Patent ID: 8427714
Filing Date: 2013-04-23
Classification: H04N

Abstract:
1. An image-reading device comprising: a conveying member that conveys a document along a conveying path extending in a conveying direction and having a width in a width direction orthogonal to the conveying direction such that the document is positioned at a center of the conveying path in the width direction, the document having a rectangular shape, the conveying path including a reading point; a reading unit that sequentially scans and reads the document at the reading point and generates a set of image data, the set of image data indicating a scanned image extending in a first direction corresponding to the conveying direction and a second direction corresponding to the width direction, the scanned image including a top side and a bottom side confronting the top side in the first direction, when the reading unit generates the set of image data, the top side being generated at first and the bottom side being generated subsequently to the top side, the scanned image including a document image corresponding to the document, the scanned image including a document region corresponding to the document image and a background region that is outside of the document region; a specifying unit that, when the reading unit scans and reads a part of the document and generates a part of the set of image data including a part of the document image, specifies a target vertex that is positioned at topmost among at least one vertex of the part of document image; an estimating unit that defines a reference position in the scanned image corresponding to a center of the conveying path in the width direction, and estimates a size of the document based on a length in the second direction between the target vertex and the reference position; a top point detecting unit that detects a plurality of detection points located on a border between the document region and the background region as points on a top edge of the document image; a first line specifying unit that specifies a first line passing through at least two points of the plurality of detection points; a first side point specifying unit that specifies a second line extending in the second direction and passing through a point downmost among the plurality of detection points and specifies a first side point that is located on the second line as a point located on a side edge of the document image; and a third line specifying unit that specifies a third line passing through the first side point and being orthogonal to the first line, wherein the specifying unit specifies an intersection point of the first line and the third line, as the target vertex.