I'm new in deep learning world, I want to develop a project regarding live text detection on mobile camera (without taking an image by the camera), can I do it by the tesorflow object detection api ? or with anyother tensorflow api or with opencv, which way is best? other suggestions are also welcome.

Is it legal to use googlenet, alexnet, or any other pretrained model to detect obejct in image for commercial app.?? How to collect data legally for this purpose (google image, imagenet etc)?