X-ray Detector Sub-pixel Shifting for Super-resolution Imaging

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Solution Overview

Problem

Current x-ray digital radiography and computed tomography techniques face limitations in achieving high image resolution and field of view, often requiring a compromise between the two, especially with detectors like flat-panel detectors where the pixel size restricts the maximum possible resolution.

Innovation Solution

The implementation of a precise detector motion system that allows the radiation detector to translate in the x-ray beam directions perpendicular to its principal axis and along the rows and columns of pixels, enabling sub-pixel sampling and stitching of radiographs to form composite images with increased resolution and field of view, combined with advanced image acquisition and processing algorithms.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the pixel size of the radiation detector is reduced to improve image resolution, then the manufacturing cost and device complexity increase significantly

Engineering Contradiction:
Improveimage resolutionVSAvoiddetector complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent divides the imaging task into multiple segments by acquiring radiographs at different sub-pixel shifted positions. Instead of using a single high-resolution detector, the system segments the measurement process into multiple lower-resolution measurements taken at different positions, which are then computationally combined to achieve super-resolution imaging.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent adds a temporal dimension to the imaging process by acquiring multiple radiographs over time at different detector positions. This transforms a two-dimensional spatial sampling problem into a three-dimensional problem (x, y, time), allowing resolution enhancement through temporal sequencing of measurements.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Area of stationary object

If the detector size is increased to expand the field of view, then the detector area and cost increase

Engineering Contradiction:
Improvefield of viewVSAvoiddetector size
Core Design Contradiction:
Area of stationary objectVSDevice complexity

Solution Approach 1:

The patent segments the field of view acquisition into multiple overlapping radiographs taken at different detector positions. By systematically moving the detector to adjacent positions and acquiring images at each position, the system constructs a composite image with an expanded field of view that exceeds the physical detector dimensions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces dynamic motion of the detector along translation stages to expand the effective field of view. Instead of using a static large-area detector, the system dynamically positions a smaller detector at multiple locations, combining the images to achieve a larger effective imaging area.

Inventive Principle:
Principle #15Dynamics

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 significantly enhances both the imaging resolution and field of view beyond the physical limitations of the detector, allowing for more detailed 3D reconstructions in industrial applications such as non-destructive evaluation of objects.

Implementation Method 1

a two-dimensional pixelated area radiation detector having a plane arranged perpendicular to an emission direction of the x-ray beam

Methodology Applied
Scientific EffectX-ray detection: Photoelectric Effect

Data Source

PatentEP2984473B1High-resolution computed tomography
Publication Date: 2017.07.19 ILLINOIS TOOL WORKS INC
  • EP2984473B1 patent drawingFigure 1
  • EP2984473B1 patent drawingFigure 2
  • EP2984473B1 patent drawingFigure 3

AI summary

An x-ray imaging system (10), such as a X-ray computerised tomographic system, may acquire a series of radiographs at different detector positions along a first translation axis or a second translation axis parallel to orientation directions of detector pixels of a radiation detector (14). In a first embodiment, the different detector positions may be separated by a distance less than a linear size of the radiation detector (14) along the first translation axis or the second translation axis, respectively. The radiographs may be assembled into a radiograph larger than each radiograph in the series of radiographs, resulting in image stitching. In a second embodiment, the different detector positions may be separated by a distance less than a pixel size of the radiation detector (14), also referred as sub-pixel shifting of the detector. The radiographs may be assembled to form a radiograph with a higher resolution than the acquired radiographs, resulting in superresolution.