Design And Application Evaluation Of Spatial Frequency Domain Imaging System Control Software Based On LabVIEW

China is a big producer and consumer of agricultural products.The quality inspection of agricultural products is related to the quality of life and food safety of its citizens.Traditional spectrum detection technology is not fully aware of the scattering of light with biological tissue and the light transmission process in the organization,because of the biological tissue is often complex and heterogeneous high scattering medium,so the traditional spectrum analysis technology in the detection of quality indicators shortcomings associated with the organizational structure,although the structure and chemical information exists in records of signal,but usually do not provide detailed meaning.Spatial frequency domain imaging technology is a non-contact wide field optical imaging technology,which can realize agricultural products separately research the characteristic of the absorption and scattering of light,measured absorption coefficient and the scattering coefficient respectively reflect the organization's internal chemical information and structural information.Although spatial frequency domain imaging technology can be used for quality inspection of agricultural products,it can not realize rapid detection of agricultural products.It has shortcomings in hardware,algorithm and software control.Especially in software control,spatial frequency domain imaging technology has low automation.Most of the operations are done manually,with low efficiency and human error.In order to solve the software problems,this paper designed a spatial frequency domain imaging system control software based on LabVIEW development environment.Using the flat-type biological tissue solid imitation and Apple's optical property detection experiments for system calibration,software operation evaluation and spatial frequency optimization.The optical properties of pork are detected based on the optimized frequency,and the variation of the optical properties of pork with time is explored.The main research contents and conclusions of this paper are as follows:1.Designed a spatial frequency domain imaging system control software based on LabVIEW development environment.The control software includes a serial communication module,a parameter setting module,and a function module.Serial communication module mainly realizes the control of the projector and the hard trigger signal of camera.Parameter setting module mainly realizes the selection of the wavelength,the input of the spatial frequency and the control of distance between sample and camera.Function module mainly realizes image acquisition,data fitting,target classification and spatial frequency optimization.The software controls the normal operation of the spatial frequency domain imaging system.2.The spatial frequency domain imaging system control program based on Lab VIEW is used to detect the optical property parameters of the flat biological tissue solid phantom and apple,and realize the system correction and spatial frequency domain optimization.In this paper,three spatial frequencies(0.112 mm-1,0.126 mm-1 and 0.14 mm-1)are preferred from 16 spatial frequencies.With the frequency optimization,the relative errors of the absorption coefficient and the reduced scattering coefficient in the detection results are both decreased.In the apple optical property parameters detection experiment,the average value of the reduced scattering coefficient and absorption coefficient of 150 apples were 1.04 mm-1 and 0.014 mm-1 respectively.They were consistent with the literature reports,which proved that the space frequency domain imaging system controlled by Lab VIEW software is feasible to detect the optical characteristics of apple.3.The experiment of pork optical property detection based on the preferred frequency verified the stability of LabVIEW control software operation and the accuracy and efficiency of system operation under software control.During the experiment,the LabVIEW control software parameter input and target classification modules are stable.The image acquisition interval is reduced from 3?4 s to 200 ms.Three preferred frequencies are used for data fitting,and when the region of interest is 20 mm x 20 mm,the data processing time is about 1 minute.Data processing efficiency is greatly improved.At the same time,the image fitting results are within the normal reference range reported in the literature.It proved that the spatial frequency domain imaging system based on LabVIEW control software can correctly detect the optical property parameters of pork.4.Under the visible light wavelength,the variation of optical properties of pork with storage time was studied.It was found that the reduced scattering coefficient of pork changed stably within 0-50 h with the extension of time,and decreased linearly with the increase of time after 50 h.It is because the reduced scattering coefficient of biological tissue is related to the structure of the tissue.As the storage time increases,the internal structure of the pork changes,causing a change in the reduced scattering coefficient.However,the absorption coefficient of pork does not change significantly with time,because in the visible light range,the diffuse reflection image only carries the structural information of the tissue and contains little chemical information.The absorption coefficient is only sensitive to the chemical information of the tissue.Therefore,it is difficult to detect the absorption coefficient of pork tissue in the visible light band with storage time changes.