Imaging Apparatus Noise Reduction via Dynamic Signal Period Control
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Solution Overview
Problem
Existing imaging apparatuses face challenges in reducing noise during pixel addition, particularly when using CCDs, as increased multiple sampling requires faster A/D converters, leading to decreased frame rates and prominent low-frequency noise.
Innovation Solution
The imaging apparatus controls pulse widths of horizontal synchronization signals to extend feed-through and signal periods during pixel addition, enabling multiple sampling and noise reduction processing, which includes correlated double sampling, A/D conversion, and average value calculation to minimize random noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If multiple sampling is increased to reduce noise, then noise reduction is improved, but frame rate decreases and low-frequency noise becomes obvious
Solution Approach 1:
The patent dynamically adjusts the feed-through period length based on whether pixel addition is being performed. During pixel addition, the feed-through period is extended to enable multiple sampling for noise reduction. When pixel addition is not performed, the feed-through period is shortened to maintain high frame rates. This dynamic adaptation resolves the contradiction between noise reduction and frame rate maintenance.
Solution Approach 2:
The patent changes the timing parameters (feed-through period duration) based on the operational mode. By extending the feed-through period specifically during pixel addition operations, the system enables multiple sampling to reduce noise without permanently sacrificing frame rate. This parameter change allows the system to optimize for noise reduction only when necessary.
2Object-affected harmful factors
If feed-through period and signal period are extended to enable multiple sampling, then noise reduction is improved, but scanning time increases
Solution Approach 1:
The patent implements dynamic timing adjustment where the feed-through period is extended only during pixel addition operations when noise reduction is needed. During normal operations without pixel addition, the timing remains optimized for speed. This dynamic approach allows the system to gain noise reduction benefits without permanently increasing scanning time.
Solution Approach 2:
The extended feed-through period is applied periodically or conditionally only when pixel addition is being performed, rather than continuously. This periodic application of the extended timing allows multiple sampling to occur when needed for noise reduction, while maintaining faster scanning rates during other operations.
Data Source
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AI summary
An imaging apparatus is provided with control means, noise reduction processing means and pixel value calculation means. The control means control pulse widths of horizontal synchronization signals outputted to an imaging device such that a feed-through period and a signal period, in a case in which pixel addition in the horizontal direction is performed at the imaging device and imaging signals are outputted, are longer than a feed-through period and a signal period, in a case in which pixel addition in the horizontal direction is not performed at the imaging device. The noise reduction processing means execute noise reduction processing to reduce the effects of noise produced in the imaging signals. The pixel value calculation means calculate a pixel value on the basis of a first signal sampled in the feed-through period and a second signal sampled in the signal period.