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. For Earth Flyby the light levels are high enough that TDI is not needed except for the methane band and for nightside imaging. 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. TDI vertically shifts the image one row each 3.2 milliseconds over the course of the exposure, cancelling the scene motion induced by rotation. For the illumination conditions at Jupiter such short exposures would result in unacceptably low SNR, so the camera provides Time-Delayed-Integration (TDI). The spacecraft spin rate would cause more than a pixel's worth of image blurring for exposures longer than about 3.2 milliseconds. Junocam has four filters: three visible (red/green/blue) and a narrowband "methane" filter centered at about 890 nm. At the nominal spin rate of 2 RPM, frames are acquired about every 400 milliseconds.
The filter strips are scanned across the target by spacecraft rotation. 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 detector has multiple filter strips, each with a different bandpass, bonded directly to its photoactive surface. Like previous MSSS cameras (e.g., Mars Reconnaissance Orbiter’s Mars Color Imager) Junocam is a "pushframe" imager. That this can be minimized for future imaging. Progress to determine exactly what conditions cause stray light problems so This results in scattered light in the image.įor science purposes we will simply crop out the portions of the image To get enough photons for an image we need to Have a methane filter, included for the polar science investigation, that isĪlmost at the limits of our detector’s wavelength range. Another comparison we made was to test different compression We imaged at two different geometries, looking directly down at the poleĪnd looking at closest range at a more oblique angle, to see which would give See which would be best for the polar region and a very high TDI level (longĮxposure) to try to detect Jupiter’s aurora. The time-delayed-integration (TDI), which determines the integration time, to For example, we took 4 images of the north Were designed to find optimal viewing geometries and camera settings. The first perijove pass of Jupiter was a test run for Other tips about the gallery click on the “Gallery Organization” tab. Left, select your favorite artist(s), and then click on “Filter”. If you have a favorite “artist” you can create your own We are writing papers for scientific journalsĪnd using your contributions – always with appropriate attribution ofĪnd we are working out ways to showcase them as art. I have used them to report to the scientific community. Particular atmospheric feature, as well as adding your own color enhancements,Ĭreating collages and adding advanced color reconstruction.įor those of you who have contributed – thank you! Your labors of love have illustrated articles We’d love to see range from simply cropping an image to highlighting a Your creations for us to enjoy and share.
We invite you toĭownload them, do your own image processing, and we encourage you to upload
0 kommentar(er)
