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 55 Io Flyby in Full HD and 30-Fold Time-Lapse, Reconstructed From JunoCam Data
On 2023 OCT 15, 10:52:50 UT, NASA's Juno spacecraft successfully made its Perijove 55 Jupiter flyby.
This video uses 19 of the raw Perijove 55 JunoCam images together with SPICE trajectory data to reconstruct the 105 minutes from 2023-10-15T06:00:00.000 to 2023-10-15T07:45:00.000 when Juno flew by Jupiter's volcanic moon Io just a few hours before closest approach to Jupiter.
The video is blended from scenes, each scene rendered from one of the raw JunoCam images. For each scene, the respective undelying raw JunoCam image was rendered to a sequence of stills, with each still reprojected to a camera position along Juno's trajectory according to SPICE kernels. Assumed camera positions correspond to spacecraft trajectory positions in time steps of 1 second.
The sequence of blended stills was finally converted to an MP4 file using the ffmpeg tool. The stills themselves were rendered from the raw data using a home-made and proprietary software.
The camera appears to change it's overall spectral quantum efficiency over time and presumably mostly due to Jupiter's harsh radiation environment, generally resulting in a gradually increasing reddish cast in the images if keeping color calibration constant. Therefore, it's relevant to provide the adjusted and applied linear radiometric factors used for balancing colors. This video used a constant set of relative radiometric factors derived from the PJ 54 flyby. The applied factors are (0.734; 1.0; 3.023) for (red;green;blue) respectively.
After linearizing the raw data with subsequent radiometric adjustment, the stills were gamma-stretched to the square-root of linear radiometric data. Overall, the resulting colors should be not identical but fairly close to the colors the majority of unaided human eyes would see.
Unlike for most Jupiter images and videos, Io is sufficiently rich in contrast that acceptable images can be achieved without color and brightness stretching.
Rememeber that the Juno mission can only be successful with a team effort, involving a very skilled professional staff acting in the background.