  This paper focuses on investigation of confidential documents leaks in the
form of screen photographs. Proposed approach does not try to prevent leak in
the first place but rather aims to determine source of the leak. Method works
by applying on the screen a unique identifying watermark as semi-transparent
image that is almost imperceptible for human eyes. Watermark image is static
and stays on the screen all the time thus watermark present on every captured
photograph of the screen. The key components of the approach are three neural
networks. The first network generates an image with embedded message in a way
that this image is almost invisible when displayed on the screen. The other two
neural networks are used to retrieve embedded message with high accuracy.
Developed method was comprehensively tested on different screen and cameras.
Test results showed high efficiency of the proposed approach.
