| Currently there are many ways about study of brain function. Near-infrared spectroscopy (NIRS) has several advantages compared to other functional mea-surement methods, such as functional magnetic resonance imaging (fMRI), po-sitron emission tomography, and electroencephalography (EEG). The advantag-es include good temporal resolution and measurement of both oxygenated (HBO2) and deoxygenated (HBR) hemoglobin, portability, low restraints of subjects, and low cost of the measurement equipment. The performance of near-infrared spectroscopy is sometimes degraded by the systemic physiological interference in the extracerebral layer. The systemic physiological interference is caused by heart beat and respiration. The suppression of this kind of systemic interference is relatively easy because the correlation between the interference and the functional response of brain functional activity is usually low. Systemic interference caused by heart beat can be effectively removed using a low pass filtering technique.The interference caused by breathing can be removed by us-ing least squares fit technique.In this paper I used Near-infrared spectroscopy (NIRS) to design and pro-duce a complete hardware detection system, including sensor probe module, the analog low-pass filtering module, the central monitoring and controlling module, light source driver module. I chose OPT301 as the sensor probe module and the DSP2812 as a central monitoring and control module to manage the entire cir-cuit detection.I designed PC software to display blood oxygen information.I made the system functional analysis in order to ensure that the system is reliable, accurate, and stable for oxygen detection. Using the carrier blocking experiments is to verify the implementation of the system which can effectively measure the human body. Finally I make the brain experiments using the low-pass filtering and least squares fit technique. The interference is effectively removed. |
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