Will HDR imaging change solar H-alpha imaging?

In the upcoming months two interesting CMOS sensors should show up on the market in Basler Ace and Ximea cameras. Those sensors are CMOSIS CMV4000 and e2v EV76C560. The CMOSIS sensor is big (1" diagonal) but the key feature of both sensor is high dynamic range imaging. HDR/WDR imaging would be a new feature for H-alpha solar imaging.

lin-log response of e2v CMOS sensor

High dynamic range would allow imaging prominences alongside the Sun disk without the need of overexposing it. Ximea API supports lin-log response of the e2v sensor and HDR support for CMOSIS should be added in the future. There is no info if Basler Ace (equipped with CMOSIS sensor) will support the HDR mode - but it's possible. All of those cams haven't been released yet and thus haven't been tested in solar imaging - although e2v EV76C560 was tested without the HDR mode in IDS cameras and it did work quite nicely - here and here.

e2v sensors use lin-log response, where strong signals are read with logarithmic response. This cause strong signals to create weaker response than in typical linear mode. e2v states it can provide even 120 dB of dynamic range. CMOSIS can do up to 90 dB in double-read linear mode. Aside of HDR modes those sensors have quite good sensitivity and noise performance. They are also fast. Most of CMOSIS based cams uses Camera Link to allow max framerates. The GigE and USB3 cams allow only limited framerate... but do you need more than 90 FPS of an 2048 x 2048 frame?


Astronomy and Astrophotography, 3 May 2012, Piotr MaliƄski

Comment article
RkBlog main page Search RSS Contact