The measuring accuracy of laser optical sensors is gradually degraded over time as a result of geometrical fluctuations of the laser beam. In a previous study by the present group, a method was proposed for stabilizing the laser beam by means of a rotating optical diffuser. In the present study, the effects of the key diffuser parameters, namely the rotational speed (ω), the particle radius (r), and the particle concentration (c), on the performance of the proposed system are evaluated both numerically and experimentally. The results confirm that given an appropriate setting of the three parameters, the proposed system reduces the variation of the image centroid position and improves the measuring accuracy of the laser optical sensor as a result.
Physiological changes in the retinal vasculature are commonly indicative of such disorders as diabetic retinopathy, glaucoma, and age-related macular degeneration. Thus, various methods have been developed for noninvasive clinical evaluation of ocular hemodynamics. However, to the best of our knowledge, current ophthalmic instruments do not provide a true color blood flow imaging capability. Accordingly, we propose a new method for the true color imaging of blood flow using a high-speed pulsed laser photography system. In the proposed approach, monochromatic images of the blood flow are acquired using a system of three cameras and three color lasers (red, green, and blue). A high-quality true color image of the blood flow is obtained by assembling the monochromatic images by means of image realignment and color calibration processes. The effectiveness of the proposed approach is demonstrated by imaging the flow of mouse blood within a microfluidic channel device. The experimental results confirm the proposed system provides a high-quality true color blood flow imaging capability, and therefore has potential for noninvasive clinical evaluation of ocular hemodynamics.