Spirit and Opportunities Images from JPL???

[rlb2]

I’m trying to get the color to the images in some of the images I display here to be close to true color as I can but what I get from JPL on there releases is a mixed bag of different looks. I know that you will get different looks depending on the time of day, filters used, raw images are raw, etc. etc.. <br /><br />The big problem I'm having with their releases is that they all show a very dusty Mars but you cant see anywhere where the rover has gone that they kicked up some dust. The dusty looking rocks the rover rolls over should also kick up some dust that would be visible in the images, like at the Sojourny site. The solar panels lasted for over twice the time they said they would, so this tells me there isn't as much dust at Spirits and Opportunity site as there were at Pathfinders. <br /><br />Here is a small piece of a just released 50 meg image JPL released. In the image you see the solar panels appear to be completely covered in dust, panels should be black. In this image it appear to be getting dark on Mars by the color of the sky so the panels should be darker with a light dusting, not the color as viewed. There are plenty more things to look at in this image that I haven't discussed yet. I have some rover images thet were taken terrestrially that show different colors then JPL has shown on Spirits true colors. <br /><br />Anyone have any good images of the rovers top view prior to launch? The ones I have been using give me a good idea so far if I am close to true color. When I get filtered images of the rovers on Mars I use that to process the different filters and compare it to my terrestrial images. I get different results than JPL as to what is true color.<br /> <div class="Discussion_UserSignature"> Ron Bennett </div>

 

[spacechump]

I know where your confusion lies. I'm posting the sundial image. It looks as if one of the filters was in the infrared area given how the dyes light up (the dyes' colors are different through different infrared, visible and ultraviolet combos). So while this may be "approximate color" it looks like JPL padded the stitched images with infrared or near infrared filter combos. So, yeah, the solar panels will look different.<br /><br />As for your problem with dust? How much would you think it would kick up? You can see the tracks in the panorama leading all the way to Bonneville. Remember Spirit <i>barely</i> inches along so its not like a kid riding his bike across a dry baseball diamond.

 

[spacechump]

Oops, here's the image of the sundial.<br /><br />

 

[thechemist]

Hi rlb2,<br /><br />Have you tried to use the MER Analyst's Notebook ? It includes all data from the MERs 30 first Sols, including raw PanCam filter images corrected for exposure and other instrument factors. Full manuals and references to research articles on imaging are provided.<br /><br />Daniel Crotty has a nice web page with a couple of such corrected images.<br /><br />The Mars Exploration Rover Forum has a discussion going on on MER imaging using raw PanCam data. According to the discussion of the good people there, color approximation is only possible by using the officially released PDS data in the first link of this post. <div class="Discussion_UserSignature"> <em>I feel better than James Brown.</em> </div>

 

[rlb2]

<font color="orange">I know where your confusion lies. I'm posting the sundial image. It looks as if one of the filters was in the infrared area given how the dyes light up (the dyes' colors are different through different infrared, visible and ultraviolet combos).<font color="white"><br /><br />I would guess that they used the L2,4,6 filters for that frame of the sundial, it makes the light blue turn pink.<br /><br />Check this out below. The image on the left is JPLs the image on the right is mine. If you look close you can see the background through one of the reflective canisters as marked.</font></font> <div class="Discussion_UserSignature"> Ron Bennett </div>

 

[rlb2]

Thanks for those links here are a couple more that I have.<br /><br />A very good site here. <br /><br />http://www.atsnn.com/story/30048.html<br /><br />Another one from Cornel in pdf format.<br /><br />http://athena.cornell.edu/pdf/tb_pancam.pdf<br /> <div class="Discussion_UserSignature"> Ron Bennett </div>

 

[rlb2]

I did something with your sundial. You know it must not be too much fun putting together all those separate images like JPL does to get the panoramic views because of the different times of the day they were taken. <br /><br />Here is a good site that explains the sundial and filter differences.<br /><br />http://www.atsnn.com/story/30048.html<br /><br />Check this out.<br /> <div class="Discussion_UserSignature"> Ron Bennett </div>

 

[slinted]

Thanks for mentioning my website TheChemist.<br /><br />I'm currently working on publishing a gallery of all MER images that were taken using all 6 visible light filters (so far data is available in the RAD format in the PDS release for Spirit Sol 1-70 (70-90 is currently missing from the RAD directories) and Opportunity 1-30.<br /><br />I was trying to use calibration target / sundial to figure out the proper whitepoint for each image, but I soon realized that wouldn't work directly, mainly because the dust accumulation (either on the sundial itself, the camera optics, or both) was a significant factor even over just a few sols. The only way I'll be able to derive the illumination from the sundial images will be to model out the dust accumulation.<br /><br />Here's an image to show the effect on Spirit's sundial, from sol 1 to sol 70.<br /><br /> http://www.lyle.org/~markoff/collections/spiritsol1_70_sundial.gif<br /><br />Daniel Crotty

 

[thechemist]

You're welcome Slinted !<br /><br />I have followed your site and your endeavours with MER imaging and eagerly await your color composites from the RAD files.<br /><br />Since I don't have an account at the MER forum (I admit I am a long time lurker there <img src="/images/icons/wink.gif" />) I grab the chance to ask you a question here at SDC.<br /><br />I tried to do some L456 RGB composites using MRD and MRL files from the MER analyst depository.<br />I know only RAD files should be used for that, but I lack the suitable imaging software that can correct for radiance using the two Radiance Factors parameters.<br />For quick and dirty approximate color, I tried MRD and MRL PanCam files, which I had the impression are also at least partially radiance-corrected.<br /><br />However I noticed MRD and MRL L456 RGB composites do not give the same color, although the MRLs are simply linearized MRDs (which I understand has nothing to do with color, but with camera lense effects).<br /><br />Any clue on this discrepancy ?<br /><br />Many thanks, and keep up the good work !<br /><br />TheChemist <div class="Discussion_UserSignature"> <em>I feel better than James Brown.</em> </div>

 

[slinted]

I haven't worked much with the MRD/MRL files, so I can't speak to that directly. But, even though they aren't the RAD files, there are scaling factors attached to MRD/MRL though they are almost all scaled identically ( Image_Radiance_Offset = 0 , Radiance_Scaling_Factor = 1 e-05 ) If for some reason the MRD files were scaled according to different factors than the MRLs, that could cause a difference in the colors. Other than that, I'm not sure.<br /><br />There are a lot of 'derived' statistics in the PDS tags of the files that should help to determine where the differences are. In the /* IMAGE DATA ELEMENTS */ section, there are Min/Max/Median values for each image. If the scalings were identical, then those values should be as well. Hopefully this will help you diagnose the problem a little better. <br />

 

[mah_fl]

Wow, that sundial image sure does show the dust accumulation. Also you have to remember that the surface of Mars has been around a lot longer than the Rovers. Though Mars is refered to as "The Red Planet", its not exactly what we in the UK refer to as "Post Ofice Red" is it ? BTW everyone keep up with the colour image production as I don't know how to do them. (Allthough I have altered some colour images to what I think they should look like, from time to time.)

 

[slinted]

The true-color galleries I've been working on are finally completed and can be viewed at http://www.lyle.org/~markoff/ (in the calibrated section)<br /><br />There are still some issues with the scaling of brightness, but I feel confident in the coloration. I was surprised as to how monotonous it came out, with little variation in color, but I was working from the calibrated files, which I trust more than my judgement of what it would should look like. <br /><br />As they've seen across most of the mission so far, especially from RATings that they've done, everything is covered with the same dusty material on the surface. Also, the dust in the air creates seems to be creating a very 'reddened' spectrum of light that hits the surface, exacerbating that effect even further, which helps to explain further the bland nature of the colors.

 

[thechemist]

What an enormous amount of work on your site !<br />Many thanks Daniel for these wonderful Mars color galleries ! <br /><br />I'm sure Michael Lyle's server will see some very serious traffic <img src="/images/icons/wink.gif" /><br /> <div class="Discussion_UserSignature"> <em>I feel better than James Brown.</em> </div>