用于高能射线透视成像的大型图像对比度增强算法

A NEW CONTRAST ENHANCEMENT ALGORITHM FOR LARGE TRANSMISSION IMAGE WITH HIGH ENERGY X-RAY SOURCE

对于采用高能X射线获得的大型透视图像而言,图像值域范围过宽和局部图像反差较小是其特点。如何处理得到整体清晰同时细节突出的透视图像是一个技术难点。针对这一难点,本文提出了一种全局自适应均衡与局部动态放大相结合的对比度增强算法,该算法能有效提高高能射线透视图像的整体对比度并同时突出细节。这种新的算法能在灰度值范围分布较广的情况下实现局部不同增强倍数的要求,达到细节对比度增强和全局清晰的效果。由于增强倍数可以局部动态调整,使得这种改进可以适合各种对比度增强的要求。在实际的应用中,对于其他成像技术的处理也有很好的参考价值。

It is a key technology to acquire an easily perceived large X-ray transmission image with clearly defined and unquestionable particular. Especially for a radiation scanning system adopted high X-ray source. Usually there are some disadvantages for a normal radiative large scanning image such as the range of global pixel values is too large and the local area does not show a striking contrast. In order to improve the clearness of scanning images captured from high energy X-ray source, a new enhancement algorithm that combined global adaptive equalization with local dynamic enhancement was proposed in this paper. The new method will not only effectively increase the global contrast of high-energy radiative image, but also intensify local details. Our experiments show this method will give observer a clearer global radiative image both with enough local contrast in dealing with the large range of gray values distribution. Because the new algorithms?contrast enhancement coefficient function can be adjusted dynamically and locally, the new algorithms are not only adaptive to the process of radiative image but also having great reference value to the other grayscale images.