基于互相关的图像匹配亚像素定位

Image Orientation Algorithm with Subpixel Accuracy Based on Correlative Matching Method

本文提出了一种新颖的基于抛物线拟合原理的亚像素求取算法。为了简单快速的获得亚像素定位精度,本文根据相关峰所呈现出的特性,用抛物线拟合经相关峰顶点切开的纵切面轮廓。沿不同的方向纵切,就可获得不同方向上的拟合抛物线,而根据每一条拟合抛物线可获得其对应顶点。最后根据所获得的点,进一步求取到各点距离之和的最小值点,其对应位置即为所求。从而实现了以点来描述线(每个点代表一条抛物线),以线(所有的拟合抛物线)来描述面的思想,以便于更真实详细的描述相关峰顶点附近峰面所呈现出来的特性。实验证明,该算法具有较高的亚像素提取精度,能达到0.01级别的像素精度。

A new sub-pixel algorithm based on the principle of the parabola fitting is proposed. According to the condition of the correlation peak, the outline of the longitudinal section along the climax of the correlation peak is fitted by parabola. The longitudinal section is executed along different direction to acquire different parabola, and then the climax of parabola can be gained from every parabola. The optimum position is the point, where the sum of distance is the least from it to all other points. Thus, it is realized that the line of parabola is described by point and the surface of correlation peak is described by line, which can show more truly the condition of the correlation peak. The experimental results show that the algorithm maintains a high precision of the subpixel extraction.