unsigned int *p_var, unsigned int *p_mean)
uint32_t *p_var,uint32_t  *p_mean)
void variance(uint8_t *p, int size,	int rowstride,			 unsigned int *p_var, unsigned int *p_mean){	int i,j;	unsigned int v,s,s2;	s = s2 = 0;	for (j=0; j<size; j++)	{		for (i=0; i<size; i++)		{			v = *p++;			s+= v;			s2+= v*v;		}		p+= rowstride-size;	}	*p_mean = s/(size*size);	*p_var = s2 - (s*s)/(size*size);}