Character slant recognition in a word image

Claim 1

An image processing apparatus for correcting the character slant in a word image in electronic form, which image comprises a plurality of pixels arranged in rows and columns, each having a corresponding image value, the apparatus comprising: a slant value storage for storing a local slant flag for pixels of the word image, a row slant flag (I) for rows of the image and a shear parameter (G); scanning logic, coupled to said slant value storage, for scanning the electronic form of the image and applying a local slant test to the image values of each image pixel and the neighboring pixels thereto, the local slant test detecting color change patterns in the neighborhood of the pixel to determine whether in the image at the pixel there is local character slant to the left, to the right or neither and said scanning logic storing a local slant flag in the slant value storage accordingly; logic coupled to said slant value storage, for reading from the slant value storage, combining the local slant flags for the pixels in each row and applying a significance test to the result (S) of the combination to generate, and store in the slant value storage, a row-slant flag (I) for the row, which row-slant flag is indicative of whether in the row there is significantly greater number of pixels with local slant indicators showing a local character slant to the right, a significantly greater number of pixels in the row with local slant indicators showing a character slant to the left or neither; said logic for reading from the slant value storage and combining the row-slant flags (I) for all of the rows to determine the shear parameter (G); and said logic applying a shear transformation to the electronic form of the image in accordance with the determined shear parameter (G).

Claim 11

A method of operating image processing apparatus to correct the character slant in a word image in electronic form, which image comprises a plurality of pixels arranged in rows and columns, each having a corresponding image value, the method comprising the steps of: scanning the electronic form of the image and applying a local slant test to the image values of the pixel and the neighboring pixels thereto, the local slant test detecting color change patterns in the neighborhood of the pixel to determine whether in the image at the pixel there is local character slant to the left, to the right or neither and storing a local slant flag accordingly; reading from storage and combining the local slant flags for the pixels in each row, and storing the result (S) of the combination; applying a significance test to the result (S) of the combination to generate, and store, a row-slant flag (I) for the row, which row-slant flag is indicative of whether in the row there is significantly greater number of pixels with local slant flags showing a local character slant to the right, a significantly greater number of pixels in the row with local slant flag showing a character slant to the left or neither; reading from storage and combining the row-slant flags (I) for all of the rows to determine a shear parameter (G); applying a shear transformation to the electronic form of the corrected image in accordance with the determined shear parameter (G); and outputting correction signals to write said corrected image in storage.

Claim 12

A method of operating image processing apparatus to correct the character slant in a word image in electronic form, which image comprises a plurality of pixels arranged in rows and columns, each having a corresponding image value, the method comprising the steps of: scanning the electronic form of the image and applying a local slant test to the image values of the pixel and the neighboring pixels thereto, the local slant test detecting color change patterns in the neighborhood of the pixel to determine whether in the image at the pixel there is local character slant to the left, to the right or neither and storing a local slant flag accordingly; reading from storage and combining the local slant flags for the pixels in each row, and storing the result (S) of the combination; applying a significance test to the result (S) of the combination to generate, and store, a row-slant flag (I) for the row, which row-slant flag is indicative of whether in the row there is significantly greater number of pixels with local slant flags showing a local character slant to the right, a significantly greater number of pixels in the row with local slant flag showing a character slant to the left or neither; reading from storage and combining the row-slant flags (I) for all of the rows to determine a shear parameter (G); applying a shear transformation to the electronic form of the corrected image in accordance with the determined shear parameter (G); and outputting correction signals to write said corrected image in storage.