Patent ID: 7911646

Claim:
A method of multilevel halftoning comprising: determining a gray level of an object to be rendered; selecting or generating a halftone cell comprising a pixel gray level setting for each of a plurality of pixels associated with the halftone cell, the selecting or generating being based on the determined gray level of the object and a first pixel gray level for a rendering device adapted to render a pixel at one of two or more levels of tone wherein: if the determined gray level of the object is equal to the first pixel gray level for a rendering device, then selecting or generating a first halftone cell for a gray level associated with the first pixel gray level for the rendering device wherein all pixels associated with the halftone cell have a tone level about the level of the first pixel gray level; if the determined gray level of the object is less than the first pixel gray level for a rendering device, then selecting or generating a second halftone cell for a gray level associated with less than the first pixel gray level for the rendering device wherein a plurality of pixels associated with the second halftone cell each have a tone level about the level of the first pixel gray level and the associated plurality of pixels are disposed with reference to the second halftone cell according to a first defined pattern wherein a quantity of the plurality of pixels in relation to all of the pixels associated with the second halftone cell is in proportion to the determined gray level of the object in relation to the first pixel gray level; and if the determined gray level of the object is greater than the first pixel gray level for a rendering device, then selecting or generating a third halftone cell for a gray level associated with a second pixel gray level that is greater than the first pixel gray level for the rendering device, wherein a first plurality of pixels associated with the third halftone cell each have a tone level at the level of the first pixel gray level and a second plurality of pixels associated with the third halftone cell each have a tone level of a second pixel gray level that is greater in value than the level of the first pixel gray level and the second plurality of pixels having a tone level at the second pixel gray level are disposed with reference to the third halftone cell according to a second defined pattern wherein a quantity of the second plurality of pixels having a tone level of about the second pixel gray level in relation the first plurality of pixels of the halftone cell having a tone level of about the first pixel gray level is based on a total quantity of pixels comprising the third halftone cell and is in proportion to the determined gray level of the object related to the second pixel gray level and the first pixel gray level; and halftoning the object with the selected or generated halftone cell.