US 6,310,984 B2 · Image processing system with image cropping and skew correction

Abstract

A system and method is described for automatically determining in a scanned document image the presence of unwanted extraneous information caused by an extraneous device and scanner background information. Once the presence of this information is determined, the system and method of the present invention can compute, for instance, skew and crop statistics. From this, the image can be automatically deskewed and cropped appropriately without the background and extraneous information. The system and method accomplishes this by first determining the presence of unwanted extraneous and background information and then appropriately processing the document image. The extraneous information is ignored during deskew and crop computations. Also, the scanner background and the extraneous information are prevented from being included in the final digital representation of the image.

Claims20

Dependent claims

A method using a digital processor for automatically determining a skew angle of a document image inside a scan image having a plurality of scan lines of pixels, comprising:

(A) successively receiving the scan lines of pixels of the scan image by the digital processor;
(B) automatically locating predefined background pixels in the scan image by the processor and comparing a neighborhood of pixels located around a group of scan lines with the background pixels to define left and right image boundaries for each group of scan lines;
(C) digitally forming at least one edge segment by extending at least one image boundary between successive groups of scan lines during receipt of the scan lines;
and
(D) calculating a slope of all of the digitally formed edge segments that are longer than a predetermined length value to automatically determine the skew angle without manual guidance.

2 more elements

An apparatus, comprising:

(A) a storage medium;
(B) a computer executable program stored on the storage medium, the computer executable program, when executed, automatically determines a skew angle of a document image inside a scan image having a plurality of scan lines of pixels, wherein the computer executable program comprises,
(I) a first set of instructions that receives the scan lines of pixels of the scan image;
(II) a second set of instructions that automatically locates predefined background pixels in the scan image and compares a neighborhood of pixels located around a group of scan lines with the background pixels to define left and right image boundaries for each group of scan lines;
(III) a third set of instructions that forms one or more edge segments by extending one or more image boundaries between continuous groups of scan lines during receipt of the scan lines;
and
(IV) a fourth set of instructions that calculates a slope of all of the formed edge segments that are longer than a predetermined length value to automatically determine the skew angle without manual guidance.

4 more elements

Dependencies are inferred from the claim text.

Image processing system with image cropping and skew correction

Life of this patent

Image processing system with image cropping and skew correction

Life of this patent

Abstract

Claims20