Quantitative subsurface imaging in strongly scattering media.
Quantitative subsurface imaging in strongly scattering media.
复制标题
强散射介质中的定量地下成像。
作者：
P. González;A. Kim;M. Moscoso;C. Tsogka
我们提出了一种方法来获得位于强散射介质表面附近的小障碍物或不均匀性的定量精确图像。该方法使用反向散射光的时间分辨测量来形成图像。使用该问题的辐射传输方程的渐近解，我们确定测量中的关键信息内容是通过扩散近似来建模的，该扩散近似对于较小的源-探测器距离和较浅的穿透深度有效。我们通过使用玻恩近似对已知背景光学特性的不均匀性影响进行线性化，进一步简化了该模型。所得模型用于两阶段成像算法。首先，使用多信号分类（MUSIC）方法的修改来确定不均匀性的空间位置。然后，我们利用这些结果，通过最小二乘近似确定不均匀性的定量值。我们发现，这种两阶段方法对于沿着与零源-探测器间隔相对应的穿透深度重建一维图像序列最有效，而不是同时使用多个源-探测器距离上的测量。该方法仅限于散射平均自由路径数量级的穿透深度和边界测量之间的距离。
We present a method to obtain quantitatively accurate images of small obstacles or inhomogeneities situated near the surface of a strongly scattering medium. The method uses time-resolved measurements of backscattered light to form the images. Using the asymptotic solution of the radiative transfer equation for this problem, we determine that the key information content in measurements is modeled by a diffusion approximation that is valid for small source-detector distances, and shallow penetration depths. We simplify this model further by linearizing the effect of the inhomogeneities about the known background optical properties using the Born approximation. The resulting model is used in a two-stage imaging algorithm. First, the spatial location of the inhomogeneities are determined using a modification of the multiple signal classification (MUSIC) method. Using those results, we then determine the quantitative values of the inhomogeneities through a least-squares approximation. We find that this two-stage method is most effective for reconstructing a sequence of one-dimensional images along the penetration depth corresponding to null source-detector separations rather than simultaneously using measurements over several source-detector distances. This method is limited to penetration depths and distances between boundary measurements on the order of the scattering mean-free path.