3 research outputs found

    Circular Coding with Interleaving Phase

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    ABSTRACT A general two-dimensional coding method is presented that allows recovery of data based on only a cropped portion of the code, and without knowledge of the carrier image. A description of both an encoding and recovery system is provided. Our solution involves repeating a payload with a fixed number of bits, assigning one bit to every symbol in the image whether that symbol is data carrying or non-data carrying with the goal of guaranteeing recovery of all the bits in the payload. Because the technique is applied to images, for aesthetic reasons we do not use fiducials, and do not employ any end-of-payload symbols. The beginning of the payload is determined by a phase code that is interleaved between groups of payload rows. The recovery system finds the phase row by evaluating candidate rows, and ranks confidence based on the sample variance. The target application is data-bearing clustered-dot halftones, so special consideration is given to the resulting checkerboard subsampling. This particular application is examined via exhaustive simulations to quantify the likelihood of unrecoverable bits and bit redundancy as a function of offset, crop window size, and phase code spacing

    Stegatone performance characterization

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    Periodic, clustered-dot color screen design and stegatone performance characterization

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    Periodic clustered-dot screens are widely used for electrophotographic printers due to their print stability. Typically there are four-colorant color printing: cyan (C), magenta (M), yellow (Y), and black (K). Moreover, with the occurence of high fidelity color printing, one or more additional primary colorants, such as orange and violet, are needed to extend the gamut of printer. Nevertheless, when applied to color printing, superpositions of periodic screens may cause objectionable moire patterns. It is much harder to be solved while more and more colorant planes are superposed. Meanwhile, halftone designers also need to consider “print symmetry” (visual equality). In other words, in each colorant plane, we want the clustered dots as round as possible, in order to render more details equally in different directions, and for entire color screen set, we want the screen frequency of each colorant as close as possible. In this dissertation, we proposed a new color screen set which solves the moire problem and also gives the consideration to print symmetry issue
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