Warp escribió:
> John VanSickle <evi### [at] hotmailcom> wrote:
>> How long do you have to wait before the graininess has reliably become 
>> unnoticeable?
> 
>   I wonder if an automatic measurement and then a threshold couldn't be
> developed. For example, if a given pixel hasn't changed color for the
> last n rays which have affected that pixel, then that pixel is done.
> When all the pixels fulfill this requirement, the image is done.
> 

http://www.winosi.onlinehome.de/FAQ.htm

> Is there any stop criteria for the render process in the current
> release?
 >
> No. When the image is pretty enough in your opinion, you have to stop
> manually by selecting Render/Stop from the pulldown-menu.
 >
> I am experimenting with the local contrast as a stop criteria. It
> starts with a high value because of the noise, and if the image gets
> smoother and the noise reduces with each iteration, the local
> contrast converges to a certain end-value. Unfortunately this value
> is not known until the image is finished. So I let the renderer
> calculate the difference between the current local contrast and the
> one from the iteration before. This difference value goes to zero
> when the image has reached its final contrast after an infinite
> number of iterations. I thought to stop the renderer when it reaches
> a certain small difference value, but in practice the difference
> function is very noisy too, giving zero or even negative values very
> early. You can trace these two values during rendering in the
> File/Info-Dialog (bottom right).

Post a reply to this message