HISTS = VL_SAMPLINTHIST(INTHIST, BOXES) samples the integral histogram INTHIST to obtain the histograms of the specified BOXES.

INTHIST is a MxNxK array, where M x N are spatial'' dimensions, and K is the number of histogram bins. INTHIST may be of class UINT32 or DOUBLE.

Each box is a four dimensional vector [IMIN JMIN IMAX JMAX]' of class UINT32 and correspond to the index set [IMIN, IMAX] x [JMIN, JMAX]. To specify an empty box, let IMIN > IMAX.

HISTS stores one histogram per column (one for each box) and has K rows, one for each histogram bin. HIST is of the same class of INTHIST.