You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: harris.m
    path of file: ./repos/2015_Face_Detection/vlfeat/toolbox/noprefix
    
    the code of the file until where you have to start completion: function varargout = harris(varargin)

    
function varargout = harris(varargin)
% VL_HARRIS  Harris corner strength
%  H = VL_HARRIS(I,SI) computes the Harris corner strength of the image I
%  at ``integration'' scale SI.
%
%  The Harris strength [1] of a pixel is a statistic of the gradient
%  of the image integrated in a neighborhood of that pixel. This
%  neighborhood is a Gaussian window of variance SI.
%
%  In computing the Harris corner strength, there is a second scale
%  parameter, the ``derivation'' scale SD, which is the variance of
%  the Gaussian kernel used to pre-smooth the image I before computing
%  its gradient. SI and SD are independ