调制法提高体表内部虚拟超谱图信号检测信噪比

摘要

体表内部虚拟超谱图将皮肤组织中的成分和结构信息有机融合表达,具有“图谱合一”的特点,有望应用于临床体表组织疾病的快速检查,但由于检测中信号微弱,极易受到环境光的影响和仪器本身暗电流的限制.为解决这一问题提出斩光盘对光源进行方波调制的方法,搭建实验平台,选择大功率的超连续谱激光和应用广泛的溴钨灯两种光源,在人为添加红色激光、紫色激光干扰和自然环境光干扰三种环境中,采用非调制和调制光源对人体手臂进行VIHBS对比实验,并对调制后的信号实现FFT解调处理.实验结果表明,调制法能够有效的消除环境光和暗电流的影响,提高信号检测的信噪比,为人体组织微弱光学信号的检测开辟了新的思路.%Virtual internal hyperspectrum of body surface which can express and properly mix the information of skin's composition and structure was expected to apply in the human disease quick-diagnosis, but the weak detected signal was easily impacted by ambient light and dark current from the instrument, so square wave modulated by chopper disk was proposed to resolve this issue. First, we built the experiment platform, and selected both laser and bromine tungsten lamp as the light source, then compared the virtual hyperspectrum of non-modulated and modulated light on human arm in the environment with artificial interference, and demodulated the modulated signal by FFT method. The experiment result showed that modulation method could effectively eliminate the impact brought by environmental light and dark current and improve the signal to noise ratio (SNR), suggesting a new approach to detect human's weak optical signals.