Error while training the trainCasca​deObjectDe​tector...p​lease help!

Hello, please help me to solve following problem. I have 30k positive images with ROIs and 60k negatives (without ROIs). Then I start training the standart Viola classifier by trainCascadeObjectDetector function after ten minutes on stage 1 of training process I've got error: "Error using ocvTrainCascade Error in generating samples for training. No samples could be generated for training the first cascade stage"

Why is it? What is wrong? Appreciate any help, thank you.

[Dima Lisin]

Hi Andrew,

How many stages are you trying to train? And what is the negative samples factor?