X-ray diagnostic apparatus and method for operating an x-ray diagnostic apparatus for determining quality values
2 Assignments
0 Petitions
Accused Products
Abstract
The invention relates to an angiographic x-ray diagnostic apparatus with an x-ray radiator having an x-ray tube, with a patient positioning table having a radiation-transparent positioning plate and mattress, with an x-ray detector, with an imaging system, an image processing unit and a measuring device to which the output signals of the x-ray detector are fed and which has a first device for determining a value determining the reproduction quality of clinically relevant objects, a second device for determining local variances of the noise in a homogenous image region of different x-ray images and a device for taking the ratio of the output values of the two devices.
-
Citations
40 Claims
-
1-17. -17. (canceled)
-
18. Angiographic x-ray diagnostic apparatus, comprising:
-
an x-ray radiator including an x-ray tube;
a patient positioning table including a radiation-transparent positioning plate and mattress;
an x-ray detector;
an imaging system;
an image processing unit; and
a measuring device connected to the x-ray detector for acquiring output signals of the x-ray detector, the measuring device comprising;
a first device for determining a quality value related to a reproduction quality of a clinically relevant object;
a second device configured to calculate a local variance of a noise present in a homogenous image region of different x-ray images; and
a calculation device for calculating a ratio of the quality value and the local variance of noise. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36)
-
-
37. A measuring method for checking an x-ray diagnostic apparatus, the method comprising:
-
digitally acquiring fluoroscopic series of x-ray images of a technical phantom and storing the acquired digital data;
calculating a difference between a dynamic image and a background image;
predicting a measuring field;
determining a-priori information about the shape of a clinically relevant object;
applying a Hough transformation on a gray value image corresponding to the difference;
determining a contrast of the clinically relevant object from the Hough-transformed gray value image;
calculating a square of the determined contrast;
calculating a noise variance by determining a sum of a noise variance of a homogenous image region and a variance of the background image;
determining a contrast-to-noise ratio of the determined contrast and the calculated noise variance;
dynamically averaging a square of the contrast-to-noise ratio; and
determining a Clinical Relevant Fluoroscopy Performance (CRFP) index for the x-ray diagnostic apparatus.
-
-
38. The measuring method for checking an x-ray diagnostic apparatus, the method comprising:
-
digitally acquiring fluoroscopic series of x-ray images of a technical phantom and storing the acquired digital data;
calculating a difference between a dynamic image and a background image;
predicting a Region of Interest (ROI);
determining a-priori information about the shape of a clinically relevant object;
determining a variance of the clinically relevant object based on a gray value image corresponding to the calculated difference, calculating a noise variance by determining a sum of a noise variance of a homogeneous image region and the variance of the background image;
determining a ratio of the noise variance and the variance of the background image;
dynamically averaging the determined ratio; and
determining a Clinical Relevant Fluoroscopy Performance (CRFP) index for the x-ray diagnostic apparatuses.
-
-
39. A measuring method for checking a clinically relevant object using a standardized x-ray diagnostic apparatus, the method comprising:
-
digitally acquiring fluoroscopic series of x-ray images of the clinically relevant object and storing the acquired digital data by the standardized x-ray diagnostic apparatus;
calculating a difference between a dynamic image and a background image;
predicting a measuring field;
determining a-priori information about the shape of the clinically relevant object;
applying a Hough transformation on a gray value image of the calculated difference;
determining a contrast of the clinically relevant object from the Hough-transformed gray value image;
calculating a square of the determined contrast;
calculating a noise variance by determining a sum of a noise variance of a homogeneous image region and a variance of the background image;
determining a contrast-to-noise ratio of the determined contrast and the calculated noise variance;
dynamically averaging a square of the contrast-to-noise ratio; and
determining a Clinical Relevant Fluoroscopy Performance (CRFP) index for the clinically relevant object.
-
-
40. A measuring method for checking a clinically relevant object using a standardized x-ray diagnostic apparatus, the method comprising:
-
digitally acquiring fluoroscopic series of x-ray images of the clinically relevant object and storing the acquired digital data by the standardized x-ray diagnostic apparatus;
calculating a difference between a dynamic image and a background image;
predicting a Region of Interest (ROI);
determining a-priori information about the shape of the clinically relevant object;
determining a variance of the clinically relevant object using a gray value image corresponding to the calculated difference;
calculating a noise variance by determining a sum of a noise variance of a homogeneous image region and a variance of the background image;
determining a ratio of the noise variance and the variance of the background image;
dynamically averaging the determined ratio; and
determining a Clinical Relevant Fluoroscopy Performance (CRFP) index for the clinically relevant object.
-
Specification