Systems and methods for compensating for streaks in images

A method for compensating for streak defects in an image formed using an image forming device that forms the image on a receiving material that is translated through the image forming device along a process direction, comprising:

• printing a compensation pattern usable to determine a difference in gray level between an actual gray level value and an intended gray level value at a cross-process-direction image-forming device pixel location in the image, comprising:
• printing a plurality of gray level portions, each gray level portion having a gray level that is different from the other gray level portions and extending along the cross-process-direction, the plurality of gray level portions arranged along the process direction,
• printing a first set of alignment marks adjacent to a first end of the plurality of gray level portions, the first set of alignment marks having at least one row of marks extending along the cross-process-direction, and
• printing a second set of alignment marks adjacent to a second end of the plurality of gray level portions, the second set of alignment marks having at least one row of marks extending along the cross-process-direction;
• scanning the compensation pattern to generate a set of scanned image data, the scanned image data defining an image value for each of a plurality of cross-process direction scanned image pixel locations;
• analyzing the scanned image data based on the cross-process direction scanned image pixel locations of the marks of the first and second sets of alignment marks to determine at least one actual gray level value for at least one of the plurality of gray level portions for at least one cross-process-direction image-forming device pixel location;
• generating, for each analyzed cross-process-direction image-forming device pixel location, for each analyzed gray level portion of that analyzed cross-process-direction image-forming device pixel location, a compensation parameter based on the determined actual gray level value for that analyzed gray level portion and the intended gray level value for that analyzed gray level portion;
• and
• correlating determined line widths of each alignment mark to the gray level values of the gray level portions and the associated compensation parameters.

A computer-readable product including computer-readable program instructions for providing a compensation pattern usable to determine a difference in gray level between an actual gray level value and an intended gray level value at a cross-process-direction image-forming device pixel location in an image formed using an image forming device, the program instructions comprising:

• instructions for printing a plurality of gray level portions, each gray level portion having a gray level that is different from the other gray level portions and extending over a plurality of cross-process-direction pixel locations along the cross-process-direction, the plurality of gray level portions arranged along the process direction,
• instructions for printing a first set of alignment marks adjacent to a first end of the plurality of gray level portions, the first set of alignment marks having at least one row of marks extending along the cross-process-direction, and
• instructions for printing a second set of alignment marks adjacent to a second end of the plurality of gray level portions, the second set of alignment marks having at least one row of marks extending along the cross-process-direction, wherein
• the first set of alignment marks adjacent to the first end of the plurality of gray level portions comprises a plurality of rows of marks extending along the cross-process-direction such that the marks of each row are offset from the marks of other ones of the plurality of rows of the first set and, for each row, each mark of that row is spaced apart from adjacent marks of that row by a number of cross-process-direction image-forming device pixel locations at least equal to the number of the plurality of rows of the first set;
• and
• the second set of alignment marks adjacent to the second end of the plurality of gray level portions comprises a plurality of rows of marks extending along the cross-process-direction such that the marks of each row are offset from the marks of other ones of the plurality of rows of the second set and, for each row, each mark of that row is spaced apart from adjacent marks of that row by a number of cross-process-direction image-forming device pixel locations at least equal to the number of the plurality of rows of the second set.

A storage medium storing a set of program instructions executable on a data processing device and usable to create data for compensating for streak defects in an image formed using an image forming device that forms the image on a receiving material that is translated through the image forming device along a process direction, the set of program instructions comprising:

• instructions for printing a compensation pattern usable to determine a difference in gray level between an actual gray level value and an intended gray level value at a cross-process-direction image-forming device pixel location in the image, comprising:
• instructions for printing a plurality of gray level portions, each gray level portion having a gray level that is different from the other gray level portions and extending along the cross-process-direction, the plurality of gray level portions arranged along the process direction,
• instructions for printing a first set of alignment marks adjacent to a first end of the plurality of gray level portions, the first set of alignment marks having at least one row of marks extending along the cross-process-direction, and
• instructions for printing a second set of alignment marks adjacent to a second end of the plurality of gray level portions, the second set of alignment marks having at least one row of marks extending along the cross-process-direction;
• instructions for scanning the compensation pattern to generate a set of scanned image data, the scanned image data defining an image value for each of a plurality of cross-process direction scanned image pixel locations;
• instructions for analyzing the scanned image data based on the cross-process direction scanned image pixel locations of the marks of the first and second sets of alignment marks to determine at least one actual gray level value for at least one of the plurality of gray level portions for at least one cross-process-direction image-forming device pixel location;
• instructions for generating, for each analyzed cross-process-direction image-forming device pixel location, for each analyzed gray level portion of that analyzed cross-process-direction image-forming device pixel location, a compensation parameter based on the determined actual gray level value for that analyzed gray level portion and the intended gray level value for that analyzed gray level portion;
• wherein:
• the instructions for printing the first set of alignment marks adjacent to the first end of the plurality of gray level portions comprise instructions for printing a plurality of rows of marks extending along the cross-process-direction such that the marks of each row are offset from the marks of other ones of the plurality of rows of the first set and, for each row, each mark of that row is spaced apart from adjacent marks of that row by a number of cross-process-direction image-forming device pixel locations at least equal to the number of the plurality of rows of the first set;
• and
• the instructions for printing the second set of alignment marks adjacent to the second end of the plurality of gray level portions comprise instructions for printing a plurality of rows of marks extending along the cross-process-direction such that the marks of each row are offset from the marks of other ones of the plurality of rows of the second set and, for each row, each mark of that row is spaced apart from adjacent marks of that row by a number of cross-process-direction image-forming device pixel locations at least equal to the number of the plurality of rows of the second set.

A storage medium storing a set of program instructions executable on a data processing device and usable to create data for compensating for streak defects in an image formed using an image forming device that forms the image on a receiving material that is translated through the image forming device along a process direction, the set of program instructions comprising:

• instructions for printing a compensation pattern usable to determine a difference in gray level between an actual gray level value and an intended gray level value at a cross-process-direction image-forming device pixel location in the image, comprising:
• instructions for printing a plurality of gray level portions, each gray level portion having a gray level that is different from the other gray level portions and extending along the cross-process-direction, the plurality of gray level portions arranged along the process direction,
• instructions for printing a first set of alignment marks adjacent to a first end of the plurality of gray level portions, the first set of alignment marks having at least one row of marks extending along the cross-process-direction, and
• instructions for printing a second set of alignment marks adjacent to a second end of the plurality of gray level portions, the second set of alignment marks having at least one row of marks extending along the cross-process-direction;
• instructions for scanning the compensation pattern to generate a set of scanned image data, the scanned image data defining an image value for each of a plurality of cross-process direction scanned image pixel locations;
• instructions for analyzing the scanned image data based on the cross-process direction scanned image pixel locations of the marks of the first and second sets of alignment marks to determine at least one actual gray level value for at least one of the plurality of gray level portions for at least one cross-process-direction image-forming device pixel location;
• instructions for generating, for each analyzed cross-process-direction image-forming device pixel location, for each analyzed gray level portion of that analyzed cross-process-direction image-forming device pixel location, a compensation parameter based on the determined actual gray level value for that analyzed gray level portion and the intended gray level value for that analyzed gray level portion;
• and
• instructions for correlating determined line widths of each alignment mark to the gray level values of the gray level portions and the associated compensation parameters.