[Radiance-general] help pfilt and low values dgp
Jan Wienold
jan.wienold at epfl.ch
Thu Aug 13 07:23:17 PDT 2015
Hi Jasper,
you definitely should use a newer version of evalglare.
If you go to the website:
http://www.ise.fraunhofer.de/radiance
you can at least download the 1.11 version-which doesn't have this bug.
The will be a new version of evalglare coming out in the next days/weeks
(version 1.17) - this will be announced separately here in that group.
Regarding your image: Your calibration must span the luminance-range you
want to measure.
If you calibrate between 1cd/m2-1000 cd/m2 it does not tell you anything
how accurate you are when measuring 100000cd/m2!
So if you want to measure the luminance of the sun, then you have to
make sure your camera is calibrated for such high luminances as well.
I guess when you want to measure several million cd/m2 you might need a
grey filter. At ISE we had several filters down to 0.0001 transmittance,
so it was easy to measure also towards the sun and the increase of noise
for the lower luminaces doesn't hurt so much.
Your coating on the window play a minor role in that case... honestly
for the sun you can be lucky to measure with one or 2 orders of
magnitude, so if your glazing is 0.75 or 0.4 in light transmittance is
negligible compared to the difference between 5000 and 200000000 cd/m2 !
The picture you have in dropbox is also difficult to check with an
illuminance meter when you integrate the values to an illuminance value,
because the sun is so much on the side and has a very flat angle of
incidence to your measuring plane. For example when your angle of
incidence for the light source (here sun) is 80° and your "uncertainty"
for putting the sensor in the right plane wold be 2.5 degree (it is very
difficult to put it more accurate), then you have automatically an
uncertainty in your sensor reading of 25% (of the illuminance)! (because
illuminance is cos-weighted and a difference in angle for large angles
is big for the cosinus).
Good luck!
best,
Jan
Am 8/12/15 um 3:21 PM schrieb Jasper Overduin:
> Im using evalglare 1.10 release 30.09.2012 with windows 7
> The photos are calibrated with a (il)lumination pistol with 4
> different measurements (with maximum deviation of 0.4 cd/m2)
> There is a certain coating on the window, not sure what kind. but as
> you said the difference is huge.
>
> Within the program of HDRscope there is a similar function and gives
> and errer as well if i use an external Ev value.
>
> 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 <mailto:overduin.jasper at gmail.com>
> *Skype *jasper.overduin
>
> On 12 August 2015 at 06:39, Jan Wienold <jan.wienold at epfl.ch
> <mailto:jan.wienold at epfl.ch>> wrote:
>
> Hi Jasper,
> hi Alstan,
>
> I guess there are several issues in that case. First of all, as
> Alstan wrote, you should crop the image and provide the correct
> lens specification to evalglare. Be aware that editing the header
> could be dangerous, because sometimes editors add strange
> characters or you don't see tabs in the header with marks the view
> string there as "invalid" . In case the header is interpreted
> "wrong" in evalglare, the results could be really random and could
> differ for more than 100% from the right ones (e.g. the
> calculation of the vertical illuminance, see presentation on the
> Radiance workshop in 2012). The header treatment is much more
> robust since the evalglare version 1.08, but still the user should
> take care of providing a correct header. evalglare is relying on a
> correct radiance header. To be on the safe side, you should always
> use the command option to provide the correct view option to
> evalglare.
> Also you should make sure, that you use a view type which really
> corresponds to your lens. If your real lens is a hemispherical
> fish eye and you provide -vta as view string, the angles and
> solid angles are calculated wrong in evalglare and you get wrong
> results. So make sure that you use -vta only if your lens is a
> angular fish eye.
> And please don't use the -1 option in evalglare!!! This is a
> special (undocumented) option to get fast results on images
> calculated without ambient calculations. If you use it for normal
> images, the glare sources might not detected correctly and you
> could get big differences. It is working mostly properly in images
> with large black areas (-ab 0).
> Since the -1 option is not robust for normal images, this option
> is undocumented. There exist also other undocumented options since
> 2009 for hdr treatment(e.g. pixel overflow correction, image
> fillup when ccd-array is smaller than the projected image...), but
> these options are by purpose undocumented because they should be
> used only in special cases and can cause wrong results when not
> used properly.
>
> If I look at your image, I guess your calibration is not correct.
> The sun has a luminance of 2e10 cd/m2. In case of low
> transmittance glazing you still have a luminance of Xe9 cd/m2,
> lets say at least 1e9cd/m2, which is factor 200000 higher than you
> measured!!! And be aware you you might have to deal with blooming
> effects when you have a pixel overflow (especially when looking
> into the sun). Not sure about your camera setting, but if you
> still have an overflow for the shortest exposure, you should think
> of adding a neutral grey filter to reduce the overall
> transmittance to the ccd.
>
> Finally I can't reproduce the 0 output of evalglare. I used your
> image and used as well the 2500lux as input (even if the image is
> not cropped correctly and the view string is wrong). See here:
> /evalglare -i 2500 pmar_sin_03.hdr//
> //Notice: Low brightness scene. Vertical illuminance less than 380
> lux! dgp might underestimate glare sources//
> //dgp,dgi,ugr,vcp,cgi,Lveil: 0.311778 18.132195 21.670120
> 44.798004 27.925421 58.052605 //
>
> /But I always get an non-0 result, I never experienced this
> before. I tried the linux ,the mac and also the windows version
> with your image - it didn't happen. So which version are you
> using? Which operating system? (type evalglare -v to find out)
>
> @Alstan: Can you provide me another example where this happens as
> well? Which version are you using? Which operating system?
>
> A zero value should never appear, except your image is completely
> black.
>
> Best,
> Jan
>
>
>
> Am 8/11/15 um 5:33 PM schrieb J. Alstan Jakubiec:
>> Hi Jasper,
>>
>> This is one of the tricky aspects of doing glare analysis with
>> your own HDR images. A couple of pointers are below,
>>
>> * You will need to crop your image to a square aspect about the
>> image center using the pcompos
>> <http://radsite.lbl.gov/radiance/man_html/pcompos.1.html>
>> tool. There was a helpful discussion on maintaining image
>> exposure values while doing this here
>> <http://www.radiance-online.org/pipermail/radiance-general/2011-March/007701.html>.
>> * The -vv and -vh parameters are just best guesses according
>> the HDR generation software. Once you have cropped the image,
>> you will want to open the resulting HDR in a text editor and
>> manually change the header 'VIEW' field to include -vta -vv
>> 180 -vh 180. You may also specify them via the command line
>> at this point, as you have done. I like to keep it associated
>> with the image.
>> * After that, unless I am forgetting something (others can
>> chime in), you are ready to run evalglare. I would run it
>> with the -d flag, which will report a lot of details. Most
>> usefully, it reports illuminance as derived from the image,
>> which you can compare to your measured Ev value to check the
>> validity of the HDR. If your HDR is well-calibrated, not
>> inputting the measured illuminance value should be perfectly
>> accurate.
>> * I suspect that inputting measured illuminance is somewhat
>> broken in the current version of evalglare as I have the same
>> problem that you do. One option is to use the -1 option to
>> evalglare, which will return only a single DGP value. It
>> seems to avoid this error.
>> > evalglare -1 -i 2500 image.hdr
>>
>> By the way, to avoid some of this cropping and exposure value
>> pain, I use an image-processing tool (like PIL for Python) these
>> days that can maintain EXIF data while cropping the source jpeg
>> files. Though perhaps the cure is worse than the disease in this
>> case..
>>
>> Best,
>> Alstan
>>
>> On 8/11/2015 11:08 PM, Jasper Overduin wrote:
>>> Dear all,
>>>
>>> I have changed my lens to one with 180 circular view to do a
>>> contrast analysis (hdrscope) and meanwhile the glare analysis in
>>> evalglare. If i use the commands in evalglare getinfo i get the
>>> (HDR composed with photosphere on a mac, calibrated with
>>> luminance pistol) i get a value for the lens -vv and -vh which
>>> is not over 100, with a lens of 180. I can imagine that the
>>> photo ratio and the lens are not the same and that causes this
>>> problem. But when I enter the external measured Ev, the value
>>> the dgp goes somehow to zero. The fact that the gdp is zero with
>>> a maximum luminance of 5600 cd/m2 and Ev of 2500 lux makes me a
>>> bit suspicious. How accurate is the result of the dgp without
>>> external vertical lux? is it possible to use this value?
>>>
>>> hdr files and printscreens of evalglare
>>> https://www.dropbox.com/sh/ei1y4d2v6hapdsr/AACgVMPd1o0EdK-0q8CFvUGga?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 <mailto:overduin.jasper at gmail.com>
>>> *Skype *jasper.overduin
>>>
>>> On 1 May 2015 at 12:15, Jan Wienold <jan.wienold at epfl.ch
>>> <mailto:jan.wienold at epfl.ch>> wrote:
>>>
>>> Hi Jasper,
>>>
>>> I briefly looked at your image - for sure you get a low DGP
>>> value if your illuminance at camera (or eye) level is only
>>> about 300lux... It is not the matter of the fish eye lens it
>>> is a matter of your lighting condition.
>>> When I remember correctly, for the experiments I did for my
>>> PhD, the people adjusted the blinds in a way, that they had
>>> 2500-3000 lux at the eye level and they were less than 20%
>>> of them dissatisfied. So a value of 300 means one order of
>>> magnitude less light at the eye level and a much lower
>>> adaptation level.
>>> So I definitely understand the low DGP value in that case.
>>> The images themselves look reasonable, so I don't think
>>> there is a problem in calibration/processing so far (at
>>> least not for these low luminance levels-it might be more
>>> tricky to calibrate for the high luminance values when you
>>> get stray-light from the multiple lenses).
>>>
>>> If all your images are like that it means you have a very
>>> low daylight contribution at the place you measure. I'm not
>>> sure if DGP is then the right way to measure glare in that
>>> case - as I wrote it is made more for the daylight oriented
>>> workplace with higher levels and also to take into account
>>> very high luminances (e.g. sun or specular reflections of
>>> the sun). DGP might be modified in future, but these
>>> experiments are just starting.
>>>
>>> Jan
>>>
>>>
>>>
>>>
>>>
>>>
>>> Am 4/30/15 um 10:41 PM schrieb 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
>>>> <mailto:overduin.jasper at gmail.com>
>>>> *Skype *jasper.overduin
>>>>
>>>> On 30 April 2015 at 13:55, Jan Wienold
>>>> <jan.wienold at epfl.ch <mailto: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
>>>>> <mailto:overduin.jasper at gmail.com>
>>>>> *Skype *jasper.overduin
>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> Radiance-general mailing list
>>>>> Radiance-general at radiance-online.org
>>>>> <mailto:Radiance-general at radiance-online.org>
>>>>> http://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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>>>
>>> --
>>> 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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>
> --
> 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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--
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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