Scan reading method

Claim 2

The scan reading method according to claim 1, wherein said one-line image density data in said main scan direction are image density data which are thinned out by a predetermined method.

Claim 3

The scan reading method according to claim 1 or 2, wherein said one-line image density data in said main scan direction are image density data within an effective image area in said main scan direction.

Claim 4

The scan reading method according to anyone of claims 1 to 3, wherein at least one-line of a first line in which said average density value do not become less than said threshold value after a plurality of lines in which said average density value is less than said threshold value have continued and a first line in which said average density value is less than said threshold value after a plurality of lines in which said density said average density value is said threshold value or greater have continued is detected as the edge portion of said original.

Claim 5

The scan reading method according to anyone of claims 1 to 3, wherein when a predetermined number of lines in which said average density value is less than said threshold value continue, these lines are judged as an area being out of the original region to detect the edge portion of said original.

Claim 6

A scan reading method of detecting an edge of an original by which said original mounted on a platen and a scanner including a light source for illuminating said original sequentially or simultaneously in a main scan direction are relatively moved a subscan direction substantially orthogonal to said main scan direction and an image of said original is photoelectrically read at each pixel by two-dimensionally scanning said original, and then at least one edge of said original in said subscan direction is detected, comprising the steps of: taking one-line image density data in said main scan direction of said scanner in a predetermined position in said subscan direction averaging said one-line image density data in said main scan direction to take an average density value of said line by; calculating a variation rate of said line or one of a plurality of line provided in front of said line by using said average density value data of a predetermined number of lines; repeating the calculation from a subscan start point on the side of one end of said platen to a subscan end point on the side of the other end thereof in accordance with scanning of said scanner; completing a distribution chart of said variation rate with respect to said subscan position; searching thereafter said variation rate distribution chart; and detecting the edges of said original by judging that a line in which an absolute value of said variation rate is less than a predetermined infinitesimal value is out of the original region.

Claim 7

The scan reading method according to claim 6, wherein said one-line image density data in said main scan direction are image density data which are thinned out by a predetermined method.

Claim 8

The scan reading method according to claim 6 or 7, wherein said one-line image density data in said main scan direction are image density data within an effective image area in said main scan direction.

Claim 9

The scan reading method according to anyone of claims 6 to 8, wherein at least one line of a first line in which said absolute value of said variation rate exceeds said infinitesimal value after a plurality of lines in which said absolute value of said variation rate is less than said infinitesimal value have continued and a first line in which said absolute value becomes less than said infinitesimal value after a plurality of lines in which said absolute value of said variation rate is said infinitesimal value or greater have continued is detected as the edge portion of said original.

Claim 10

The scan reading method according to anyone of claims 6 to 8 wherein when a predetermined number of lines in which said absolute value of said variation rate is less than a predetermined infinitesimal value continue, these lines are judged as an area being out of the original region to detect the edge portion of said original.

Claim 11

A scan reading method for a density auto-measurement, automatically measuring an original image density by executing a prescan in a subscan direction with a scanner for reading a one-line image density of an original mounted on a platen at each pixel in a main scan direction, comprising the steps of: taking, into a line memory, one-line image density data in said main scan direction which have been photoelectrically read by use of said scanner; preparing a density histogram of said image density data of a previously specified main scan trimming range from said one-line image density data taken into said line memory; storing said histogram in a main memory; repeating the storage process with respect to a previously specified subscan trimming range to complete said histogram of the entire subscan trimming range; and calculating thereafter highlight and shadow densities by use of said histogram.

Claim 12

The scan reading method according to claim 11, wherein said one-line image density data in said main scan direction are image data which are thinned out by a predetermined method.

Claim 13

A scan reading method for a density auto-measurement, of automatically measuring an original image density by executing a prescan in a subscan direction with a scanner for reading a one-line image density of an original mounted on a platen at each pixel in a main scan direction, comprising the steps of: taking, into a line memory, one-line image density data in said main scan direction which have been photoelectrically read by use of said scanner; calculating an average density value of said line by averaging said one-line image density data taken into said line memory with respect to an effective image area in said main scan direction; making a discrimination of an original region from said average density value; trimming said one-line image density data taken into said line memory in said main scan direction when said line is within said original region; preparing thereafter a density histogram of said image density data of said main scan trimming range; storing said density histogram in a main memory; repeating the storage process with respect to said entire original region to complete said histogram of the entire original region; calculating thereafter highlight and shadow densities by use of said histogram; and detecting at least one edge of said original.

Claim 14

The scan reading method according to claim 13, wherein said one-line image density data in said main scan direction are image density data which are thinned out by a predetermined method.

Claim 15

The scan reading method according to claim 13 or 14, wherein said original region is detected by judging that a line in which said average density value is less than a predetermined density value, or an absolute value of a variation rate of said average density value is less than a predetermined infinitesimal value is out of the original region.

Claim 16

The scan reading method according to claim 13 or 14, wherein when a predetermined number of lines in which said average density value is less than said predetermined density value, or said absolute value of said variation rate of said density average value is less than said predetermined infinitesimal value continue, these lines are judged as an area being out of the original region.

Claim 17

The scan reading method according to claim 13 or 14, wherein when the difference between a maximum value and a minimum value of said one-line image density data is smaller than predetermined values, and when said average density value of said one line is less than said predetermined density value or said absolute value of said variation rate of said average density value of said one-line is less than said predetermined infinitesimal value, it is judged that this one-line is out of the original region.

Claim 18

The scan reading method according to anyone of claims 13 to 17, wherein said main scan directional trimming range is determined from said main scan one-line image density data value at each pixel within said line memory by eliminating pixel points at which said image density data value is less than said predetermined density value, or said absolute value of said variation rate of said image density data value is less than said predetermined infinitesimal value.

Claim 19

The scan reading method according to anyone claims 13 to 17, wherein said main scan directional trimming range is determined depending on a first pixel point at which said image density data value becomes larger than said predetermined density value, or an absolute value of said image density data value becomes larger than said predetermined infinitesimal value, and a first pixel point at which said data value is less than said predetermined density value, or said absolute value is less than said predetermined infinitesimal value.