A sign that all is not what it seems in the MER data - a strange mark has appeared.

And no, I don't think the marsrover/NASA site has better images than the PDS, the fact that they are JPEGs is a sign that they cannot be better.

I did not suggest that the public marsrover/nasa site is better than the PDS.

There are examples of photos taken here on Earth with the cameras on the MERs and they are much better than we get to see coming from the rovers on Mars.

Are you suggesting that the MER images stored in the PDS are the best images NASA have?

Somehow, I do not think that they would spend all that money and accept that the result is a truly terrible GIF file which is what you are telling us. There must be more to it than that.

Originally posted by qmantoo
There are examples of photos taken here on Earth with the cameras on the MERs and they are much better than we get to see coming from the rovers on Mars.

Does that take into account all the rovers' photos or are you comparing the photos taken on Earth with the worst photos from the rovers?

Are you suggesting that the MER images stored in the PDS are the best images NASA have?

Yes, from those that I have seen.

Somehow, I do not think that they would spend all that money and accept that the result is a truly terrible GIF file which is what you are telling us.

Why do you keep on talking about GIFs? The PDS images are not GIFs, they are IMG files.

reply to post by ArMaP

Does that take into account all the rovers' photos or are you comparing the photos taken on Earth with the worst photos from the rovers?

Why would you suppose that I would compare the worst MER pictures with the best from Earth taken by the same camera. That would be ridiculous. However, we do expect to get comparable results - quality wise because the instruments are the same.

See the article here saying that the Pancam has a resolution of 1mm per pixel at 10 feet. Do you think we get that?
www.universetoday.com...

From 10 feet away, Pancam has a resolution of 1 millimeter per pixel. “It’s Mars like you’ve never seen it before,” says Steven Squyres, Cornell professor of astronomy and principal investigator for the suite of scientific instruments carried by the rovers

My comment - Are you suggesting that the MER images stored in the PDS are the best images NASA have?

Yes, from those that I have seen.

Yes me too, and so I wonder where all the better ones are? (see above about the resolution of the pancam)

Why do you keep on talking about GIFs? The PDS images are not GIFs, they are IMG files.

Because when I have extracted the rover IMG files, there is a gif inside, that's why. As I say, if you know anywhere which has tif images of mars rover images I would be interested to see them.

Originally posted by qmantoo
Why would you suppose that I would compare the worst MER pictures with the best from Earth taken by the same camera. That would be ridiculous. However, we do expect to get comparable results - quality wise because the instruments are the same.

Sorry for that, as you said, it would be ridiculous to compare those photos with the worst from the rovers, but did you compare them with the best?

See the article here saying that the Pancam has a resolution of 1mm per pixel at 10 feet. Do you think we get that?

Yes, resolution is just one characteristic of an image, and not the best to identify the quality of the image.

Yes me too, and so I wonder where all the better ones are? (see above about the resolution of the pancam)

I don't think there are better ones. Could you point me to the images taken on Earth that you used to compare with the images from Mars? Thanks in advance.

Because when I have extracted the rover IMG files, there is a gif inside, that's why. As I say, if you know anywhere which has tif images of mars rover images I would be interested to see them.

That's strange, IMG files have a text header and then an uncompressed image, not a GIF file. As a test I loaded just the image part of an IMG file into a hex file editor and it starts with this:

80 08 A9 08 91 08 C1 09 39 08 A9 08 A9 08 A9 08 A9 08 F0 09 08 08 A9 08 91 08 A9 09 20 08 C1 08 91 08 F0 09 08 08 A9 09 08

A GIF file looks like this:

47 49 46 38 39 61 A0 02 D4 02 F7 00 00 00 00 00 01 01 01 02 02 02 03 03 03 04 04 04 05 05 05 06 06 06 07 07 07 08 08 08 09

The first bytes of a GIF file are always those, they represent the text "GIF89a" that identifies the file as a GIF.

...did you compare them with the best?

I must have looked at thousands of images from the rovers. Why are you asking me all these questions when it is obvious, and you have said so yourself in this thread, that the ones we get to see are not very good. I would say that they are nothing compared with what we would expect to come from a proper science mission.

From my investigations, images in IMG files are not in raw uncompressed state. You cannot just strip off the header and save the rest of the IMG file as a GIF file or whatever format it is in. This means that looking in a hex editor is not going to give you the encoding of the embedded file. I wish it was that easy.

When I used the NASA program ImageView on windows the images were in GIF format as far as I can remember. That was a year or two ago.

The images taken on Earth were from the Cornell University and have now been removed. Consequently you can try, but all I get is a 404 error.
athena.cornell.edu...
and
athena.cornell.edu...
These were taken of the lab and zooming in, you could see the details of the posters and notices on the walls. I have them saved somewhere but without an 'official' source they are no good to anyone but me.

I can see we are not getting anywhere here, so I will just say thankyou for your involvement and the answers you have given me.
Q

Originally posted by qmantoo
I must have looked at thousands of images from the rovers. Why are you asking me all these questions when it is obvious, and you have said so yourself in this thread, that the ones we get to see are not very good. I would say that they are nothing compared with what we would expect to come from a proper science mission.

I don't remember exactly what I said, but the photos changed a lot during the mission, with the first ones not being that good, then getting very good and starting to get worst and worst with time, as expected.

From my investigations, images in IMG files are not in raw uncompressed state.

From my use (and from the specification), images in IMG files are in raw uncompressed format, after a header describing the file and the image, along with other data that may be added. I think that's what they call a "label", that can also be in a different file.

You cannot just strip off the header and save the rest of the IMG file as a GIF file or whatever format it is in.

No, you can't, but that's because the format used in the image part of the IMG file doesn't follow the specifications for any common file format, like GIF. If you strip off the header you will have a block of pixels with exactly the size of the image, so for a 1024 x 1024 pixels image you will get a 1,048,576 bytes file.

This means that looking in a hex editor is not going to give you the encoding of the embedded file. I wish it was that easy.

That's one of the uses of a hex editor, to show you exactly what's in the file. If it was a GIF file then it must start with those six characters, that's what the file specification for GIF files says.

When I used the NASA program ImageView on windows the images were in GIF format as far as I can remember. That was a year or two ago.

Nasa View (the one I use) gives us the possibility of saving as JPEG or GIF, the IMG file must follow the IMG specification.

The images taken on Earth were from the Cornell University and have now been removed. Consequently you can try, but all I get is a 404 error.
athena.cornell.edu...
and
athena.cornell.edu...

That explains why I couldn't find them.

Once more, the Internet Archive comes to the rescue of old web pages.
Pancam

I can see we are not getting anywhere here, so I will just say thankyou for your involvement and the answers you have given me.
Q

Thank you for the discussion.

yes, if you go to the wayback machine and enter
"athena.cornell.edu/popups/news/midnight_pan0.html" in the first search box and "wayback Machine" in the second righthand box, click Go. Select July 7th 2007 and the correct image pops up. This is the one I meant and thanks for finding it in the internet archive. Thats good you found it. As you can see there are some really good close-ups of the filing cabinet stickers etc if you click on the red boxes.

I don't remember exactly what I said, but the photos changed a lot during the mission, with the first ones not being that good, then getting very good and starting to get worst and worst with time, as expected.

Why would it be expected? Everytime it seems like you are making excuses for low-grade image products. There is NO excuse for this and you and I both know it. If we begin to see dead pixels, then I can accept that the ccd or cmos chips are failing, however, I and many others have old digital cameras which do not have (or only 1 or 2) dead pixels in them and I believe that NASA would have better than standard ones.

No, you can't, but that's because the format used in the image part of the IMG file doesn't follow the specifications for any common file format, like GIF. If you strip off the header you will have a block of pixels with exactly the size of the image, so for a 1024 x 1024 pixels image you will get a 1,048,576 bytes file.

Really? OK well then it should be fairly easy to chop off the label part and save the raw part as a png or whatever.

I still think it is not as easy as you believe as there are quite a few IMG converter programs which only work on a few types of IMG product - such as MRO images or LRO images. This is because the IMG format can have many different possibly nested OBJECT types inside the label and the actual file can hold data in various formats - tables, images, text, whatever there is a specification for, and there are many specs. If it was as simple as you say, there would be no issue with the different formats and a converter which works for one type of product would work for them all.

That's one of the uses of a hex editor, to show you exactly what's in the file. If it was a GIF file then it must start with those six characters, that's what the file specification for GIF files says.

I understand this, however you have confirmed that there is only a GIF or JPEG possible output from using ImageView from NASA. Now, the actual image inside the IMG raw image file may be able to be saved as a PNG if we had the appropriate different software (and some alternative to ImageView which has these limits of only saving to JPEG or GIF format)

the IMG file must follow the IMG specification.

The IMG file format is very flexible (see above)

Originally posted by qmantoo
As you can see there are some really good close-ups of the filing cabinet stickers etc if you click on the red boxes.

I was expecting better images, those images have more noise than I thought.

Why would it be expected?

Because the first photos are taken in an untested environment, then, after the camera is calibrated they get better and then they get worse because the lens and filters get more and more dust. That's what I was expecting.

Really? OK well then it should be fairly easy to chop off the label part and save the raw part as a png or whatever.

No, you cannot save the raw image part a PNG because the PNG format is not like that. Every file format has their own specifications, and for a file to be a PNG, GIF, BMP (the closest to the raw IMG format that I know), etc. it has to follow those specifications.

I still think it is not as easy as you believe as there are quite a few IMG converter programs which only work on a few types of IMG product - such as MRO images or LRO images. This is because the IMG format can have many different possibly nested OBJECT types inside the label and the actual file can hold data in various formats - tables, images, text, whatever there is a specification for, and there are many specs.

Yes, the IMG format is somewhat like the TIFF format, it can have almost anything inside it.

If it was as simple as you say, there would be no issue with the different formats and a converter which works for one type of product would work for them all.

Photoshop can open several of those images, you just have to tell it the height, width, number of bits per pixel and where the image starts inside the IMG file.

I understand this, however you have confirmed that there is only a GIF or JPEG possible output from using ImageView from NASA.

ImageView has only those two possibilities.

Now, the actual image inside the IMG raw image file may be able to be saved as a PNG if we had the appropriate different software (and some alternative to ImageView which has these limits of only saving to JPEG or GIF format)

I use IMG2PNG, a free (I don't remember if it's open source or not) command line program and a small program that I made to open IMG files and save them as PNG by using IMG2PNG.

The IMG file format is very flexible (see above)

Yes, but it must follow the specification, like all file types.