Patent ID: 7728850

Claim:
An image processing apparatus comprising: a controller for processing image data of a document including a plurality of drawn elements, the plurality of drawn elements having portions where upper drawn elements are superimposed over lower drawn elements such that the lower drawn elements have concealed portions, the controller comprising a classification unit and a layer image data generation unit; the classification unit classifying of drawn elements into a respective one of a plurality of element types, the plurality of element types comprising a first element type and a second element type, the first element type and the second element type being different element types, wherein one of the elements types is a character type; and the layer image data generation unit generating a plurality of layer image data that include the drawn elements as classified by the classification unit, the plurality of layer image data including a first layer image data and a second layer image data, wherein the first layer image data includes drawn elements of the first element type and the second layer image data includes drawn elements of the second element type; determining the superimposed portions of lower drawn elements of the first layer image data concealed by portions of upper drawn elements of the second layer image data and deleting the concealed portions of the first layer image data; determining the superimposed portions of lower drawn elements of the second layer image data concealed by portions of upper drawn elements of the first layer image data and deleting the concealed portions of the second layer image data; and outputting edge information for the each layer image data.