diff --git a/body_expose.tex b/body_expose.tex index 39cc9b1..7e5d555 100644 --- a/body_expose.tex +++ b/body_expose.tex @@ -331,6 +331,35 @@ Practically, the auto-encoder is trained separately for every object class that is considered "known". Pidhorskyi et al trained it on the MNIST\cite{Lecun1998} data set, once for every digit. +For this thesis it needs to be trained on the SceneNet RGB-D +data set using MS COCO classes as known classes. As in every +test epoch all known classes are present, it becomes +non-trivial which of the trained auto-encoders should be used to +calculate novelty. To phrase it differently, a true positive +detection is possible for multiple classes in the same image. +If, for example, one object is classified correctly by SSD as a chair +the novelty score should be low. But the auto-encoders of all +known classes but the "chair" class will give ideally a high novelty +score. Which of the values should be used? The only sensible solution +is to only run it through the auto-encoder that was trained for +the class the SSD model predicted. This provides the following +scenarios: +\begin{itemize} + \item true positive classification: novelty score should be low + \item false positive classification and correct class is + among the known classes: novelty score should be high + \item false positive classification and correct class is unknown: + novelty score should be high +\end{itemize} +\noindent +Negative classifications are not listed as these are not part +of the output of the SSD and cannot be given to the auto-encoder +as input. Furthermore, the 2nd case should not happen because +the trained SSD knows this other class and is very likely +to give it a higher probability. Therefore, using only one +auto-encoder fulfils the task of differentiating between +known and unknown classes. + \section{Contribution} This section will outline what exactly the scientific as well as @@ -356,11 +385,11 @@ a better object detection performance. The GPND approach uses the auto-encoder losses and results to identify novel cases and therefore mark detections as false positive. Subsequently these detections can be discarded as well. By comparing the object -detection performance after discarding the identified false -positive cases, the effectiveness of both approaches can be -compared with each other. It is interesting to research if the -GPND approach results in a better object detection performance -than the dropout sampling provides. +detection performance after discarding the identified false positive +cases, the effectiveness of both approaches can be compared with each +other. It is interesting to research if the GPND approach results in +a better object detection performance than the dropout sampling +provides. The formulated hypothesis, which is repeated after this paragraph, combines both aspects and requires a similar or better result in