Bit depth for binning pixels on ZWO ASI 294 MM Pro

maropapa
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Bit depth for binning pixels on ZWO ASI 294 MM Pro

Post by maropapa »

Hi,

I try to use ZWO ASI 294 MM Pro with bin 2*2 mode. If " save without scale to 16 bit" feature is not set, the result is saved in 16bit, every 4th channel has a value. This is correct, because the camera has a 12 bit ADC, and if you bin 4 pixels, you will have 14 bit result. That is multiplied by 4 to go to 16 bit, so I expect every 4th channel has a valid value which is the case.

Now when I check "save without scale to 16 bit" I would expect to get 14 bit depth, 12bit from ADC and summ up 4 of them, the result shall be 14 bit. However the file contains only 12 bits. I think this loss is not intended. Binning should also be taken into accout by the SharpCap. (Or may be I missed a point?)

Best regards,
Tamas
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Re: Bit depth for binning pixels on ZWO ASI 294 MM Pro

Post by admin »

Hi,

it looks like the ZWO camera SDK only reports the true bit depth of the camera (12 bits per pixel) – I'd need to write some code to adjust that for the binning setting if you're using the 2 x 2 binning option.

I've already made changes in SharpCap 3.3 so that the choice between the 11 and 47 megapixel modes is made by a separate read mode option rather than having it hidden in amongst the binning options. I will look into making the change to the effective frame bit depth in SharpCap 3.3 as well.

cheers,

Robin
maropapa
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Re: Bit depth for binning pixels on ZWO ASI 294 MM Pro

Post by maropapa »

Great news Robin, Thanks, Tamas
maropapa
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Re: Bit depth for binning pixels on ZWO ASI 294 MM Pro

Post by maropapa »

Hi Robin,

I went on with testing Sharpcap 4.0 with my camera and found another oddity. When I use 11Megapixel mode, with 1x1 binning, the pixel size is reported false: 2.315. While this is the true pixel dimension, the internal logic of the camera bins pixel. That is why it has only 11 Megapixels. The correct value should be 4.63.

Let me know if you need test images.

Best regards,
Tamas
Chris A
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Re: Bit depth for binning pixels on ZWO ASI 294 MM Pro

Post by Chris A »

Just to point out an error regarding the ASI 294MC Pro has a 14bit ADC w/ 13 stops DR and not 12 bit ADC.

Chris A
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Re: Bit depth for binning pixels on ZWO ASI 294 MM Pro

Post by admin »

Hi,

thanks for the reminder on this - I have just made changes to set the effective bit depth of the frame to 12 or 14 bits depending on the 46/11 megapixel resolution choice and also to set the pixel size appropriately. These will be in next week's update. Since I don't have one of these cameras to test with, I be grateful if someone could have a look after the update comes out to confirm if I've got this right or not.

Cheers, Robin
maropapa
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Re: Bit depth for binning pixels on ZWO ASI 294 MM Pro

Post by maropapa »

Hi Robin,

I tested with v4.0.7529.0, 64 bit.
Here comes the test results:
1. The 46Megapixel mode reports 4.63 pixel size, the 11MP mode 2.315. Just the opposite would be good. Maybe that you need to change an if-condition.
2. The 11MP mode reports 14 bits and stores 14 bit pixels correctly.
3. The 46MP mode reports also 14 bits, but that is incorrect, should report only 12.
4. In the 46MP mode pixels are represented as 14 bit numbers, only every fourth channel has a value. That fits with point 3, but we should get 12 bit pixel with 4095 max value.

I hope that I was clear. Let me know if you need more assistance.

Best regards,
Tamas
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Re: Bit depth for binning pixels on ZWO ASI 294 MM Pro

Post by admin »

Hi,

Ok, I can see the inverted condition on the 'if' statement and will fix that - I also think I understand why the bit depth in the file is unchanged and I think I have a fix for that too - I'd be grateful if you can rerun these tests with next week's update.

cheers,

Robin
maropapa
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Re: Bit depth for binning pixels on ZWO ASI 294 MM Pro

Post by maropapa »

Hi Robin,

I tested version: v4.0.7572.0, 64 bit

All the problems look as corrected in this version.

Thanks a lot!
Tamas
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Re: Bit depth for binning pixels on ZWO ASI 294 MM Pro

Post by Gamewarden »

I have the zwo 294 uncooled camera. I keep hearing it has two modes one 11 mp and the other 46,000 mp or so. How do I access the greater resolution?

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