Resolution-triggered sharpening for scaling of a digital-matrix image

Apparatus for printing an image on a print medium as marks formed in an array having output-device resolution, based upon input image data defining a pixel array having input-data resolution;

• said apparatus comprising:
• means for finding at least one equivalent gray-scale level for a selected element of the input data, and for each of a plurality of elements of the input data that are near the selected element, respectively;
• means for automatically adjusting the equivalent gray-scale level for the selected element to derive a new equivalent gray-scale level which depends upon:
• a function of both the output-device resolution and the input-data resolution, and
• the found equivalent gray-scale levels for the selected element and each of said plurality of near elements;
• means for using said new equivalent gray-scale level to form corresponding output data having said output-device resolution;
• and
• means for defining and evaluating said function of both the output-device resolution and input-data resolution for the selected element;
• and wherein:
• said function is a function of the ratio of the input-data resolution to the output-device resolution for the selected element;
• and
• said function is a step-function of the said ratio.

Apparatus for printing an image on a print medium as marks formed in an array having output-device resolution, based upon input image data defining a pixel array having input-data resolution;

• said apparatus comprising:
• means for finding at least one equivalent gray-scale level for a selected element of the input data, and for each of a plurality of elements of the input data that are near the selected element, respectively;
• means for automatically adjusting the equivalent gray-scale level for the selected element to derive a new equivalent gray-scale level which depends upon:
• a function of both the output-device resolution and the input-data resolution, and
• the found equivalent gray-scale levels for the selected element and each of said plurality of near elements;
• and
• means for using said new equivalent gray-scale level to form corresponding output data having said output-device resolution;
• and wherein:
• the adjusting means comprise means for adjusting the equivalent gray-scale level for the selected element to a new equivalent gray-scale level which is substantially equal to:
• the found equivalent gray-scale level for the selected element, plus
• the product of (a) the said function and (b) a function of the found equivalent gray-scale levels for the selected element and each of said plurality of near elements.

Apparatus for printing an image on a print medium as marks formed in an array having output-device resolution, based upon input image data defining a pixel array having input-data resolution:

• said apparatus comprising:
• means for finding at least one equivalent gray-scale level for a selected element of the input data, and for each of a plurality of elements of the input data that are near the selected element, respectively;
• means for automatically adjusting the equivalent gray-scale level for the selected element to derive a new equivalent gray-scale level which depends upon:
• a function of both the output-device resolution and the input-data resolution, and
• the found equivalent gray-scale levels for the selected element and each of said plurality of near elements;
• and
• means for using said new equivalent gray-scale level to form corresponding output data having said output-device resolution;
• and wherein:
• the adjusting means comprise means for adjusting the equivalent gray-scale level for the selected element to a new equivalent gray-scale level which is substantially equal to:
• the found equivalent gray-scale level for the selected element, plus
• the product of (a) said function and (b) the difference between:
• the found equivalent gray-scale level for the selected element and
• an average of the found equivalent gray-scale levels for each of said plurality of near elements.

Apparatus for preparing an image to print on a print medium as marks formed in an array having output-device resolution, based upon input image data defining a pixel array having input-data resolution;

• said apparatus comprising:
• means for using said input data to form corresponding output data having said output-device resolution;
• means, operating entirely at said output-device resolution, for finding at least one equivalent gray-scale level for a selected element of the output data, and for each of a plurality of elements of the output data that are near the selected element;
• means, also operating entirely at said output-device resolution but in advance of halftoning, for automatically adjusting the equivalent gray-scale level for the selected element to a new equivalent gray-scale level which depends upon:
• a function of both the output-device resolution and the input-data resolution, and
• the found equivalent gray-scale levels for the selected element and each of said plurality of near elements.

Apparatus for preparing to print an image on a print medium as marks formed in an array having output-device resolution, based upon input image data defining a pixel array having input-data resolution;

• said apparatus comprising:
• means for enhancing contrast within the image before error diffusion or other halftoning;
• and
• means for automatically turning the enhancing means on or off selectively, depending on a relationship between the output-device resolution and the input-data resolution.

A method of printing an image on a print medium as marks formed in an array having output-device resolution, based upon input image data defining a pixel array having input-data resolution;

• said method comprising the steps of:
• finding at least one equivalent gray-scale level for a selected element of the input data, and for each of a plurality of elements of the input data that are near the selected element, respectively;
• automatically adjusting the equivalent gray-scale level for the selected element, at said input-data resolution, to derive a new equivalent gray-scale level, still at said input-data resolution;
• wherein said new gray-scale level depends upon:
• a function of both the output-device resolution and the input-data resolution, and
• the found equivalent gray-scale levels for the selected element and each of said plurality of near elements;
• using said new equivalent gray-scale level to form corresponding output data having said output-device resolution;
• and
• printing the selected element on such print medium using said output data.