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Multilevel screening mapping tone values to control signal values for greater color or shade fidelity and reduced print aberrations

  • US 7,969,617 B2
  • Filed: 06/04/2008
  • Issued: 06/28/2011
  • Est. Priority Date: 06/12/2007
  • Status: Active Grant
First Claim
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1. A method of producing a printed output on a substrate using a drop emitting device adapted to emit a plurality of ink quantities in response to a control signal, the method comprising the steps of:

  • a. receiving image data corresponding to a pixel of an image to be printed, the received image data comprising a tone value;

    b. generating a threshold value for use in a screening operation based on the location of the pixel within the image to be printed;

    c. mapping the received tone value to a mapped tone value using a first tone mapping, the mapped tone value being generated based on the received tone value;

    d. performing the screening operation by comparing the mapped tone value with the threshold value;

    e. mapping the received tone value to a control signal value using a first control mapping if the output of the comparison performed in previous step (d) indicates a first relationship, the control signal value being generated based on the received tone value; and

    f. repeating steps (c) to (f) if the output of the comparison performed in previous step (d) indicates a second relationship, wherein step (c) comprises using an alternate tone mapping and step (e) comprises using an alternate control mapping.

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