Semi-transparent embedded watermarks
A watermark image may be generated that includes a first set of encoded pixels each of which is assigned a first transparency value and a second set of encoded pixels each of which is assigned a second transparency value, the second transparency level being different from the first transparency level. The encoded pixels may be distributed among a set of blank pixels such that each encoded pixel neighbors one or more blank pixels in the watermark image, and in particular at least two blank pixels in the watermark image. Herein, each blank pixel may be assigned the second transparency value. The watermark image may be overlaid and blended over a background source image to create an encoded source image. A decoder system may recover encoded information from the encoded source image.
1. A method, comprising:
receiving an encoded image at a computing system, wherein the encoded image includes a set of encoded pixels that encode data in the encoded image, and each encoded pixel encodes a portion of the data and is associated with a respective set of one or more non-encoded pixels located at pre-defined positions of the encoded image relative to the encoded pixel, wherein the sets of non-encoded pixels are interspersed among the set of encoded pixels and form spaces between the set of encoded pixels;
for each encoded pixel in the set of encoded pixels, decoding a value represented by the encoded pixel by comparing a color of the encoded pixel to colors of the respective set of non-encoded pixels located at the pre-defined positions relative to the encoded pixel; and
using the values decoded from the set of encoded pixels to recover data that was encoded in the encoded image.
2. The method of claim 1 , wherein the encoded image results from blending a semi-transparent watermark image over a background source image, wherein the semi-transparent watermark image contains an initial set of encoded pixels and an initial set of non-encoded pixels.
3. The method of claim 2 , wherein:
the initial set of encoded pixels in the semi-transparent watermark image each encodes one of a first value or a second value;
pixels from the initial set of encoded pixels that are encoded with the first value are assigned a first transparency value;
pixels from the initial set of encoded pixels that are encoded with the second value are assigned a second transparency value; and
pixels from the initial set of non-encoded pixels are assigned the second transparency value.
4. The method of claim 3 , wherein:
pixels from the initial set of encoded pixels that are encoded with the first value are colored a first color; and
pixels from the initial set of encoded pixels that are encoded with the second value are colored a second color.
5. The method of claim 4 , wherein the first color is black, the first transparency value is a semi-transparent value, and the second transparency value is a fully transparent value.
6. The method of claim 1 , wherein the respective set of non-encoded pixels for each encoded pixel in the encoded image are located adjacent to the encoded pixel and at least one of the non-encoded pixels for each encoded pixel is located between the encoded pixel and another encoded pixel in the set of encoded pixels.
7. The method of claim 1 , wherein using the values decoded from the set of encoded pixels to recover the data that was encoded in the encoded image comprises recovering a watermark from the encoded image.
8. The method of claim 1 , wherein decoding the value represented by the encoded pixel by comparing a color of the encoded pixel to colors of the respective set of non-encoded pixels located in the pre-defined positions relative to the encoded pixel comprises (i) assigning a first decoded value to the encoded pixel if the color of the encoded pixel is determined to be within a defined tolerance of the colors of the respective set of non-encoded pixels, or (ii) assigning a second decoded value to the encoded pixel if the color of the encoded pixel is determined not to be within the defined tolerance of the colors of the respective set of non-encoded pixels.
9. The method of claim 1 , wherein decoding the value represented by the encoded pixel by comparing a color of the encoded pixel to colors of the respective set of non-encoded pixels located in the pre-defined positions relative to the encoded pixel comprises:
determining an average of the colors of the respective set of non-encoded pixels; and
comparing the color of the encoded pixel to the average of the colors of the respective set of non-encoded pixels.
10. The method of claim 1 , wherein decoding the value represented by the encoded pixel by comparing a color of the encoded pixel to colors of the respective set of non-encoded pixels located in the pre-defined positions relative to the encoded pixel comprises:
comparing the color of the encoded pixel to the respective color of each non-encoded pixel in the respective set of non-encoded pixels; and
assigning a first decoded value or a second decoded value to the encoded pixel according to whether the color of the encoded pixel is within a defined tolerance of the respective color of at least a threshold number of non-encoded pixels in the respective set of non-encoded pixels.
11. A system, comprising:
one or more processors; and
one or more computer-readable media having instructions stored thereon that, when executed by the one or more processors, cause performance of operations comprising:
receiving an encoded image at a computing system, wherein the encoded image includes a set of encoded pixels that encode data in the encoded image, and each encoded pixel encodes a portion of the data and is associated with a respective set of one or more non-encoded pixels located at pre-defined positions of the encoded image relative to the encoded pixel, wherein the sets of non-encoded pixels are interspersed among the set of encoded pixels and form spaces between the set of encoded pixels;
for each encoded pixel in the set of encoded pixels, decoding a value represented by the encoded pixel by comparing a color of the encoded pixel to colors of the respective set of non-encoded pixels located at the pre-defined positions relative to the encoded pixel; and
using the values decoded from the set of encoded pixels to recover data that was encoded in the encoded image.
12. The system of claim 11 , wherein the encoded image results from blending a semi-transparent watermark image over a background source image, wherein the semi-transparent watermark image contains an initial set of encoded pixels and an initial set of non-encoded pixels.
13. The system of claim 12 , wherein:
the initial set of encoded pixels in the semi-transparent watermark image each encodes one of a first value or a second value;
pixels from the initial set of encoded pixels that are encoded with the first value are assigned a first transparency value;
pixels from the initial set of encoded pixels that are encoded with the second value are assigned a second transparency value; and
pixels from the initial set of non-encoded pixels are assigned the second transparency value.
14. The system of claim 13 , wherein:
pixels from the initial set of encoded pixels that are encoded with the first value are colored a first color; and
pixels from the initial set of encoded pixels that are encoded with the second value are colored a second color.
15. The system of claim 14 , wherein the first color is black, the first transparency value is a semi-transparent value, and the second transparency value is a fully transparent value.
16. The system of claim 11 , wherein the respective set of non-encoded pixels for each encoded pixel in the encoded image are located adjacent to the encoded pixel and at least one of the non-encoded pixels for each encoded pixel is located between the encoded pixel and another encoded pixel in the set of encoded pixels.
17. The system of claim 11 , wherein using the values decoded from the set of encoded pixels to recover the data that was encoded in the encoded image comprises recovering a watermark from the encoded image.
18. The system of claim 11 , wherein decoding the value represented by the encoded pixel by comparing a color of the encoded pixel to colors of the respective set of non-encoded pixels located in the pre-defined positions relative to the encoded pixel comprises (i) assigning a first decoded value to the encoded pixel if the color of the encoded pixel is determined to be within a defined tolerance of the colors of the respective set of non-encoded pixels, or (ii) assigning a second decoded value to the encoded pixel if the color of the encoded pixel is determined not to be within the defined tolerance of the colors of the respective set of non-encoded pixels.
19. The system of claim 11 , wherein decoding the value represented by the encoded pixel by comparing a color of the encoded pixel to colors of the respective set of non-encoded pixels located in the pre-defined positions relative to the encoded pixel comprises:
determining an average of the colors of the respective set of non-encoded pixels; and
comparing the color of the encoded pixel to the average of the colors of the respective set of non-encoded pixels.
20. One or more non-transitory computer-readable media having instructions stored thereon that, when executed by one or more processors, cause the one or more processors to perform operations comprising:
receiving an encoded image at a computing system, wherein the encoded image includes a set of encoded pixels that encode data in the encoded image, and each encoded pixel encodes a portion of the data and is associated with a respective set of one or more non-encoded pixels located at pre-defined positions of the encoded image relative to the encoded pixel, wherein the sets of non-encoded pixels are interspersed among the set of encoded pixels and form spaces between the set of encoded pixels;
for each encoded pixel in the set of encoded pixels, decoding a value represented by the encoded pixel by comparing a color of the encoded pixel to colors of the respective set of non-encoded pixels located at the pre-defined positions relative to the encoded pixel; and
using the values decoded from the set of encoded pixels to recover data that was encoded in the encoded image.