In this paper we study a class of Riemannian metrics on the space of unparametrized curves and develop a method to compute geodesics with given boundary conditions. It extends previous works on this topic in several important ways. The model and resulting matching algorithm integrate within one common setting both the family of H 2 -metrics with constant coefficients and scale-invariant H 2 -metrics on both open and closed immersed curves. These families include as particular cases the class of first-order elastic metrics. An essential difference with prior approaches is the way that boundary constraints are dealt with. By leveraging varifold-based similarity metrics we propose a relaxed variational formulation for the matching problem that avoids the necessity of optimizing over the reparametrization group. Furthermore, we show that we can also quotient out finite-dimensional similarity groups such as translation, rotation and scaling groups. The different properties and advantages are illustrated through numerical examples in which we also provide a comparison with related diffeomorphic methods used in shape registration.2000 Mathematics Subject Classification. 68Q25, 68R10, 68U05. 1 Note, that the invariance of the metric is only a necessary condition for a metric on the space of parametrized curves to induce a metric on unparametrized curves. However, all the metrics considered in this article do induce Riemannian metrics on the quotient space. For details, see [36].2 This result has been later extended to the space of parametrized curves in [3]. 3 The article [37] studied the family of elastic metrics with different choices of parameters on the space of parametrized curves. This analysis was, however, not extended to the space of unparametrized curves, which is the more relevant object for applications.