POV-Ray : Newsgroups : povray.advanced-users : Color matching functions Server Time: 17 Jun 2019 13:18:15 GMT
  Color matching functions (Message 1 to 4 of 4)  
From: Mike Horvath
Subject: Color matching functions
Date: 22 Mar 2017 03:12:30
Message: <58d1eb9e$1@news.povray.org>
The CMFs I am currently using are in 5nm steps from 360nm to 830nm, 
which is 95 steps total.

Are there more detailed samples? Are there more detailed samples for D65 
illumination too? The CMFs and illuminations should have the same number 
of steps in the same range, since my script is set up to iterate through 
both sets of samples at the same time. Not sure what to do if the sample 
tables aren't the same sizes.

Thanks.


Mike


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From: Mike Horvath
Subject: Re: Color matching functions
Date: 22 Mar 2017 08:27:05
Message: <58d23559$1@news.povray.org>
On 3/21/2017 11:12 PM, Mike Horvath wrote:
> The CMFs I am currently using are in 5nm steps from 360nm to 830nm,
> which is 95 steps total.
>
> Are there more detailed samples? Are there more detailed samples for D65
> illumination too? The CMFs and illuminations should have the same number
> of steps in the same range, since my script is set up to iterate through
> both sets of samples at the same time. Not sure what to do if the sample
> tables aren't the same sizes.
>
> Thanks.
>
>
> Mike


Wikipedia says you can just interpolate between the 5nm points to 
generate narrower ones. Lightsys uses a spline apparently.


Mike


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From: clipka
Subject: Re: Color matching functions
Date: 22 Mar 2017 16:35:43
Message: <58d2a7df$1@news.povray.org>
Am 22.03.2017 um 04:12 schrieb Mike Horvath:
> The CMFs I am currently using are in 5nm steps from 360nm to 830nm,
> which is 95 steps total.
> 
> Are there more detailed samples? Are there more detailed samples for D65
> illumination too? The CMFs and illuminations should have the same number
> of steps in the same range, since my script is set up to iterate through
> both sets of samples at the same time. Not sure what to do if the sample
> tables aren't the same sizes.

http://cvrl.ioo.ucl.ac.uk/ provides some spectral data tables in steps
as small as 0.1nm.

I guess a lot of that is interpolated though. To my knowledge, the
original data was measured in steps of 5nm.


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From: Alain
Subject: Re: Color matching functions
Date: 22 Mar 2017 22:35:10
Message: <58d2fc1e@news.povray.org>
Le 17-03-22 à 04:27, Mike Horvath a écrit :
> On 3/21/2017 11:12 PM, Mike Horvath wrote:
>> The CMFs I am currently using are in 5nm steps from 360nm to 830nm,
>> which is 95 steps total.
>>
>> Are there more detailed samples? Are there more detailed samples for D65
>> illumination too? The CMFs and illuminations should have the same number
>> of steps in the same range, since my script is set up to iterate through
>> both sets of samples at the same time. Not sure what to do if the sample
>> tables aren't the same sizes.
>>
>> Thanks.
>>
>>
>> Mike
>
>
> Wikipedia says you can just interpolate between the 5nm points to
> generate narrower ones. Lightsys uses a spline apparently.
>
>
> Mike

Yes, Lightsys use splines everywhere.
Most of the time, a linear spline is enough, but you may want to use 
some other kind of spline.


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