Sinogram-based scattered ray correction in computer tomography
A method is for scattered ray correction of projection measurement data recorded by a computer tomography system. In an embodiment, the method includes recording, localizing, identifying and correcting. In the recording, projection measurement data is recorded from a plurality of projection angles and the projection measurement data is captured in a sinogram. In the localizing, features in the projection measurement data of the sinogram are localized in a defined angle range about a projection angle. In the identifying, a scatter distribution for the projection angle is identified from the localized features by way of a trained identification algorithm. In the correcting, the projection measurement data of the projection angle is corrected on the basis of the scatter distribution.
1. A method for correction of projection measurement data recorded by a computer tomography system, comprising:
recording projection measurement data from a plurality of projection angles and capturing the projection measurement data in a sinogram;
localizing features in the projection measurement data of the sinogram in an angle range about a projection angle;
identifying a scatter distribution for the projection angle from the localized features by way of a trained identification algorithm; and
correcting the projection measurement data of the projection angle on the basis of the identified scatter distribution.
2. The method of claim 1 , wherein the trained identification algorithm is based on a machine learning process, a statistical method, a mapping rule, mathematical functions or an artificial neural network.
3. The method of claim 2 , wherein the features include at least one of width, position, intensity, shape and morphology of the attenuation in the projection measurement data.
4. The method of claim 2 , wherein the scatter distribution includes at least one of intensity entries, count entries and energy entries of scattered photons.
5. The method of claim 2 , wherein the correcting includes a mathematical operation.
6. A non-transitory computer-readable data medium containing program code of a computer program for performing the method of claim 2 when the computer program is executed on a computer.
7. The method of claim 1 , wherein the features include at least one of width, position, intensity, shape and morphology of the attenuation in the projection measurement data.
8. The method of claim 7 , wherein the scatter distribution includes at least one of intensity entries, count entries and energy entries of scattered photons.
9. The method of claim 1 , wherein the scatter distribution includes at least one of intensity entries, count entries and energy entries of scattered photons.
10. The method of claim 1 , wherein the correcting includes a mathematical operation.
11. A non-transitory memory storing a computer program comprising program code for performing the method of claim 1 when the computer program is executed on a computer.
12. A non-transitory computer-readable data medium containing program code of a computer program for performing the method of claim 1 when the computer program is executed on a computer.
13. A method for adapting an identification algorithm for identifying a scatter distribution from projection measurement data recorded by a computer tomography system or from simulated projection measurement data, the method comprising:
generating training data comprising a plurality of sinograms and a plurality of scattered ray sinograms based on the sinograms;
extracting features in the training data;
localizing the features in the plurality of sinograms as a function of a projection angle;
mapping the localized features in an angle range about the projection angle as a function of scatter radiation distribution for the projection angle; and
adapting the identification algorithm based upon the mapped features.
14. A training unit for training an identification algorithm, comprising at least one processor for performing the method of claim 13 .
15. A non-transitory memory storing a computer program comprising program code for performing the method of claim 13 when the computer program is executed on a computer.
16. A non-transitory computer-readable data medium containing program code of a computer program for performing the method of claim 13 when the computer program is executed on a computer.
17. A computing unit for correcting projection measurement data recorded by a computer tomography system, comprising:
at least one processor, configured to:
record projection measurement data from a plurality of projection angles and capture the projection measurement data in a sonogram,
localize features in the projection measurement data of the sinogram in an angle range about a projection angle,
identify a scatter distribution for the projection angle from the localized features by way of a trained identification algorithm, and
correct the projection measurement data of the projection angle on the basis of the identified scatter distribution.
18. A computer tomography system comprising the computing unit of claim 17 .