[X] My Assistant

[dilo]

Left/right pairs from both rovers and both sources (JPL and Exploratoriun) shows a systematic difference of jpeg files dimension in favour of right version (tipically 5% on NavCam/PanCam pairs). See example.
Moreover, you If you look carefully to images, you will find, there is a clear difference in terms of fine details:
I do not know if this strange issue is due to different jpeg compression ratio on the server or is more serious (lens difference? extremely improbable!).
Other explainations??? (Maybe people often dowloading .img uncompressed images can answer... )

I noticed this from the very first Sols, but apparently no one highlighted it here and most people continue to use left images to make stitch or other considerations... viceversa, I reccomend to use always right version, when possible!!!

[fredk]

Well, even though I started this resurgence in the L vs R topic, I'm embarrased that I never noticed the effect until earlier this year. (Time to start reading the imagery forum regularly!)

I checked several of the jpl navcam jpegs. The effect is very prominent on all Oppy navcam pairs I looked at; a good example is this left navcam and the corresponding R navcam. (Ahh, those were great days, huh? What would that heatshield look like...)

I never saw nearly as big a difference with Spirit. For example, this and this.

Also, this L navcam noise doesn't look like ICER compression noise. Here's an example of an image with obvious compression artifacts.

Next, I went ahead and looked at some pds images. Here's the above sol 115 Oppy L navcam view; top is jpl site jpg, bottom is mrd pds:

Here are the R views (jpeg top, mrd pds bottom):


The result: The L pds is far cleaner than the L jpeg. Curiously the R pds has a slightly dirtier look than the R jpeg!

It appears that there's something about the way the Oppy L navcam jpegs are processed on earth that introduces extra noise. The noise definitely does not originate with the rover cameras.