Method of removing foil shadows of a synchronous grid, and a radiographic apparatus using the same
AssigneeShimadzu Corporation
InventorAkinori Fujita
Life of this patent
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Abstract
Grid foil shadows of a synchronous grid are removable by obtaining an approximate fluoroscopic image by extracting detection signals of pixels not influenced by the grid foil shadows from a fluoroscopic image and carrying out an interpolation process thereon, obtaining a grid foil shadow image by determining a difference between the fluoroscopic image and the approximate fluoroscopic image, obtaining a foil shadow standard image by averaging the grid foil shadow image in a longitudinal direction of the grid foil shadows, and removing the grid foil shadows by determining a difference between the fluoroscopic image and the foil shadow standard image.
Claims12
A grid foil shadow removing method for a radiographic apparatus having a synchronous grid with grid foil strips arranged at regular intervals so that grid foil shadows fall on middles of pixels which detect radiation, the grid foil shadow removing method comprising:
- an approximate fluoroscopic image calculating step for obtaining an approximate fluoroscopic image by extracting detection signal values of pixels free from influences of the grid foil shadows from a fluoroscopic image and carrying out an interpolation process thereon;
- a grid foil shadow image calculating step for obtaining a grid foil shadow image by determining a difference between the fluoroscopic image and the approximate fluoroscopic image;
- a foil shadow standard image calculating step for obtaining a foil shadow standard image by averaging the grid foil shadow image in a longitudinal direction of the grid foil shadows;
- and
- a foil shadow removing step for removing the grid foil shadows from the fluoroscopic image based on the foil shadow standard image.
A radiographic apparatus comprising:
- a radiation emitting device for emitting radiation to a patient;
- a radiation detecting device having pixels arranged in a two-dimensional array for detecting the radiation transmitted through the patient;
- a synchronous grid arranged at regular intervals so that grid foil shadows fall on middles of the pixels;
- an approximate fluoroscopic image calculating unit for calculating an approximate fluoroscopic image by extracting a pixel set free from influences of the grid foil shadows from a fluoroscopic image transmitted through the patient and detected and carrying out an interpolation process thereon;
- a grid foil shadow image calculating unit for obtaining a grid foil shadow image by determining a difference between the fluoroscopic image and the approximate fluoroscopic image;
- a foil shadow standard image calculating unit for obtaining a grid foil shadow standard image by averaging the grid foil shadow image in a longitudinal direction of the grid foil shadows;
- and
- a foil shadow removed image calculating unit for obtaining a foil shadow removed image by removing the grid foil shadows from the fluoroscopic image based on the grid foil shadow standard image.
Dependencies are inferred from the claim text.