A novel multiplexed velocimeter using a proprietary grating is proposed for measuring the velocity of particles in blood vessel. Two orthogonal gratings are multiplexed. The specially designed multiplexed grating is imaged on a microscopic region using a laser diode. The light scattered by the moving particles is collected using the same imaging lens and detected by a detector. The resulting electronic signal contains both two components of velocity, which can be separated using an electronic signal processor.
We briefly review holographic endoscopes and propose a system using a photorefractive fiber to record hologram inside the body. We also propose a system similar to a stereomicroscope to see the 3-D image of an object inside the body in real-time.