Development of blood vessel searching system for HMS

摘要

In this study, we develop a new 3D miniature blood vessel searching system by using near-infrared LED light, a CMOS camera module with an image processing unit for a health monitoring system (HMS), a drug delivery system (DDS) which requires very high performance for automatic micro blood volume extraction and automatic blood examination. Our objective is to fabricate a highly reliable micro detection system by utilizing image capturing, image processing, and micro blood extraction devices. For the searching system to determine 3D blood vessel location, we employ the stereo method. The stereo method is a common photogrammetric method. It employs the optical path principle to detect 3D location of the disparity between two cameras. The principle for blood vessel visualization is derived from the ratio of hemoglobin's absorption of the near-infrared LED light. To get a high quality blood vessel image, we adopted an LED, with peak a wavelength of 940nm. The LED is set on the dorsal side of the finger and it irradiates the human finger. A blood vessel image is captured by a CMOS camera module, which is set below the palmer side of the finger. 2D blood vessel location can be detected by the luminance distribution of a one pixel line. To examine the accuracy of our detecting system, we carried out experiments using finger phantoms with blood vessel diameters of 0.5, 0.75, 1.0mm, at the depths of 0.5 ~ 2.0 mm from the phantom's surface. The experimental results of the estimated depth obtained by our detecting system shows good agreements with the given depths, and the viability of this system is confirmed.