\clearpage \section*{Abstract} Object detection in open set conditions is an important part of applying object detection to real world data sets. The key question is how to identify unknown or novel data. This thesis compares vanilla SSD and SSD with dropout sampling on the MS COCO data set. The hyper parameters confidence threshold, entropy threshold, usage of non-maximum suppression, and usage of dropout layers during testing are varied to create different scenarios. Both results from macro and micro averaging are presented. Results show a significant improvement of the object detection performance with a higher confidence threshold. The usage of non-maximum suppression improves performance as well. Usage of dropout layers during training does not provide a better result, a lower keep ratio decreases the performance.