i need a more detailed explaining for spacial histogram uniform lbp c++ code

when i ask i meant any one post alink or a website which explain the code, i understand many functions in code but i confused about where calling them and some implementations of them
thanks alot

ok...
in code there is a function initUniform this function call another function initHistogram why the first function call the second and what is the use of initHistogram i don't understand what is the channel

void LBPFeatures::initUniform()
{
lookup.resize(255);
int index=0;
for(int i=0;i<=255;i++)
{
bool status=checkUniform(i);
if(status==true)
{
lookup[i]=index;
index++;
}
else
{
lookup[i]=59;
}
}
spatialhist Hist;
Hist.initHistogram();

}

void spatialhist::initHistogram()
{
vector<int> channel;
channel.push_back(0);
hist.setChannel(channel);
vector<int> size;
size.push_back(sizeb+1);
hist.setHistSize(size);

}