Kriging can be seen as a point interpolation which requires a point map as input and returns a raster map with estimations and optionally an error map. The estimations are weighted averaged input point values, similar to the Moving Average operation. The weight factors in Kriging are determined by using a user-specified semi-variogram model (based on the output of the Spatial correlation operation), the distribution of input points, and are calculated in such a way that they minimize the estimation error in each output pixel. The estimated or predicted values are thus a linear combination of the input values and have a minimum estimation error. Two methods are available: Simple Kriging and Ordinary Kriging. The optional error map contains the standard errors of the estimates.
Besides Simple and Ordinary Kriging, you can also use the operations Anisotropic Kriging, Universal Kriging, CoKriging, or Kriging from Raster.