Exploiting hybrid methods for enhancing digital x-ray images

The principle objective of image enhancement is to process an image so that the result is more suitable than the original image for a specific application. This paper presents a novel hybrid method for enhancing digital X-Ray radiograph images by seeking optimal spatial and frequency domain image enhancement combinations. The selected methods from the spatial domain include: Negative transform, Histogram equalization and Power-law transform. Selected enhancement methods from the frequency domain include: Gaussian low and high pass filters and Butterworth low and high pass filters. Over 80 possible combinations have been tested, where some of the combinations have yielded in an optimal enhancement compared to the original image, according to radiologist subjective assessments. Medically, the proposed methods have clarified the vascular impression in hilar regions in regular X-Ray images. This can help radiologists in diagnosing vascular pathology, such as Pulmonary Embolism in case of thrombus that has been logged in pulmonary trunk, which will appear as a filling defect. The proposed method resulted in more detailed images hence, giving radiologists additional information about thoracic cage details including clavicles, ribs, and costochondral junction.