Display synchronization using colored anchors
A method for distributing information includes producing a symbol ( 26, 64, 72, 74, 76, 78, 80, 90 ) to be overlaid on at least one primary image presented on a first display screen ( 24, 62 ) the symbol encoding a specified digital value in a set of color elements ( 28, 82, 92 ) having different, respective colors. A message is received from a client device ( 32, 68 ) containing an indication of the specified digital value decoded by the client device upon capturing and analyzing a secondary image of the first display screen. In response to the message, an item of information ( 50, 70 ) relating to the primary image is transmitted to the client device, for presentation on a second display screen ( 34 ) associated with the client device.
1. A method for presenting information, comprising:
receiving a specified digital value for display;
assigning digital codes to a set of color elements having different, respective colors, to be identified in an image as red, green, blue, cyan, magenta and yellow color elements, respectively;
selecting the respective colors of the color elements, such that the color elements exhibit red, green, and blue intensity characteristics when measured in an sRGB color space that satisfy a relation:
(
1
-
H
c
0
-
L
c
0
L
c
1
-
L
c
0
-
H
c
1
-
L
c
1
H
c
1
-
H
c
0
)
>
0.8
for each color c=red, green, blue,
wherein H 1 c and L 1 c are the highest and lowest observed values, respectively, of the color c among the color elements that are expected to contain the color c, while H 0 c and L 0 c are the highest and lowest observed values of the color c among the color elements that are expected not to contain the color c; and
presenting a symbol that encodes the specified digital value for imaging by a computing device, the symbol comprising a plurality of the color elements having the colors selected so as to encode the specified digital value using the assigned digital codes.
2. The method according to claim 1 , wherein the respective colors of the color elements further comprise black and white, wherein the white color elements are expected to contain all of the colors c, while the black color elements are expected not to contain any of the colors c.
3. The method according to claim 1 , wherein producing the symbol comprises printing the symbol on a tangible medium.
4. The method according to claim 1 , wherein producing the symbol comprises generating a signal so as to cause the symbol to be presented on an electronic display.