[HDRI] ximage and hdri

[Giulio]

photoshop cs4 pro?
cool!
On 2 Jun 2009, at 20:15, Chris Cox wrote:

> Wouldn’t it be a little faster to just create a mask (selection is  
> easiest in this case) in Photoshop and use the average filter?
>
> Chris
>
>
> On 6/1/09 2:18 PM, "Giulio" <geotrupes at mac.com> wrote:
>
> low teck approach, just command line:
> I would just generate a mask with photoshop, an image with just white
> and black pixels, but in RGB.
> convert it to tiff and then to pic    (ra_tiff -r ).
> use pcomb with image 1 and image 2 and write an expression that takes
> value of pixels in your HDR only if they are inside of the mask, all
> the others null (basically multiply image 1 by image 2, check that the
> mask contains 0 and 1 only!).
> use pvalue on the filtered image and convert to numbers
> use total and get the sum of all data from filtered image, TL
> count the white pixels in the mask (pvalue and total for example), TN
> TL/TN = average luminance within the mask
> ....
> the whole thing can be written in a script.
> and perhaps also put together with a nice sequence of pipes.
> G
>
>
> On 1 Jun 2009, at 21:29, Roberto Rodriguez wrote:
>
> > I´m a PhD student from Argentina, member of a research team
> > advocated to
> > the study of natural lighting. We are exploring the HRDI technique
> > and we
> > found a limitation while using hdrgen and ximage: Only squared
> > shapes are
> > avaiable to average Luminances, and we need to calculate the mean
> > Luminances for radial shapes (circular, toroidal) in order to get  
> the
> > luminance contrast in the field of view.
> >
> > How can we overcome this? Can we "borrow" the source code of ximage
> > so we
> > can write a script acording to our needs?
> > Thank you.
> >
> > --
> > Dis. Ind. Roberto G. Rodriguez
> > Laboratorio de Ambiente
> > Humano y Vivienda-LAHV
> > INCIHUSA-CRICYT-CONICET
> > Av. Ruiz Leal s/n, Pque. Gral. San Martín
> > (5500) Mendoza, Argentina
> > Tel. 54-261-5244334
> > Fax: 54-261-4287370
> > rgrodriguez at mendoza-conicet.gov.ar
> > http:www.cricyt.edu.ar
> >
> >
> >
> >
> > --
> > Dis. Ind. Roberto G. Rodriguez
> > Laboratorio de Ambiente
> > Humano y Vivienda-LAHV
> > INCIHUSA-CRICYT-CONICET
> > Av. Ruiz Leal s/n, Pque. Gral. San Martín
> > (5500) Mendoza, Argentina
> > Tel. 54-261-5244334
> > Fax: 54-261-4287370
> > rgrodriguez at mendoza-conicet.gov.ar
> > http:www.cricyt.edu.ar
> >
> >
> >
> >
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>
>
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