Automatic assessment of foetal biometric parameter using GVF snakes

Abstract

Ultrasonographic foetal biometry is the most widespread method used to establish gestational age and monitor its growth. In this paper, a method for automatic measurement of G.Sac diameter has been presented. The classical segmentation methods failed completely or require post-processing step to remove invalid object boundaries in the segmentation results. However, problems associated with traditional mode, initialisation and poor convergence to concave boundaries of the snakes, have limited their utility. A new external force for active contours can largely solve both problems. This external force, known as Gradient Vector Force (GVF), is computed as a diffusion of the gradient vectors of a binary edge map derived from the image. The resultant field has a large capture range and forces active contours into concave regions. The intensity images are taken as input and a GVF snake is initialised. The snake deforms and finally reveals the contour of the G.Sac.