Serial scanner apparatus, bi-directional error correction method therefor, and storage medium

A serial scanner apparatus comprising:

• an image sensor mounted on a carriage, said image sensor bi-directionally reading image data of a bi-directional error correction image by reciprocally moving the carriage in a predetermined area including the image;
• a CPU programmed to calculate an error correction value by comparing image data obtained during forward reading of said image sensor with image data obtained during backward reading of said image sensor;
• and
• a CPU programmed to correct a bi-directional error by using the calculated error correction value,
• wherein said CPU programmed to calculate compares black data in the image data obtained during forward reading with black data in the image data obtained during backward reading, said image data obtained by said image sensor which reads the bi-directional error correction image having an image pattern in which black data having a width corresponding to a reading interval of said image sensor and white data having a width which is a sum of the reading interval and a predetermined width are arranged alternately, and based on a difference in detected positions of the black data, said CPU programmed to calculate calculates the error correction value.

A bi-directional error correction method of a serial scanner apparatus comprising the steps of:

• bi-directionally reading, with an image sensor, image data of a bi-directional error correction image on a reading material by mounting the image sensor on a carriage and reciprocally moving the carriage in a predetermined area including the reading material;
• calculating an error correction value by comparing image data obtained during forward reading with image data obtained during backward reading;
• and
• correcting a bi-directional error by using the calculated error correction value, wherein density for an arbitrary point of the image data obtained during forward reading and density of image data read at a position near the arbitrary point in the image data obtained during backward reading are detected, and the error correction value is calculated based on a difference in the detected densities, wherein the bi-directional error correction image has an image pattern whose density linearly changes in a predetermined area.

A bi-directional error correction method of a serial scanner apparatus comprising the steps of:

• bi-directionally reading, with an image sensor, image data of a bi-directional error correction image on a reading material by mounting the image sensor on a carriage and reciprocally moving the carriage in a predetermined area including the reading material;
• calculating an error correction value by comparing image data obtained during forward reading with image data obtained during backward reading;
• correcting a bi-directional error by using the calculated error correction value;
• comparing black data in the image data obtained during forward reading with black data in the image data obtained during backward reading, said image data obtained by the image sensor which reads the bi-directional error correction image having an image pattern in which black data having a width corresponding to a reading interval of the image sensor and white data having a width which is a sum of the reading interval and a predetermined width are arranged alternately;
• and
• calculating the error correction value based on a difference in detected positions of the black data.

A storage medium storing a program in the form readable by a computer of a serial scanner apparatus, said program comprising the steps of:

• bi-directionally reading image data of a bi-directional error correction image by an image sensor mounted on a carriage by reciprocally moving the carriage, having the image sensor, in a predetermined area including a reading material having the bi-directional error correction image;
• calculating an error correction value by comparing image data obtained during forward reading of the image sensor with image data obtained during backward reading of the image sensor;
• and
• correcting a bi-directional error by using the calculated error correction value, wherein in the step of calculating the error correction value in said program, black data in the image data obtained during forward reading is compared with black data in the image data obtained during backward reading, said image data obtained by the image sensor which reads the bi-directional error correction image having an image pattern in which black data having a width corresponding to a reading interval of the image sensor and white data having a width which is a sum of the reading interval and a predetermined width are arranged alternately, and the error correction value is calculated based on a difference in detected positions of the black data.

A serial scanner apparatus comprising:

• an image sensor which is mounted on a carriage and reads an image in forward moving and backward moving of the carriage, wherein the carriage moves reciprocally;
• a mark arranged at a position where the mark can be read by said image sensor in both of the forward moving and the backward moving;
• an image buffer memory which stores a first image which is obtained by reading an image region including said mark by said image sensor in the forward moving, and a second image which is obtained by reading the image region including said mark by said image sensor in the backward moving;
• and
• a CPU programmed to calculate an error correction value, the error correction value being used for controlling reading/writing of image data to said image buffer memory so that a position of image data of said mark in the first image in the forward direction coincides with a position of image data of said mark in the second image in the forward direction,
• wherein, a position error of the image read in the forward moving and the backward moving of said carriage is cancelled by controlling reading/writing of image data read by said image sensor to said image buffer memory on the basis of the error correction value.