Method for distortion correction of X-ray images, and device for carrying out the method
AssigneeU.S. Philips Corporation
InventorsReiner H. Koppe, Erhard P. A. Klotz
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Abstract
A distorted input image, produced by an X-ray exposure and composed of pixels defined by their position and their respective input image value, is transformed into a substantially distortion-free output image composed of pixels defined by their position and their output image value. Improvement is achieved in that the transformation utilizes a determination of the position of the corner points of the pixels of the output image (or the input image) as well as the surface area of a polygon defined by the corner points in the input image (output image).
Claims4
A method for transforming a distorted input image (Bi) produced by an X-ray exposure and composed of pixels defined by their positions and their respective input image values, into a substantially distortion-free output image (B.sub.o) composed of pixels each having a periphery defined by corner points interconnected by edges, said pixels being defined by their position in said array and their output image value, wherein the positions of corner points of the pixels of the output image (B.sub.o) in the input image (Bi) are determined as well as the areas of polygons defined by the corner points of the pixels of the output image in the input image such that there is a different polygon in the input image associated with each pixel in the output image, each polygon covering fractions of one or more pixels in the input image, each pixel of the output image being assigned an output image value which corresponds to the sum of the products of the input image values times the fraction of input pixel area covered by the associated polygon.
A device for transforming a distorted input image (B.sub.i) produced by an X-ray exposure into a substantially distortion-free output image (B.sub.o) comprising:
- a) an X-ray system for forming the input image by way of an X-ray exposure,
- b) an image converter for converting the input image into a series of digital image values constituting the input image (B.sub.i),
- c) a storage device for storing input image values,
- d) means for determining the position of corner points of the output image in the input images as well as the areas of polygons defined by the positions of said corner points of the output image in the input image such that there is a different polygon in the input image associated with each pixel in the output image, and
- e) means for assigning the image values of the pixels of the output image based on fractions of areas of pixels in the input image covered by the associated polygons in the input image and the image values of the covered pixels.
Dependencies are inferred from the claim text.