Panoramic Tomographic Image Artifact Reduction
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Solution Overview
Problem
Existing methods for producing panoramic tomographic images using 2D X-ray devices suffer from artifacts caused by opposing jaw structures, which are not effectively reduced and often require higher radiation exposure, with virtual correction methods resulting in lower resolution compared to classic 2D images.
Innovation Solution
A method that involves calculating a first panoramic tomographic image from acquired 2D X-ray projection images, modifying these images using low-pass filtering or horizontal mirroring to enhance artifact weighting, and then combining them with defined weighting factors to produce a third image with reduced artifacts, achieved through software calculations on conventional 2D X-ray devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If virtual correction methods are used to reduce artifacts, then artifact reduction is achieved, but image resolution decreases
Solution Approach 1:
The patent segments the artifact reduction process into multiple steps: acquiring multiple 2D projection images from different angles, reconstructing a 3D volume, identifying artifact regions, and selectively correcting only those regions while preserving high-resolution anatomical structures. This segmented approach allows artifact reduction without compromising overall image resolution.
Solution Approach 2:
The patent applies local quality by performing artifact correction only in specific regions where artifacts are detected, rather than uniformly processing the entire image. The correction algorithm identifies artifact-prone areas (such as regions with high absorption or inconsistent projection values) and applies correction selectively, maintaining high resolution in anatomically relevant regions while reducing artifacts locally.
2Object-affected harmful factors
If 3D volume imaging is used to reduce artifacts, then artifact reduction is achieved, but radiation exposure increases
Solution Approach 1:
The patent applies partial action by using a limited set of 2D projection images acquired from specific angles rather than performing a complete 360-degree scan. The system acquires projections at selected angular positions sufficient to reconstruct the 3D volume and identify artifacts, reducing total radiation exposure while maintaining artifact reduction effectiveness.
Solution Approach 2:
The patent creates a virtual 3D copy of the patient's anatomy from multiple 2D X-ray projections. This virtual 3D model is then used to identify and correct artifacts without requiring additional physical 3D scanning that would increase radiation exposure. The copying approach allows artifact analysis and correction in silico.
3Measurement precision
If beam angle is adjusted to anatomical structures, then image quality of specific structures improves, but artifact reduction is limited
Solution Approach 1:
The patent transitions from 2D image analysis to 3D volumetric analysis by reconstructing the anatomy from multiple 2D projections. This dimensional change allows the system to view structures from multiple angles simultaneously, identify artifacts that may obscure anatomical structures, and correct them without compromising the quality of anatomical structure visualization.
Solution Approach 2:
The patent implements feedback by using the reconstructed 3D volume to inform the artifact correction process. The system analyzes the 3D data to identify regions with artifacts, then applies corrections to the 2D projection images or the final reconstructed image, and iteratively refines the correction based on the resulting image quality, ensuring both anatomical structure clarity and artifact reduction.
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 method allows for automated and simple reduction of artifacts in panoramic tomographic images without increasing radiation exposure, maintaining or improving image resolution by modifying and combining images to correct for opposing jaw artifacts, using conventional 2D X-ray devices and software processing.
Implementation Method 1
X-rays produced by means of an X-ray source irradiate the object and are acquired by means of an X-ray detector, wherein, during a movement of the X-ray source and the X-ray detector around the object, a number of 2D X-ray projection images are acquired from different acquisition directions
Data Source
AI summary
The invention relates to a method for producing a panoramic tomographic image (1, 11, 60) of an object (2) to be recorded using a 2D panoramic X-ray device (3), in the course of which X-rays (4) produced by means of an X-ray source (5) irradiate the object (2) and are acquired by means of an X-ray detector (7), wherein, during a movement of the X-ray source (5) and the X-ray detector (7) around the object (2), a number of 2D X-ray projection images (30) are acquired from different acquisition directions (6). A first panoramic tomographic image (1) is calculated from the acquired 2D X-ray projection images (30) using a reconstruction method, wherein the acquired 2D X-ray projection images (30) are modified using a modification method, wherein, from the modified 2D X-ray projection images (40, 50) and using the reconstruction method, a second panoramic tomographic image (11) is calculated with a higher weighting of artifacts (20) relative to anatomical structures (17, 18, 19), wherein a third panoramic tomographic image (60) with significantly reduced artifacts is calculated.