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Recovering sensor analysis data

Posted: Sat Feb 12, 2022 12:09 pm
by StuartT
I located the JSON files created by the sensor analysis. It contains the read noise and e/ADU values for each gain level, but it doesn't seem to contain all the info presented at the conclusion of the analysis (such as full well depth, dynamic range etc). Where is that info stored?

I forgot to do a screen grab of the results for all my cameras, can the table be regenerated somehow in SharpCap at a later date?

Thanks

Re: Recovering sensor analysis data

Posted: Sat Feb 12, 2022 2:30 pm
by admin
Hi,

The read noise and e/ADU are the keys to calculating the rest of the data - for instance

FWD = 2^(bit depth) * e/ADU
Relative gain at gain X = (e/ADU for minimum gain) / (e/ADU for gain X)
Dynamic range = (FWD / read noise)
Dynamic range (stops)= log base 2(FWD / read noise)

Most of the data (apart fron the dynamic range) can be recovered from the 'Sensor Data' tab of the Smart Histogram Brain window - there is a button below the graph to copy the sensor data to the clipboard.

cheers,

Robin

Re: Recovering sensor analysis data

Posted: Sun Feb 13, 2022 10:17 am
by StuartT
Can I just check, in your formula for FWD is the bit depth that of the camera's ADC or the mode (as in RAW8, RAW16?

Re: Recovering sensor analysis data

Posted: Sun Feb 13, 2022 1:42 pm
by admin
Hi,

for FWD you have to use the bit depth of the ADC for high bit depth modes, but for 8 bit mode you use 8. Basically you are calculating the total number of ADU levels that the camera has in that mode.

cheers,

Robin

Re: Recovering sensor analysis data

Posted: Sun Feb 13, 2022 2:54 pm
by StuartT
ok.

What confused me is the ASI224MC has a 12 bit ADC, but seems to have a RAW16 mode (acc to SharpCap). How is that possible?

https://astronomy-imaging-camera.com/product/asi224mc

Re: Recovering sensor analysis data

Posted: Mon Feb 14, 2022 12:57 pm
by admin
Hi,

ZWO have designed their SDK around all camera data being turned to 16 bit data (unless you are using 8 bit mode). So with a 12 bit sensor, the data is multiplied by 16 to use the full 16 bit range. There was not a reliable way to get the true bit depth of the sensor from the SDK, so SharpCap doesn't try and just offers the 8 and 16 bit options.

cheers,

Robin