[Radiance-general] help pfilt and low values dgp

[Jasper Overduin]

>
> Thank you for the fast reply. We are still having some problems with the
> outcome of Evalglare. With an external luxometre we have done some tests
> now. The DGP is still very low or zero. It seems that in almost all the
> case the DGP is low. In literature we read that values above 20% are
> normal. What do you think? is the data much better if we use a full 180
> degree lens?
>
> .hdr file https://www.dropbox.com/s/l10x7tri49btr8r/ff.hdr?dl=0
print screen cmd
https://www.dropbox.com/s/yv1lamhiirjhvxq/imp%20pan.jpg?dl=0
test.pic https://www.dropbox.com/s/nspdu01477mchsz/test.pic?dl=0


> Greetings Jasper
>
>
>
>
>
> *Jasper Overduin*
> MSc Building Technology graduate student at Delft University of Technology
>
> *S* Groenhoevelaan 3
> *P* 2343 BP Oegstgeest
> *T* +31 6 15 64 48 56 (NL)
> *T* +56 9 51 11 76 48 (CL)
> *E *overduin.jasper at gmail.com
> *Skype *jasper.overduin
>
> On 30 April 2015 at 13:55, Jan Wienold <jan.wienold at epfl.ch> wrote:
>
>>  Hi Jasper,
>>
>> why are you using -vth -vh 140 -vv 80 when in your header of the HDR
>> image the view is specified as  -vtv -vh 98.797409 -vv 75.402067 ?
>> Manipulating the lense type is really dangerous - in that case you change
>> from a perspective view to a hemispherical fish eye view, without changing
>> the image!!
>>
>> If I apply evalglare for your image I get 0.17 as DGP (which is still
>> very low, but you have only 2000cd/m2 as maximum value, so this can be
>> expected). Be aware, that DGP accounts only for glare from a high amount of
>> daylight and/or spots of extreme luminances (>50000cd/m2), but not for
>> contrasted glare between task (e.g. Monitor) and immediate surroundings for
>> lower adaptation levels. This is subject of current research (also here at
>> EPFL) and there might be an extension of the DGP in future, depending on
>> the outcome of new experiments.
>>
>> Back to the lens-type:
>> It is extremely important, that the right view type is given to
>> evalglare, otherwise ALL calculated values (it doesn't matter if this is
>> evalglare or findglare) are wrong. These errors could be huge, more than
>> 100% for calculating the illuminance out of a 180 degree image.
>>
>> If you manipulate an image by pcomb, in general the view is marked as
>> "invalid" in the header, because with that tool you could manipulate the
>> image in a way, that the original view is not valid any more. This is why
>> from evalglare version 1.0 on a check on the header was included, because
>> many people were creating wrong headers without knowing it and then
>> evalglare was calculating wrong values, when the header was invalid.
>>
>> In addition for calculating the DGP it is important to have the
>> illuminance at camera level. evalglare calculates this value out of the
>> image. But if the image does not cover 180 degree, then the calculated
>> value for the illuminance is too low. For that reason, the -i option was
>> included, so you can provide the illuminance to evalglare (when you measure
>> it with an illuminance sensor).
>>
>> So in your case, you should measure the illuminance just besides the
>> lens.
>> Then (in case this is the right lens description) you should use
>> evalglare -i LUXVALUE -vtv -vh 98.797409 -vv 75.402067 IMAGE_NAME
>> or better, if your task is always at the same place:
>> evalglare -i LUXVALUE -vtv -vh 98.797409 -vv 75.402067  -T 395 230 .6 -c
>> CHECK_FILE_PICTURE IMAGE_NAME
>>
>> good luck!
>>
>> Jan
>>
>>
>>
>> Am 4/30/15 um 6:04 PM schrieb Jasper Overduin:
>>
>>  Somehow cant use the command pfilt or change the pcomb, does this has
>> to do with the program Radiance? I have installed the version of windows
>> from the site, with evalglare v1.11windows . The problem is that I have
>> composed a .hdr (out of 7 jpg on a mac) and after using the command
>> c:/HDRI>evalglare -vth -vh 140 -vv 80 image.hdr all the dgp results are
>> really low, less than 5%. The problem can be in the .hdr (calibrated as
>> well) or is in the way evalglare is not working as it shoot on my computer.
>>
>>
>>
>>  *.hdr file* (post-it is calibration point 167,98)
>> https://www.dropbox.com/s/4z69y358yt8ii4z/1_sv_am.hdr?dl=0
>> *images* original
>> https://www.dropbox.com/sh/adyyxjkv6eykyek/AAC96QUTpLh_Ef2U8Mppki8ta?dl=0
>> *command printscreen*
>> https://www.dropbox.com/s/0pbn105p0z0iinu/Imp%20pan.jpg?dl=0
>>
>>
>>  Need the help!
>>
>>  Greetings Jacobus
>>
>>
>>  *Jasper Overduin*
>> MSc Building Technology graduate student at Delft University of Technology
>>
>>  *S* Groenhoevelaan 3
>>  *P* 2343 BP Oegstgeest
>>  *T* +31 6 15 64 48 56 (NL)
>> *T* +56 9 51 11 76 48 (CL)
>>  *E *overduin.jasper at gmail.com
>> *Skype *jasper.overduin
>>
>>
>> _______________________________________________
>> Radiance-general mailing listRadiance-general at radiance-online.orghttp://www.radiance-online.org/mailman/listinfo/radiance-general
>>
>>
>> --
>> Dr.-Ing.  Jan Wienold
>> Ecole Polytechnique Fédérale de Lausanne (EPFL)
>> EPFL ENAC IA LIPID
>> http://people.epfl.ch/jan.wienold
>> LE 1 111 (Office)
>> Phone    +41 21 69 30849
>>
>>
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>>
>>
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