Method for detecting fraud in a value document such as a check

A method of determining a spacing between a first line and a second line in a document having a first edge and a second edge substantially perpendicular to said first edge, said second line being substantially parallel to said first line, comprising:

• creating an electronic image of said document using a scanner having an image generating surface having a first axis and a second axis, wherein said electronic image is created by scanning said document with said first edge being angled relative to said first axis of said scanner, said image generating surface having a matrix of a plurality of rows and columns of pixels, wherein when said electronic image is generated:
• (i) said first line and said second line have a first slope relative to said first axis, (ii) said first line covers each of a first plurality of pixels in a first one of said columns by a respective first coverage amount, and (iii) said second line covers each of a second plurality of pixels in a second one of said columns by a respective second coverage amount wherein the respective first coverage amount for said one of said first plurality of pixels is approximately 50%, and wherein the respective second coverage amount for said one of said second plurality of pixels is approximately 50% and
• determining the spacing between said first line and said second line based on said slope, a first location in said matrix of one of said first plurality of pixels, and a second location in said matrix of one of said second plurality of pixels.