Per-channel color barcodes for displays

1. A method of decoding a coherent RGB color barcode captured by a mobile device RGB camera by imaging the coherent RGB color barcode displayed by a RGB display comprising:

displaying a coherent RGB color barcode on said RGB display to provide a displayed coherent RGB color barcode;

capturing an image of said displayed coherent RGB color barcode by said mobile device RGB camera to provide a captured image of said coherent RGB color barcode displayed on said RGB display;

localizing synchronization patterns in said captured image to determine a geometric layout of the coherent color barcode and an alignment of the geometric layout to the captured image of the coherent RGB color barcode;

estimating parameters of an RGB cross-channel interference in said captured image by using regions of said captured image that comprise synchronization pattern regions and known predetermined pilot block values for these regions set during the coherent barcode encoding process;

using said estimated parameters to apply a per pixel color interference cancellation process to said image of said displayed coherent RGB color barcode to extract two or three separate monochrome grey images of each barcode of said coherent RGB color barcode; and

decoding said two or three separate monochrome grey images to provide a decoded data for corresponding barcode of said coherent RGB color barcode displayed on said RGB display.

2. The method of claim 1 , wherein said mobile device RGB camera comprises a smartphone or tablet computer camera.

3. The method of claim 1 , wherein said step of providing a RGB display comprises providing a computer controlled LCD or LED display.

4. The method of claim 1 , wherein said step of estimating parameters of the RGB cross-channel interference comprises estimating a color interference matrix, and said step of applying said per pixel color interference cancellation to said image of said displayed coherent RGB color barcode comprises applying a matrix transform determined by said estimated color interference matrix to RGB values in each pixel of said captured image of said coherent RGB color barcode displayed on said RGB display.

5. The method of claim 4 , wherein said step of estimating parameters of the RGB cross-channel interference comprises estimating a color interference matrix by a least squares process.

6. A method of decoding a coherent RGB color barcode captured by a mobile device RGB camera by imaging the coherent RGB color barcode displayed by a RGB display comprising:

displaying a coherent RGB color barcode on said RGB display to provide a displayed coherent RGB color barcode;

capturing an image of said displayed coherent RGB color barcode by said mobile device RGB camera to provide a captured image of said coherent RGB color barcode displayed on said RGB display;

localizing synchronization patterns in said captured image to determine a geometric layout of the coherent color barcode and an alignment of the geometric layout to the captured image of the coherent RGB color barcode; and

extracting as separate monochrome grey images and decoding at least two of three R, G, and B channels of said captured image of coherent RGB color barcode to provide a decoded data for corresponding barcode of said coherent RGB color barcode displayed on said RGB display.

7. A method of decoding an incoherent RGB color barcode captured by a mobile device RGB camera by imaging the incoherent RGB color barcode displayed by a RGB display comprising:

displaying an incoherent RGB color barcode on said RGB display to provide a displayed incoherent RGB color barcode;

capturing an image of said displayed incoherent RGB color barcode by said mobile device RGB camera to provide a captured image of said incoherent RGB color barcode displayed on said RGB display;

locating a spatial region corresponding to the incoherent RGB color barcode in said captured image;

estimating parameters of a RGB cross-channel interference in said captured image by using image RGB values in said located spatial region;

using said estimated parameters to apply a per pixel color interference cancellation process to said captured image of said displayed incoherent RGB color barcode to extract two or three separate monochrome grey images of each barcode of said incoherent RGB color barcode; and

decoding said two or three separate monochrome grey images to provide a decoded data for corresponding barcode of said coherent RGB color barcode displayed on said RGB display.

8. The method in claim 7 , wherein the locating of a spatial region corresponding to the incoherent RGB color barcode in said captured image further comprises extracting at least one of three R, G, and B channels of said captured image of coherent RGB color barcode as a separate monochrome grey image and localizing synchronization patterns for the monochrome barcode in said monochrome grey image and using said localization to identify a spatial region corresponding to the incoherent RGB color barcode.

9. The method of claim 7 , wherein said mobile device RGB camera comprises a smartphone or tablet computer camera.

10. The method of claim 7 , wherein said step of providing a RGB display comprises providing a computer controlled LCD or LED display.

11. The method of claim 7 , wherein said step of estimating parameters of the RGB cross-channel interference comprises estimating a color interference matrix, and said step of applying said per pixel color interference cancellation to said image of said displayed incoherent RGB color barcode comprises applying a matrix transform determined by said estimated color interference matrix to the RGB values in each pixel of said captured image of said coherent RGB color barcode displayed on said RGB display.

12. The method of claim 11 , wherein said step of estimating parameters of the RGB cross-channel interference comprises an expectation-maximization EM-type procedure to estimate said color interference matrix by an alternating least squares process.

13. The method of claim 12 , wherein said EM-type procedure continues until an objective function is minimized below a preset threshold.

14. A method of decoding an incoherent RGB color barcode captured by a mobile device RGB camera by imaging the incoherent RGB color barcode displayed by a RGB display comprising:

displaying an incoherent RGB color barcode on said RGB display to provide a displayed incoherent RGB color barcode;

capturing an image of said displayed incoherent RGB color barcode by said mobile device RGB camera to provide a captured image of said incoherent RGB color barcode displayed on said RGB display;

extracting as separate monochrome grey images at least two of three R, G, and B channels of said captured image of incoherent RGB color barcode; and

locating and decoding monochrome barcodes embedded in said at least two of three R, G, and B channels of said captured image of said incoherent RGB barcode to provide a decoded data for corresponding barcodes of said incoherent RGB color barcode displayed on said RGB display.

15. The method of claim 14 wherein the locating of the monochrome barcode embedded in a channel further comprises localizing synchronization patterns for the monochrome barcode in said monochrome grey image and using said localization to determine a geometric layout of the monochrome barcode and an alignment of the geometric layout to the monochrome grey image in the channel.