With all of the different opinions aired here, I decided to track the process of the pictures from the ESA Mars Explorer, just to know more about it.
This is what I found.
The HRSC is a camera assembly with a linescan camera with a line resolution of more than 5000 pixels at about 10 meters per pixel, and a super high
resolution camera with a resolution of 1024 X 1032, which is used sparingly for super high resolution images at about 2.5 meters per pixel.
The raw linescan and SHR data is fed to a bank of 4 COMPRESSION units, where the PICTURE is COMPRESSED using JPEG COMPRESSION or PIXEL SUMMATION. The
resulting IMAGE is then stored in memory.
The Mars Explorer has a 6 to 8 hour window every day to send data, and will do so at a rate of about 30 to 40Kb per second.
So what does this mean?
It means that even the raw unaltered data received by ESA is a highly compressed image which has been lossy(losing colours and accuracy but gaining
smaller size) compressed by the spacecraft itself.
Then comes processing in Germany and possibly another Jpeg compression to make it into an internet friendly size.
The images shown and promoted by people who desparately wants to believe(Mars Anomaly Research) are cropped, resized, recoloured images already
HEAVILY JPEG compressed atleast once and then compressed again and stretched onto a 3D model for our viewing pleasure. And that's before they are
cropped and resized and recoloured by people who want to believe there is something there.
Also, I can't say for sure, but I believe that the black and white image is actually not a line scan image, but a Super High Resolution image, which
is compressed using a PIXEL SUMMATION algorithm.
Seriously folks, we are discussing compression artifacts and nothing more. When large data are reduced to single digit percentages using lossy
compression, you get compression artifacts like this.
berlinadmin.dlr.de...
berlinadmin.dlr.de...
www.esa.int...
en.wikipedia.org...
[edit on 18-4-2008 by aaa2500]