Accurate band-to-band registration of AOTF imaging spectrometer using motion detection technology

• A method using the undiffracted beam of AOTF to detect motion of spectral images is proposed.
• The distortion is found to be an easily overlooked factor affecting image motion detection.
• A reflective optical system has been proposed to reduce distortion and chromatic aberration.
• Experiments show the accurate spectral image registration capability of this technique.

This paper concerns the problem of platform vibration induced band-to-band misregistration with acousto-optic imaging spectrometer in spaceborne application. Registrating images of different bands formed at different time or different position is difficult, especially for hyperspectral images form acousto-optic tunable filter (AOTF) imaging spectrometer. In this study, a motion detection method is presented using the polychromatic undiffracted beam of AOTF. The factors affecting motion detect accuracy are analyzed theoretically, and calculations show that optical distortion is an easily overlooked factor to achieve accurate band-to-band registration. Hence, a reflective dual-path optical system has been proposed for the first time, with reduction of distortion and chromatic aberration, indicating the potential of higher registration accuracy. Consequently, a spectra restoration experiment using additional motion detect channel is presented for the first time, which shows the accurate spectral image registration capability of this technique.