Troubles with Image Integration Flat and Dark generation DSLR`s?

[Atreides]

First of all hello and Happy Holidays .
I write because I found something that is rare for me when used for generate  Image Intregration Dark Frames and Flat Frames obtained with modified DSLR cooled (RAWs were obtained by a Canon 1000D cooled to -8 ° C).
The following message appears on each reading of each frame:

Reading FITS: 32-bit floating point, 3 channel(s), 3906x2602 pixels: 100%
MRS noise evaluation: \
** Warning: No convergence in MRS noise evaluation routine - using k-sigma noise estimate.—
** Warning: No convergence in MRS noise evaluation routine - using k-sigma noise estimate.|
** Warning: No convergence in MRS noise evaluation routine - using k-sigma noise estimate.done.
Scale factors   :   1.00147  1.00507  1.00267
Zero offset     :  +0.000000e+000 +1.541134e-004 +2.155779e-005
Noise estimates :  2.805e-002 1.566e-002 1.894e-003
Weight          :     0.99706    1.00054    1.00559



Could it be that I need to add a pedestal in the calibration of Bias frames? Is it because of something I did wrong?
Thank orientation.
regards





Hola  y Felices Fiestas lo primero de todo.
Escribo porque he detectado algo que para mi es raro a la hora de utilizar Image Intregration para generar los Dark Frames y Flat Frames obtenidos con DSLR modificada y refrigerada (los RAWs fueron obtenidos por una Canon 1000D refrigerada a -8ºC ).
Aparece el siguiente mensaje en cada lectura de cada frame:


Reading FITS: 32-bit floating point, 3 channel(s), 3906x2602 pixels: 100%
MRS noise evaluation: \
** Warning: No convergence in MRS noise evaluation routine - using k-sigma noise estimate.—
** Warning: No convergence in MRS noise evaluation routine - using k-sigma noise estimate.|
** Warning: No convergence in MRS noise evaluation routine - using k-sigma noise estimate.done.
Scale factors   :   1.00147  1.00507  1.00267
Zero offset     :  +0.000000e+000 +1.541134e-004 +2.155779e-005
Noise estimates :  2.805e-002 1.566e-002 1.894e-003
Weight          :     0.99706    1.00054    1.00559

¿Puede ser que necesito añadir un pedestal en la calibración de los Bias frames? ¿Es debido a algo que he hecho mal?
Agradezco orientación.
Saludos

[Cleon_Wells]

I think this is normal for images that have little or no signal pixels.

Quote from Juan’s post.

“Nope. Noise evaluation does not try to evaluate information contents; that's a much more complex and difficult task. It just tries to make a relative measurement of the intensity of the noise in the image. Roughly, this is done through classification: for each image, the algorithm divides the whole set of pixels into two disjoint sets: noise pixels and signal pixels. Then the noise estimate is derived from the variance of the set of noise pixels.”

http://pixinsight.com/forum/index.php?topic=3320.0

Cleon

[pfile]

right - you might as well just turn off noise evaluation (which, somewhat obscurely mean you must uncheck "use file cache") when integrating darks or bias frames. they should not be weighted anyway so there's no need to go through the extra step of evaluating the noise.

there's probably not much noise in the flats either since the exposures are short and the camera is so cold. anyway those should not be weighted by noise content either.