ROI Imaging


I would like to buy a ZWO ASI 183MMC for imaging galaxies using lucky imaging techniques. Unfortunately, the pictures are too heavy (20 MP) and it will take time to download and time to stack. So I would like to define a region of interest to only download the “center” of the picture…

Is it possible to do it with SGP ? If so, how ?

Thank you ! :slight_smile:

Question never answered. Although I would use it for a different reason is ROI an option in SG-Pro ? If so how?

Not at the moment. Currently we only support subframes for focus images.


Continuing this thread if possible - I think this is a very key feature. I’m considering a full frame purchase (zwoasi 6200 mm pro) and I have the same question. The camera supports region of interest reduction down to APS-C size, can I configure this in SGP to utilize? Many targets I don’t need the giant field of view - I can’t imagine this wouldn’t be a big feature request as these full frame sensor cameras are coming down in price and common now -

I can only assume there must have been some discussion on CN or some YouTube video covering this within the last 15 minutes as we just received 2 requests for this within about 5 minutes of each other :smiley:

I’ll have to do some research on how ROI is implemented in that camera. Is this purely a subframe or is it some other capability of the camera that would have to be exposed through the ASCOM driver? if it’s a subframe then how would this differ from just capturing full frame and then cropping the data?


Sorry, I don’t understand what you mean by ‘subframe’ in SGP context, perhaps this is what is used for autofocusing or displayed in quick rendering or something in the UI? Or do you just mean a single capture, as in ‘sub’ that we use to stack overall? In either case, I’m talking about a single capture from a full frame sensor - the data captured is HUGE. We are talking about reducing a single frame capture, this is possible via ROI and ASP-C reduction of sensor activity by the drivers provided by manf.

ROI is really important imho, you can ‘just crop’ but these full frame image files are HUGE! So you are forced as a user to expend a TON of cabbage ($$) with extra processor, extra ram, HUGE storage volumes to do many many caputre files that you then just crop in processing post stack!! That is crazy! When many many targets the huge field of view of the full frame sensor just isn’t needed, so if you reduce the ROI, you should be able to greatly reduce the file size. Make sense? Thanks Jared for investigating - and yes, I understand with both the ASCOM and I believe in the native drivers from ZWOASI (and I think from QHY and others) they have implemented a back-down capability to reduce the processor utilization down to the APS-C size. It would be SUPER cool if we could actually specify the region of interest to anything we want, and the file size of each capture was reduced in a ratio or something - but even just giving us the ability to knock the field of view down (roi) to the APS-C size would be a HUGELY valuable new feature for us in SGP. I understand CCD pilot and SharpCap and others already support this feature, not sure about NINA but I think they do as well or are working on it. Thank you for investigating!!!

So happy my demand is under investigation. I still really need this feature.

Where did this “APS-C size” limitation come from or is this just something you’re mentioning somewhat randomly? I only ask because subframing is generally very user defined and it sounds like what you’re referring to is something that is defined internally to the camera.


Hi, I endorse the requests for Region of Interest i(ROI) maging as mentioned before. I like working with SGP very much. One of the reasons being the use of equipment profiles that I can set up for different types of astrophotography. However, recently I got interested in short (say tenths of seconds to several seconds) exposure photography for deep sky photography of e.g. bright planetary nebula. II have a ASI 1600 MM Cool camera with 4656 time 3520 pixels. Downloading and storing these images takes about 3 second in SGP. Under normal use with long exposures (a minute or longer) this is not a problem. But it is seriously annoying if one wants to take e.g. 1000 1 sec exposures. Native ASICAP software enables one to select a ROI. And as explained above by others, for many targets this could be much smaller than using the entire sensor, making downloading and storing significantly faster, increasing the “frame rate”. If ASICAP provides the ROI option, then why is this not (yet) a possibility in SGP? It would seriously improve the versatility of SGP.

1 Like

Rudy I am in the same boat (I have a 2600MC Pro) and would love to be able to do lucky imaging with subframes for tiny PN’s… this just isn’t really feasible at the moment (don’t have the storage for 50mb FIT files per sub) . We can currently do a ROI for frame and focus - surely it can be done for imaging too?

Cheers, Mike

1 Like

Has ROI imaging been implemented in SGP 4?
If not, is it on the horizon?

It’s not something we are actively considering right now, but that doesn’t mean it can’t be. As I read through this thread, it sure seems like folks are referring to use of subframes (ROI) as a part of a sequence. Currently, SGPro only supports subframe as a part of frame and focus. The only things that I’m concerned with is that the intent of the feature is to reduce both the amount of download bandwidth and disk space occupied by data. If the camera implements subframes (not all do), the disk space savings would be guaranteed, but there is no guarantee whatsoever that there will be a reduction in download bandwidth as this would be manufacturer dependent (i.e. some camera may see a reduction and others may not, but all can be made to see it if you sweet talk the driver’s author).

It’s not that we are opposed to this, just that we must decide how to spend our limited time and the requests for this over the years have been fairly low. That said, we can consider this a “bump” and see if, given that huge sensors have more market saturation now, maybe the importance of a feature like this is become more popular.