Watermarking of images
View Patent ↗Techniques and mechanisms described herein facilitate the watermarking of images. According to various embodiments, a watermark image to apply to a digital image is identified. The digital image may include a plurality of image pixel data values. Each of the image pixel data values may designate a color of a corresponding pixel in the digital image. The watermark image may include a plurality of watermark pixel data values. Each of the watermark pixel data values may designate a color change to a corresponding pixel. The watermark image may be of relatively low frequency and may exhibit relatively gradual transitions and relatively constant color tone. The watermark image may be superimposed on at least a portion of the digital image to create a watermarked digital image.
1. A method comprising:
identifying a watermark image to apply to a video frame, the video frame including a plurality of image pixel data values, each of the image pixel data values designating a color of a corresponding pixel in the video frame, the watermark image including a plurality of watermark pixel data values, each of the watermark pixel data values designating a color change to a corresponding pixel, the watermark image identifying a recipient of the video frame;
transforming the video frame from the spatial domain into the frequency domain;
superimposing the watermark image on at least a portion of the video frame in the frequency domain to create a watermarked video frame, the watermarked video frame including a plurality of watermarked image pixel data values corresponding to the image pixel data values altered by the color change designated in the corresponding watermark pixel data values; and
transmitting the watermarked image to a plurality of video frame recipients, wherein watermarked images transmitted to different recipients include different watermarks;
wherein the watermark image comprises an image gradient that represents a gradual, directional change in the color or intensity of the watermark.
2. The method recited in claim 1 , the method further comprising:
dividing the image pixel data values into a plurality of image pixel blocks, wherein the watermark image is superimposed on selected ones of the image pixel blocks.
3. The method recited in claim 1 , wherein the watermark image encodes a data message.
4. The method recited in claim 1 , wherein the data message is encoded in a frequency or amplitude of waves represented in the watermark image.
5. A system comprising:
a memory module operable to store a watermark image for applying to a video frame, the video frame including a plurality of image pixel data values, each of the image pixel data values designating a color of a corresponding pixel in the video frame, the watermark image including a plurality of watermark pixel data values, each of the watermark pixel data values designating a color change to a corresponding pixel, the watermark image identifying a recipient of the video frame;
a processor operable to transform the video frame from the spatial domain into the frequency domain and to superimpose the watermark image on at least a portion of the video frame in the frequency domain to create a watermarked video frame, the watermarked video frame including a plurality of watermarked image pixel data values corresponding to the image pixel data values altered by the color change designated in the corresponding watermark pixel data values; and
a communications interface operable to transmit the watermarked image video frame to a plurality of video frame recipients, wherein watermarked images transmitted to different recipients include different watermarks;
wherein the watermark image comprises an image gradient that represents a gradual, directional change in the color or intensity of the watermark.
6. The system recited in claim 5 , wherein the processor is further operable to:
divide the image pixel data values into a plurality of image pixel blocks, wherein the watermark image is superimposed on selected ones of the image pixel blocks.
7. The system recited in claim 5 , wherein the watermark image encodes a data message.
8. The system recited in claim 5 , wherein the data message is encoded in a frequency or amplitude of waves represented in the watermark image.
9. One or more non-transitory computer readable media having instructions stored thereon for performing a method, the method comprising:
identifying a watermark image to apply to a video frame, the video frame including a plurality of image pixel data values, each of the image pixel data values designating a color of a corresponding pixel in the video frame, the watermark image including a plurality of watermark pixel data values, each of the watermark pixel data values designating a color change to a corresponding pixel, the watermark image identifying a recipient of the video frame;
transforming the video frame from the spatial domain into the frequency domain;
superimposing the watermark image on at least a portion of the video frame in the frequency domain to create a watermarked video frame, the watermarked video frame including a plurality of watermarked image pixel data values corresponding to the image pixel data values altered by the color change designated in the corresponding watermark pixel data values; and
transmitting the watermarked video frame to a plurality of video frame recipients, wherein watermarked images transmitted to different recipients include different watermarks;
wherein the watermark image comprises an image gradient that represents a gradual, directional change in the color or intensity of the watermark.