion is that raw images should stay unaltered.
Also the darker ones mentioned above represent better that it is Mars we are looking at and not Earth.