Image data compensation for optical or spatial error in an array of photosensitive chips

A method of processing image data from a multi-chip array, the array including a plurality of photosensitive chips placed end to end substantially in a traverse direction, each chip in the plurality of chips including a respective row of photosensors aligned in an x direction between respective ends for said each chip, comprising:

• generating, using a processor for at least one specially programmed computer, a Δy optical error value substantially equal to a difference in a process direction, orthogonal to the transverse direction, between an actual location for a first photosensor and an apparent location for the first photosensor, the apparent location due to optical error;
• and,
• storing, in a memory element for the at least one specially programmed computer, respective outputs from the photosensors in the array for first and second scan lines, wherein the actual location is included in the first scan line;
• and the method further comprising retrieving, using the processor, the stored output of the first photosensor for the second scan line for use as at least part of useful image data for the first photosensor, a choice of which first and second lines are used for correction with respect to a reference line is related to the Δy optical error value.

A method of processing image data from a multi-chip array, the array including a plurality of photosensitive chips placed end to end in sequence substantially in a transverse direction starting with a first chip, and forming respective gaps between adjacent pairs of chips, and each chip in the plurality of chips including a respective row of photosensors aligned in an x direction between respective longitudinal ends for said each chip, comprising:

• generating, using a processor for at least one specially programmed computer, a cumulative Δy spatial error value by summing respective Δy spatial error values for each gap between a chip including a photosensor and the first chip in the sequence, a Δy spatial error value for a gap substantially equal to a difference in a process direction, orthogonal to the transverse direction, between respective desired positions for chips adjacent the gap and respective actual positions between the chips adjacent the gap;
• storing, in a memory element for the at least one specially programmed computer, respective outputs for the photosensors in the array for first and second scan lines, at least a portion of a location of the photosensor in the chip in the desired position included in the first scan line;
• and,
• retrieving, using the processor, a stored output of the photosensor for the second scan line for use as at least part of useful image data for the first photosensor, a choice of which first and second lines are used for correction with respect to a reference line is related to the cumulative Δy spatial error value.

A method of processing image data from a multi-chip array, the array including a plurality of photosensitive chips placed end to end in sequence substantially in a transverse direction starting with a first chip, and forming respective gaps between adjacent pairs of chips, and each chip in the plurality of chips including a respective row of photosensors aligned in an x direction between respective longitudinal ends for said each chip, comprising:

• generating, using a processor for at least one specially programmed computer, a cumulative error value for a first photosensor, the cumulative error value including respective differences in the transverse direction and in a process direction, orthogonal to the transverse direction, with respect to a reference point in the array and a location of the first photosensor, the location related to optical error or to spatial error in placement of a chip including the first photosensor;
• storing, in a memory element for the at least one specially programmed computer, respective outputs from the photosensors in the array for first and second scan lines, the location of the first photosensor included in the first scan and a choice of which first and second lines are used for correction with respect to a reference line is related to the cumulative error value;
• and,
• retrieving, using the processor, for use as at least part of useful image data for the first photosensor:
• a stored output of the first photosensor for the second scan line;
• or,
• a stored output of a second photosensor for the first or second scan line.

An apparatus for generating or reproducing a document, comprising:

• a multi-chip array, the array including a plurality of photosensitive chips placed end to end in substantially a transverse direction, each chip in the plurality of chips including a respective row of photosensors aligned in an x direction between respective ends for said each chip;
• a processor for at least one specially programmed computer for generating a cumulative error value for a first photosensor in the array, the cumulative error value including respective differences in the transverse direction and in a process direction, orthogonal to the transverse direction, between a reference point in the array and a location of the first photosensor, the location related to optical error or to spatial error in placement of a chip including the first photosensor;
• and,
• a memory element for the at least one specially programmed computer for storing respective outputs for the first photosensor and a second photosensor in the array, the first and second photosensors in first and second scan lines, respectively, and a choice of which first and second lines are used for correction with respect to a reference line is related to the cumulative error value, wherein the processor is for retrieving, for use as at least part of useful image data for the first photosensor:
• a stored output of the first photosensor for the second scan line;
• or,
• a stored output of the second photosensor for the first or second scan line.