why when I used groundTruthLabeler I got empty image (black)?

I used groundTruthLabeler and after apply pixel label end export it to folder I found it totally black as shown in attached images?how can I fix it?and groundTruthLabeler is dofferent than image segmenter app to creat groundTruth or both are doing same thing? and is it effect when I used evaluationSemanticSegementation?

[yasmin ismail]

@Image Analyst