Error using trainFaste​rRCNNObjec​tDetetor

Hi everyboday.I tried to use trainFasteRCNNObjectDetector function to vechile detection by 100 training image.but I have got following errors: Error using vision.internal.cnn.parseInputsFasterRCNN>iAllGroundTruthBoxes (line 308) allBoxes = vertcat( groundTruth{:,1:end}{:} ); Error using vision.internal.cnn.parseInputsFasterRCNN (line 172) allBoxes = iAllGroundTruthBoxes(trainingData); Error using trainFasterRCNNObjectDetector (line 239) vision.internal.cnn.parseInputsFasterRCNN(... any suggestion how to avoid this? thank you