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|   | Gaussian< T > Class Template Reference |  | 
#include <vigra/gaussians.hxx>
| Public Types | |
| typedef T | argument_type | 
| typedef T | result_type | 
| typedef T | value_type | 
| Public Member Functions | |
| unsigned int | derivativeOrder () const | 
| Gaussian (T sigma=1.0, unsigned int derivativeOrder=0) | |
| result_type | operator() (argument_type x) const | 
| double | radius (double sigmaMultiple=3.0) const | 
| value_type | sigma () const | 
The Gaussian function and its derivatives.
Implemented as a unary functor. Since it supports the radius() function it can also be used as a kernel in resamplingConvolveImage().
#include <vigra/gaussians.hxx>
 Namespace: vigra 
| typedef T value_type | 
the value type if used as a kernel in resamplingConvolveImage().
| typedef T argument_type | 
the functor's argument type
| typedef T result_type | 
the functor's result type
| 
 | explicit | 
Create functor for the given standard deviation sigma and derivative order n. The functor then realizes the function
![\[ f_{\sigma,n}(x)=\frac{\partial^n}{\partial x^n} \frac{1}{\sqrt{2\pi}\sigma}e^{-\frac{x^2}{2\sigma^2}} \]](form_57.png) 
Precondition:
| Gaussian< T >::result_type operator() | ( | argument_type | x | ) | const | 
Function (functor) call.
| value_type sigma | ( | ) | const | 
Get the standard deviation of the Gaussian.
| unsigned int derivativeOrder | ( | ) | const | 
Get the derivative order of the Gaussian.
| double radius | ( | double | sigmaMultiple = 3.0 | ) | const | 
Get the required filter radius for a discrete approximation of the Gaussian. The radius is given as a multiple of the Gaussian's standard deviation (default: sigma * (3 + 1/2 * derivativeOrder() – the second term accounts for the fact that the derivatives of the Gaussian become wider with increasing order). The result is rounded to the next higher integer. 
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© Ullrich Köthe     (ullrich.koethe@iwr.uni-heidelberg.de)  | 
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