Banding issues with ASI 178MC: Page 3

Banding issues with ASI 178MC

shannonm

Hi Sean,

I sent an email to chad.cao at zwoptical.com yesterday with a Dropbox link to a series of raw dark images, plus two stacked. The difference between using the camera on USB3 vs USB2 is shocking - the banding is much more obvious in the USB3 darks.

If my data changes drastically by simply using a different USB port, then I think there is a problem. All 4 images were acquired with identical exp and gain, only the USB port and Turbo USB setting was changed in SharpCap. All were median stacked in PI with no normalization or pixel rejection and stretched to the exact same values.

Thank you for your response,

ShannonM

https://drive.google.com/open?id=1lgaCDMVm6BUS6ejoDsMCZVhxs8Af-Wwt *this is an updated version of the one I sent to Chad, the older one did not have each master dark stretched to the same values, I let PI do an auto stretch which complicated the issue more than helping it.

PS - TomR, exactly. It seems as if this is how the 178 is and a replacement/repair would not do much to help the situation.

shannonm

Update:

ZWO has offered to repair my camera which honestly does not make sense to me because it doesn't seem to be broken, this seems to be the way this camera works (which is badly for anything other than planetary).

is there any chance someone else out there with the ASI178mc uncooled camera could take 10 dark frames, one with USB2 and another with USB3 (all other setting identical) and upload them to Dropbox so I could see if my camera is truly in need of repair or if this is a faulty design by ZWO?

I am posting this same message on every imaging forum I'm a member of as well as my local clubs. I am happy to return the camera if everyone else's dark frame results don't change between USB2 and USB3 - but if they do, then it's a bad design and I want a different camera.

I'll post my results here as I get them.

tomr

Hi Shannon,

I posted a masterdark of my 178mc here at the forum a few months ago. The camera was plugged into the USB 3 port and usb speed at value 60. At the USB 2 port, there is no banding but a lot of amplifyer noise instead. ZWO has not offered me a fake repair yet, though. Chad told me, that he would try to reproduce the banding, but there has been just silence since. I have the impression that ZWO support is just a bunch of blah blah.

Thomas

chad

Hi Shannon & TomR,

We are really confused about this question.

We're sure there's a problem. But so far, not only me, but also Sean, Sam, and other colleagues, we've all been tested, but none of us have ever repeat the problem. So we don't know what we can do next. We have held several meetings on this problem, but there is no reliable conclusion.

For Shannon's camers, we checked, the camera's hardware works fine. So it should not be a hardware issue.

the attachment is a main dark filed of 178MM(Color has no effect on the dark field)，Take in MaxIm DL,by ASCOM, High Dynamic range, and set the USB to 60, 0.05s exposure. Beside, a 183Pro is working too, in Sharpcap and 183's USB bandwidth is 100%.

And please check:

If you have any new information, please let me know. And I am always keep an eye on this issue.

Thanks

Chad

chad

Sorry, forget the image:

tomr

Chad, your posted image still looks like a single dark frame instead of a stacked masterdark of lets say 100 frames and therefore it seems that you still do not quite understand the problem.

Besides that it's a bad sign that you think that your camera has a problem and your company keeps selling it.

But maybe you can tell us with a little bit more detail what you have done to reproduce the problem. On my system and the systems of other complaining customers the problem was apparent right from the beginning with the default settings of the camera.

Thomas

Support@ZWO

TomR wrote:
Chad, your posted image still looks like a single dark frame instead of a stacked masterdark of lets say 100 frames and therefore it seems that you still do not quite understand the problem.

Besides that it's a bad sign that you think that your camera has a problem and your company keeps selling it.

But maybe you can tell us with a little bit more detail what you have done to reproduce the problem. On my system and the systems of other complaining customers the problem was apparent right from the beginning with the default settings of the camera.

Thomas

gentlemen，I have a suggestion，if you think your camera have problems，please send a emal to us : support(at)zwoptical.com

tomr

jeffbax wrote:
Sam, this issue is known. Don't act like ZWO is discovering Something. As I say, I sold mine due to this problem.

It is an actual and often reported problem on ASI 178.

Plenty of images showing the problem allready have been sent to you. Instead of acting surprised and doing nothing I think it is now your turn to either fix the problem or quit selling the camera.

Thomas

chad

Hi All，

I repeat the issue in the last few minutes of last friday. The conditions for its recurrence are really strict.

And we are trying to solve it in this week, So please give us some time.

Thanks

Chad

shannonm

Excellent news! I've been emailing back and forth with Chad and he has written a new DLL that seems to have significantly reduced or even eliminated the horizontal banding issue. I've got to give ZWO credit for fixing it so fast after they were able to reproduce the issue - it was less than a week.

They asked me to test it and the results were great, though I can only test dark frames inside until the weather clears up. I asked if I could share this and they said yes. Please remember, this new DLL is still in testing so back up your current one first, try this at your own risk, etc etc.

This dropbox folder contains two screen shots, before and after the new DLL was installed as well as a folder with the new DLL in it. I included a small READ ME file with directions on installing it, but feel free to ask if you have any questions. Again - this DLL is still in the testing phase.

https://www.dropbox.com/sh/5iel2vztktqdytu/AABLWGwsXt9VkZXfQGWTYJu6a?dl=0

Huge thanks to Chad and Sean for getting to the bottom of this.

tomr

I can confirm Shannons report concerning the fixed banding issue in masterdarks with the new dll that Chad sent to mee, too. I had to update my Firecapture installation from Version 2.5 to V2.6, to test this because the older versions of FC use a different flavour of the ZWO SDK, which is not compatible with the current SDK. If you use Chads dll in older FC versions, it will not detect asi cameras.

My next testing step will be, to check how the new dll behaves in real astronomical imaging sessions including planetary imaging with high framerates. The masterdarks created so far look very promising for DS imaging.

Support@ZWO

TomR wrote:
I can confirm Shannons report concerning the fixed banding issue in masterdarks with the new dll that Chad sent to mee, too. I had to update my Firecapture installation from Version 2.5 to V2.6, to test this because the older versions of FC use a different flavour of the ZWO SDK, which is not compatible with the current SDK. If you use Chads dll in older FC versions, it will not detect asi cameras.

My next testing step will be, to check how the new dll behaves in real astronomical imaging sessions including planetary imaging with high framerates. The masterdarks created so far look very promising for DS imaging.

That's sound good, looking forward to your good news!

shannonm

TomR,

I'm thrilled to hear your tests are showing an improvement, too. I have another week to 10 days of rain ahead, so it will be awhile before I can give this a real world test. But I am very hopeful! My planetary images never suffered from banding because the SNR ratio is so good with those. I only had issues when doing DSOs with a low SNR.

Whenever I image a DSO from now on, I will be connecting via USB2 with the USB traffic set as low as it will go. I won't need fast frame rates for those and it looks like the images will be much cleaner. I look forward to seeing your images with this fix.

Shannon

tomr

Shannon, I've done my tests with the camera connected to a USB 3 port. Since the banding is not present at this port any more, I would strongly suggest to use these ports instead of the USB 2 ports. At the USB 2 ports there is a lot of amplifyer glow, which is not present at the USB 3 port.

This is a masterdark created from 100 frames taken with the following settings:

Frames captured=100

File type=SER

Binning=no

ROI=3096x2080

ROI(Offset)=0x0

FPS (avg.)=0

Shutter=1.00s

Gain=350 (68%)

Gamma=50

HardwareBin=off

AutoExposure=off

AutoGain=off

USBTraffic=60 (off)

AutoHisto=75 (off)

HighSpeed=off

SoftwareGain=10 (off)

WBlue=50 (off)

Brightness=400 (off)

FPS=100 (off)

WRed=50 (off)

Histogramm(min)=0

Histogramm(max)=4095

Histogramm=100%

Noise(avg.deviation)=n/a

Limit=100 Bilder

Sensor temperature=32.7°C

This is a huge improvement over the previous camera driver.

shannonm

TomR, my darks show a vast improvement as well. I see your point about USB2, but in this example there is a tremendous difference between the statistics using USB2 vs USB3. Ok, maybe not *tremendous* - the median pixel value with USB2 is 3.something, while with USB3 it is 12.something. Honestly, I saw reduced amp glow with USB2 instead of USB3. But since I was not specifically testing for that, maybe I missed it?

These are "mini" master darks created with 10 images, 15s exp 50 gain, median stacked with no pixel rejection or normalization. All 4 images have been stretch the exact same amount. I need to try this again, but with an exposure of 60 secs and see what that shows. Perhaps 15s wasn't enough to show the true difference in amp glow. Thanks for posting all the info about your image, that is very helpful to know that we are comparing apples to apples.

tomr

Shannon, since asi 178mc is a USB 3 camera, it should work well on these ports. My tests showed a tremendous improvement of deep sky camera performance on these ports compared to the previous version of the camera driver. Now, if you noticed that the camera still performs better in DS imaging at the USB 2 port than at the USB 3 port, then in my opinion there is still some work for Chad to do. I definitely want to use the camera at the USB 3 port for planetary and lunar imaging and it would be a pain in the arse to switch ports between deep sky and planetary imaging sessions.

chad

HI All，

Because this change may cause data to be lost when bandwidth is low, I limited it to USB3.0. USB2.0 remains the same.

For this update, it is a test version only for you. I'll include it in the next Release. So you only need to upgrade to the latest version in the future.

Thanks

Chad

tomr

Last night I tried to do test the new dll, but the sky was not dark, the moon rising and clouds approaching. I imaged NGC 6210 for 40 minutes. The banding was gone, but the overall sky brightness was too high, so this is inconclusive. I have to wait some more time to get a darker sky or do some imaging with the old dll, too, for comparison. At least the inner part of NGC 6210 was resolved nicely.

I also tested Jupiter imaging at 100fps for 30 minutes in a row and this worked without problems with the new dll.

tomr

This image of NGC 6826 is based on 1 hour exposure time with my ASI 178mc during moonlight but better transparency compared to my last DS test effort. The banding is gone and and so from my point of view the issue has been finally resolved. I'll use the new dll from now on till Chad integrates it into the official driver release.

Support@ZWO

I'm so happy to see this problem has been solved!

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