Development And Application Of A Single Integrating Sphere System For Detecting Optical Properties Of Fruit Tissue

Measuring technique with integrating sphere is mainly used for the in vitro detection of optical properties of biological tissues. Aiming at this solution, on the one hand, we can utilize the integrating sphere system to detect the agricultral products’optical parameters indirectly, and analyze the agricultral products’ quality qualitatively. On the other hand, the tissue optical model of agricultral products can be established based on the measured optical parameters, and it can provide more reliable reference for the design of detection device, which is applied for the internal nondestructive detection of agricultural products.In this study, kiwifruit was taken as the sample, and we designed and established the manual and automatic detection device for the measurement of agricultural products’optical parameters based single integrating sphere technology. In addition, optical properties of different parts of kiwifruit were measured.The main research contents were as follows:1. A single integrating sphere based manual system was designed. Then, a single integrating sphere based automatic system was developed from the manual system. It has two key technical improvements:the automatic sample handling stage and the control system, which made the automatic measurement come true, simplifying the experimental operation and shortening the measurement time. The time one measurement cost was reduced to about 2 minutes by using the single integrating sphere based automatic system, while it cost 15 minutes by using manual system.2. The total transmission and total diffuse reflection of Intralipid, polystyrene and Biomimic phatom were measured, respectively. Based on the measured data, the absorption coefficient μa and the reduced scattering coefficient μs’ of kiwifruit tissues were calculated using the inverse adding-doubling (IAD) method. The results showed that both the two single integrating sphere based systems were reliable.3. The optical properties of kiwifruit tissues from three parts, including the flesh part, the seeds part, and the seed base part, were measured by using the two single integrating sphere based systems at the wavelength of 632.8 nm, respectively. The results showed that there were significant differences among the μs’ values and μa values of the fresh part, the seed part and the seed base part. The μa value of kiwifruit tissue was located in 0.055 mm-1 to 0.383 mm-1. And the μs’ value of kiwifruit tissue was located in 0.151 mm-1 to 1.200 mm-1. Compared to the optical properties of kiwifruits reported, the results of this study were reliable.While this study completing the target well, further researches still can be done in the following several aspects:First, inversion algorithm for integrating sphere based system should be combined with the control program, so that the optical properties parameters can be obtained from the control window directly; Secondly, some improvements may be carried on the light source, realizing the measurement of the optical properties of sample in continuous wavelength range; In addition, the g value was not measured in this study, further works should be done to develop the single integrating sphere based automatic system, so that the g value can be achieved in automatic measurement.