Image Reading Device Modulation Signal Amplitude Control
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Solution Overview
Problem
Conventional image reading devices experience variations in image signal levels due to the SSCG, leading to oblique stripes in the output image, which are difficult to correct, especially when produced in large numbers, as the variation can vary significantly between different signal processing systems.
Innovation Solution
The solution involves detecting the modulation signal from the SSCG, varying its amplitude to match the image signal variation, and superimposing it on the image signal to correct the variation, using an amplitude controller and various configurations such as DAC, shift registers, and capacitors to achieve precise amplitude control, ensuring the modulation signal is properly phased and noise-resistant.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a frequency-modulated clock is used to drive the CCD and AFE, then the radiation noise peak level is reduced, but the image signal varies according to the modulation period causing oblique stripes
Solution Approach 1:
The patent detects the modulation signal from the SSCG that causes image signal variation, varies its amplitude to match the image signal variation, and superimposes it on the image signal. This converts the harmful modulation effect into a beneficial correction by using the same modulation signal to cancel out the unwanted variations, thereby eliminating oblique stripes while maintaining the benefits of frequency modulation for radiation noise reduction
Solution Approach 2:
The patent employs a feedback mechanism where the modulation signal is detected from the SSCG output, its amplitude is controlled to match the image signal variation, and then superimposed on the image signal. This closed-loop approach continuously compensates for the modulation-induced variations, ensuring stable image signal levels while maintaining the frequency modulation benefits
2Manufacturing precision
If the amplitude of the modulation signal is increased to correct larger variations, then the correction effectiveness improves, but the noise resistance deteriorates
Solution Approach 1:
The patent uses an amplitude controller to dynamically adjust the amplitude of the modulation signal based on the detected image signal variation. This dynamic control allows the system to optimize the correction effectiveness for each signal condition while maintaining noise resistance by avoiding excessive amplitude that would amplify noise
Solution Approach 2:
The patent changes the amplitude parameter of the modulation signal to match the image signal variation. By controlling the amplitude parameter dynamically, the system achieves effective correction of signal level variations while maintaining optimal noise resistance through precise parameter matching rather than fixed high amplitude
3Object-affected harmful factors
If the modulation period is made asynchronous to the main scanning line to reduce visible patterns, then the phase variation shifts gradually across lines, but oblique stripes still appear
Solution Approach 1:
The patent converts the harmful phase variation effect into a beneficial correction by detecting the modulation signal and superimposing it with varied amplitude on the image signal. This approach uses the same asynchronous modulation that causes phase shifts to provide the correction signal, thereby eliminating oblique stripes while maintaining the asynchronous timing that reduces visible patterns
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 effectively corrects the image signal variations, reducing oblique stripes and ensuring high-quality images by robustly controlling the amplitude of the modulation signal, even with individual differences in signal processing systems, resulting in a consistent and high-quality output.
Implementation Method 1
The SSCG 2 cyclically modulates the frequency of a received clock signal
Implementation Method 2
converting of the image to a digital image signal... a photoelectric conversion device
Data Source
Figure 1~2(d)
Figure 3
Figure 4A~4D
AI summary
An image reading device includes a charge-coupled device (4) that generates and outputs an image signal, a timing generator (3) that outputs a frequency-modulated clock, a modulation signal detector (10) that detects a modulation signal being a signal corresponding to a change in frequency of the clock, an amplitude controller (11) that controls an amplitude of the modulation signal, and a signal combining unit (8) that superimposes the modulation signal after the amplitude is controlled on the image signal.