Superresolved tomographic measurements in scattering media

为了用CCD相机测量强散射介质中物体的反射率分布，研究了基于光学低相干反射计和光学调频反射计的两种检测方法。通常，检测到的图像被不期望的散射光劣化。因此，本课题也对信号恢复问题进行了研究。研究结果如下：1.为了真实的实时处理光强起伏，研制了一套矩图像处理系统。其结果是，在低于30 Hz的频率波动的强度定量成像.利用图像处理系统对低相干干涉仪输出的时变干涉图样进行了检测。深度分辨率为10 μ m。这个系统被用来调查一个很好的对象。作为线性扫描光学频率的高功率光源，使用DBR激光器（分布式布拉格反射器激光器）。在没有跳模效应的情况下，频率调制的最大宽度为46 GHz。结果表明，深度分辨率为2.0 mm.用矩量图像处理系统测量了放置在0.1%内禀水溶液中7mm深度处的平面物体的空间反射率分布。已检测到1.0%的反射率差异.研究了带约束的迭代反褶积方法的信号恢复问题。对于含噪信号，可采用预滤波技术。

In order to measure a reflectivity-distribution of object in strongly scattering media with a CCD camera, two detection methods based on an optical low coherence reflectometry and an optical frequency-modulated reflectometry have been investigated. In general, the detected images are degraded by undesired scattering light. So, the signal recovery problems are also invstigated in this reserch project. The results are shown as follows :1. To process the intensity fluctuation at real time, a moment image processing system was developed. As a result, the intensity fluctuating at frequencies lower than 30 Hz was quantitatively imaged.2. The image processing system was applied to detect the time-varied interference pattern from the low coherence interferometer. The depth-resolution was 10 mum. This system was used to investigate a fine object.3. As a high power light source to sweep linearly the optical frequency, a DBR laser (Distributed Bragg Reflector laser) was used. The maximum width of the frequency modulation was 46 GHz without a mode-hop effect. The result shows the depth-resolution of 2.0 mm.4. The spatial reflectivity distribution of the flat object placed at 7 mm depth in o.1 % intralipid solution was measured with the moment image processing system. The reflectivity difference of 1.0 % has been detected.5. The signal recovery problem with a constrainted iterative deconvolution method was investigated. For the noisy signal, the pre-filtering technique is available.