分布式全息孔径成像系统形位误差校正

Correction of shape and position errors of distributed holographic aperture imaging system

分布式全息孔径数字成像技术是利用数字全息技术记录子孔径的复振幅信息,再通过孔径间复振幅拼接实现综合成像的一种主动成像技术。在工程应用中,成像系统的装配误差会使子孔径复振幅间产生形位误差,进而使孔径综合后的图像变模糊。在已有的方法中,大多是以相似变换模型校正形位误差,但是复振幅与理想复振幅间是复杂的投影变换关系,所以基于相似变换模型的方法不再适用。首先提出一种在像面校正复振幅间形位误差的方法,该方法先通过像面图像配准对像面复振幅进行投影变换校正,再对校正后的像面复振幅进行逆菲涅尔衍射,得到形位误差校正后的瞳面复振幅。进而搭建了分布式全息孔径成像系统,并采用在像面校正复振幅间形位误差的方法有效地校正了形位误差。

Distributed holographic aperture digital imaging technology is an active imaging technology which uses digital holographic technology to record sub-aperture complex amplitude information,and then realizes comprehensive imaging through complex amplitude stitching between apertures.In engineering applications,it is well known that the assembly error of the imaging system will cause the shape and position errors between the sub-aperture complex amplitudes,and then blur the image after aperture synthesis.While in the existing methods,the shape and position errors are mostly corrected by the similar transformation model,but the relationship between the complex amplitude and ideal complex amplitude is complex projection transformation,so the method based on the similar transformation model is no longer applicable.Firstly,a method for correcting the shape and position errors between complex amplitudes on the image plane is proposed.In this method,projection transformation correction on the image plane complex amplitude is performed firstly through image registration,and then inverse Fresnel diffraction is performed on the corrected image plane complex amplitude to obtain the complex amplitude of the pupil plane corrected for shape and position errors.Then a distributed holographic aperture imaging system is built,and the shape and position errors are effectively corrected by correcting the shape and position errors between complex amplitudes on the image plane as suggested in this work.