Scatter correction
In one embodiment of a method of and apparatus for correcting for scatter, an object, which may be the jaw of a dental patient, is subjected to x-rays or other penetrating radiation. An intensity distribution of the transmitted radiation is detected. A first array of voxel data representing the absorption of the radiation by the object is reconstructed from the detected intensity. A radiation scatter pattern is calculated by forward projection from the first array using one or more point spread functions. The detected intensity is corrected using the calculated radiation scatter pattern. A second array of voxel data representing the absorption of the radiation by the object is reconstructed from the corrected detected intensity.
1 . A method of correcting for scatter, comprising:
subjecting an object to penetrating radiation;
detecting an intensity distribution of the transmitted radiation;
reconstructing from the detected intensity a first array of voxel data representing the absorption of the radiation by the object;
calculating by forward projection from the first array using one or more point spread functions a radiation scatter pattern;
correcting the detected intensity using the calculated radiation scatter pattern; and
reconstructing from the corrected detected intensity a second array of voxel data representing the absorption of the radiation by the object.
2 . A method according to claim 1 , further comprising repeating the process of calculating, correcting, and reconstructing one or more times.
3 . A method according to claim 1 , wherein detecting an intensity distribution comprises detecting an amount of radiation received at an array of detectors.
4 . A method according to claim 1 , further comprising generating and displaying an image representing the object from the second array of voxel data.
5 . A method of correcting for scatter, comprising:
subjecting a target object to penetrating radiation;
detecting the intensity of the transmitted radiation;
correcting the detected intensity using a scatter pattern for a known object similar to the target object; and
reconstructing from the corrected detected intensity an array of data representing the absorption of the radiation by the object.
6 . A method according to claim 5 , wherein the target object is at least part of a human head, and the known object is an artificially created phantom head or partial head.
7 . A method according to claim 6 , wherein the target object comprises at least part of the mandibular and/or maxillary regions of the head of a dental patient.
8 . A method according to claim 5 , further comprising generating and displaying an image representing the object from the array of data.
9 . A method for generating a scatter pattern from a known object, comprising:
subjecting the known object to penetrating radiation;
detecting an intensity distribution of the transmitted radiation;
calculating a pattern of radiation transmitted by the object with no scatter; and
subtracting the calculated transmitted radiation pattern from the detected intensity distribution.
10 . A computer program to cause a computer to correct data for scatter, comprising instructions to cause the computer to:
receive data representing an intensity distribution of radiation transmitted by an object subjected to penetrating radiation;
reconstruct from the detected intensity a first array of voxel data representing the absorption of the radiation by the object;
calculate by forward projection from the first array using one or more point spread functions a radiation scatter pattern;
correct the detected intensity distribution using the calculated radiation scatter pattern; and
reconstruct from the corrected detected intensity a second array of voxel data representing the absorption of the radiation by the object.
11 . A computer program according to claim 10 , further comprising instructions to cause the computer to repeat the process of calculating, correcting, and reconstructing one or more times.
12 . A computer program according to claim 10 , wherein the instructions to detect an intensity distribution comprise instructions to detect an amount of radiation received at an array of detectors.
13 . A computer program according to claim 10 , further comprising instructions to cause the computer program to generate and display an image representing the object from the second array of voxel data.
14 . A computer program according to claim 8 on a machine-readable medium.
15 . A computer program to cause a computer to correct data for scatter, comprising instructions to cause the computer to:
subject a target object to penetrating radiation;
detect the intensity of the transmitted radiation;
correct the detected intensity using a scatter pattern for a known object similar to the target object; and
reconstruct from the corrected detected intensity an array of data representing the absorption of the radiation by the object.
16 . A computer program according to claim 15 , further comprising instructions to cause the computer program to generate and display an image representing the object from the array of data.
17 . A computer program according to claim 15 on a machine-readable medium.