Intensity-Modulated X-Ray Imaging With Narrow-Band Noise Filtering
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Solution Overview
Problem
Existing X-ray imaging systems suffer from quantum noise and background noise, leading to degraded image quality, contrast, and resolution, necessitating increased exposure or use of contrast enhancing agents, which are undesirable.
Innovation Solution
Implementing intensity modulated X-rays with a narrow band filtering system and grid-based modulation, along with masked sub-pixels, to enhance the signal-to-noise ratio (SNR) and dynamic range, reducing noise by modulating the X-ray source's intensity at frequencies ranging from 130 Hertz to 10 MHz.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If constant intensity X-ray source is used, then system simplicity is maintained, but signal-to-noise ratio and image quality are degraded
Solution Approach 1:
The patent applies periodic action by modulating the X-ray source intensity at a specific frequency (e.g., 130 Hz) rather than using constant intensity. This modulation creates a time-varying signal that can be distinguished from noise through frequency-selective detection, thereby improving signal-to-noise ratio while maintaining reasonable system complexity through electronic control.
Solution Approach 2:
The patent introduces an intermediary narrow band filter that selectively passes the modulated frequency signal while blocking other frequencies. This filter acts as a mediator between the modulated X-ray source and the detector, enabling noise rejection and improving measurement precision without requiring complex system architecture.
2Measurement precision
If exposure time is increased to reduce noise, then image quality improves, but productivity decreases
Solution Approach 1:
By using periodic modulation of the X-ray source at a known frequency, the patent enables the detector to integrate signal over time while simultaneously rejecting noise through frequency discrimination. This allows for faster imaging because the modulated signal can be extracted from noise even with shorter integration times, thus improving both image quality and productivity.
Solution Approach 2:
The patent replaces the mechanical approach of simply increasing exposure time with an electronic signal processing approach. By modulating the source and using frequency-selective filtering, the system achieves noise reduction through electronic means rather than prolonged mechanical exposure, thereby maintaining high imaging speed.
3Measurement precision
If contrast enhancing agents are used to improve image quality, then measurement precision improves, but harmful factors increase
Solution Approach 1:
The patent converts the potentially harmful quantum noise and background noise into distinguishable frequency components through modulation. By encoding the useful signal at a specific frequency and filtering out other frequencies, the system transforms noise from a harmful factor into a separable component, improving image quality without requiring harmful contrast agents.
4Measurement precision
If dynamic range of pixels is increased through masking, then measurement precision improves, but device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing each pixel into multiple sub-pixels with different masking patterns. This segmentation allows each sub-pixel to capture different intensity ranges, and by combining their outputs, the system achieves an extended dynamic range. The complexity is managed through regular geometric patterns in the masking, which simplify fabrication and signal 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 improves image quality and resolution without increasing exposure or using contrast agents, allowing for higher contrast and resolution with reduced noise, enabling faster and more precise imaging of soft tissues.
Implementation Method 1
a narrow band filter in operable communication with the X-ray detector and configured to filter the signal received by the X-ray detector before it is converted by the A/D converter. The narrow band filter can be centered at the predetermined frequency.
Implementation Method 2
an X-ray source configured to provide X-rays towards the X-ray detector. The X-ray source can be further configured to modulate an amplitude of intensity, of the X-rays provided, at a predetermined frequency.
Implementation Method 3
an analog-to-digital (A/D) converter in operable communication with the X-ray detector and configured to convert a signal received by the X-ray detector to a digital signal.
Implementation Method 4
a multiplier in operable communication with the narrow band filter and configured to multiply the signal received by the X-ray detector before it is converted by the A/D converter and after it is filtered by the narrow band filter.
Implementation Method 5
a digital signal processor (DSP) in operable communication with the A/D converter and configured for either asynchronous demodulation of the digital signal or synchronous demodulation of the digital signal.
Data Source
AI summary
Systems and methods for X-ray imaging using intensity modulated X-rays are provided. A narrow band filtering system can be used to improve the signal-to-noise ratio (SNR) and contrast of X-ray imaging. Systems and methods can also include a modification to an X-ray tube to permit grid-based intensity modulation and/or a masking scheme for sub-pixels to increase the dynamic range of the resulting pixels. Four different types of X-ray imaging systems can be used and can include intensity modulated X-rays through a narrow band filtering system to improve the SNR and contrast of X-ray imaging.