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.
Fifteen Views of Io from Juno's PJ55 encounter
On October 15, 2023, NASA’s Juno spacecraft flew past Jupiter’s volcanic moon Io and acquired these amazing images using its JunoCam camera. The closest of these images (first image in the second row) was acquired from a distance of only 11,680 kilometers (7,260 miles). Many of the images in this montage of fifteen JunoCam images are the best resolution images acquired of Io in 22 years when NASA’s Galileo spacecraft performed one of its final satellite encounters. Images such as these will provide Io research with plenty of analysis work for years to come. They cover Io’s anti-Jovian hemisphere before going over Io’s north polar region and settling out over the satellite’s sub-Jovian hemisphere.
These images reveal new details about Io’s north polar region an area dotted with non-volcanic mountains, some as tall as 6000 meters (20,000 feet). Conversely, relatively few volcanoes are visible in this region, a relationship seen in other regions of Io, where concentrations of mountains and volcanoes seem to be anti-correlated. The regions photographed also seem to be relatively stable over the last 16–22 years, when Io was last imaged by Galileo and New Horizons. In addition to previously noted changes at Volund, Chors Patera, and a lava flow east of Girru Patera, the biggest notable change is a large flow field that has formed out of the southern end of Surt.
Each image has been aligned using a control point network using USGS’s Integrated Software for Imagers and Spectrometers (ISIS) and map projected to a point-perspective projection, providing the least amount of distortion compared to the original up-close images). Image scales vary from 29.6 kilometers (18.4 miles) to 7.9 kilometers (4.9 miles) per pixel.
