Radiation Source-Detector Distance Measurement Using Collimator Opening
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Solution Overview
Problem
Existing radiography systems face challenges in accurately measuring the distance between a radiation source and a radiation detector, especially when the marker is obscured by a subject.
Innovation Solution
An information processing device equipped with a processor and memory, which acquires a captured image of a marker, derives the marker distance, and calculates the distance between the radiation source and the radiation detector based on the marker distance and positional relationships.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the marker is provided on the housing of the electronic cassette, then the distance measurement can be performed using a camera image, but the marker may be hidden by a subject making it difficult to appropriately measure the distance
Solution Approach 1:
The patent introduces a collimator with a specific opening as an intermediary element. The collimator opening serves as a new marker that is always visible and not obscured by the subject, replacing the traditional marker on the electronic cassette housing. This intermediary structure enables reliable distance measurement regardless of subject position.
Solution Approach 2:
The patent shifts the measurement reference from the electronic cassette housing to the collimator opening, which is positioned in a different spatial dimension relative to the radiation source and subject. This dimensional change ensures the marker (collimator opening) remains visible and measurable even when the subject obscures traditional markers.
2Ease of operation
If a marker is used for distance measurement, then the distance can be calculated from camera images, but the measurement fails when the marker is obscured by the subject
Solution Approach 1:
The collimator opening acts as a reliable intermediary marker that maintains consistent visibility. By using the collimator opening instead of markers on the electronic cassette, the system ensures both ease of operation (automatic measurement) and measurement precision (consistent marker visibility).
Solution Approach 2:
The collimator structure itself provides the measurement reference through its opening, eliminating the need for separate markers that could be obscured. The collimator serves dual purposes: radiation beam collimation and distance measurement reference, making the system self-sufficient for accurate measurement.
Data Source
AI summary
A CPU acquires a distance image or a visible light image obtained by imaging a marker for measuring an SID as an object to be imaged using a TOF camera or a visible light camera. In addition, the CPU derives a marker distance between the TOF camera or the visible light camera and the marker from an image of a marker region corresponding to the marker in the acquired distance image or visible light image. Further, the CPU derives the SID on the basis of the derived marker distance and information indicating a positional relationship between an acquisition unit and the marker.