George D T, Bogen D K
Philadelphia Heart Institute, Presbyterian Medical Center, PA 19104.
IEEE Trans Biomed Eng. 1991 Sep;38(9):919-24. doi: 10.1109/10.83612.
A new low-cost strain measurement system has been developed for the mechanical testing of biological soft tissues. The technique creates four spots of light on a tissue sample surface by piercing the tissue sample with two pairs of small light-conducting optical fibers (one pair for each axis of a biaxial stretch), terminated by high intensity infrared emitters. A large-area photodiode, located below the tissue sample, detects the light emitted from the two pairs of light-spots. Analog and digital circuitry analyze the current signal from the photodiode to determine the position of a light-spot in real time. Each infrared emitter is sequentially cycled "on" at a rate of 3 kHz and the resulting photodiode current signal, after being converted to a voltage signal, is held by an integrated circuit sample and hold amplifier. Analog differencing of pairs of light-spot voltage signals provides a final output proportional to the separation between coaxial light-spots.
一种用于生物软组织力学测试的新型低成本应变测量系统已被开发出来。该技术通过用两对小的导光光纤（用于双轴拉伸的每个轴各一对）穿透组织样本，在组织样本表面产生四个亮点，光纤末端为高强度红外发射器。位于组织样本下方的大面积光电二极管检测从两对亮点发出的光。模拟和数字电路分析来自光电二极管的电流信号，以实时确定亮点的位置。每个红外发射器以3 kHz的速率依次循环“开启”，所得的光电二极管电流信号在转换为电压信号后，由一个集成电路采样保持放大器进行保持。对亮点电压信号对进行模拟差分，提供与同轴亮点之间的间距成比例的最终输出。
