Patent ID: 7570792

Claim:
An image processing apparatus which extracts an irradiation field area whose overall size is a circle shape or a square shape, in an image taken by radiography, comprising: first irradiation field recognition means for extracting a closed curve obtained by connecting a plurality of irradiation field end candidate points as a perimeter of the irradiation field area in the image; shape analysis means for determining whether an overall shape of the irradiation field area extracted by said first irradiation field recognition means is a circle shape or a square shape on the basis of the perimeter or an area surrounded by the perimeter; and second irradiation field recognition means for extracting an overall shape of the irradiation field area as a circle shape when said shape analysis means determines that the overall shape of the irradiation filed area is the circle shape, and extracting an overall shape of the irradiation filed area is the square shape when said shape analysis means determines that the overall shape of the irradiation filed area is the square shape.