return value for ASIGetDataAfterExp

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Doliometer
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Joined: Thu Nov 08, 2018 7:25 pm

return value for ASIGetDataAfterExp

Post by Doliometer » Tue Nov 27, 2018 6:51 am

Regarding indi/3rdparty/indi-asi/ASICamera2.h, ASIGetDataAfterExp for ASI290MM,

what does it mean when a pixel is assigned a value >= 2^12? I am getting values like 5251, for which log base 2 is ~12.36.

for purposes of preparing to stack images, what then would be the maximum value returned for each pixel?

i am assuming but do not know that this function feeds the INDI function ExposureComplete of PrimaryCCD else there may be an intermediary transformation.

thanks.

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Support2@ZWO
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Re: return value for ASIGetDataAfterExp

Post by Support2@ZWO » Wed Nov 28, 2018 8:06 am

HI,
Because in computer system, the length of the data is usually 8bit, 16 bits, 32bit or 64bit. So when we get a 12bit data from sensor, we will move 4bit left, and fix 0 into the low 4 bit. After this, we will get a 16bit data. This means when we get 1 from sensor, we will output 16.
For your value of 5251, I am not sure if your image had beed processed. Usually, if it is the raw data, this should not happen. We did not find this problem before. So I think you can make sure that if your image is the raw data. If not the raw data, after processed, this value is normal.
Thanks
Chad
ZWO Driver Engineer
Location:lon=120.6 lat=31.3
SuZhou China

WarnerGrict
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return value for ASIGetDataAfterExp

Post by WarnerGrict » Sun Jan 13, 2019 2:08 pm

These functions return values from the ac.ini. If there is no ac.ini, then default values are returned. Default values are the same and are hardcoded.

So the problem is that ac.ini is missing.

hugo52
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Joined: Wed Jul 24, 2019 5:04 pm

Re: return value for ASIGetDataAfterExp

Post by hugo52 » Sat Jul 27, 2019 8:12 pm

Chad, pls advice if it is possible during exposion change the gain temporary to 0
Regards Hugo

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Support2@ZWO
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Re: return value for ASIGetDataAfterExp

Post by Support2@ZWO » Mon Jul 29, 2019 1:33 am

Hi Hugo,
Usually, during the exposure, modifying the gain is useless. Usually, after the exposure starts, even if the gain and brightness are modified, the sensor will only take effect on the next image.
Thanks
Chad
ZWO Driver Engineer
Location:lon=120.6 lat=31.3
SuZhou China

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