| Traffic accidents,industrial accidents,natural disasters and wars may cause traumatic brain injury in human brain(Traumatic Brain Injury,TBI),and early diagnosis of TBI injury is an important determinant to reduce the high fatality rate of severe craniocerebral hematoma and improve the quality of life after discharge.Near-infrared light technology can achieve rapid diagnosis of cerebral hematoma,which is one of the key directions to solve this problem.However,in today's medical conditions,it is impossible to accurately detect craniocerebral hematoma by using the conventional detection method to detect the low signal-to-noise ratio(SNR)of the cerebral hematoma signal,which makes the doctor unable to accurately judge the patient's condition.It is highly likely that the disease will be delayed,even endangering life or causing an irreversible lifelong disability.In this paper,we aim at the problem of low SNR in the detection of NIR noninvasive brain hematoma.Based on the SNR enhancement of target signal detection,a fast digital phase locking algorithm based on weak signal detection is introduced.Firstly,we use LabView to simulate the effectiveness of the fast phase-locked algorithm and design an experiment to verify the fast digital phase-locked algorithm.Secondly.Secondly,according to different modulation methods,the influence of SNR enhancement is different.From the perspective of detection error,the SNR under the four modulation schemes is analyzed,and the simulation experiment and experimental verification are carried out to select the optimal modulation scheme.The experimental results show that the SNR of the detection signal of the fast digital phase locking algorithm with 1kHz modulation intensity is 10-20dB higher than the direct light intensity,In changing the modulation mode of 1 kHz modulation,we choose three kinds of modulation methods of square wave,triangular wave and sawtooth wave,The SNR of triangular wave modulation is higher than the SNR of both square wave and sawtooth wave,10dB and 2dB respectively.Since multi-detector detection can improve the detection accuracy,single-source and multi-detector detection methods are used to further enhance the SNR.And further improve the effect of SNR on cerebral hematoma detection based on fast phase-locked algorithm.Further analysis SAE neural network is used to establish hematoma parameters(position x.depth y,size(radius)r.absorption coefficient ?a and scattering coefficient ?s)and optical density model to enhance SNR pair effect of hematoma parameter reconstruction accuracy.For the research focus,the complex brain model is simplified to normal biological tissue,hematoma heterogeneity in normal tissues.First,hematoma has been solved for forward problems using NIRFAST.Secondly,a model of hematoma parameters and optical densities was established by using SAE on 2500 samples.Hematoma parameters were reconstructed on 110 samples.Partial least square fitting was used to obtain the correlativity between hematoma parameters and actual results with 93.86%-99.91%correlation.Finally,12 samples of triangular wave drive modulation and DC drive mode are respectively taken into the model for reconstruction.The experimental results show that the correlation degree of the triangular wave driven hematoma parameters is between 96.5%and 99.68%,which increases by 84.67%and 85.86%respectively compared with the DC drive in hematoma parameters depth and size(radius).Triangular wave modulation enhances the accuracy of SNR in reconstructing the hematoma parameters of SAE neural network.Therefore,enhancing the SNR improves the accuracy of detecting the location and degree of noninvasive cerebral hematoma detection.In this paper.we combine the oversampling fast digital phase lock algorithm to enhance the SNR of near-infrared brain hematoma detection method,and provide a high-SNR detection method for clinical medicine,which can make up for the shortcomings of low current SNR in medical detection. |
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