呼气相胸片的识别研究

根据呼气相胸片中肺部区域灰度较高的特点，通过边缘提取和边缘跟踪确定胸部区域，运用最大类间方差方法确定图像分割的阈值．再提取出肺部区域，然后求出肺部的灰度均值。但这样的结果并不理想。于是在此基础上提出修正方案，即以肺部灰度均值和骨骼灰度均值的比值作为特征值．即比例法。此方法可以较客观的识别呼气相胸片。最后用类间距离对这两种方法进行了量化比较。

Study on Identification of Expiratory Phase X-ray Image

To divide the lung from the original X-ray image, the maximum classes square error is employed in finding the threshold. Then the thorax is ascertained according to the edge-detection and tracking-bug method, and the lung is divided from the thorax by the thresholding segmentation method. The gray mean in the lung is regarded as the eigenvalue to identify the image, but it doesn not work well. In view of the dosage of the X-ray exposure and the difference between persons, a new method that adopts the ratio of the gray in lungs to the gray in bones as the eigenvalue is brought forward to identify the image. And the two methods are compared by using the distance between classes. The result shows that the second method is more effective.