Embedding Information in an Image for Fast Retrieval

A computer program product for encoding a bit-string in an image, the computer program product comprising a non-transitory computer readable storage medium containing computer program code for:

• defining a lesser thickness and a greater thickness;
• assigning each of the values 0 and 1 exclusively to the lesser thickness and the greater thickness;
• adding a solid circle of a first color with fixed radius to the center of a region in the image, and around the solid circle an inner boundary ring of a second color of either the greater thickness or the lesser thickness;
• for each successive bit in the bit-string:
• selecting a thickness for the bit from the lesser thickness and the greater thickness that matches the assigned value;
• adding a ring of the selected thickness to the region that alternates from a prior ring in the region between the first color and the second color;
• adding an outer boundary ring of either the greater thickness or the lesser thickness, different from the thickness of the inner boundary ring;
• and
• storing the completed image.

A method for extracting a bit-string from an image, comprising:

• capturing an image of an encoded bit-string using a camera-equipped device;
• grayscaling the captured image;
• locating the center of the captured image;
• determining a direction of travel in the image from the center of the captured image;
• determining a first thickness corresponding to a value of 0 and a second thickness corresponding to a value of 1;
• detecting rings in the captured image along the direction of travel from the center, and for each ring:
• measuring the thickness of the ring, and applying clustering techniques to identify it as having the first thickness or the second thickness;
• and
• appending to a bit-string a value of 0 if the ring has the first thickness corresponding to the value of 0;
• or appending to the bit-string a value of 1 if the ring has the second thickness corresponding to the value of 1;
• and
• storing the completed bit-string.

A computer program product for extracting a bit-string from an image, the computer program product comprising a non-transitory computer readable storage medium containing computer program code for:

• capturing an image of an encoded bit-string using one of a plurality of camera-equipped devices;
• grayscaling the captured image;
• locating the center of the captured image;
• determining a direction of travel in the image from the center of the captured image;
• determining a first thickness corresponding to a value of 0 and a second thickness corresponding to a value of 1;
• detecting rings in the captured image along the direction of travel from the center, and for each ring:
• measuring the thickness of the ring, and applying clustering techniques to identify it as having the first thickness or the second thickness;
• and
• appending to a bit-string a value of 0 if the ring has the first thickness corresponding to the value of 0;
• or appending to the bit-string a value of 1 if the ring has the second thickness corresponding to the value of 1;
• and
• storing the completed bit-string.