X-ray imaeg contrast enhancement based on tissue attenuation

Abstract

X-ray imaging is an efficient tool for health inspection. The energy of received X-ray could reveal the density inside human body and be represented in an X-ray image. In general, the bright regions of an X-ray image are of interest since most important matters compactly locating in those regions. However, the low contrast property of the bright regions makes inspectors hard to tell the details. Hence, contrast enhancement of X-ray images especially in the bright regions becomes critical. In the paper, unlike previous algorithms which work well in the dark regions, we thus proposed a tissue attenuation method to enhance the bright regions. We assume the X-ray intensity is composed of tissues and other important details. By locally attenuating the ratios of tissues over the image, we could adaptively enhance the important details especially in the bright regions. To adjust the ratios, a two-step procedure was proposed. First, the tissue component was separated from a given image based on local contrast maximization. Second, an attenuation adjustment was performed to control the ratio of removable tissues in order to correctly enhance contrast. Experimental results also demonstrate the effectiveness of our method.