Recursive X-Ray Image Noise Reduction With Cumulative Motion Maps
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Solution Overview
Problem
Existing noise reduction techniques for low-dose X-ray images, such as recursive filtering, struggle with motion blur and ineffective noise reduction due to varying threshold settings, especially when subject motion is present, leading to degraded image quality.
Innovation Solution
An image processing device and method that utilizes a cumulative motion map to accumulate noise reduction processing over time, incorporating a motion map generation, statistical value map, and adaptive thresholding to generate a noise-reduced output image through a recursive approach.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a fixed threshold value is used in recursive filtering to discriminate motion and noise, then the method is simple to implement, but noise reduction performance deteriorates due to varying noise intensity and variance under different imaging conditions
Solution Approach 1:
The patent applies dynamics by transitioning from a fixed threshold to an adaptive threshold that dynamically adjusts based on the statistical characteristics of the image data. The threshold is calculated using the standard deviation of the difference map and a predetermined coefficient, allowing it to automatically adapt to varying noise levels and imaging conditions without requiring manual intervention or complex pre-processing.
2Measurement precision
If a high threshold value is used to eliminate motion blur, then motion detection is improved, but noise reduction efficiency decreases due to suppression of recursive filtering effectiveness
Solution Approach 1:
The patent applies parameter changes by modifying the threshold value based on the standard deviation of the difference map. Instead of using a fixed high threshold, the system calculates an adaptive threshold that scales with the noise level (standard deviation), allowing optimal motion detection while maintaining noise reduction efficiency. This dynamic parameter adjustment enables the system to distinguish between motion and noise more accurately under varying imaging conditions.
3Object-affected harmful factors
If low-dose X-rays are used to minimize radiation exposure, then patient safety is improved, but image quality deteriorates due to increased quantum mottle and noise concentration
Solution Approach 1:
The patent applies feedback by using the difference map (which captures noise and motion information) to adaptively adjust the threshold for motion detection. The threshold is calculated based on the standard deviation of the difference map, creating a feedback loop where the system continuously monitors image characteristics and adjusts its processing parameters accordingly. This feedback mechanism enables effective noise reduction and motion discrimination even in low-dose images with high quantum mottle.
Data Source
AI summary
An image processing device for performing noise reduction processing on images obtained by radiation imaging using a recursive way includes: an image input unit that receives frame-by-frame images obtained by the radiation imaging; a motion map generation unit that generates a motion map having motion detection information for each pixel of a difference map obtained by a difference between a current frame image and a previous frame image; a cumulative motion map generation unit that generates a cumulative motion map based on the generated motion map and a cumulative motion map up to a previous frame; a statistical value map generation unit that generates a statistical value map formed by assigning a statistical value representing a motion probability of each pixel of the cumulative motion map; and an output image generation unit that generates an output image of a current frame by mixing the current frame image and the output image of the previous frame based on the cumulative motion map.