A ROBUST AND ACCURATE METHOD FOR CALCULATING THE FRACTAL SIGNATURE OF TEXTURE IN MACRORADIOGRAPHS OF OSTEOARTHRITIC KNEES
A ROBUST AND ACCURATE METHOD FOR CALCULATING THE FRACTAL SIGNATURE OF TEXTURE IN MACRORADIOGRAPHS OF OSTEOARTHRITIC KNEES
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DOI：
10.3109/14639239109012130
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发表时间：
1991-04-01
期刊：
影响因子：
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通讯作者：
BUCKLANDWRIGHT, JC
中科院分区：
文献类型：
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作者：
LYNCH, JA;HAWKES, DJ;BUCKLANDWRIGHT, JC
在膝关节骨关节炎中，胫骨中的水平骨小梁弯曲，导致X线片上出现水平条纹。 任何试图了解和监测疾病过程的尝试都必须检查这些变化。 我们以前已经描述了一种方法，分析这些图像中的纹理，使用数学形态学操作的膨胀和腐蚀来计算图像分形维数如何随分辨率而变化。 这种随分辨率的变化就是分形特征。 分形维数的计算应独立于图像值的线性变换，它表明，需要仔细选择形态结构元素。 在本文中，我们描述了依赖我们的方法计算的分形签名图像采集和数字化参数。 与骨关节炎变化导致的特征变化相比，由于像素大小、X射线暴露和患者重新定位的变化导致的误差很小。 使用对正交结构元素，一个调谐到计算由于水平图像结构和其他垂直图像结构的签名，纹理方向性检查。 在个体膝关节中的两个结果签名之间的差异被示出为在骨关节炎中看到的纹理变化的量度。
In osteoarthritis of the knee, horizontal trabeculae in the tibia thicken, leading to the appearance of horizontal striations on radiographs. Any attempt to understand and monitor the disease process must examine these changes. We have previously described a method of analysing the texture in these images that uses the mathematical morphology operations of dilation and erosion to calculate how image fractal dimension varies with resolution. This variation with resolution is the fractal signature. Calculation of fractal dimension should be independent of linear transformations in image values, and it is shown that careful choice of morphological structuring element is required for this. In this paper we describe the dependence of our method of calculating the fractal signature on image acquisition and digitization parameters. Errors due to variations in pixel size, X-ray exposure, and patient repositioning are small compared to the changes seen in the signature due to osteoarthritic change. Using pairs of orthogonal structuring elements, one tuned to calculate the signature due to horizontal image structure and the other for vertical image structure, texture directionality is examined. The difference between the two resulting signatures in individual knees is shown to be a measure of the change in texture seen in osteoarthritis.