[argyllcms] Re: XYZ and wavelength interval
- From: Matthieu DUBAIL <matthieu.dubail@xxxxxxxxx>
- To: argyllcms@xxxxxxxxxxxxx
- Date: Wed, 30 Jun 2010 21:33:48 +0200
Yes!!!!!!!!!!!!!!!!
Everythink is much more clear now. Thank you very much!
Matthieu DUBAIL
www.presse-bouton.com
2010/6/30 <Skyforce.Shen@xxxxxxx>
> Dear Matthieu:
>
>
>
> You should modify CIEXYZ formulas like below:
>
> X = SUMPRODUCT( "CubicSplineTransformedData" ;
> "StandartObserverx" ) * 5 * .683002
> Y = SUMPRODUCT( "CubicSplineTransformedData" ;
> "StandartObservery" ) * 5 * .683002
> Z = SUMPRODUCT( "CubicSplineTransformedData" ;
> "StandartObserverZ" ) * 5 * .683002
>
>
>
> The number 683 is connected to the modern (1979) definition of the
> candela<http://en.wikipedia.org/wiki/Candela>,
> the unit of luminous
> intensity<http://en.wikipedia.org/wiki/Luminous_intensity>.
> (reference from http://en.wikipedia.org/wiki/Luminosity_function)
>
>
>
> FYI.
>
>
>
> [image: untitled]
>
> *Skyforce Shen*
>
> *Electronic System* *Div.*
> *Project Team IV,RSEE4*
> AU Optronics Corporation
> No.23 Li-Hsin Rd.
> Hsinchu Science Park
> Hsinchu 30078, Taiwan, R.O.C.
> Tel: +886-3-500-8800 Ext. 6304
> Fax: +886-3-567-9036
> skyforce.Shen@xxxxxxx
> AUO.com <http://auo.com/>
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> *From:* argyllcms-bounce@xxxxxxxxxxxxx [mailto:
> argyllcms-bounce@xxxxxxxxxxxxx] *On Behalf Of *Matthieu DUBAIL
> *Sent:* Wednesday, June 30, 2010 9:42 AM
> *To:* argyllcms@xxxxxxxxxxxxx
> *Subject:* [argyllcms] Re: XYZ and wavelength interval
>
>
>
> Hi Keith,
> Thank you for the answer.
> I'm still not able to get the same results as Argyll.
> Here is how I did the measurement and calculation:
> 1. Measured with colormunki ang Argyll using -H option for high definition
> spectral measurement (from 350nm to 750nm every 3,33nm)
>
> 2. Used cubic spline to transform the spectral datas from 380nm to 730nm
> every 5nm
>
> 3. Picked up the 5nm CIE 2° standart observer.
>
> 4 Calculated the XYZ using the following formulas on Excel:
> X = SUMPRODUCT( "CubicSplineTransformedData" ;
> "StandartObserverx" ) * 5
> Y = SUMPRODUCT( "CubicSplineTransformedData" ;
> "StandartObservery" ) * 5
> Z = SUMPRODUCT( "CubicSplineTransformedData" ;
> "StandartObserverZ" ) * 5
>
> I'm getting:
> X = 63,5
> Y = 67,66
> Z = 69,36
>
> While Argyll gives me:
> X = 43,37
> Y = 46,21
> Z = 47,37
>
> What am I doing wrong?
>
> I attached spectral graphic file on how cubic spline perform and standart
> observer used (normalise at 555nm).
>
> I fear once I answered this question, I might have a few more on
> phototometric (Lux and Guide number calculation) and radiometric (Joule
> calcultation) to ask.......
>
> Thank you by advance,
>
> Matthieu DUBAIL
> www.presse-bouton.com
>
>
>
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