A few observations on the Mars Express TIFF images. This is a boring, lengthy post.
I tried to keep it short. But this post evolved into this....It is an important read.
The TIFF image options of the following sources are FALSE...
http://www.esa.int/esa-mmg/mmg.pl?b=b&...e=y&start=4http://www.esa.int/esa-mmg/mmg.pl?b=b&...=y&start=10http://www.esa.int/SPECIALS/Mars_Express/SEM565R03EF_1.htmlhttp://www.esa.int/SPECIALS/Mars_Express/SEM4FHSZEFF_0.htmlAccording to the HRSC Camera website, All initial images are JPEG compressed before transmission to Earth.
Two excerpts of the HRSC Camera website....
Data Compression Electronics (DCE)
The DCE consists of 4 Compression Units (CU) and the microcontroller (MC). The input buffers of the 4 CUs are directly linked to the four signal chains of the Camera Head.
Each CU works individually and uses a parameter table controlled JPEG compression algorithm. After compression, an 80C31 microcontroller combines the data streams via multiplexing to a serial output.
Data reduction and output
Combining the nine channels and the SRC together in full resolution, would result in an enormous data rate. The main antenna has a limited data rate and has a maximum of 8 hours per Earth-day for contact with the ground station. Thus there is a need of data reduction. This is performed by two methods - pixel summation and compression. The pixel summation creates averages of adjacent pixels. The 1X1 summation keeps the full resolution. The 2X2 summation creates an average of a square with an edge-length of 2 pixels. This decreases the data volume by a factor of four. Further options are a 4X4 and an 8X8 summation. The second method is a JPEG based data compression. After extensive tests with sample data, the compression factor has been determined to a variable factor between 4 and 10. This enables a compression of the data at acceptable losses in quality.
HRSC Camera Website:
http://berlinadmin.dlr.de/Missions/express...kameraeng.shtmlMy question is..Where are they getting large TIFF images from????
Which image is the correct one????Is it the JPEG or the TIFF??
Is the Mars Express spacecraft transmitting large file TIFF images??
I can save a small file JPEG as a TIFF. Usually, The image remains the same.
There is a better loss-less option..Use PNG format.
Link: PNG versus TIFF:
http://morris-photographics.com/photoshop/...png-format.htmlTIFF link:
http://en.wikipedia.org/wiki/Tagged_Image_File_FormatJPEG link:
http://en.wikipedia.org/wiki/JPEGI do realize there is an option to bypass the compression algorithms. Even so, I have found flaws in their TIFF images.
I download a TIFF image of Noctis Labyrinthus and done some experimenting. Using Adobe Photoshop CS3, I would save this file as a JPEG. I experimented with various JPEG
compression settings...Number 3 to 11. I have found little difference in image quality. I detect slight variations and that's it. The image remains the same for all practical purposes.
Both JPEG and TIFF versions basically agree with each other.
Noctis Labyrinthus:
http://www.esa.int/esa-mmg/mmg.pl?b=b&...=y&start=51I experimented with a Cydonia TIFF image.
Link:
http://www.esa.int/esa-mmg/mmg.pl?b=b&...=y&start=10With this Cydonia image, The TIFF image changes drastically. The only image that makes sense is when saved as a number 7 JPEG. This is the same as their JPEG image option.
They might as well remove their TIFF image option.
In any case, TIFF or JPEG, All the Cydonia features are still present. Except the TIFF version has data missing, changed or subdued..Especially around the "Pyramid" (Refer to post 284,Page 19). This data magically reappears in their "pretty JPEG version". This image data appears when the TIFF image is compressed to a JPEG.I have also found natural geologic features remain
unchanged in both JPEG and TIFF. It seems only the anomalous objects differ significantly between JPEG and TIFF. Conclusion: Their TIFF image of Cydonia has been selectively edited or
programmed to change when compressed to a JPEG.
I did some experimenting with the TIFF image of Nepenthes Mensae. My initial observations reveal a poor washed out image. Forget about anomalies....I am talking about the image in a general sense. All the natural geology is inferior compare to the JPEG.
I went ahead and perform the same experiment, Save the TIFF image as a JPEG.There was no change at all.
The same degraded ugly image persists. Most all the anomalous objects are still present..Just degraded in this "Ugly TIFF version". Some anomalies are missing completely.
As with the Cydonia TIFF, There are hints of selective editing.
Adobe Photoshop CS3 has a Navigator tab with a Zoom slider. When the Nepenthes TIFF is reduced to 50%, Both TIFF and JPEG images match. At any other setting, the image reverts back to the "Ugly image". I tried to reduce the TIFF image using a bicubic sharper technigue...This did not work. Very unusual.
I do not trust their TIFF images. This holds true for their other TIFF images of Mars. I will stick to their JPEG's as the "Correct" images of Mars.
While NASA practices outright suppression and alterations of their images, The ESA is playing games with their TIFF images. The ESA is mixing confusion tactics with legitimate disclosure.
Until someone from the ESA/Mars Express can explain their TIFF images, My initial conclusion of their TIFF images of Cydonia, Hebes Chasma, and Nepenthes Mensae regions will be unchanged...These images are FALSE. These TIFF images should not be used for any reason.
