Radiation Image Capturing Apparatus Lag Correction Control
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Solution Overview
Problem
Radiation image capturing apparatuses face issues with lag due to electric charges generated during irradiation, leading to uneven image data reconstruction and difficulty in obtaining true image data, especially when an interface between the apparatus and radiation generating device is not constructed.
Innovation Solution
A radiation image capturing apparatus with a control unit that manages scanning lines and readout circuits to acquire dark image data before irradiation, detect irradiation initiation, and correct image data by subtracting offset data to remove lag-induced offsets, ensuring accurate image data reconstruction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the radiation image capturing apparatus is irradiated with radiation during reset process, then the conversion ratio of radiation to image data is lowered, but the apparatus can still accumulate electric charges
Solution Approach 1:
The control unit detects irradiation initiation before the reset process is completed and interrupts the reset process. By taking preliminary action to stop the reset process when irradiation is detected, the apparatus prevents the loss of accumulated electric charges and maintains high conversion ratio of radiation to image data.
2Measurement precision
If the reset process is interrupted by irradiation, then the electric charges can be accumulated properly, but the image data acquisition is delayed
Solution Approach 1:
The control unit continuously monitors the accumulated electric charge amount and compares it with a predetermined threshold. When the threshold is reached, the control unit automatically interrupts the reset process and initiates readout. This feedback mechanism ensures accurate image data acquisition while minimizing time delay by optimizing the interruption timing.
3Adaptability or versatility
If the apparatus operates without an interface with radiation generating device, then the apparatus can be used independently, but the timing coordination between irradiation and readout is difficult
Solution Approach 1:
The radiation image capturing apparatus detects irradiation initiation itself using its own radiation detection elements, without requiring an external interface with the radiation generating device. The control unit autonomously monitors accumulated electric charges and determines when to interrupt reset and initiate readout, enabling independent operation while simplifying timing control.
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 effectively removes lag-induced offsets from image data, improving image quality by ensuring accurate reconstruction of true image data and reducing residual images in subsequent captures.
Implementation Method 1
a so-called direct-type radiation image capturing apparatus which generates an electric charge according to the dose of the emitted radiation such as X-ray and converts the electric charge thus generated into an electric signal
Implementation Method 2
a so-called indirect-type radiation image capturing apparatus which converts emitted radiation into an electromagnetic wave having other wavelength such as a visible light by way of a scintillator
Data Source
AI summary
If a control unit of a radiation image capturing apparatus acquires dark image data before photographing and at the same time detects initiation of irradiation of radiation based on image data read out by carrying out a readout process of the image data, the control unit applies off-voltage to all the scanning lines and shifts to an electric charge accumulation mode, and after the irradiation is over, sequentially applies on-voltage to each of the scanning lines, causes the scanning lines to carry out readout process of main image data from each of radiation detection elements, and subsequently acquires offset data in a condition where radiation is not irradiated to correct the main image data read out by the photographing or main image data read out by a photographing carried out after the former photographing based on offset lag part calculated from the offset data and the dark image data.