Radiation Image Sensor Layout for Accurate AEC Signal Separation
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Solution Overview
Problem
Existing radiation image capturing devices face accuracy issues in automatic exposure control (AEC) due to signals being combined from regions with and without objects, leading to incorrect termination of radiation exposure.
Innovation Solution
The device includes separate signal lines for detection and image capturing pixels, allowing for independent acquisition of irradiation information, and a signal processing circuit that processes these signals to improve AEC accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If detection pixels are arranged in a large block corresponding to the entire receptor field, then the device structure is simplified, but the AEC accuracy deteriorates because signals cannot be separately acquired from regions with and without objects
Solution Approach 1:
The patent divides the detection pixels into multiple separate blocks, each corresponding to a specific receptor field, rather than using a single large block. This segmentation allows signals to be separately acquired from different regions (with and without objects), thereby improving AEC accuracy while maintaining reasonable structural complexity
Solution Approach 2:
The patent assigns different functional qualities to different regions by placing detection pixels in specific receptor fields where objects are expected. Each detection pixel block is optimized for its specific region, enabling accurate local measurement of irradiation information rather than averaged global measurement
2Device complexity
If signals are acquired from all detection pixels in a large block, then the signal processing is simplified, but incorrect AEC decisions occur when regions with and without objects are mixed
Solution Approach 1:
The signal processing circuit is designed to process signals from separate detection pixel blocks independently. Each block corresponds to a specific receptor field, allowing the system to evaluate irradiation information from different regions separately and make reliable AEC decisions based on appropriate regions only
Solution Approach 2:
The patent extracts and separates the signals from detection pixels located in regions with objects from those in regions without objects. By taking out only the relevant signals for AEC evaluation, the system avoids incorrect decisions that would result from mixing signals from regions with and without objects
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 arrangement enables precise control of radiation exposure by separately acquiring signals from detection pixels, enhancing AEC accuracy and reducing exposure dose.
Implementation Method 1
a plurality of pixels 101 include a plurality of image capturing pixels 101a for acquiring a radiation image and a plurality of detection pixels 101c for acquiring irradiation information of radiation separately from a radiation image
Data Source
AI summary
A radiation image capturing device including an image capturing region in which pixels are arranged, signal lines, a signal processor, and a driver is provided. The pixels include image capturing pixels and detection pixels for acquiring irradiation information. The image capturing region includes receptor fields each constituted by a predetermined number of pixels which are continuous in a row direction and a column direction. Each receptor field includes detection regions each including one or more detection pixel, the detection regions being connected to different signal lines for each of detection regions in each receptor field. The signal processor acquires the irradiation information based on signals supplied from detection pixels arranged in each of the detection regions by causing the driver to drive detection pixels which are arranged in a receptor field set for acquisition of the irradiation information.