Wang Yu-Ping, Wu Qiang, Castleman Kenneth R, Xiong Zixiang
Advanced Digital Imaging Research, LLC., 2525 South Shore Blvd., Suite 100, League City, TX 77573, USA.
IEEE Trans Med Imaging. 2003 May;22(5):685-93. doi: 10.1109/TMI.2003.812255.
Chromosome banding patterns are very important features for karyotyping, based on which cytogenetic diagnosis procedures are conducted. Due to cell culture, staining, and imaging conditions, image enhancement is a desirable preprocessing step before performing chromosome classification. In this paper, we apply a family of differential wavelet transforms (Wang and Lee, 1998), (Wang, 1999) for this purpose. The proposed differential filters facilitate the extraction of multiscale geometric features of chromosome images. Moreover, desirable fast computation can be realized. We study the behavior of both banding edge pattern and noise in the wavelet transform domain. Based on the fact that image geometrical features like edges are correlated across different scales in the wavelet representation, a multiscale point-wise product (MPP) is used to characterize the correlation of the image features in the scale-space. A novel algorithm is proposed for the enhancement of banding patterns in a chromosome image. In order to compare objectively the performance of the proposed algorithm against several existing image-enhancement techniques, a quantitative criteria, the contrast improvement ratio (CIR), has been adopted to evaluate the enhancement results. The experimental results indicate that the proposed method consistently outperforms existing techniques in terms of the CIR measure, as well as in visual effect. The effect of enhancement on cytogenetic diagnosis is further investigated by classification tests conducted prior to and following the chromosome image enhancement. In comparison with conventional techniques, the proposed method leads to better classification results, thereby benefiting the subsequent cytogenetic diagnosis.
染色体带型模式是核型分析的非常重要的特征，基于此进行细胞遗传学诊断程序。由于细胞培养、染色和成像条件，图像增强是在进行染色体分类之前理想的预处理步骤。在本文中，我们为此应用了一族微分小波变换（Wang和Lee，1998年），（Wang，1999年）。所提出的微分滤波器有助于提取染色体图像的多尺度几何特征。此外，可以实现理想的快速计算。我们研究了小波变换域中带型边缘模式和噪声的行为。基于边缘等图像几何特征在小波表示中跨不同尺度相关的事实，使用多尺度逐点乘积（MPP）来表征尺度空间中图像特征的相关性。提出了一种用于增强染色体图像中带型模式的新算法。为了客观地比较所提出算法与几种现有图像增强技术的性能，采用了一种定量标准，即对比度改善率（CIR）来评估增强结果。实验结果表明，所提出的方法在CIR度量以及视觉效果方面始终优于现有技术。通过在染色体图像增强之前和之后进行的分类测试，进一步研究了增强对细胞遗传学诊断的影响。与传统技术相比，所提出的方法导致更好的分类结果，从而有利于后续的细胞遗传学诊断。
