Rapid detection of page orientation

Claim 1

A method of orienting an image of a document of unknown orientation for processing, comprising: producing an electronic representation of the image of the document; operating on the electronic representation of the image to locate ascenders and descenders of characters in said image, wherein an ascender is a character portion extending upward from a character row and a descender is a character portion extending downward from the character row; determining the difference between the number of character ascenders and descenders; orienting the electronic representation of the image in a direction based upon the difference between the number of character ascenders and descenders located in said electronic representation.

Claim 2

A method of orienting an image of a document of unknown orientation for processing, comprising: producing an electronic representation of the image of the document; operating on the electronic representation of the image to locate ascenders and descenders of characters in said image, wherein an ascender is a character portion extending upward from a character row and a descender is a character portion extending downward from the character row; determining the difference between the number of character ascenders and descenders; orienting the electronic representation of the image in a direction based upon the difference between the number of character ascenders and descenders located in said electronic representation.

Claim 9

A method of orienting an image of a document for processing, comprising: feeding the document into a document scanner to produce an electronic representation of the image of the document; morphologically operating on the image to locate the number of character ascenders in the image of the document, wherein a character ascender is a character portion extending upward from a character row; morphologically operating on the image to locate the number of character descenders in the image of the document, wherein a character descender is a character portion extending downward from the character row; determining the difference between the number of character ascenders and descenders; accepting the image as correct if the difference between the number of character ascenders and the number of character descenders is larger than a predetermined amount, reorienting the image 180° if the difference between the number of character descenders and the number of character ascenders is larger than the predetermined amount, and reorienting the image 90° if the difference between the number of character ascenders and the number of character descenders is less than the predetermined amount.

Claim 10

A method of orienting an image of a document for processing, comprising: feeding the document into a document scanner to produce an electronic representation of the image of the document; morphologically operating on the image to locate the number of character ascenders in the image of the document, wherein a character ascender is a character portion extending upward from a character row; morphologically operating on the image to locate the number of character descenders in the image of the document, wherein a character descender is a character portion extending downward from the character row; determining the difference between the number of character ascenders and descenders; accepting the image as correct if the difference between the number of character ascenders and the number of character descenders is larger than a predetermined amount, reorienting the image 180° if the difference between the number of character descenders and the number of character ascenders is larger than the predetermined amount, and reorienting the image 90° if the difference between the number of character ascenders and the number of character descenders is less than the predetermined amount.

Claim 14

A method of orienting a scanned image of Roman text comprising the steps of: a. dilating the scanned image with a horizontal structuring element to form a dilated image bitmap; b. eroding the dilated image bitmap with a pattern ascender set of structuring elements, forming a first eroded image bitmap, said pattern ascender set providing ascender pixel integrity, wherein an ascender is a character portion extending upward from the character row; c. counting a number, N a , of "on" pixels in the first eroded image bitmap; d. eroding the dilated image with a pattern descending set of structuring elements, forming a second eroded image bitmap, said pattern descending set providing descender pixel integrity, wherein a descender is a character portion extending downward from the character row; e. counting a number, N d , of "on" pixels in the second eroded image bitmap; f. when ##EQU6## (1) rotating the bitmap 90°, (2) aligning a result bitmap, and (3) repeating step b. through e. on a result bitmap image; g. and when ##EQU7## (1) rotating the bitmap 180° degrees, (2) and aligning the result bitmap.

Claim 15

A method of orienting a scanned image of Roman text comprising the steps of: a. dilating the scanned image with a horizontal structuring element to form a dilated image bitmap; b. eroding the dilated image bitmap with a pattern ascender set of structuring elements, forming a first eroded image bitmap, said pattern ascender set providing ascender pixel integrity, wherein an ascender is a character portion extending upward from the character row; c. counting a number, N a , of "on" pixels in the first eroded image bitmap; d. eroding the dilated image with a pattern descending set of structuring elements, forming a second eroded image bitmap, said pattern descending set providing descender pixel integrity, wherein a descender is a character portion extending downward from the character row; e. counting a number, N d , of "on" pixels in the second eroded image bitmap; f. when ##EQU6## (1) rotating the bitmap 90°, (2) aligning a result bitmap, and (3) repeating step b. through e. on a result bitmap image; g. and when ##EQU7## (1) rotating the bitmap 180° degrees, (2) and aligning the result bitmap.

Claim 16

A method of orienting a scanned image of Roman text, comprising the steps of: a) morphologically operating on the scanned image to locate a number of ascenders, N a , in the scanned image, wherein an ascender is a character portion extending upward from a character row; b) morphologically operating on the scanned image to locate a number of descenders, N d , in the scanned image, wherein a descender is a character portion extending downward from the character row; c) when an absolute value of N a -N d is greater than an expected value, N e and When N a <N d : rotating a bitmap 180°, and placing the 180° rotated bitmap in memory; and d) when the absolute value of N a -N d is less than the expected value N e : rotating the bitmap 90°, placing the 90° rotated bitmap in memory, creating a new first image, and repeating steps a) through d), using the new first image.

Claim 17

A method of orienting a scanned image of Roman text, comprising the steps of: a) morphologically operating on the scanned image to locate a number of ascenders, N a , in the scanned image, wherein an ascender is a character portion extending upward from a character row; b) morphologically operating on the scanned image to locate a number of descenders, N d , in the scanned image, wherein a descender is a character portion extending downward from the character row; c) when an absolute value of N a -N d is greater than an expected value, N e and When N a <N d : rotating a bitmap 180°, and placing the 180° rotated bitmap in memory; and d) when the absolute value of N a -N d is less than the expected value N e : rotating the bitmap 90°, placing the 90° rotated bitmap in memory, creating a new first image, and repeating steps a) through d), using the new first image.