[Radiance-general] Fwd: errors from hdrgen

[Axel Jacobs]

Martin Matusiak wrote:

>"Poor covergence of order 1 fit"
>  
>
Ignore this one, this is a debug message and only means that things are 
not running as smoothly as they could.

>"Cannot solve for response function"
>  
>
That is more of a problem. Essentially, the dynamic range of the images 
has gaps between them or is clipped on either side of the range. Try:

- Taking images at smaller f-stop intervals
- remove images that are too bright or too dark
- include darker or lighter images.

We keep having this problem with webhdr, but here doesn't seem to be a 
rule of thumb for getting it right. If the worst comes to the worst, you 
can disable hdrgen's built-in auto exposure routine and do a hand-jobby, 
but this is more difficult.
https://luminance.londonmet.ac.uk/webhdr/

You should also save the coefficients from a run that doesn't create any 
errors/warning and re-use them when you do get them. Please note that 
the response curve is/can be different even between two cameras of the 
same model/make, so don't mix-n-match them.

Axel