Watermark signal generating method
View Patent ↗An apparatus 10 for generating wartermark signals to be embedded as a digital watermark in real-time contents includes: input means 12 for inputting the real-time contents; an input buffer 14 for storing the real-time contents; generation means for generating wartermark signals corresponding to predicted intensities of the real-time contents from divided real-time contents; and an output buffer 18 for storing the generated wartermark signals to be outputted. The generation means is configured by including prediction means 16 for predicting intensities of the wartermark signals; control means 20 for controlling embedding by use of a message to be embedded as the digital watermark in the divided real-time contents; and means 22 for generating the wartermark signals to be outputted.
1. A watermark signal generating method for generating watermark signals to be embedded as a digital watermark in real-time contents of a plurality of video frames, comprising the steps of:
inputting the real-time contents;
storing the real-time contents;
generating, from the real-time contents, watermark signals to be outputted corresponding to predicted intensities of the real-time contents; and
storing the generated watermark signals to be outputted, wherein
the generation step includes the steps of:
dividing each of the video frames into tiles including pixels with respective associated luminances;
analyzing luminance distribution in a selected tile by calculating an average of luminances from the pixels within the selected tile;
generating an average luminance for each tile in the video frame;
predicting intensities of the watermark signals from a weight assigned to the average luminance of each tile of each video frame of the real-time contents after a predetermined lapse of time;
generating a value to be embedded for the purpose of controlling a value of the watermark signal to be outputted by use of a message to be embedded as a digital watermark in the real-time contents; and
controlling the watermark signals to be outputted according to the value to be embedded, and generating the watermark signals to be outputted by use of the intensity prediction of the watermark signals if the value to be embedded is positive, and not generating the watermark signals to be outputted if the value to be embedded is negative.