Halftoning with changeable error diffusion weights

Error diffusion halftoning of image data for a target pixel comprising:

• determining a halftone output value for the target pixel based on a comparison between a threshold and the image data for the target pixel plus accumulated error;
• and
• diffusing error between the halftone output value and the image data plus accumulated error for the target pixel in predetermined proportions to image data of pixels adjacent the target pixel;
• wherein the predetermined proportions vary based at least in part on value of the image data plus accumulated error for the target pixel.

Error diffusion halftoning of image data for a target pixel comprising:

• accessing a look-up table that stores pre-calculated error diffusion amounts, wherein the pre-calculated error diffusion amounts are accessible based on input error plus accumulated error, and wherein error diffusion values in the look-up table are pre-calculated based on error diffusion coefficients that vary based at least in part on image data plus accumulated error;
• determining a halftone output value for the target pixel;
• accessing the look-up table using the image data plus accumulated error for the target pixel so as to obtain error diffusion amounts;
• and
• adding the error diffusion amounts to adjacent pixels.

Error diffusion halftoning of image data for a target pixel comprising:

• obtaining access to a look-up table that stores pre-calculated error diffusion amounts, wherein the pre-calculated error diffusion amounts are accessible from the look-up table based on output error, and wherein error diffusion amounts in the look-up table are pre-calculated based on error diffusion coefficients that vary based at least in part on output error;
• determining a halftone output value for the target pixel;
• calculating output error based on the difference between the halftone output value of the target pixel and image data plus accumulated error for the target pixel;
• accessing the look-up table based on the output error so as to obtain error diffusion amounts for adjacent pixels;
• and
• adding the error diffusion amounts to adjacent pixels.

Error diffusion halftoning of image data for a target pixel comprising:

• determining a halftone output value for the target pixel based on a comparison between a threshold and the image data for the target pixel plus accumulated error;
• and
• diffusing error between the halftone output value and the image data plus accumulated error for the target pixel in predetermined proportions to image data of pixels adjacent the target pixel;
• wherein the threshold varies based at least in part on value of the output error.

Error diffusion halftoning of image data for a target pixel comprising:

• determining a halftone output value for the target pixel based on a comparison between a threshold and the image data for the target pixel plus accumulated error;
• and
• diffusing error between the halftone output value and the image data plus accumulated error for the target pixel in predetermined proportions to image data of pixels adjacent the target pixel;
• wherein the threshold varies based at least in part on value of the image data plus accumulated error for the target pixel.

Error diffusion halftoning of image data for a target pixel comprising:

• accessing a look-up table that stores halftone output values as a function of image data plus accumulated error, wherein the halftone output values are pre-calculated using thresholds that vary based at least in part on image data plus accumulated error;
• accessing the look-up table using the image data plus accumulated error for the target pixels so as to obtain halftone output value for the target pixel;
• and
• diffusing output error between the image data plus accumulated error for the target pixel and the halftone output value to adjacent pixels.

Error diffusion halftoning of image data for a target pixel comprising:

• accessing a look-up table that stores halftone output values as a function of image data plus accumulated error, wherein the halftone output values are pre-calculated using thresholds that vary based at least in part on output error;
• accessing the look-up table using the image data for the target pixels so as to obtain halftone output value for the target pixel;
• and
• diffusing output error between the image data for the target pixel and the halftone output value to adjacent pixels.

Error diffusion halftoning of image data for a target pixel comprising:

• determining a halftone output value for the target pixel based on a comparison between a threshold and the image data for the target pixel plus accumulated error;
• and
• diffusing error between the halftone output value and the image data plus accumulated error for the target pixel in predetermined proportions to image data of pixels adjacent the target pixel;
• wherein the predetermined proportions vary based at least in part on value of the output error, wherein, in said determining step, the threshold is varied based at least in part on value of the output error, and wherein the threshold is varied cyclically.

Error diffusion halftoning of image data for a target pixel comprising:

• determining a halftone output value for the target pixel based on a comparison between a threshold and the image data for the target pixel plus accumulated error;
• and
• diffusing error between the halftone output value and the image data plus accumulated error for the target pixel in predetermined proportions to image data of pixels adjacent the target pixel;
• wherein the predetermined proportions vary based at least in part on value of the image data plus accumulated error for the target pixel, wherein, in said determining step, the threshold is varied based at least in part on value of the image data plus accumulated error for the target pixel, and wherein the threshold is varied cyclically.

Error diffusion halftoning of image data for a target pixel comprising:

• accessing a look-up table that stores pre-calculated error diffusion amounts, wherein the pre-calculated error diffusion amounts are accessible based on input error plus accumulated error, and wherein error diffusion values in the look-up table are pre-calculated based on error diffusion coefficients that vary based at least in part on image data plus accumulated error;
• determining a halftone output value for the target pixel;
• accessing the look-up table using the image data plus accumulated error for the target pixel so as to obtain error diffusion amounts;
• adding the error diffusion amounts to adjacent pixels, and
• wherein, in said determining step, the threshold is varied based at least in part on value of the image data plus accumulated error for the target pixel and wherein the threshold is varied cyclically.

Error diffusion halftoning of image data for a target pixel comprising:

• obtaining access to a look-up table that stores pre-calculated error diffusion amounts, wherein the pre-calculated error diffusion amounts are accessible from the look-up table based on output error, and wherein error diffusion amounts in the look-up table are pre-calculated based on error diffusion coefficients that vary based at least in part on output error;
• determining a halftone output value for the target pixel;
• calculating output error based on the difference between the halftone output value of the target pixel and image data plus accumulated error for the target pixel;
• accessing the look-up table based on the output error so as to obtain error diffusion amounts for adjacent pixels;
• adding the error diffusion amounts to adjacent pixels, and
• wherein in said determining step, the threshold is varied based at least in part on value of the output error and wherein the threshold is varied cyclically.