will generate a coldframe, based of the reference cold frame and a fit, based on the sensor temperature and exposure time.
INPUT
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exposuretime: integer
the exposure time
sT:
a:
bnew:
sT: float
sensor temperature, see get_sensor_temp_by_program
a: numpy array
fit coefficient image A for the reconstruction, see the files on the E4-Server
bnew: numpy array
fit coefficent image B for the reconstruction, see the files on the E4-Server
coldref: numpy array
the reference cold frame as the base for the reconstruction
the reference cold frame as the base for the reconstruction, see download_hot_cold_reference_by_times
RESULT
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cirebiuld: numpy array
the reconstructed cold frame
NOTE
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the fitting coefficients have been calculated from several known cold frames for different sensors temperature, the procedure have been applied for each camera separatly