Channel-wise barcodes for color display applications
Karthik Dinesh, Jiangfeng Lu, Shingirai Dhoro, Gaurav Sharma · Journal of Electronic Imaging · 2019
We present a channel-wise (CW) framework for data embedding in display images using barcodes. Data are embedded in one or more channels of the color image encoded as a monochrome barcode pattern and extracted from the corresponding channels by the decoder. We highlight two advantageous schemes, realized in the proposed framework: red, green, blue CW barcodes (RGB-CWBs), and blue channel image-barcodes (BC-IBs). Compared with a conventional monochrome black and white barcode BW-B with the same spatial footprint, RGB-CWBs utilize the three channels of color image more effectively and enable a three-fold increase in data rate, whereas BC-IBs significantly reduce the embedding distortion by exploiting the reduced sensitivity of the visual system to spatial detail in blue colors. For RGB-CWBs, we develop an effective framework for the cancellation of cross-channel interference between the display and capture channels using a model for the display and capture processes and for the ambient illumination. Model parameters required for interference cancellation (IC) are learned on-the-fly using either expectation-maximization or through suitable design of the synchronization patterns as “pilot-blocks.” Extensive experiments over multiple display and capture devices validate the advantages of the framework: RGB-CWBs (with IC) and the BC-IBs offer bit error rates comparable to their monochrome counterparts while providing either a three-fold increase in data rate or a significant reduction in distortion, respectively.