Superresolved tomographic measurements in scattering media

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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.