How to train object detector for Line and Polygon Labels?

I can train object detector oly for Rectangle ROI labels:

[imds,pxds] = objectDetectorTrainingData(gTruth);

cds = combine(imds,pxds);

But I also have to detect Line and Polygon labels on my images. There are Line and Polygon label types in the image labeller. But there is absolutely no information about how to get training data of them.