[ VIGRA Homepage | Function Index | Class Index | Namespaces | File List | Main Page ]
|   | XYZ2LabFunctor [Color Space Conversions] |  | 
Convert standardized tri-stimulus XYZ into perceptual uniform CIE L*a*b*. More...
#include <vigra/colorconversions.hxx>
| Public Types | |
| typedef TinyVector< T, 3 > | argument_type | 
| typedef NumericTraits< T > ::RealPromote | component_type | 
| typedef TinyVector < component_type, 3 > | result_type | 
| typedef TinyVector < component_type, 3 > | value_type | 
| Public Member Functions | |
| template<class V> | |
| result_type | operator() (V const &xyz) const | 
#include <vigra/colorconversions.hxx>
 Namespace: vigra
The functor realizes the transformation
![\[ \begin{array}{rcl} L^{*} & = & 116 \left( \frac{Y}{Y_n} \right)^\frac{1}{3}-16 \quad \mbox{if} \quad 0.008856 < \frac{Y}{Y_n}\\ & & \\ L^{*} & = & 903.3\enspace \frac{Y}{Y_n} \quad \mbox{otherwise} \\ & & \\ a^{*} & = & 500 \left[ \left( \frac{X}{X_n} \right)^\frac{1}{3} - \left( \frac{Y}{Y_n} \right)^\frac{1}{3} \right] \\ & & \\ b^{*} & = & 200 \left[ \left( \frac{Y}{Y_n} \right)^\frac{1}{3} - \left( \frac{Z}{Z_n} \right)^\frac{1}{3} \right] \\ \end{array} \]](form_21.png) 
where  is the reference white point.
 is the reference white point.  represents the lighness ("brightness") of the color, and
 represents the lighness ("brightness") of the color, and  code the chromaticity.
 code the chromaticity.
Traits defined:
FunctorTraits::isUnaryFunctor is true (VigraTrueType) 
| typedef TinyVector<T, 3> argument_type | 
the functor's argument type
| typedef NumericTraits<T>::RealPromote component_type | 
the result's component type
| typedef TinyVector<component_type, 3> result_type | 
the functor's result type
| typedef TinyVector<component_type, 3> value_type | 
| result_type operator() | ( | V const & | xyz | ) | const | 
apply the transformation
| 
© Ullrich Köthe     (ullrich.koethe@iwr.uni-heidelberg.de)  | 
html generated using doxygen and Python
 |