1 / 23

Camera Comparison Signal Level and SNR

Steve Conard Willow Oak Observatory, Gamber, MD International Occultation Timing Association (IOTA) Oct 20, 2012. Camera Comparison Signal Level and SNR. Disclaimer.

bberger
Download Presentation

Camera Comparison Signal Level and SNR

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Steve Conard Willow Oak Observatory, Gamber, MD International Occultation Timing Association (IOTA) Oct 20, 2012 Camera ComparisonSignal Level and SNR

  2. Disclaimer • Bruce, Russ, and I had originally hoped to do a thorough comparison of several video and digital interface cameras that could used for IOTA’s observations • Due to personal time limitations and weather, we didn’t accomplish what we had intended • It became a much a less controlled test, with fewer cameras, than we had originally intended • View it as a quick comparison of several common cameras as typically used in real-world conditions

  3. Disclaimer • Data collection was not as well controlled as I had hoped • Intended to have a parallel telescope recording the same field at the same time • Did not take the time to fully learn to use the Flea camera—resulting in only 8-bit data collected • The data have not rigorously been analyzed, and may contain errors • More data is available to be analyzed when time permits

  4. Test Hardware • C-14 on CGE mount • Focal reducer used to set f/number at about 4.0 • In roll-off observatory • Video data through IOTA-VTI to Canon ZR-65 recorder • Flea data through Firewire to desktop PC

  5. Cameras • “Control” was a Stellacam EX (my SN 01) • Other video cameras • Stellacam EX (SN 02) • Watec 902 Ultimate (SN 01 and 02) • PC164C-EX2 • Firewire camera • Flea 3 FL3-FW-03S3M-C • All arrays are ½” format except the PC164C-EX2 which is 1/3”

  6. Method • Used same field for each camera • EplisonLyra (“Double Double”) selected to have easy reference, and was fairly high in the sky • Reference camera used before and after to look for changes • Tried to pick nights with good transparency and no visible clouds • Tangra used for data analysis • Used auto aperture selection • Picked up to 6 stars for comparison

  7. Video Cameras Only • Weather clear, reasonable transparancy • Tangra apertures left to automatic selection • Collected data with Stellacam EX 1 at 1 and 2 fields integration • Collected data all other cameras • Varied gain on one Watec • Used 1 and 2 fields on the second Stellacam EX • Collected data with Stellacam EX 1 at 1 and 2 fields integration • Only minor difference in signal before/after with Stellacam EX 1

  8. Signal Level

  9. SNR

  10. Sample Images Stellacam EX SN 1 Before Stellacam EX SN 2

  11. Sample Images Watec 902 Ultimate SN 1 Watec 902 Ultimate SN 2

  12. Sample Images PC164C-EX2 Stellacam EX SN 1 After

  13. Discussion • PC164C-EX2 may give the best combination of SNR and signal level • Significantly better at all but the brightest targets, where SNR may fold over (may not be the best choice for a bright asteroid over a fainter star) • It also may have other issues that weren’t investigated here • Watec 902 Ultimate and Stellacam EX’s are very similar • Watec can produce almost as much signal as the PC164C-EX2 when the gain is very high

  14. Flea vsStellacam 30 Hz • Weather clear, reasonable transparancy • Tangra apertures left to automatic selection • Collected data with Stellacam EX 1 at 1 and 2 fields integration • Collected data with Flea 3 • Max’ed out the gain at 24 dB • Maximized exposure time at a 30 Hz readout rate • Important: Flea was used in 8 bit mode • Collected data with Stellacam EX 1 at 1 and 2 fields integration • Only minor difference in signal before/after with Stellacam EX 1

  15. Signal Level

  16. SNR

  17. Sample Images Stellacam EX 2 Fields Flea 3

  18. Discussion • Stellacam has much larger signal level • This may not be true with Flea at 12-bits • Roughly the same SNR for fainter targets, possible advantage to Flea for brighter ones

  19. Flea vsStellacam ~2 Hz • Weather clear, reasonable transparancy (same time as video comparison above) • Collected data with Stellacam EX 1 at 32 fields integration • Collected data Flea at 1.875 Hz, max exposure • Gain at 24 dB • Flea at 8 bits • Collected data with Stellacam EX 1 at 32 fields integration • Only minor difference in signal before/after with Stellacam for the fainter targets—the bright ones showed more change for some reason

  20. Signal Level

  21. SNR

  22. Sample Images Stellacam EX 2 Fields Flea 3

  23. Discussion • Stellacam has much larger signal level • This may not be true with Flea at 12-bits • Roughly the same SNR for fainter targets, Stellacam showing saturation on brighter ones

More Related