摘要
光学特性参数准确测量有助于解析光学技术的检测机理,为农产品品质安全检测提供理论依据。结构光反射成像以其宽屏非接触成像、深度辨析和成像分辨率可控等优点,逐渐成为光学特性检测领域的研究热点。该研究首先通过已知光学特性的双层样本对结构光反射成像系统进行标定,然后利用该系统采集苹果、猕猴桃和芒果的结构光反射图像,结合分步方法进行图像解调和参数拟合,从而得到果皮和果肉组织的吸收系数和约化散射系数,最后比较该技术与单积分球技术测得的光学特性差异,并分析潜在影响因素。结果表明:双层标定样本首层和次层组织的光学特性测量误差分别小于19%和28%;水果果皮组织的光学特性参数普遍高于果肉组织,果皮和果肉组织的吸收系数曲线能反映色素等成分在特定波长的吸收峰;切片组织离体时间和厚度测量误差均会对单积分球技术测量水果组织光学特性产生不可忽略的影响。该研究为双层组织光学特性参数的准确测量提供新方法。
Light absorption and scattering are two basic phenomena during the interaction of light with biological tissues,which are characterized by the absorption coefficient and reduced scattering coefficients.Measurement of the optical properties has always been an important research topic,because they are related to the tissue chemical constituents and physical structures.Moreover,quantification of the optical properties can help us to understand light propagation in biological tissues,interpret measurement data,optimize optical devices,and improve food quality and safety assessment.Much research on optical properties measurement has been focused on biological tissues that can be simplified as homogeneous media.However,most fruits are composed of distinct layers with different optical properties.It is thus desired that appropriate multilayer models should be used to estimate optical properties of each layer.Due to complicated analytical models and parameter estimation procedures,optical properties measurement of two-layered turbid media is prone to error,which has brought a major challenge.As a relatively new optical technique,structured illumination reflectance imaging(SIRI)has shown the capability in measuring optical properties during the last decade,due to its advantages of wide-field imaging,and depthand resolution-varying characterization.In this research,a SIRI system,which was mainly composed of the light source,digital projector,high-performance CCD camera,liquid crystal tunable filter and sample stage,was first constructed and calibrated using two-layered samples with known optical properties.Then images of three varieties of fruit(i.e.,apples,kiwifruits,and mangos)were captured using the calibrated SIRI system.Coupled with the stepwise method for image demodulation and inverse parameter estimation,optical properties of the fruit skin and flesh were estimated,respectively.Finally,the discrepancies for estimating the optical properties between the SIRI and single integrating sphere(SIS)techniques were compared
作者
胡栋
孙通
应义斌
Hu Dong;Sun Tong;Ying Yibin(School of Engineering,Zhejiang A&F University,Hangzhou 311300,China;College of Biosystems Engineering and Food Science,Zhejiang University,Hangzhou 310058,China)
出处
《农业工程学报》
EI
CAS
CSCD
北大核心
2020年第7期284-291,共8页
Transactions of the Chinese Society of Agricultural Engineering
基金
浙江省自然科学基金项目(LQ20C130002)
农业部重点实验室开放课题(2016NYZD18003)。
关键词
光学特性
水果
结构光反射成像
双层
单积分球
optical properties
fruit
structured illumination reflectance imaging
two-layered
single integrating sphere
