IMAGE PROCESSING GALLERY

The first perijove pass of Jupiter was a test run for JunoCam. The set of 28 images taken were designed to find optimal viewing geometries and camera settings. For example, we took 4 images of the north pole. We used two different settings for the time-delayed-integration (TDI), which determines the integration time, to see which would be best for the polar region and a very high TDI level (long exposure) to try to detect Jupiter’s aurora. We imaged at two different geometries, looking directly down at the pole and looking at closest range at a more oblique angle, to see which would give us the best results. We ran through a similar set of tests for the south pole. Another comparison we made was to test different compression settings.

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 gallery displays images from JunoCam itself, as well as uploads from the community. 

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.

Like previous MSSS cameras (e.g., Mars Reconnaissance Orbiter’s Mars Color Imager) Junocam is a "pushframe" imager. The detector has multiple filter strips, each with a different bandpass, bonded directly to its photoactive surface. Each strip extends the entire width of the detector, but only a fraction of its height; Junocam's filter strips are 1600 pixels wide and about 155 rows high. The filter strips are scanned across the target by spacecraft rotation. At the nominal spin rate of 2 RPM, frames are acquired about every 400 milliseconds. Junocam has four filters: three visible (red/green/blue) and a narrowband "methane" filter centered at about 890 nm. 

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.