Widely used for surface slopes measurements and for three-dimensional shape reconstruction, deflectometry is a particularly powerful technique that can also be applied for defects detection on specular surfaces. In the visible domain, deflectometry is usually based on the projection of complex encoded light patterns and necessitates heavy processing that makes it not suitable for inline inspection. In this paper, A new deflectometry based approach that is more adapted for inline inspection of linearly moving parts (parts on conveyors) is proposed. Based on a more affordable and a simpler hardware setup, the new approach allows at the same time for a proper localization and a precise geometrical quantification of any defects on the scanned specular surfaces. The proposed approach uses a fast and simple processing algorithm that lends itself very well to real-time inspection. The new method is tested and validated in laboratory for the inspection of defects on specular surfaces of plastic parts.