HDRComposition

[erikgu]

Hi

I am using HDRComposition to compose 10*15sec, 10*30sec, 20*240sec and 15*600sec images of M42. The images are taken with a dslr, Canon 60d. I have done the nonlinear steps and the initial stretch. My problem comes up when i doing the HDRMultiscaleTransform. The stars that is nearest to the trapz, excuse my english i am norwegian, is devided in to several rings. The rest of the stars seems to be ok. The ringing was not that strong when i processed the image without the 600 sec. exposures.

Hope for hits that can help me to com further with the processing.

Erik G


 

[georg.viehoever]

Experiment with the Binarization Threshold and Mask Smoothness parameters. This usually helps. If this fails, you may want to try the GradientDomain/GradientHdrComposition process.

Georg

[erikgu]

Hi George !

Thanks for the reply. I will try this. Do you know if there is a turorial/description that shows/describes the effect of the  Binarization Threshold and Mask Smoothness parameters that can help me to nail the correct settings more easily than just trial and error.


Erik G.

[Juan Conejero]

Hi Erik,

Welcome to PixInsight Forum. Take a look at the official announcement of the HDRComposition tool, which I posted back in September 2010:

http://pixinsight.com/forum/index.php?topic=2320.0

There you'll find an example with an M42 image and some practical hints. The binarization threshold parameter defines where each image will be replaced with data from a lower exposure. The default value normally works very well but sometimes has to be decreased (rarely increased). The mask smoothness parameter is not very critical so you can leave it by default and concentrate on the threshold. The generated masks will give you accurate information about the composition process.

[erikgu]

Hi Juan,

Thanks for the welcome and the parameter setting hint. An adjustment of the binarization threshold from default 0.8 to 0.7 was the change needed.

I have one other issue, it is a to get a good color calibration. There are few areas that can be selected as previews. Most of them has few stars.  Is that actually a problem ?, can preview(s) of the M42 nebula itself be used ?

Erik G.