Integrity of the information provided by a perception system is crucial for advanced driver assistance systems intended for safety applications, like obstacle avoidance systems. A method to ensure integrity is to use different kinds of perception sources. Lidars are key sensors for multiple objects detection and tracking. Stereo vision systems (SVS) can be used to improve the tracking but, in this paper, we use also SVS to confirm the real existence of potential obstacles thanks to 3D dense reconstruction in focused regions of interest. Synchronization issues between the different sensors are addressed using predictive filtering. The proposed approach is evaluated in real conditions thanks to five use cases relevant to urban situations. Results show that this visual confirmation strategy is efficient.