IMAGE PROCESSING GALLERY
One of the biggest challenges for Juno is Jupiter's intense radiation belts, which are expected to limit the lifetime of both Juno’s engineering and science subsystems. JunoCam is now showing the effects of that radiation on some of its parts. PJ56 images show a reduction in our dynamic range and an increase in background and noise. We invite citizen scientists to explore new ways to process these images to continue to bring out the beauty and mysteries of Jupiter and its moons.
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. We 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.
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. 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”.
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.
Perijove 31 flyby experimental animation
This is an experimental animation showing Jupiter as seen from the Juno spacecraft during its perijove 31 flyby on December 30, 2020. The flight path follows the spacecraft from 21:08:59 to 22:43:29 on December 30, 2020. In this movie everything happens about 13 times faster than it really did. The flight path is taken from the relevant SPICE kernels.
To create the animation I used all of the JunoCam RGB images from image PJ31_7 to image PJ31_43 and also a small patch from image PJ31_47. This is a total of 34 images. An important goal was to show everything at the highest resolution possible. This made it impossible to assemble all of the images into one map-projected mosaic of Jupiter; that map would have been far too big (about 160,000 x 80,000 pixels). Instead, several seamless map-projected mosaics covering different parts of the planet at various resolutions were created. The resolution of these maps ranges from 80 pixel/degree to 450 pixels/degree. The effects of the varying solar illumination were removed using a slightly modified Lambert illumination model combined with a new limb darkening function. The maps were then processed to enhance the contrast and colors a bit.
The animation was then rendered by using different maps for different parts of the animation. When rendering the animation, shading was applied using the same illumination model as the one originally used to remove the illumination, i.e. modified Lambert and a new limb darkening function. The parameters were slightly modified in order to slightly increase the brightness of dimly lit areas near the terminator and poles relative to bright areas.
Overall, Jupiter's appearance should be fairly realistic but some artistic license has been used. As mentioned above, the contrast was increased but not as much as I usually do in the enhanced versions of images I have processed. This makes various subtle details more obvious. Jupiter didn't look realistic with a perfectly sharp limb so I also added some atmospheric effects. These effects are a bit exaggerated, especially in the dimly lit polar areas. For example Jupiter's bluish sky at the limb is brighter and more conspicuous here than it is in most of Juno's images. On the other hand the atmospheric effects reduce the overall contrast a bit - but not so much as to cancel out the previously mentioned contrast enhancement.
To show Jupiter in its full splendor the animation has a very wide field of view (90°).