Radiation Imaging Readout Circuit with Switchable Integration Amplifier
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Solution Overview
Problem
Radiation imaging apparatuses using flat panel detectors often produce images with insufficient quality due to low dynamic range and resolution, which is inadequate for medical diagnosis and nondestructive inspection, especially when motion artifacts are present.
Innovation Solution
A radiation imaging apparatus with a readout circuit that operates in multiple modes, featuring an integration amplifier with adjustable current driving capability to switch between high and low current modes, allowing for improved signal amplification and reduced switching noise, thereby enhancing image quality and reducing motion artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If readout is performed in a mode with low dose, small dynamic range, and low resolution, then the time interval between imaging processes can be made short and motion artifact can be reduced, but image quality becomes insufficient for diagnosis
Solution Approach 1:
The integration amplifier's current driving capability is made dynamically switchable between first and second modes. In the first mode, high current driving capability is provided to enable fast readout with short time intervals, reducing motion artifacts. In the second mode, lower current driving capability is provided to maintain adequate image quality for diagnosis. This dynamic adjustment resolves the contradiction by matching the amplifier's performance characteristics to the specific imaging requirements.
Solution Approach 2:
The patent changes the operational parameters of the integration amplifier by switching between different current driving capabilities. This parameter change allows the system to optimize the trade-off between readout speed (for reducing motion artifacts) and image quality (for adequate diagnosis), resolving the technical contradiction through controlled parameter variation.
2Speed
If high current driving capability is provided in the integration amplifier, then readout speed increases and motion artifact reduces, but power consumption increases
Solution Approach 1:
The integration amplifier's current driving capability is dynamically adjusted based on imaging mode requirements. High current driving capability is activated only when fast readout is needed (first mode), while lower current driving capability is used when image quality is the priority (second mode). This dynamic adjustment resolves the contradiction between speed and power consumption by providing high performance only when necessary.
Solution Approach 2:
Instead of continuously providing high current driving capability, the system provides high capability only partially - specifically during first mode imaging operations where fast readout is required. This partial application of high performance resolves the contradiction by avoiding unnecessary power consumption during second mode operations where adequate image quality can be achieved with lower current driving capability.
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
The solution enables the acquisition of high-quality images by shortening readout times and reducing switching noise, particularly in energy subtraction and continuous imaging modes, while maintaining low power consumption in still image capture modes.
Implementation Method 1
an integration amplifier configured to amplify the signal read out from the pixel array
Implementation Method 2
a sample and hold circuit configured to hold the signal amplified by the integration amplifier
Data Source
AI summary
A radiation imaging apparatus is provided. The apparatus includes a pixel array in which pixels are arranged, and a readout circuit configured to read out the signal from the pixel array, and configured to operate in a plurality of modes including a first mode and a second mode in which a time between imagings is longer than in the first mode. The readout circuit includes an integration amplifier configured to amplify the signal read out from the pixel array, and a sample and hold circuit configured to hold the signal amplified by the integration amplifier, the integration amplifier is configured to be able to switch a current driving capability for driving an input node of the sample and hold circuit, and the current driving capability in the first mode is higher than the current driving capability in the second mode.