一种基于多级小波域分解的时域扩散光学层析成像方法的研究

面向基于有限差分光扩散模型的平板乳腺扩散光学层析反演问题,提出了一种有效提高图像重建质量的方法.与基于全空间域离散像点的传统重建算法不同,本方法采用小波函数对吸收系数和散射系数在空间域进行多尺度分解,在减少低分辨率重建中光学参量的个数、有效改善重建过程病态性的同时,通过逐级细化分解尺度,最终提高了图像的量化度和空间分辨率.数值模拟表明,该方法可实现目标体边对边4 mm的空间分辨率,量化度明显高于传统算法.

Multi-Level Wavelet Domain Decomposition Based Time-Domain Diffuse Optical Tomography

A method of improving image reconstruction quality for time-domain breast diffuse optical tomography is proposed based on panel detection and finite-difference method. A multi-level scheme is presented that uses discrete wavelet transform to reach different resolution levels of wavelet domain decomposition and in some degree to reduce the number of unknown optical parameters at coarse resolution levels and alleviate the ill-posedness of inverse problem. Compared with the traditional full-spatial domain voxel based algorithm, this method can efficiently improve the reconstruction quality and spatial resolution. Numerical simulation results illustrate that the spatial edge-to-edge resolution of the reconstructed image is 4 mm and the quantitativeness is significantly improved.