在同步辐射X 射线成像中，时常会出现对比度不高或对比度不均匀的问题，这将导致图像中样品的一些细节信息难以被观察和分析。针对这一问题，提出一种X 射线图像对比度增强的算法。该算法以同态滤波为核心，结合图像降噪预处理及灰度调整，以现图像的对比度增强，并提高图像质量。编写程序实现该算法，并通过对分辨率靶图像和海洋鱼类样品的X 射线图像进行测试。结果表明，该算法可以很好地增强灰度分布不均匀的低对比度X射线图像，使样品信息显示更清晰，灰度分布更均匀。同时，对X 射线图像的降噪效果明显。

In the process of synchrotron radiation X- ray imaging, the X- ray image with lower or uneven contrast is obtained invariably, this causes some details of the sample in the image are difficult to observe and analyze. In order to solve the problem, a new algorithm is proposed to enhance the X- ray image and get a higher contrast. The algorithm is based on homomorphic filtering, and combined with image denoising pretreatment and gray level adjustment, so that the contrast can be enhanced and the image quality can be improved simultaneously. Furthermore, the algorithm is realized by writing program, and the X- ray images of a resolution target and marine fish are utilized to test the performance of the proposed algorithm. The results show that the proposed algorithm can well enhance the low contrast X-ray images with uneven distribution of gray level, and show the sample detail information more clearly, the gray level distributes more equably. Concurrently, the effect of X-ray image denoising is obvious.