Method for correcting a raw X-ray image, and an X-ray diagnostic system

Abstract

In order to ensure the preparation of an undistorted X-ray image of an examination image by an X-ray detector including an active pixel matrix with at least two detector plates, a method is provided. In at least one embodiment, a method for correcting a raw X-ray image includes changing, as a function of a deviation between correction values from pixel readout elements of a first detector plate and correction values from pixel readout elements of at least one further detector plate, the correction values of pixel readout elements of at least one detector plate, or preparing new correction values for the pixel readout elements of at least one detector plate. Further, the method in at least one embodiment includes carrying out a correction of the raw X-ray image with the changed correction values, or a carrying out a correction with the original correction values and the new correction values.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The invention and further advantageous refinements in accordance with the features of the claims and subclaims are explained in more detail below with the aid of schematically illustrated example embodiments in the drawings, without thereby limiting the invention to these example embodiments. In the drawings:

FIG. 1 shows an active matrix of an X-ray detector that is composed of two detector plates;

FIG. 2 shows an active matrix of an X-ray detector that is composed of four detector plates;

FIG. 3 shows a section through an X-ray detector with an active matrix according to FIG. 2;

FIG. 4 shows an example embodiment of inventive correction method for an X-ray detector composed of two detector plates.

FIG. 5 shows a method for preparing an offset image for the correction method in accordance with FIG. 4;

FIG. 6 shows a further an example embodiment of an inventive correction method for an X-ray detector composed of two detector plates;

FIG. 7 shows a method for preparing a new correction image for the correction method in accordance with FIG. 4;

FIG. 8 shows a third example embodiment of an inventive correction method for an X-ray detector composed of two detector plates; and

FIG. 9 shows an example embodiment of an inventive x-ray diagnostic system with an X-ray source, an X-ray detector and a correction unit.

Claims

1. A method for correcting a raw X-ray image of a digital X-ray detector including an active pixel matrix with pixel readout elements, the matrix including at least two detector plates, the method comprising: at least one of changing, as a function of a deviation between correction values from pixel readout elements of a first detector plate and correction values from pixel readout elements of at least one further detector plate, the correction values of pixel readout elements of at least one detector plate, andpreparing, as a function of a deviation between correction values from pixel readout elements of a first detector plate and correction values from pixel readout elements of at least one further detector plate, new correction values for the pixel readout elements of at least one detector plate; andcarrying out a correction of the raw X-ray image with at least one of the changed correction values, and the original correction values and the new correction values.

2. The method as claimed in claim 1, wherein the deviation is reduced by mutual matching of the correction values.

3. The method as claimed in claim 1, wherein the deviation is reduced by carrying out a normalization of correction values of a correction image, and a further correction image is divided electronically in pixel-wise fashion by the normalized correction image.

4. The method as claimed in claim 1, wherein the deviation is determined by a comparison of correction values from pixel readout elements of the first detector plate with correction values from pixel readout elements of at least one further detector plate.

5. The method as claimed in claim 1, wherein the deviation is determined by a comparison of a mean value of correction values from pixel readout elements of the first detector plate with a mean value of correction values from pixel readout elements of at least one further detector plate.

6. The method as claimed in claim 5, wherein the deviation is reduced by forming an absolute difference value of the mean values, and the absolute difference value is at least one of added to the correction values of the detector plate with the relatively lower mean value, and subtracted from the correction values of the detector plate with the relatively higher mean value.

7. The method as claimed in claim 1, wherein the method is used for dynamic X-ray applications.

8. The method as claimed in claim 1, wherein the method is respectively carried out for each recording mode.

9. The method as claimed in claim 1, wherein the correction values of dark image values are formed.

10. The method as claimed in claim 1, wherein the correction image is prepared from the changed correction values and is subtracted electronically from the raw X-ray image.

11. The method as claimed in claim 9, wherein the correction is performed in the setting of an offset correction.

12. The method as claimed in claim 1, wherein the new correction values from pixel readout units of the detector plate with the lower mean value are set to the value of the deviation, and the remaining new correction values are set to the value zero and wherein first the original correction values and then the new correction values are subtracted from the raw values of the raw X-ray image in pixel-wise fashion.

13. The method as claimed in claim 1, wherein the new correction values from pixel readout units of the detector plate with the higher mean value are set to the value of the deviation, and the remaining new correction values are set to the value zero, and wherein the original correction values are added to the raw values of the raw X-ray image, and subsequently the new correction values are subtracted from the corrected raw values of the raw X-ray image.

14. An X-ray diagnostic system, comprising: an X-ray detector including an active pixel matrix, the matrix including a first detector plate and at least one further detector plate, with pixel readout elements;an X-ray source; anda correction unit including at least one storage element and an image processing unit, the correction unit being provided to correct a raw X-ray image taken with the aid of the X-ray detector, in which, as a function of a deviation between correction values from pixel readout elements of the first detector plate and correction values from pixel readout elements of at least one further detector plate, at least one of the correction values of at least one detector plate are changeable and new correction values are prepareable for at least one detector plate via the correction unit, the correction unit further being provided to carry out correction of the raw X-ray image with at least one of the changed correction values, and the original correction values and the new correction values.

15. An X-ray diagnostic system for carrying out a method of claim 2.

16. The method as claimed in claim 1, wherein the deviation is reduced by carrying out a normalization of correction values of a correction image to a value of one, and wherein a further correction image is divided electronically in pixel-wise fashion by the normalized correction image.

17. The method as claimed in claim 9, wherein the correction is performed at least one of during and after an offset correction.

18. A computer readable medium including program segments for, when executed on a computer device, causing the computer device to implement the method of claim 1.

19. An X-ray diagnostic system for correcting a raw X-ray image of a digital X-ray detector including an active pixel matrix with pixel readout elements, the matrix including at least two detector plates, the system comprising: means for at least one of changing, as a function of a deviation between correction values from pixel readout elements of a first detector plate and correction values from pixel readout elements of at least one further detector plate, the correction values of pixel readout elements of at least one detector plate, andpreparing, as a function of a deviation between correction values from pixel readout elements of a first detector plate and correction values from pixel readout elements of at least one further detector plate, new correction values for the pixel readout elements of at least one detector plate; andmeans for carrying out a correction of the raw X-ray image with at least one of the changed correction values, and the original correction values and the new correction values.