Emgu CV Library Documentation
PyrDown Method
NamespacesEmgu.CVImage<(Of <(TColor, TDepth>)>)PyrDown()()()

www.emgu.com/wiki
Performs downsampling step of Gaussian pyramid decomposition. First it convolves this image with the specified filter and then downsamples the image by rejecting even rows and columns.
Declaration Syntax
C#Visual BasicVisual C++
public Image<TColor, TDepth> PyrDown()
Public Function PyrDown As Image(Of TColor, TDepth)
public:
Image<TColor, TDepth>^ PyrDown()
Return Value
The downsampled image

Assembly: Emgu.CV (Module: Emgu.CV) Version: 1.3.0.0 (1.3.0.0)