Simultaneous High Dynamic Range Algorithm, Testing, and Instrument Simulation

Abstract

Within an imaging instrument's field of view, there may be many observational targets of interest. Similarly, within a spectrograph's bandpass, there may be many emission lines of interest. The brightness of these targets and lines can be orders of magnitude different, which poses a challenge to instrument and mission design. A single exposure can saturate the bright emission and/or have a low signal to noise ratio (SNR) for faint emission. Traditional high dynamic range (HDR) techniques solve this problem by either combining multiple sequential exposures of varied duration or splitting the light to different sensors. These methods, however, can result in the loss of science capability, reduced observational efficiency, or increased complexity and cost. The simultaneous HDR method described in this paper avoids these issues by utilizing a special type of detector whose rows can be read independently to define zones that are then composited, resulting in areas with short or long exposure measured simultaneously. We demonstrate this technique for the sun, which is bright on disk and faint off disk. We emulated these conditions in the lab to validate the method. We built an instrument simulator to demonstrate the method for a realistic solar imager and input. We then calculated SNRs, finding a value of 45 for a faint coronal mass ejection (CME) and 200 for a bright CME, both at 3.5 $R_{\odot }$ -- meeting or far exceeding the international standard for digital photography that defines a SNR of 10 as acceptable and 40 as excellent. Future missions should consider this type of hardware and technique in their trade studies for instrument design.

arXiv comment9 pages, 5 figures, accepted to ApJ

References in corpus (10)

• Alfven Wave Solar Model (AWSoM): Coronal Heating
• Solar Orbiter: Exploring the Sun-heliosphere connection
• The SWAP EUV Imaging Telescope Part I: Instrument Overview and Pre-Flight Testing
• Data Constrained Coronal Mass Ejections in A Global Magnetohydrodynamics Model
• Miniature X-Ray Solar Spectrometer (MinXSS) - A Science-Oriented, University 3U CubeSat
• A Heavy Molecular Weight Atmosphere for the Super-Earth π Men c
• Is pi Men c's atmosphere hydrogen-dominated? Insights from a non-detecton of Hy Ly-alpha absorption
• SWAP Observations of the Long-Term, Large-Scale Evolution of the EUV Solar Corona
• The Sun's Dynamic Extended Corona Observed in Extreme Ultraviolet
• Non-parametric PSF estimation from celestial transit solar images using blind deconvolution

Cited by in corpus (2)

• Defining the Middle Corona
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