Linux Journal: Transform Methods and Image Compression

Usenet comp.graphics: JPEG FAQ

Usenet comp.compression: Compression FAQ (contains sections about JPEG)

Wikipedia: JPEG

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After the past couple of days it's goot to get some reassurance that my brain is behaving somewhat normally again.

OK, I'm wound-down over this and wish to extend my heartfelt thanks to all who have been so theraputic and informative. Gadzooks I would like to see something really colossal emerge from all the effort and energy consumed by the space science community. They deserve to score a success of truly cosmic proportions.

Perhaps it's a good time for me to just shut-down, but now that the door's open I'd sure like to keep in touch with you folk. Is there a thread for iconoclasts?

Having made a fool of myself, I remain quite grateful for your patience.

It seems to me that nothing was wasted in the least.
You're not to shut down- you're opening up.
And instead of stubbornly trying to convince everyone that they were wrong, you stepped up to bat and did some learning.

You might be amazed how rare that is, how few people do that. You did not make a fool of yourself, you demonstrated that you are not a fool.

BillyG, I hope you stick around.

I wouldn't say you'd made a fool of yourself. I would suggest, however, that a bit more politeness would have been in order.

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Gillian

"Now everyone was giving her that kind of look UFOlogists get when they suddenly say, 'Hey, if you shade your eyes you can see it is just a flock of geese after all.'"

"You can't erase icing."

"I can't believe it doesn't work! I found it on the internet, man!"

People who wind up there may have have been drawn by this descriptive text and these keywords. Now, they might be drawn here. If so, I hope they consider reading this whole topic.

Also:

And...

Shudder.

Here's a little more for the more discerning searcher:

Keywords: skeptical, skeptic, skepticism, critical thinking, debunk, truth, reality, image compression, jpeg, jpg, artifacts, mars express, mars, martian, hale crater, fields, buildings, technology, baloney, bilge, bunk, bunkum, claptrap, flapdoodle, flimflam, hogwash, hokum, hooey, hot air, humbug, humbuggery, malarkey, poppycock, tommyrot, tripe, wrong

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Apologies extended for abrupt manner. Am a subscriber to the idea that the kindest thing we can do for our friends is to give them a face-saving way to back down from the ridiculous positions they take from time-to-time.
Modifications to signature and avatar posted in effort to facilitate better communications.
Now I'm off to read all the threads and try to come up with some rather more informed questions, but I have to do laundry and buy beer too.

The bachelor combo.

Lawdy, lawdy, lawdy there's lots of things in this clogsite, or whatever it is. I could spend several days just cruising the back alleys of Bad Astronomy. So far, the Conspiracy Theories threads are the truly most astonishing (IMHO) collections.

....So how did the picture of the resistor get into the Hale .jpegs?
Was it a residue remaining from someone not running the disk through the diskwasher thououghly enough?

C'mon, guys 'n gals...How did this image wind up like this. Please let's not get into a weenie-roast about how real it isn't, it exists and I love a good joke. So how'd it get itself done?

Yo! -VanRijn- The other day when you were massaging my meanderings, you came up with a link about the Mars Express bird performing .jpeg compression way up thar (presumably) before sending the pics back to earth.

If .jpeg is as lossy as it would seem to be, why would they bother to put it into a spacecraft in the first place?

Why is lossy compression used at all? It saves bandwidth and in this case, they obviously decided that the advantages outweighed the disadvantages.

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I say there is an invisible elf in my backyard. How do you prove that I am wrong?

Disclaimer: Avatar is not an official NASA image and does not imply any specific interplanetary or interstellar capability.

The Leif Ericson Cruiser

I don't know what you're referring to. You're going to need to provide more information. An image link and specific reference would be good.

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I say there is an invisible elf in my backyard. How do you prove that I am wrong?

Disclaimer: Avatar is not an official NASA image and does not imply any specific interplanetary or interstellar capability.

The Leif Ericson Cruiser

-Van Rijn- The link in the signature field in my posts is the image I'm torqued-out over.

Since the ESA also provides a .tiff file of some of the Hale Crater shots, they must have a variety of schemes to select from. So it stands to reason to me that they are _not_ compressing everything before sending it back here. Don't they just send back the raw data in it's most complete form?

I mean, it's not like they have to pay for 'air-time'....or do they?

They do. The Mars-Earth links don't support much bandwidth, there's several other probes from several space organizations competing for what's there, and the ground stations here on Earth are rather more involved than sticking a satellite dish up somewhere. Plus, the probes themselves have limited lifetimes. Given the cost of Mars Express and the initial planned mission duration, probe time cost works out to about $190 per minute, completely ignoring ground equipment and salaries for the operators, and bandwidth taken from other probes. And it may take over half an hour to receive a response to a command, due to simple distance and lightspeed lag.

Presumably they do have ways of getting uncompressed data for specific observations, but given the time this takes away from other observations and requires reconfiguring the probe (at some risk to the probe itself due to the possibility of a mistaken command or other glitch) to process and send such images, so they would need a very good reason to do so. And some of those images are synthesized here on Earth from images and other data sent from Mars. JPEG compressing the result of assembling many small JPEG images into one large mosaic will add artifacts, using TIFF makes sense even though the source images were JPEG compressed.

-cjameshuff-
(Experiencing another 'ah-ha!' moment, I) GOT IT!
Thank you, maestro.
Hey I went off to visit Malin's site. They talk about configuring your browser to accept [PDS .IMQ format or PDS .IMG type application/octet stream and save it to disk]
Could you take a minute, please, and enlighten me a little about this. I have this rather pedestrian browser from Microsoft and nothing obvious gives me a clue.

I'm getting hooked on this stuff.

It's amazing how when you think you know about something, you can look deeper and find out just how little you actually knew, huh?

Happens to me a lot...

-neverfly- 10-4 on that.
My problem is that I get all excited and there's no better 'high' for me than when my little wet brain gets itself a new channel.

I'm stoked about the quality of the information you'alls are pouring in here. I'm no space scientist, but my career was (I'm retired now) as a video presentation specialist in the convention services industry in San Francisco where I spent twenty years in scientific sessions paying attention to the quality of the imaging. I may not have known anything about the subjects, and there were many, but I had to pay professional attention to every detail of the presentations. So there's lots of useless data bouncing around in my head. I probably qualify in several vague medical specialties based solely on contact hours.

I did IGU conferences for years. (Albedo, airglow, sun) Cognito, ergo sum.

It also rendered my flame-proof on the net, but we're all doing asbestos we can, right?.....(appropriate smiley deleted for security reasons.)

Oh, I thought that had already been rather thoroughly discussed. I don't see any "resistors." I do see obvious compression artifacts in a JPEG image that's been manipulated to enhance the artifacts: enlarged too much, converted to grayscale, inverted, and contrast enhanced.

As the document I quoted earlier in thread showed, the Mars Express uses JPEG-like lossy compression on board, so you can't assume any images would be free of compression artifacts. Beyond that, there is additional processing that varies depending on the type of image created (and the color composite images would necessarily require more processing).

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I say there is an invisible elf in my backyard. How do you prove that I am wrong?

Disclaimer: Avatar is not an official NASA image and does not imply any specific interplanetary or interstellar capability.

The Leif Ericson Cruiser

JPEG compression includes a parameter that influences how much quality is allowed to degrade. Pick any photograph you have, load it up in any software that can save the file as .jpg, and look around the advanced options. Usually there is a setting for quality factor. Try saving the file to a new name, with 95%, and after re-opening the original file, save it again to another new name, this time with 10%. Compare.

The point of this post is, even if the quality factor is at 99%, the compression of the image data is still huge, and thus the savings worthwhile for spacecraft onboard storage, and transmission to earth. In that scenario there is very little loss of data.

Now the image is on Earth, and ESA wants to show off, and put it on a website. If you load a website you don't want it to take 10 minutes, so ESA compresses the image with a little more data loss, but a lot more file size reduction. The image is still great to look at, even if some detail has been lost, or some compression artifacts start to show up.

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"Ignorance more frequently begets confidence than does knowledge" -- Charles Darwin
"Your right to hold an opinion is not being contested. Your expectation that it be taken seriously is." -- Jason Thompson
Meet the OOONG TOE.

This 'resistor', lying on its side with the lead cut and bent into a curlie-cue.

Attached Thumbnails

 

Here's another close-up:

Attached Thumbnails

 

close up of what though? I see a black mark that looks like a squashed letter J.

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Yeh...me too.

There's more blather bout this going-on on YouToob, but the thing that really hits home for me is that 80-meters per pixel these 'structures' would have to be just too huge. The scale seems all wrong somehow the more I get into it.

I'd still like to know more about this process. Lots of people (well, ok that's relative) are heaving and retching over these pictures, like I did. Why are these patterns showing-up like this? I can't buy coincidence.

In the Hale Crater shots, there is what appears to be an immense pyramid in the upper left middle (sorta) with what appears to be steam coming out its top.
The Malin shot of the 12-kM high 'tower' also appears to have 'steam' venting from its top.
Fumaroles exist at the bottom of several of the deepest oceans on earth. IS there any evidence that these (purported) large-scale tower-like possible but unproven to be other than .jpeg artifact psuedo-science projections of hyperactive imagination falsifications of perception errors of judgement made by uninformed ignorant savages who simply want to believe that everything is a conspiracy and the Martians are really your next-door nighbor and you better wakeup to God's message....'items', like the undersea fumaroles, are natural geothermal vents?

I second this. There is always room for one more willing to learn. Nothing wrong with knowing nothing, everything with refusing to learn. Those 'smarter' than you are simply farther down the road, but this in no way should preclude anyone from getting ON the road in the first place.

It will be a big day indeed when an extraterrestrial civilization is found, but it will be after much incredible and un-deniable evidence has been found. You may even be the one to find it--unfortunately I don't think this is it. I'm keeping my fingers crossed, and will until 'that' day.

Welcome to BAUT!

(I also second Gillianren on the politeness thing--that goes a longer way than one might imagine!)

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None to speak of

D'oh, two in a row from me. Oh well:

I have no idea, but this is something that can be researched. If an image with less compression is available it could be inspected. If a researcher with the project could be interested, more data of a specific sort necessary could be acquired. If another, future researcher could be persuaded to put this as one of their areas of interest on a similarly future mission to the Red Planet.

Were this a large geologic formation, it would still be HUGE. If the scale is indeed 40 meters/pixel, then this thing would be ENORMOUS. If it is a structure, it should be visible in decompressed shots very clearly.

There are large holes on Mars, that has been seen before. We think anyway. Not sure where the links are, though. Give me time to find them.

As for why artifacts seem to be grouped. I would suspect that when the compressing software is looking at the picture, it is looking for ways it can 'cut corners'. Anything that is the same or very similar would get compressed 'more' (I can't describe it well here, but essentially it would give an entire swath of 'similar' a code to read 'pretty much the same').

When our computers look at the code to decompress, it sees 'pretty much the same, made of two colors primarily...' and creates lines which we see as artifacts. The bigger the 'sameness' area, the stronger the artifacts. Without knowing the code or the process used to compress, I can not verify this. It would, however, be the simplest way to compress/decompress an image if quality were not a top concern.

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None to speak of

Well, gee fellers.....now I'm getting all a-twitter.

All we need is for one of the probes to send us back a picture of a transistor radio and I'll be convinced. The graphical information that we do have is not conclusive enough to confirm that there is _not_ a reason to subscribe to Rare Earth.

I want to know if the mere fact that the Hale images have excited such imaginings has been taken into sccount by the experts. I guess I'm kind of stumbling around a bit here, but why hasn't ESA come out and definitively explained to the loopys that what they are seeing is an artifact field and not a debris field.

The problem, IMHO, is that the imaging artifacts are too readily misinterperted, and there is a real danger in allowing the public to feed on misinformation. Especially in a social atmosphere where mistrust of good science has gained a foothold on the coattails of a mistrust of so many other cornerstones of our civilization.

The Hale Crater .jpeg artifacts are too curious to completely ignore, and there are likely to be rabid folk carping on this in times to come. I think we need an acommodation here, with a calm, friendly and efficient means to enlighten those willing to listen and learn, and very carefully steer away from alienating enquiring minds.

Like, if I go through the Hale Civilization shots here and post detailed photos on each and every questionable item (there really aren't that many) and we carefully describe the whys and wherefores...I think this would something like a community service.
Yes?
No?
Been-there-done-that?
Reinventing the wheel?

Over....

First to follow up on the fumarole question, here is a link from NASA/JPL regarding a discovery from Spirit that may indicate fumaroles. I don't know if the scientists ever published a conclusion, or if it remains indecisive. The article is from Dec 2007. I think there is more, there was something about a satellite image with some odd hole-like formations that may have been deep holes--not everything is an artifact, but most are. The scientists who study these things are 1) pretty good about this sort of thing and 2) VERY careful. If something (major) does slip past them, it would be a huge story indeed. Unfortunately I have no idea where the deep holes story is. If I find it I will put a link forward. Now for the rest of the post:

Emphasis mine

Correct. However, it is not NEARLY enough to prove ANOTHER Earth. There is a big difference between the two.

If I had to guess, I would say they publish the photos for public consumption in a manner that can be readily accessed even by those with dial-up, meaning small file sizes. They do this knowing that: 1) there will be artifacts and that 2) people will mistake them/claim them (the artifacts) to be what they are not.

There will ALWAYS be people to make crazy claims--that is one reason the ATM thread exists, to debate crazy ideas regardless of their validity. The more valid ones we hope survive the pummeling, the wackier ones do not. In between we have ones that are just mistakings or confusion, such as I anticipate to be the case here.

Emphasis mine
You pretty much hit it on the head!
Depends. As far as going through point by point in a forum style conversation, then yes to re-inventing the wheel. Every fourth topic in ATM and Conspiracy Theories is like this. Well, not every fourth, but I would say an average of once to twice a month. It keeps us all busy. That is why I said anyone willing to look at things critically even if a question goes against their desired outcome has a role to play. Some are more knowledgeable, but anyone who can pose a question of the critiquing sort should ask! We have our hands more than full of this sort of thing all the stinkin' time.

If you are speaking of some sort of website or blog, I think there are some, but none that are focused and regular enough to keep up with all the craziness that people attack. There is more than enough material to go around, just check out GLP or ATS for proof of that. I would LOVE to see a webring of sites and blogs, each focusing on a particular item such as psychic abilities, Mars questions/conspiracies, Planet X (in all its derivatives), chemtrails/government conspiracies, young earth psuedo-science (more the process of their 'science' than the conclusion--though the conclusion would follow soon enough), and any other claim for which the line "you're such a close minded/hypocritical skeptic" has ever been uttered. Also for things like "vaccines cause..." that isn't particularly defined in a larger category. Even with well defined subjects, each site would have to have several authors working to catch up with the craziness. Once caught up it might be possible for a handful to keep up. Maybe.

I am thinking of starting one for YECness. I think there are plans for a couple others, but as I am not heavily involved I can not say for sure.

Each place could, of course, have a chatroom/forum, but since this and a handful of others are already well established it may work better just to channel visitors to the established discussion areas where rational folks visit and are known. IDK, just some ideas.

I digress. Yes, there is always a place for questioning and answering, so long as it is done reasonably and considerately. A LOT happens here, and in each of the areas I mentioned (and more, the list is hardly exhaustive) there is work to be done in actively chasing down the ideas and misconceptions in each area. Right now it is all we can do to work passively in keeping up with the edges that make their way here. Having a specific site which we could be confident sending people to for common misconceptions or questions would clear up some of the longer yet always repeating debates that happen here, or at least make them more manageable.

ETA: D'oh! How could I forget the Clavius Base Moon Landing site! One of the primary persons responsible is JayUtah, who posts here at BAUT frequently.

Here is a link to a random photo I selected that Clavius Moon Base debunks. There is a LOT more at that site, I would recommend a visit.

Unfortunately, the skeptic/scientific community has been a lot slower getting information out there in a complete, reputable fashion and the proverbial butt is being kicked by the "anything but science" part of the population. Hopefully that will change.

Oh, and don't worry if you don't know everything. If you are interested in building a site, information is absolutely necessary, but if information is all you lack it can be gotten with a little work. Being rational and pursuing good answers is far more important than having every "i" dotted and "t" crossed.
And time, of course--but it doesn't have to appear overnight. Once the site is ready to go there are ways to make it visible, but the site has to be built first. And Billy, even if you do have a site and pose some questions that aren't "mainstream" I think that would be ok--or maybe make that one section of the site (as opposed to having the 'pyramid' you mentioned, for example) appear on each page. A section called "things I don't understand yet but think there's a more reasonable explanation than 'aliens built it but nothing else' or something like that. A site/blog dissecting Bart Sibrel, Cydonia, etc would go a long way, even if it did have the occasional odd question out.

I'm going to go write a post describing what I mean in more general terms in...another section. Be back later.

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None to speak of

Oh good grief.. The comic Donald Duck has excited many, many imaginings. Why doesn't Disney come right out with proof that Donald Duck isn't a real person, and that the stories in the comics are not based on facts?

ESA is being financed by my tax money. I don't want them to waste that money on debating loonies on the Internet. After all, those that have their mind made up won't change it over what any government agency says. Re-read your threads. How many times have you been told it was compression artifacts, and how often have you emphatically responded that it was absolutely impossible? How would the same explanation as you had from us before help, if it came from ESA?

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"Ignorance more frequently begets confidence than does knowledge" -- Charles Darwin
"Your right to hold an opinion is not being contested. Your expectation that it be taken seriously is." -- Jason Thompson
Meet the OOONG TOE.

-Slang-
Please excuse me if I'm bothering you.

Since ESA is the source, perhaps a very short statement from them would go further to debunk the loopies than volumes of invictive.

After reading your responses I am left with the sense that I must be too dumb to buy beer.

I have never seen .jpeg artifacts before that have the forms that these artifacts in the Hale pictures take. It is something new for me. And If I were an analyst at ESA with one whit of an idea of how interested parties could be confused or otherwise excited, I'd take appropriate measures to avert misunderstandings wherever possible. Or at least refer the ssue to the ESA Public Relations department. Public sentiment has lots to do with publicly-funded programs.

That's all.