矩阵既可以用单个坐标,可以用(行,列)两个坐标,ind2sub
是转换的函数
[I,J] = ind2sub(siz,IND)
[I1,I2,I3,...,In] = ind2sub(siz,IND)
The single ampersand & is the logical AND operator. The double ampersand && is again a logical AND operator that employs short-circuiting behaviour. Short-circuiting just means the second operand (right hand side) is evaluated only when the result is not fully determined by the first operand (left hand side)
A & B (A and B are evaluated)
A && B (B is only evaluated if A is true)
Position 的格式是 [x y w h]
,x y 是 lower left corner of the rectangle