Feature-based image registration for digital subtraction angiography

Digital subtraction is a powerful technique for enhancing vascular features in digital angiography. However, it requires accurate estimation of the relative motion between a contrast and a mask image. We have developed an algorithm that uses the edge features in the contrast and mask images to estimate the relative displacement. The edge detection method and the use of deterministic sign change (DSC) as a similarity measure are discussed. We use a synthesized image and clinical images to demonstrate that the edge-based method is more robust and accurate than those using the native images. The algorithm is efficient in computation and can be easily implemented in hardware for real-time applications.