X-ray Imaging Scatter Correction via Movable Blocker
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Solution Overview
Problem
Conventional X-ray imaging systems face challenges in accurately calibrating the detector position and correcting scattered radiation, leading to degraded image quality and increased radiation doses due to the use of anti-diffusion grids or unreliable calibration methods.
Innovation Solution
An X-ray imaging system with a movable blocking element having opaque and transparent zones, allowing for the acquisition of complementary image frames to accurately determine the detector position and correct scattered radiation, using image processing to estimate primary radiation intensity and interpolate scattered radiation values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an anti-diffusion grid is disposed between the X-ray source and the detector to reduce scattered radiation, then the S/P ratio is improved, but the primary radiation contribution is decreased and the radiation dose to the patient is increased
Solution Approach 1:
The patent applies preliminary action by acquiring a first image frame with the blocking element in a first position before acquiring the second image frame. This allows the system to pre-establish reference data for calibration and scatter correction without interfering with the main imaging process. The blocking element is positioned to block primary radiation in the first image frame, enabling subsequent calculation of scatter components.
Solution Approach 2:
The patent segments the imaging process into multiple steps: acquiring a first image frame with the blocking element in a first position, moving the blocking element to a second position, and acquiring a second image frame. This segmentation allows separate measurement of primary and scattered radiation components, enabling mathematical decomposition and correction of the image data.
2Measurement precision
If an anti-diffusion grid is used to reduce scattered radiation, then the S/P ratio is improved, but the radiation dose to the patient is increased by a factor of 2 to 8
Solution Approach 1:
The patent implements feedback by using the first image frame (acquired with the blocking element in the first position) to calculate correction factors that are then applied to the second image frame. The system continuously monitors and adjusts the image data based on the measured scatter radiation, allowing for real-time correction without requiring increased radiation dose.
Solution Approach 2:
The patent creates a copy of the imaging process by acquiring two image frames with the blocking element in different positions. The first image frame serves as a reference copy that allows calculation of scatter radiation characteristics, which are then used to correct the second image frame, eliminating the need for physical anti-diffusion grids.
3Ease of operation
If calibration methods using inertial sensors are used to follow the real movement of imaging components, then the calibration can be performed, but the sensors lack reliability and are subject to disturbances
Solution Approach 1:
The patent introduces an intermediary approach by using a blocking element with known geometric characteristics as a mediator between the X-ray source and the detector. The blocking element's position and shape provide reliable reference markers that can be detected in the image frames, enabling accurate calibration without relying on potentially unreliable inertial sensors.
Solution Approach 2:
The patent replaces the mechanical sensor-based calibration system with an optical/radiographic approach. Instead of using inertial sensors to track component movement, the system uses the blocking element's geometric projection in X-ray images to determine position and orientation, substituting mechanical measurement with radiographic imaging.
4Ease of operation
If calibration methods using radiopaque markers are used, then the calibration can be performed, but the image of the markers interferes with the image of the object
Solution Approach 1:
The patent applies dynamics by moving the blocking element between at least two different positions during the imaging process. The blocking element transitions from a first position in the first image frame to a second position in the second image frame. This dynamic positioning allows the system to separate calibration information from the object image, as the blocking element's projection changes position relative to the object.
Solution Approach 2:
The patent introduces another dimension by acquiring image frames at different temporal positions with the blocking element in different spatial positions. This creates a multi-dimensional data structure where the blocking element's known geometric projection in different positions provides calibration information that can be mathematically separated from the object image data.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables accurate calibration of the imaging system and correction of scattered radiation, improving image quality while maintaining a radiation dose comparable to systems without anti-diffusion grids.
Implementation Method 1
the blocking element being formed alternately by one or more opaque zones enabling X-rays to be blocked and one or more transparent zones enabling X-rays to pass therethrough
Implementation Method 2
an X-ray source, a target object, a detector and a blocking element... a first acquisition of a first image frame... when the blocking element is in the first position
Data Source
AI summary
The invention relates to an X-ray imaging system wherein images are obtained using an X-ray blocking element, the system comprising means for determining a position of the detector (40) on the basis of coordinates of projected patterns of the blocker (20, 220) in an image in order to especially be able to perform a calibration and/or correct the contribution of the scatter radiation in a radiographic image obtained by the system.