Detection method capable of being applied to linear displacement or corner position of object

The invention relates to a detection method capable of being applied to the linear displacement or corner position of an object. In the method, the precision of position detection is determined by theterm difference of a discretized sequence, and the related characteristics of the discretized sequence, such as the term difference, the term number and the like, can be determined according to the required precision. When a measured object and a detection unit generate relative displacement or relative rotation, the detection unit outputs cosine and sine signals, the phase angle and the displacement or the rotation angle of the signals are in direct proportion in a period, a constructive function F (x) and H (x) are established, F (x) is in direct proportion to x and F (x + kpi/4) = F (x) +k * F (pi/4), and H (x) is in direct proportion to tanx. In the range of x belonging to [0,pi/4], the F(x) and H(x) are discretized and are corresponding to each other in a one-to-one manner, and thediscretized F(x) is marked