IMAGE PROCESSING GALLERY
For those of you who have contributed – thank you! Your labors of love have illustrated articles about Juno, Jupiter and JunoCam. Your products show up in all sorts of places. I have used them to report to the scientific community. We are writing papers for scientific journals and using your contributions – always with appropriate attribution of course. Some creations are works of art and we are working out ways to showcase them as art.
If you have a favorite “artist” you can create your own gallery. Click on “Submitted by” on the left, select your favorite artist(s), and then click on “Filter”. For other tips about the gallery click on the “Gallery Organization” tab.
We have a methane filter, included for the polar science investigation, that is almost at the limits of our detector’s wavelength range. To get enough photons for an image we need to use a very long exposure. In some images this results in scattered light in the image. For science purposes we will simply crop out the portions of the image that include this artifact. Work is in progress to determine exactly what conditions cause stray light problems so that this can be minimized for future imaging.
The JunoCam images are identified by a small spacecraft icon. You will see both raw and processed versions of the images as they become available. The JunoCam movie posts have too many images to post individually, so we are making them available for download in batches as zip files.
You can filter the gallery by many different characteristics, including by Perijove Pass, Points of Interest and Mission Phase.
A special note about the Earth Flyby mission phase images: these were acquired in 2013 when Juno flew past Earth. Examples of processed images are shown; most contributions are from amateurs.
The spacecraft spin rate would cause more than a pixel's worth of image blurring for exposures longer than about 3.2 milliseconds. For the illumination conditions at Jupiter such short exposures would result in unacceptably low SNR, so the camera provides Time-Delayed-Integration (TDI). TDI vertically shifts the image one row each 3.2 milliseconds over the course of the exposure, cancelling the scene motion induced by rotation. Up to about 100 TDI steps can be used for the orbital timing case while still maintaining the needed frame rate for frame-to-frame overlap. For Earth Flyby the light levels are high enough that TDI is not needed except for the methane band and for nightside imaging.
Junocam pixels are 12 bits deep from the camera but are converted to 8 bits inside the instrument using a lossless "companding" table, a process similar to gamma correction, to reduce their size. All Junocam products on the missionjuno website are in this 8-bit form as received on Earth. Scientific users interested in radiometric analysis should use the "RDR" data products archived with the Planetary Data System, which have been converted back to a linear 12-bit scale.
Flight over Jupiter (2)
An experimental and somewhat speculative animation showing a flight over Jupiter's clouds based on data from JunoCam obtained on April 10, 2020. It was created by using methane filter image PJ26_25 to construct a digital elevation model (DEM) of Jupiter's clouds (in this case really a heightfield on a spheroid). An enhanced mosaic of images PJ26_24 and PJ26_26 was then draped over the DEM.
It is assumed that the cloud altitudes are a linear function of brightness in the methane image. This assumption is not accurate but is nevertheless good enough to result in a nice DEM. It should also be mentioned that images obtained with JunoCam's methane filter do not penetrate very deeply into the atmosphere. Because of this, parts of the lowest areas in the DEM might lie deeper in the atmosphere than shown here. Vertical elevation differences are greatly exaggerated, probably at least by a factor 5 and possibly more than 10.
As expected, in general bright clouds are higher in the atmosphere than darker clouds. An interesting feature is the many 'walls' of bright clouds, some of which encircle circular or elliptical spots/vortices. Some of the 'walls' have an orange tint. It is possible that this orange color really is due to a high altitude orange haze and that the 'walls' themselves are white.
The resolution and quality of both the DEM and the color data varies and is much lower towards the end of the animation than it is earlier. It is also relatively low for about 10 seconds shortly after the start of the animation.