Hi George,
The ESP:MIXUP command currently uses a hard-wired
seed value. I've commited a modification to change this so that the
seed can be controlled via a new parameter called SEED. You can either
set this parameter to a specific integer value, or you can set it null
(i.e. SEED=!) in which case it uses a non-repeatable seed value based
on the current time and the process ID.
This change will appear in the next starlink release, which is due out
sometime within the next few weeks.
Of course, if the noise statistics in the data are Gaussian or
Poissonian, you can use the KAPPA:CREFRAME command to generate an NDF
holding noise.
David
2008/9/30 George Hau <[log in to unmask]>:
> Hi,
>
> I'm trying to use the command "mixup" in the esp package to randomise the pixels in an
> image to generate a noise image. What I'd like to do is to generate a large number of
> different noise images. However there is no way within the mixup task itself to tell it to
> start with a different random number seed, so I always end up having exactly the same
> output image everytime I run the command.
>
> Is there a way within starlink to change the seed? BTW, I'm using os x 10.5.
>
> Would appreciate any suggestion.
>
> cheers,
> George
>
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