Arijeet Patidaron Stack Overflow • Recommends
On “Detect if image has a watermark?”
You can do it via image classification.
Basically, train a CNN(Convolutional neural Network) model by feeding in some images with watermark and some without watermark in it and then use this model to judge the probability of watermark in any new image.
You can apply transfer learning on some existing pre-trained models(as of today inception v3 is the best out there) which can be retrained for your specific classification purpose.
For example this link shows how to do it to identify whether an image is that of a sunflower or a daisy or a rose.
https://www.tensorflow.org/tutorials/image_retraining
Here is a quick 5 minute tutorial about building a tensorflow image classifier: link to this video