用整体最优准则实现ISAR成像的包络对齐

ISAR成像中的包络对齐通常是基于距离像之间的相关性.本文从目标的散射点模型出发,首先通过分析和实验研究表明,近角度(转角变化小于0.1°)距离像之间具有强相关性,但随着转角的增大,由于交叉项的影响,相关性急剧下降,这也表明用相邻相关法作包络对齐,会产生漂移误差;之后,提出了通过在成像所需的距离像中散布选取十多次距离像作平均,抑制交叉项,就能得到稳定平均距离像,它和所有距离像具有强的相关性,把它作为相关模板进行对齐,能改善对齐效果 ;最后,提出整体最优准则包络对齐的迭代算法,实测数据也表明它比已有的方法要好.

Range Alignment Using Global Optimization Criterion in ISAR Imaging

Range alignment is usually based on the correlation of range profile in ISAR imaging.According to the point scatterer model of target,this paper shows that the range profiles have strong correlation within the aspect change 0.1°,but with the increase of aspect change the correlation will decrease greatly due to cross-term,which also shows that drift error will be caused when conventional neighbor amplitude correlation method is used to align the envelope.It is shown that by averaging over ten range profiles selected from the imaging needed range profiles with equal aspect change,the cross-term can be restrained,and the stable average range profile can be obtained.The average range profile has strong correlation with all range profiles,and if it is used as template,then the accuracy of range alignment can be enhanced.An iterative correlation alignment method for range alignment is proposed by using global optimization criterion.Real data validate its effectiveness.