Dust Devils In Jezero Crater, single-point repository of imagery Options

[PDP8E]

SOL 137 Dust Devil Watch
21 Frames -- stationary stance -- 5:00 PM local
A new version of the detector - noise reduction / refined structure

A nice DD in the distance ----<oops see post #33>----
GIF

[PDP8E]

SOL 140 Dust Devil Watch
360 degree quick peek (3 frames each in 5 stances) -- 2:30 PM local

Nice DD in the SW stance (4th set)
GIF

[PDP8E]

on SOL 137 my dust devil detector was TRICKED!
I was checking the location of the SOL 137 'dust devil' and it wasn't there!

The sequence of 21 images was 5 minutes and 23 seconds starting at 17:05:27 PM (late in the day... long shadows)
Here is the first and last image in a GIF


The detector dilates the area around initial image differences and made it larger....
< see post #31>

[Phil Stooke]

I don't think this one was mentioned before: on sol 129 the Navcams caught a DD against the crater wall to the SW:

https://mars.nasa.gov/mars2020-raw-images/p..._195J01_800.jpg



Phil

[PDP8E]

SOL 142 Dust Devil Watch
360 degree quick peek (3 frames each in 5 stances) -- 3:45 PM local
Looks like the same place as SOL 140
Very Quiet (I turned down the denoise knob just to see if it is that quiet... it is)
GIF

[PDP8E]

SOL 144 Dust Devil Watch
360 degree quick peek (3 frames each in 5 stances) -- 10:30 AM local
All Quiet
GIF

[PDP8E]

SOL 145 Dust Devil Watch
360 degree quick peek (3 frames each in 5 stances) -- 4:30 PM local
All Quiet -- Late in the day. -- NO DDs


abbreviated GIF

[PDP8E]

SOL 146 Dust Devil Watch
21 Frames -- stationary stance -- 3:00 PM local
ACTIVE -- a brief surface dust-gust in the center -- a strong gust on the right that blows into a type of dd?
GIF

[PDP8E]

SOL 147 Dust Devil Watch
360 degree quick peek (3 frames each in 5 stances) --3:45 PM local
Quiet -- NO DDs -- Abbreviated GIF

[PDP8E]

SOL 148 Dust Devil Watch
21 Frames -- stationary stance -- Noon local
VERY ACTIVE -- EIGHT DDs
GIF


... I hope Ingenuity survived...

[PDP8E]

REVISED SOL 148
I revved the program to move it into HSV color space (RGB is not intuitive for saturation and luminance)
The dust devils are now the correct Hue (with the brightness turned up just 33%)
It also kills the annoying scintillation from the noise and compression artifacts.

[PDP8E]

Detecting Dust Devils with multiple images is fairly straightforward: average all the frames, and compare each image to the average -- use subtract, ratio, and other techniques.
Detecting faint DDs in one image requires a different approach: increase the contrast while retaining the image quality-- somehow.
This is a test image from SOL 15 (!). The technique is Stochastic Equalization / Adaptive Contrast (SEAC)
The image has a pronounced screendoor effect from the Bayer (in the sky) and has an overall 'old-timey postcard quality', but the DD is visible and the contrast is increased
Another image 30 minutes before had no artifact at this position.
--GIF

[tau]

A storyboard for the dust devils from sol 148 (because the animated gif is too big for upload).

The difference between each image and the median of all 21 images is enlarged and then added to the median.
Since compression artifacts give large color blobs in the sky, I desaturated the sky.
The time markers start with the first image which was aquired at the local mean solar time of 12:01:50.

The large dust devil to the right of center in the first images seems to be quite close, because it casts a large shadow on the dune field in the foreground.
Later, the swirling dust around the brighter central column darkens the sky a bit.

[Phil Stooke]

That is an excellent presentation of the complex events on that sol. Thanks for posting it!

Phil

[PDP8E]

Tau, awesome work! (I hear you on the size issue!)