ASI6200MM-Pro Hardware Binning ?

[Hibou]

I am impressed with the ASI6200MM-Pro. There is no amp glow (as there is with the ASI294MM-Pro) and noise is low even with 10 minute exposures. Selected area imaging such as 1600x1200 pixels allows high frame rates for focussing, and up to x4 binning increases brightness, important for my low-light scientific imaging. I was interested to see that "Hardware binning" is proposed for this camera, and I know as Robin wrote that for CMOS it's not really "on-chip" as with a CCD. Still, "on-camera" binning would be interesting to speed up frame rates limited by usb cables. I did get hardware binning to work once, but often it crashes with SC 4.0.9538.0. Maybe I have some incompatible options. I found no mention of hardware binning in ASICap, just a choice of up to x4 binning. So is the ASI6200MM-Pro capable of binning "on-camera" or only on the SDK or driver on the PC ?

Robin wrote in a previous post:

In the ZWO case (and for any other CMOS camera that has a so-called 'hardware binning' option) there are two places the summing or averaging of pixel values can be done
1) On the camera itself
2) In the Camera SDK or driver on the PC
Option 2 is very boring - everything proceeds as for capturing at full resolution until the frame is in the driver/SDK and then some code running on the PC turns it into a smaller frame by averaging or adding pixels.
Option 1 typically has some tradeoffs... Since the binning is happening on the device itself, CPU usage on the PC may be lower, but this is usually a trivial effect. Also since less data needs to be transferred from the camera to the PC you *may* get higher frame rates if the USB bandwidth was limiting your frame rates.

[admin]

Hi,

'Hardware Binning' on ZWO cameras is pretty much all handled by the ZWO SDK. SharpCap gets to ask if the camera supports that feature and then gets to turn it on or off - other than that, SharpCap talks to the camera in precisely the same way whether or not is available or active.

So... The fact that you are seeing the option means that the SDK is reporting it as availble for your camera. Of course this could be an oversight in the SDK perhaps. It may also be that there are some undocumented restrictions on its use (ie maybe only bin2, or maybe it needs to be turned on before binning is enabled).

If you do get a chance to send a bug report when trying hardware binning, then please submit the report and let me know.

cheers,

Robin

[Hibou]

Thanks Robin. I'll explore it further and send you a bug report if the problem is not just me.

[Hibou]

OK. I switched to 4.0.9538.0-64bit to avoid memory problems, and I can select "Hardware Binning" with bin=1 and everything else default. But when I try to change to bin=2 it crashed saying the camera could not be restarted after changing Binning from 1 to 2, with an ErrorInvalidSize from call to ASISetROIFormat (see screen capture and log attached).

[admin]

Hmm,

some things to try out if you don't mind...

1) Try bin 2 without hardware binning, does that work?

2) Try setting an ROI with a width divisible by 16 and then going into bin 2 with hardware binning and see if that works.

The latter is related to some rules ZWO have to set the size of the capture area - I thought that it was the unbinned size that needed to be divisible by 8, but maybe for some cameras it is the binned size, which would make 4788 illegal, however if you pick an ROI that is divisible by 16, the size when bin2 will be divisible by 8.

cheers,

Robin

[Hibou]

That seems to be it Robin, for 4.0.9538.0-64bit
1) All software binnings work i.e. x2 x3 x4 for all ROI with no increase in frame rate
2) Hardware x2 binning works if X pixels is divisible by 16 eg X=7984 with frame rate increasing from 0.6 to 2.6 with a USB2 cable (but other binnings crash)
3) All hardware binnings work for predefined ROI areas of 1920x1200 and lower with significant increases in frame rates over USB2 cables.

I didn't check every possible combination, but apparently you understand the problem. The predefined X-ROI should be divisible by 16 for x2 binning. Brilliant ! Higher frame rates are interesting for my application.

Cheers, Alan

[admin]

Hi Alan,

thanks for confirming - I will make some changes to try to apply that rule.

cheers,

Robin

[Hibou]

Thanks Robin. So the rule is that the X of the binned image must be divisible by 8 ? It would be good to define a set of ROI that allow x4 binning as well as x2. The first would be 9568x6388 instead of 9576x6388, which would give 4784x3194 with x2 binning and 2392x1597 with x4 binning. Another of interest to me is for a 5:4 aspect ratio, with an ROI of 7968x6388 giving 3984x3194 and 1992x1597 with respectively x2 and x4 binning.

I can confirm that ROIs of 9568x6388 and 7968x6388 allow x2 hardware binning, but unfortunately they crash for x4 hardware binning, so there must be some additional rule.

Cheers Alan

[Hibou]

Returning to x2 hardware binning, it seems necessary but not sufficient for X to be divisible by 16. For example, an ROI of 4784x6388 can be x2 hardware binned, but other default ROIs such as 4784x4790 crash. So it also depends on Y, which I guess must be divisible by 4, since 2392x1596 can be x2 hardware binned. And all default ROIs from 1920x1200 down can be hardware binned because they obey both X/16 and Y/4 rules.

I'm satisfied with x2 binning of 9568x6388 and 7968x6388, but a rule for x4 hardware binning near max ROI would be great to increase frame rate.

[Hibou]

Ha! The manual says hardware binning is available for x2 and x3 but doesn't mention x4. It is also 12-bit.

The ASI6200 camera has a built-in 16-bit ADC. 12bit ADC mode for output will be used when we do hardware Bin. The ASI6200 camera supports bin2, bin3, bin4 software Binning mode and hardware bin2, bin3, the best advantage of hardware binning is the faster frame rates. If you don't care about speed, we suggest you use software binning.

So I'll see if I can find the ROI conditions for x3 hardware binning. The increased frame rate can be interesting for some applications even if the ADC is then reduced.