Document type discriminating apparatus

A method for discriminating a type of a document comprising the steps of:

• reading a document to capture an image of the document;
• detecting a type of a screen pattern used in the image;
• detecting a change in a period of the screen used in the image;
• detecting sharpness of an edge seen in the image;
• detecting a blur in a color of the edge seen in the image;
• and
• discriminating that the document is a duplicate when at least two out of four discrimination results are true, the four results being obtained by four processing of discrimination as to whether or not the type of the screen pattern is a line screen, discrimination as to whether or not a value indicating the change in the period of the screen exceeds a predetermined value, discrimination as to whether or not a value indicating the sharpness of the edge is lower than a predetermined value and discrimination as to whether or not a value indicating the blur in the color of the edge exceeds a predetermined value.

A computer program product comprising:

• a computer-readable medium;
• and
• a computer program contained on the computer-readable medium for performing the steps of:
• reading a document to capture an image of the document;
• detecting a type of a screen pattern used in the image;
• detecting a change in a period of the screen used in the image;
• detecting sharpness of an edge seen in the image;
• detecting a blur in a color of the edge seen in the image;
• and
• discriminating that the document is a duplicate when at least two out of four discrimination results are true, the four results being obtained by four processing of discrimination as to whether or not the type of the screen pattern is a line screen, discrimination as to whether or not a value indicating the change in the period of the screen exceeds a predetermined value, discrimination as to whether or not a value indicating the sharpness of the edge is lower than a predetermined value and discrimination as to whether or not a value indicating the blur in the color of the edge exceeds a predetermined value.