Patent ID: 8620090

Claim:
An image processing apparatus comprising a processor, the processor configured to function as: a line information reception unit that receives a set of information indicating (i) information on an image having a possibility of being a line and (ii) a line element being a rectangular pixel lump which constitutes a line; a prediction determination unit that determines whether or not each target line element in the image matches a predicted value of the target line element based on the information indicating the line element received by the line information reception unit, the predicted value indicating a line element which is predicted when the target line element constitutes a line at a position of the target line element; a feature amount calculation unit that calculates a feature amount of the image when the prediction determination unit determines the target line element does not match the predicted value, the feature amount of the image being calculated as equal to a number of observation failures divided by the number of target line elements; and a line determination unit that determines whether or not the image is a line based on the feature amount calculated by the feature amount calculation unit, wherein an observation failure exists when (a) the line element is not at the position of the target line element, (b) the target line element has a thickness less than a predetermined threshold, or (c) the position of the target line element is too distant from a predicted position of the target line element.