Image rotation and translation measurement based on double phase-encoded joint transform correlator.

An image rotation and translation measurement technology based on a double phase-encoded joint transform correlator (DPEJTC) is proposed. The reference and the target images are Fourier transformed. Then the magnitude of the Fourier-transformed reference (MFR) and target (MFT) images are multiplied with a high-pass emphasis filter and transformed from Cartesian space into polar space. Rotation between the reference and the target image is obtained by measuring the emphasized MFR and MFT in polar coordinates by the DPEJTC. The target image is rotated by the rotation angle in the inverse orientation to get the rotation-correction target image. Finally, translation between the reference and the target image is obtained through measuring the reference and the rotation-correction target image by the DPEJTC. Results based on digital computation are given to verify our proposal. A possible optical setup is suggested.