无人机载高光谱成像系统识别沥青路面血液痕迹研究

UAV-carried Hyperspectral Imaging System to Recognize the Bloodstain on Bitumen Road

目的研究无人机载高光谱成像系统在室外沥青路面发现和识别血液等痕迹物证的能力。方法使用旋翼式无人机搭载全息反射光栅型高光谱成像系统采集室外沥青路面血液、油漆、酱油等痕迹样本的可见-近红外波段光谱影像数据,使用光谱角制图算法分析处理所采集到的光谱影像数据。结果人体血液、酱油和油漆在600~800nm波段范围的反射率光谱存在明显差异,当光谱角制图算法阈值角度的最大值设为0.1弧度时,在30m飞行高度条件下,无人机单次起降可获取12000m^2扫描区域的光谱影像数据,能够准确发现沥青路面4cm×4cm以上面积的血液痕迹,并与油漆、酱油等痕迹相互区分,达到识别目的。结论无人机载高光谱成像系统在案事件现场搜寻和识别血液等生物检材的工作中具有应用价值。

Objective To probe into the feasibility and accuracy about the UAV(Unmanned Aerial Vehicle)-carried hyperspectral imaging system to find and recognize the bloodstain on the surface of bitumen road so as to provide a new approach for the application of UAV into criminal investigation.Methods The rotor UAV,equipped with the coaxial reflection convex holographic grating hyperspectral imaging system,was used to collect the visible and near-infrared spectral imaging data of human blood,paint,soy sauce and other sampling traces on the surface of bitumen road.Different algorithms were selected to analyze and tackle the collected spectral imaging data.Results For the human blood,soy sauce and paint,their reflectance spectra are significantly different in the waveband of 600~800 nm.With adoption of the spectral angle mapping algorithm and the related maximal angular threshold set to 0.1 radian,the UAV,flying at 30 m high,can harvest the spectral imaging data of 12000 m^2 scanning area through its one single takeoff and landing.Consequently,the bloodstain can be accurately discerned from the bitumen pavement if it is of the size over 4 cm×4 cm,having been distinguished from paint,soy sauce and other traces.Conclusions The UAV-carried hyperspectral imaging system is applicable for crime scene hunting to discover and/or perceive biological evidential materials,e.g.,the bloodstain.