| Summary: | 碩士 === 國立交通大學 === 電子工程系所 === 97 === This paper proposes a low computational overhead image reconstruction algorithm of continuous wave diffuse optical tomography (CW-DOT) which is called sub-frame reconstructed mode. The novel reconstruction algorithm was simulated and its accuracy analyzed. Moreover, it was implemented on very large scale integrated circuit.
DOT is a non-invasive medical imaging technique and uses near infrared optical source with wavelength within 650nm-950nm. By the different distribution of near infrared spectroscope (NIRS) within distinct biological tissue, the spatial and temporal change and absolute values of biological characteristics can be obtained such as absorption coefficient, scattering coefficient, concentration of oxy-hemoglobin and concentration of de- oxy-hemoglobin.
Recently, the clinical applications of DOT are in functional image reconstruction of the brain, detection of tumor in breast, and others. Non-invasive, real-time and not a source of radiation are the beneficial features of DOT. Furthermore the CW-DOT systems have small volume, low cost, high speed and other advantages. If the image reconstruction algorithm can be decreased the complex and implemented on SoC, then through cooperation with handheld instrument with wireless module, the DOT system can be more convenient to put in use in real life applications.
There are two focuses in this research. The first one aims to reduce the complexity of algorithm and reconstruct accurate image with the finite information by simulating and analyzing the different reconstructed way. Distinct geometry and location of inhomogeneous absorbers were allocated in homogenous absorbers to do simulation. Mean Square Error (MSE) was used to compare the accuracy of images. The second issue is choosing the algorithm to implement. After survey, the Jacobi Singular value decomposition was chosen to realize the inverse solution of reconstruct process and realize on hardware description language (HDL). MATLBA is used to evaluate the hardware resources. Finally, FPGA will be used to do the function identification of the image reconstruction processor.
In the future, the image reconstruction processor can be accompanied with other biomedical signal processors such as electroencephalography (EEG) or electrocardiograph (ECG) and be implemented on SoC. The urgent image modality, clinical diagnosis and bed-side monitor, real-time inspection and remote care can be made by minimizing these medical systems to handheld apparatus and bring the more welfare to our human life.
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