基于标定臂的低噪声光学相干层析成像技术

Low Noise Optical Coherence Tomography Imaging Technology Based on Demarcating Arm

针对光学相干层析(OCT)技术受散斑噪声影响严重的问题,研究了低噪声OCT成像技术。在系统中加入标定臂,利用标定信号对纵向扫描位置进行精确定位,降低检测过程中样品微位移所引入的误差;并在此基础上对各次纵向扫描信号进行曲波(curvelet)变换,采用自适应阈值法滤除图像散斑噪声,最后通过对多次纵向扫描信号的curvelet系数进行权重滤波和均值处理进一步降低散斑噪声。实验结果证明,与未经curvelet滤波的多次纵向扫描平均图像相比,低噪声OCT成像技术可以提高信噪比18.35%。

This paper describes a low noise optical coherence tomography （OCT） technology based on curvelet algorithm and a demarcating arm to decrease the speckle noise in OCT. The demarcating arm in the Michelson interferometer makes the precise positioning of A-scans possible and diminishes the displacement error caused by tissue moving. Besides, each A- scan is curvelet transformed and adaptive filtered, the curvelet coefficients are weighted, averaged and reconstructed to reduce speckle noise. Compared with traditional A-scans average method, the application of curvelet algorithm and demarcating arm in low noise OCT provides 18.35 % increase in signal to noise ratio.