Assess the curvature in flexible risers is a relevant task in ocean engineering by its direct relationships with other measurements like stress, strain or hysteretic behavior. Standards for curvature measurement implementation are nonestablished. This paper presents the development of a simplified image-based technique for remote measurement of the curvature in flexible risers by tracking color-targets. Tracking algorithms are based on the second moment of binarized particles in image-series. Curvature assessment is based on the estimation of the minimal enclosing circle in each triad of sequential targets. In addition, an analogic measurement of curvature based on the beam theory using strain-gauges is used for verification during three test of pure bending cycling load of a flexible riser. Measurements from proposed technique lie close to the values from the analogical system. The present technique can be easily scaled for remote sensing.