基于目标形貌测量的空间频域成像校正方法.

Correction Method for Spatial Frequency Domain Imaging Based on Target Profile Measurement

为了消除空间频域(SFD)成像中形貌对组织体光学特性提取精度的影响,提出了一种基于目标形貌测量的SFD成像校正方法。该方法采用相位轮廓技术获取目标的三维形貌,并对获取的SFD漫反射图像进行频率与光强校正。其中,频率校正采用基于多频查表的光学特性插值方法,入射和反射光强的校正则基于光照度定律和Minnaert模型。用基于高灵敏度锁相光子计数检测技术的单像素SFD成像系统进行实验,并用二维离散余弦变换模式的单像素成像方法获取低采样率下的目标形貌与多波长光学特性拓扑图像。实验结果表明,目标体表面形貌高度在每个像素点的误差不超过1mm,校正后重建的吸收系数和约化散射系数分别降低了51.1个百分点和6.7个百分点。

To eliminate the influence of profile on the extraction accuracy of optical characteristics of the tissue in spatial frequency domain(SFD)imaging,an SFD imaging correction method based on the target profile is proposed in this study.The method uses phase contour technology to obtain the three-dimensional(3 D)profile of the target,and corrects the frequency and light intensity of the obtained SFD diffuse reflection image.The frequency correction adopts the optical characteristic interpolation method based on the multifrequency lookup table,and the correction of the incident and reflected light intensity is based on the law of illuminance and the Minnaert model.Experiments are performed using a single-pixel SFD imaging system based on a high-sensitivity phase-locked photon-counting detection technology,and a single-pixel imaging method based on two-dimensional(2 D)discrete cosine transform is used to obtain topological images of the target profile and multiwavelength optical characteristics at low sampling rates.The experimental results show that the error of the target surface profile height at each pixel is not more than1 mm,and the reconstructed absorption coefficient and reduced scattering coefficient after correction are reduced by51.1 percentage points and 6.7 percentage points,respectively.