Functions | |
cpl_image * | hawki_image_create_variance (const cpl_image *image, double gain, double ron, int ndit, int ndsamples) |
Create the associated variance of a raw image. | |
cpl_imagelist * | hawki_imglist_create_variances_and_delete (cpl_imagelist *imagelist_raw, double gain, double ron, int ndit, int ndsamples) |
Create the associated variance of raw imagelist. |
cpl_image* hawki_image_create_variance | ( | const cpl_image * | image, | |
double | gain, | |||
double | ron, | |||
int | ndit, | |||
int | ndsamples | |||
) |
Create the associated variance of a raw image.
image | the raw image | |
gain | the gain of the detector (e-/ADU) | |
ron | the ron for one read of the detector (ADU) | |
ndit | the number of total integrations. | |
ndsamples | the number of non-destructive readouts. |
where: is the total variance in (ADU
),
is the signal in ADU of electrons in the pixel potencial well, so to the measured ADU we must first remove the bias,
is the gain of the detector (in electrons/ADU),
is the number of non-denstructive reads (ndsamples),
is the number of total integrations (ndit) and
is the readout noise of a single readout of the detector (in ADU). Note that the dimensional inconsistency of the previous expression is only apparent. The expression used, however is only approximate, and is valid for RON << S(i,j). For low signal levels there may be significant deviations
Definition at line 81 of file hawki_variance.c.
Referenced by hawki_imglist_create_variances_and_delete().
cpl_imagelist* hawki_imglist_create_variances_and_delete | ( | cpl_imagelist * | imagelist_raw, | |
double | gain, | |||
double | ron, | |||
int | ndit, | |||
int | ndsamples | |||
) |
Create the associated variance of raw imagelist.
imagelist_raw | the raw imagelist | |
gain | the gain of the detector (e-/ADU) | |
ron | the ron for one read of the detector (ADU) | |
ndit | the number of total integrations. | |
ndsamples | the number of non-destructive readouts. |
The variance is computed with the following equation:
where: is the total variance in (ADU
),
is the signal in ADU of electrons in the pixel potencial well, so to the measured ADU we must first remove the bias,
is the gain of the detector (in electrons/ADU),
is the number of non-denstructive reads (ndsamples),
is the number of total integrations (ndit) and
is the readout noise of a single readout of the detector (in ADU). Note that the dimensional inconsistency of the previous expression is only apparent. The expression used, however is only approximate, and is valid for RON << S(i,j). For low signal levels there may be significant deviations.
Definition at line 159 of file hawki_variance.c.
References hawki_image_create_variance().