Research On Key Techniques Of Cerebral Hematoma Detection Based On Near-infrared Spectroscopy

Traumatic brain injuries are commonly seen and has a high mortality.Cerebral hematoma is acknowleged as the the most hazardous secondary lesion,requiring timely diagnosis and treatment.During the war,natural disaster and traffic accident,the seasonalbe arrival of medical equipment remains a tricky problem,thus leading to the rescue equipment deficiency.The near-infrared spectroscopy technology based portable cerebral hematoma detector ranks as a way most adapted for detection of the damage scence.However,the current technology fails to settle the impact of hair,scalp hematoma and ambient light on the measurement,with a high false positive rate and the detection of bilateral hematoma invalid.Targeted at the remaining defects of current technology and device,the thesis insitutes research on the several aspects:(1)To establish the five-layer optical simulation model for craniocerebral with different hematoma degrees and calculate the transmission path,the maximum reachable depth and photon carrying information rate by Monte Carlo method.Grounded on the data analysis,the extent to which hematoma exerts influence on photon transmission path is demonstrated.Meanwhile,the validity of symmetrical measurement for unilateral hematoma is theoretically proved.Besides,the scientific basis of SD distance selection and the effective coverage area of head measuring site is given.(2)The impact of scalp layer coefficient of absorption and skull thickness on optical density measurement is systematically simulated.The major cause for false positive rate--scalp layer coefficient of absorption--is found.The PLS prediction method for scalp layer coefficient of absorption is constructed,realizing the discrimination of incredible measuring results and cutting down the false positive rate to a desirable level.The pattern identification based bilateral hematoma detection algorithm is improved.The k-means clustering algorithm for different intended measuring parts with surface absorption coefficient is established,resorting solely to the unilateral measurement of optical density hematoncus detection algorithm and addressing the bilateral hematoma issue.(3)An improved FSW-DLIA algorithm is designed.The ability to counterbalance 50 Hz power interference and white noise is examined.Experiments show that the proposed algorithm leads to a wholesome measuring effect with reduced optical modulation difficulty,complexity and compution costs.Furthermore,the proposed algorithm is efficiently applicable for 8 bit MCU,which has laid a solid foundation for the low power consumption and portability.(4)A novel sliding lens hood and elastic probe structure is designed,aiming to stave off the impact of solar radiation and probe touch on the measurement.The design of detector probe,structure,hardware,software system is completed.A prototype of the protable near-infarred hematoma detector is researched,with the originally devised equipment outdoing the traditional ones in security,portability,low cost,usability.A series of experiments using the prototype are conducted in terms of optical phantom,healthy groups and 9 sufferers from cerebral hematoma.Experiments show that the prototype excels in noise mitigation,largely reduces the false positive rate and gains a high detection sensitivity,thus settling the current problems well.Main innovation points are listed as follows:(1)Establishing the five-layer optical simulation model for craniocerebral with different hematoma degrees and researching the impact of craniocerebral on transmission path.(2)Establishing PLS method for calculating the scalp layer coefficient of absorption.(3)Designing a pattern identification based bilateral hematoma detection algorithm.(4)Proposing an improved FSW-DLIA algorithm.(5)Designing a novel sliding lens hood and elastic probe structure.