Bone Contour Tracing in Digital X-ray Images Based on Adaptive Thresholding

Abstract

An orthopedic X-ray captures bone images along with surrounding flesh and muscle components. Segmentation of the bone component with a sharp contour is a challenging task as the bone and flesh regions often have pixels with overlapping intensity range. In this paper, we propose a new technique of contour extraction by integrating an entropy-based segmentation approach with adaptive thresholding. The method eliminates the shortcomings of earlier derivative or deformable model based approaches, and can be fully automated. Experiments with several digital X-ray images reveal encouraging results especially for long-bone X-ray images.

Long-bone fracture detection in digital X-ray images based on digital-geometric techniques

“…Elementary analysis of fractured-bone contours and correction of discontinuities therein, also appeared in prior work [1], [2].…”

“…Segmentation of bone using an entropy-based approach. Entropy-based segmentation techniques [2,3] can also be used for bone-image segmentation. In this method, local-entropy represents the grayscale intensity variation in the neighborhood of a pixel.…”

“…We have compared the entropy-based segmentation approach [2] with k-means clustering [16] using the precision-recall metric [21]. It is observed that the entropy-based method exhibits higher precision-recall values compared to the k-means approach for all testcases from the medical image database compiled by us (http://oldwww.iiests.ac.in/component/content/article/ 155-itcategory/3282-medical-image-database) (shown in Fig.…”

“…It has been observed that k-means clustering may produce over-segmented bone regions in many X-ray images. Thus, we have evaluated another method based on entropy-standard deviation [2,3] for bone-region segmentation.…”

“…The segmentation of a bone region of a digital X-ray image from its flesh part and generation of exact bone-contour play a crucial role in fracture detection. The proposed tool integrates an entropy-based segmentation method [3] with an adaptive thresholding-based contour tracing [2] to generate the bone-contour of an X-ray image. The algorithm traverses the bone-contour and rectifies the false discontinuities using certain new geometric techniques.…”