Page segmentation with tilt compensation

Claim 1

A method of scanning and reproducing a page having more than one column of text or pictorial images with a column gap having substantially equal white spacings in between said columns, comprising the steps of: a. scanning said page and transforming the scanned images of the page into binary representations; b. storing said binary representations in memory; c. partitioning said binary representations into a plurality of scanline blocks, each block having a substantially equal number of scanlines arranged substantially in the same order in which they were scanned; d. identifying the column gaps in each scanline block by obtaining a plurality of vertical projection profiles for each scanline block; e. comparing the first scanline block with each of the subsequent scanline blocks and determining whether the identified column gaps in each block substantially match; f. merging the scanline blocks into at least one column block where there are matches in column gaps; g. estimating the skew angle in the merged column blocks by measuring the slope of the column gaps in the merged column blocks; and h. generating a reconstructed image from the scanned images according to the column blocks.

Claim 2

A method of scanning and reproducing a page having more than one column of text or pictorial images with a column gap having substantially equal white spacings in between said columns, comprising the steps of: a. scanning said page and transforming the scanned images of the page into binary representations; b. storing said binary representations in memory; c. partitioning said binary representations into a plurality of scanline blocks, each block having a substantially equal number of scanlines arranged substantially in the same order in which they were scanned; d. identifying the column gaps in each scanline block by obtaining a plurality of vertical projection profiles for each scanline block; e. comparing the first scanline block with each of the subsequent scanline blocks and determining whether the identified column gaps in each block substantially match; f. merging the scanline blocks into at least one column block where there are matches in column gaps; g. estimating the skew angle in the merged column blocks by measuring the slope of the column gaps in the merged column blocks; and h. generating a reconstructed image from the scanned images according to the column blocks.

Claim 5

An apparatus for scanning and reproducing a page having more than one column of text or pictorial images with a column gap having substantially equal white spacings in between said columns, comprising: a. a scanner for scanning said page and transforming the scanned images of the page into binary representations; b. a memory storing said binary representations; c. means for partitioning said binary representations into a plurality of scanline blocks, each block having a substantially equal number of scanlines arranged substantially in the same order in which they were scanned; d. means for identifying the column gaps in each scanline block by obtaining a plurality of vertical projection profiles for each scanline block; e. means for comparing the first scanline block with each of the subsequent scanline blocks and determining whether the identified column gaps in each block substantially match; f. means for merging the scanline blocks into at least one column block where there are matches in column gaps; g. means for estimating the skew angle in the merged column blocks by measuring the slope of the column gaps in the merged column blocks; and h. means for generating a reconstructed image from the scanned images according to the column blocks.

Claim 6

An apparatus for scanning and reproducing a page having more than one column of text or pictorial images with a column gap having substantially equal white spacings in between said columns, comprising: a. a scanner for scanning said page and transforming the scanned images of the page into binary representations; b. a memory storing said binary representations; c. means for partitioning said binary representations into a plurality of scanline blocks, each block having a substantially equal number of scanlines arranged substantially in the same order in which they were scanned; d. means for identifying the column gaps in each scanline block by obtaining a plurality of vertical projection profiles for each scanline block; e. means for comparing the first scanline block with each of the subsequent scanline blocks and determining whether the identified column gaps in each block substantially match; f. means for merging the scanline blocks into at least one column block where there are matches in column gaps; g. means for estimating the skew angle in the merged column blocks by measuring the slope of the column gaps in the merged column blocks; and h. means for generating a reconstructed image from the scanned images according to the column blocks.

Claim 9

A method of scanning and reproducing a page having more than one column of text or pictorial images with a column gap having substantially equal white spacings in between said columns, comprising the steps of: a. scanning said page to generate an electronic image of said page, said electronic image having a binary representation for each pixel, each pixel representing a separate area of said page; b. partitioning said electronic image into a plurality of scanline blocks, each scanline block including an array of the binary representations for a contiguous array of pixels; d. identifying the column gaps in each scanline block by obtaining vertical projection profiles for a plurality of columns of said array for each scanline block; e. comparing the first scanline block with each of the subsequent scanline blocks and determining whether the identified column gaps in each block substantially match; f. merging the scanline blocks into at least one column block where there are matches in column gaps; g. estimating the skew angle in the merged column blocks by measuring the slope of the column gaps in the merged column blocks; and h. reconstructing said electronic image according to said column blocks.

Claim 10

A method of scanning and reproducing a page having more than one column of text or pictorial images with a column gap having substantially equal white spacings in between said columns, comprising the steps of: a. scanning said page to generate an electronic image of said page, said electronic image having a binary representation for each pixel, each pixel representing a separate area of said page; b. partitioning said electronic image into a plurality of scanline blocks, each scanline block including an array of the binary representations for a contiguous array of pixels; d. identifying the column gaps in each scanline block by obtaining vertical projection profiles for a plurality of columns of said array for each scanline block; e. comparing the first scanline block with each of the subsequent scanline blocks and determining whether the identified column gaps in each block substantially match; f. merging the scanline blocks into at least one column block where there are matches in column gaps; g. estimating the skew angle in the merged column blocks by measuring the slope of the column gaps in the merged column blocks; and h. reconstructing said electronic image according to said column blocks.