基于相對點矩的SAR圖像匹配算法

　　為了解決景象匹配導(dǎo)航系統(tǒng)中圖像存在旋轉(zhuǎn)誤差以及遮擋問題，提出了一種基于相對點矩的SAR圖像匹配算法。Harris角點提取算子結(jié)合亞像素精確定位算法可以獲得高精度的特征點坐標(biāo)，而Hu不變矩具有平移、旋轉(zhuǎn)、縮放(RTS)不變性，結(jié)合兩者優(yōu)點，本文首次提出了相對點矩的概念。相對點矩同樣具有RTS不變性，可以實現(xiàn)任意旋轉(zhuǎn)角度下的圖像匹配，通過選擇合適的特征半徑，可以抵抗一定程度的遮擋。針對粗匹配點中存在的誤差匹配點，采用相似三角形原理篩選并摒棄;最后，通過最小二乘法給出最優(yōu)估計值。實驗結(jié)果表明，該算法滿足高精度、實時性和一定的抗干擾要求。

　　Abstract:

　　To solve the problem that there exits rotation error and shading in the images of the scene matching aided navigation system， a new matching algorithm for SAR image based on relative point moment invariants is proposed. Feature point coordinates of high precision can be achieved by the Harris corner point operator and the sub-pixel positioning algorithm .When Hu moment invariants with their properties of translation， rotation and scaling(RTS) invariability are combined with high precision feature points， we proposed the concept of relative point moment invariants for the first time. The relative point moment invariants also have the RTS invariability properties，therefore image matching of arbitrary rotation angle can be achieved by using the relative point moment invariants. Moreover， this matching algorithm can resist certain degree of shading. Match points witch error are excluded according to the principle of similar triangles. Finally， the optimal estimation is given by the least square method. Experimental results show that， this algorithm satisfies the high-precision， real-time and certain degree of anti-interference requirements.

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