Differential spectral imaging system for biological and environmental monitoring

利用干涉仪的透射谱、CCDRGB单元的灵敏度谱和物体的反射光谱，对波长差分成像过程进行了理论分析。利用上面所示的光谱计算获得的波长差分图像上每个像素的颜色，并重建模拟图像。以非洲菊花瓣为例，模拟图像与实际波长差分图像非常接近。还开发了其他类型的调制差分成像系统：荧光和偏振调制成像系统。即使在正常明亮的房间里，荧光调制成像系统也能提供清晰的荧光图像，如叶绿素和图章。偏振调制成像系统从玻璃窗口上和通过玻璃窗显示的图像中选择性地分离出透明图像和反射图像，差分光谱成像系统已经改进为使用窄带通滤光片(干涉滤光片)和双视光学系统，人们可以通过不同的光路同时观察来自同一物体的两个图像。新系统甚至可以拍摄运动物体或光谱特征随时间变化的物体的微分光谱图像。随着时间的推移，使用该系统可以监测人体血液的还原变化。当手腕的血流被带状止血时，手部表面附近的静脉必须充满脱氧血红蛋白。该系统直观地显示了脱氧血红蛋白扩散的变化。

The wavelength-differential imaging process has been theoretically analyzed by spectral simulation using the transmission spectra of the interferometer, sensitivity spectra of RGB cells of CCD and reflection spectrum of an object. The color of each pixel on the obtained wavelength-differential image is calculated using the spectra shown above and simulated image is reconstructed. For an example of gerbera petals, the simulated image was very close to the real wavelength-differential image.Other types of modulated differential imaging system has been developed; fluorescent-and polarization-modulation imaging system. The fluorescent-modulation imaging system provided clear fluorescent images such as chlorophyll and stamp on note even in normal bright room. The polarization-modulation imaging system selectively separated a transparent image and a reflection image from the image shown on and through a glass window.The differential-spectral imaging system has been improved into a real-time system using narrow band-pass filters (interference filters) and the dual view optics by which one can observe simultaneously two images through different optical paths from an object. The new system can even take the differential-spectral images of moving objects or objects which change their spectral characteristics with time. Change of deoxidization of human blood has been monitored over time using the system. When the blood stream of a wrist is stopped by banding, the vein near the surface of the hand must be filled with deoxyhemoglobin. The system has visualized change of the spread of deoxyhemoglobin.