Moiré Removal in Fluoroscopic X-ray Images via Frequency Analysis
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Solution Overview
Problem
Conventional methods for removing moiré in fluoroscopic X-ray images often disturb the regularity of the moiré pattern, leading to traces and ghosts in the image, especially when defective pixels are complemented, particularly when they extend in the direction of the moiré pattern.
Innovation Solution
A method that involves a moiré frequency derivation step, a defective pixel preliminary complement step where pixels are complemented with reference to a pixel apart by an integral multiple of one cycle of the moiré, a moiré removal step, an image smoothing step, and a defective pixel recomplement step to ensure accurate and disturbance-free removal of moiré and ghosts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If defective pixels are complemented using conventional statistical process, then defective regions can be filled, but the regularity of the moiré pattern is disturbed causing traces and ghosts
Solution Approach 1:
The patent applies preliminary action by performing moiré removal through frequency analysis before complementing the defective pixels. By removing the moiré pattern first, the subsequent pixel compensation does not disturb moiré regularity, thus preventing traces and ghosts while still filling defective regions effectively.
2Manufacturing precision
If moiré removal is performed by frequency analysis on images with defective pixels, then moiré can be removed, but defective pixels cause disturbance in moiré pattern regularity leading to traces and ghosts
Solution Approach 1:
The patent performs preliminary moiré removal by frequency analysis on the original image before defective pixel compensation. This preliminary action eliminates the moiré pattern while preserving its regularity, so that subsequent pixel filling does not create traces or ghosts, thereby maintaining both moiré removal accuracy and image quality.
3Ease of manufacture
If conventional complement method is used for defective pixels extending in moiré direction, then defective regions are filled, but the moiré pattern regularity is inevitably disturbed
Solution Approach 1:
The patent applies preliminary moiré removal through frequency analysis before complementing defective pixels that extend in the moiré direction. This preliminary action ensures that when pixels are filled using simple statistical processes, the moiré pattern regularity is preserved, preventing traces and ghosts while maintaining ease of processing.
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 ensures that defective pixels are complemented without disturbing the regularity of the moiré pattern, removing traces and ghosts, and maintains the original image fidelity by using a matrix operation for image smoothing, effectively handling complex shapes and multiple defective pixels.
Implementation Method 1
a sheet-like X-ray grid having strip metallic foils arranged therein is provided in the X-ray imaging equipment so as to cover the X-ray detection surface of the FPD
Implementation Method 2
a flat panel detecting element (abbreviated as FPD) that detects them
Implementation Method 3
the conventional X-ray imaging equipment performs image reconstruction by conducting frequency analysis of an image and removing frequency components of the moiré
Data Source
AI summary
Provided is a method of removing a moiré in a fluoroscopic X-ray image that preliminarily complements a defective pixel with no disturbance in regularity of a moiré pattern to ensure that no trace of the defective pixel and no ghost thereof create even when the fluoroscopic X-ray image contains the defective pixel. A moiré frequency derivation section determines frequency of the moiré that appears in the fluoroscopic X-ray image, a defective pixel preliminary complement section forms a preliminary complement image, a moiré removal section conducts frequency analysis of the preliminary complement image to form a moiré removed image, an image smoothing section performs an image smoothing process to the preliminary complement image to form a smoothed image suitable for complement of the defective pixel, and a first defective pixel recomplement section recomplements the defective pixel by superimposing the moiré removed image on the smoothed image.