PURPOSE: To measure a two-dimensional position by computing a travel in the orthogonal direction and the angle of rotation in a plane by spatial-filter arithmetic operation from the two-dimensional image data of an object to be measured.

CONSTITUTION: The image pick-up signal of an object to be measured 1 picked up by a two-dimensional CCD 2 is converted 6 into a digital signal through a read circuit 3, and input to a spatial-filter arithmetic operation section 5 as an image data. The digital signal is stored in an image memory 7, and input to spatial filters 8, 9, 10 respectively in the arithmetic operation section 5. Outputs Fs, Fc passing through the filters 8, 9 are input to phase rotary arithmetic operation sections 11, 12 together with previous values, and αΔ, βΔ are arithmetically operated. A moving vector Δ=(Δx, Δy) is obtained by a moving- vector arithmetic operation section 13, to which αΔ, βΔ are input, and travels in the two orthogonal directions are arithmetically operated by an integrator 14. An output Fw from the filter 10 is input to a phase rotary arithmetic operation section 15 together with a previous value and the angle of rotation θ is acquired, and the angle of rotation in a plane containing the orthogonal directions is computed by an integrator 16.