Moravian instruments, Inc., source: https://www.gxccd.com/art?id=531&lang=409, printed: 11.02.2025 3:33:03
Main page▹Product Overview▹Software | 20.7.2018 |
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Version 3.8 of the Scientific Image Processing System underwent significant overhaul of the important part of the core functionality, responsible for mutual alignment of multiple images. Alignment is used in various SIPS tool, like image blinking, image stacking and also in Photometry, which relies on proper image alignment when selecting the same star on individual images belonging to photometry series. |
Despite alignment worked well on series of not so different images, new alignment algorithm is more robust and reliable. It is able to properly align images with very significant mutual shift and rotation and also image series captured before and after GEM pier swap (images rotated by 180 degrees) can be properly aligned using new SIPS v3.8. Certain SIPS tools (e.g. Blink Images or Combine Images) not only determine mutual position of individual frames, but also create a transformed (not only shifted, but also rotated) version of every image in series to display them on exactly the same position. So, after alignment, Blink tool shows sequence of frames with perfectly steady stars and Combine tool creates sum of images with centroids of matching stars on the very same coordinates. Algorithm creating the transformed version of images was also improved to create new image with better sub-pixel precision and at the same time to preserve all features of the original image, like dynamic range, star flux (sum of values in individual star pixels) etc. Photometry toolThe new alignment algorithm affected also the Photometry tool, when a series of images with very significant mutual offsets were processed. Photometry in SIPS v3.8 now works more reliably on such series. Photometry report was slightly updated:
Photometry relied on image names to sort individual frames in the series. This is why previous SIPS versions failed to display light curves properly in the unlikely situation, when order of image names did not correspond to the order of exposure date/time. New v3.8 sorts images according to time of exposure when adding individual frames to the list box, so image name is no longer relevant and light curve is always displayed correctly. Bug fixesA few minor bugs were fixed in v3.8:
SIPS is a freeware and can be downloaded from the Download section of this web site. |