Radiographic Image Detector Hexagonal Pixel Binning Resolution
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Solution Overview
Problem
Radiographic image detectors with hexagonal shaped pixels face challenges in maintaining even resolution in horizontal, vertical, and diagonal directions after pixel summing, due to unevenness in pixel positions during charge combination.
Innovation Solution
The configuration of pixel groups in a honeycomb pattern with specific charge signal integration periods and switching methods ensures even resolution by forming regular hexagonal shaped regions, allowing for consistent center of gravity positions before and after binning, using a combination of switching elements and charge amplifiers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If pixel summing is performed to increase sensitivity and maintain high frame rate, then productivity is improved, but manufacturing precision deteriorates due to unevenness in pixel positions after summing
Solution Approach 1:
The pixel array is segmented into multiple readout regions, each with its own dedicated readout circuitry. This segmentation allows independent optimization of each region's center of gravity position, enabling uniform pixel positioning even after pixel summing operations are performed to increase sensitivity and frame rate.
Solution Approach 2:
The patent performs preliminary arrangement of pixel groups and readout circuit connections before pixel summing operations. By pre-configuring the hexagonal pixel patterns and assigning them to specific readout circuits in advance, the system ensures that center of gravity positions remain uniform even after charges are summed from multiple pixels, thus maintaining manufacturing precision while improving productivity.
2Measurement precision
If hexagonal shaped pixels are used to increase resolution in all directions, then measurement precision is improved, but device complexity increases due to irregular pixel arrangements
Solution Approach 1:
The patent employs hexagonal-shaped pixels with asymmetric geometric properties to achieve uniform resolution in all directions (horizontal, vertical, and diagonal). The six-fold symmetry of hexagons naturally provides equal spacing in six directions, delivering superior measurement precision compared to square pixels while the regular repeating pattern keeps device complexity manageable through standardized manufacturing processes.
Solution Approach 2:
The invention changes the fundamental geometric parameter of pixel shape from square to hexagonal, which fundamentally alters the spatial arrangement and spacing characteristics. This parameter change enables uniform resolution in all directions because hexagons provide equal distance to adjacent pixels in six directions, achieving isotropic resolution without requiring complex non-uniform arrangements.
3Measurement precision
If pixel size is reduced to increase resolution, then measurement precision is improved, but loss of substance increases due to reduced charge collection area
Solution Approach 1:
The patent implements pixel summing functionality that merges charges from multiple adjacent hexagonal pixels into a single output signal. This combining operation effectively increases the charge collection area by aggregating signals from several smaller pixels, thereby compensating for the reduced individual pixel size and preventing loss of substance while maintaining the high resolution benefits of smaller pixels.
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 maintains even resolution in all directions before and after combining charges, suppressing unevenness and enabling consistent image quality, facilitating both still and video imaging with high frame rates and improved sensitivity.
Implementation Method 1
a sensor portion which receives the irradiated radiation and generates charges
Data Source
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AI summary
The present invention provides a radiographic image detector that may maintain even resolution in 6 directions before and after 3-pixel binning process. Namely, out of plural pixels with hexagonal shaped pixel regions in a radiation detector, for plural pixel groups respectively configured from 3 pixels, 3 pixels worth of charges in the radiation detector are read together, the charge signals of these 3 pixels combined, and integrated in sequence with a charge amplifier. For specific pixel groups, out of 3 pixels configuring the specific pixel groups, the charge signals of 2 pixels worth, and the charge signal of the remaining 1 pixel worth are summed with the same charge amplifier using shifted integration timings. 3-pixel binning is thereby performed.