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## Re: Not getting Poisson Noise in octave

**From**: |
c. |

**Subject**: |
Re: Not getting Poisson Noise in octave |

**Date**: |
Mon, 3 Dec 2012 08:20:55 +0100 |

On 3 Dec 2012, at 05:44, Terry Duell wrote:
>* Hello Carlo,*
>* *
>* On Mon, 03 Dec 2012 14:56:00 +1100, c. <address@hidden> wrote:*
>* *
>*> *
>*> On 3 Dec 2012, at 00:05, Terry Duell wrote:*
>*> *
>*>> You could also try something like this...*
>*>> *
>*>> bb = aa + 3/256*randn(h,w);*
>*>> where h,w are the height, width of aa.*
>*>> *
>*>> The first approach takes 13.74 sec here, for my little test image. The *
>*>> second takes about 0.01 sec.*
>*>> The results appear quite similar, but I guess it depends on your particular *
>*>> need.*
>*> *
>*> that is equivalent to*
>*> *
>*> bb = imnoise (aa, 'gaussian', 0, sqrt(3/256))*
>*> *
>*> which works the same in Matlab and Octave, the version I proposed*
>*> is equivalent to*
>*> *
>*> bb = imnoise (aa, 'poisson')*
>*> *
>*> which is not yet implemented in Octave:*
>* *
>* [snip]*
>* *
>* OK, then I should not be making any changes to the imnoise code.*
>* *
>* Cheers,*
On the other hand I see now that poissrnd does accept a matrix as input, so:
poissrnd (aa)
works fine and is much faster than my previous version
I'll have a look at changing "imnoise" accordingly.
c.

**Not getting Poisson Noise in octave**, *Sivahari Nandakumar*, `2012/12/02`
**Re: Not getting Poisson Noise in octave**, *c.*, `2012/12/02`
**Re: Not getting Poisson Noise in octave**, *Sivahari Nandakumar*, `2012/12/02`
**Re: Not getting Poisson Noise in octave**, *Terry Duell*, `2012/12/02`
**Re: Not getting Poisson Noise in octave**, *Carnë Draug*, `2012/12/02`
**Re: Not getting Poisson Noise in octave**, *Terry Duell*, `2012/12/02`
**Re: Not getting Poisson Noise in octave**, *Carnë Draug*, `2012/12/02`
**Re: Not getting Poisson Noise in octave**, *Terry Duell*, `2012/12/02`
**Re: Not getting Poisson Noise in octave**, *c.*, `2012/12/02`
**Re: Not getting Poisson Noise in octave**, *Terry Duell*, `2012/12/02`
**Re: Not getting Poisson Noise in octave**,
*c.* **<=**
**Re: Not getting Poisson Noise in octave**, *Terry Duell*, `2012/12/03`
**Re: Not getting Poisson Noise in octave**, *c.*, `2012/12/03`
**Re: Not getting Poisson Noise in octave**, *Carnë Draug*, `2012/12/04`