Imaging Apparatus Gain Control for Frame Rate and Noise
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Solution Overview
Problem
Combining technologies for focal point detection and wide dynamic range imaging in imaging apparatuses results in a significant decrease in frame rate, with insufficient consideration for noise during signal reading.
Innovation Solution
An imaging apparatus with two photoelectric converting portions, a common charge detecting portion, and sampling and holding capacitors, along with a controlling unit that adjusts gain for amplifying pixel signals in different modes to manage noise and improve frame rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple photoelectric converting portions are used for focal point detection and wide dynamic range imaging, then imaging functionality is improved, but frame rate decreases significantly
Solution Approach 1:
The pixel is divided into multiple photoelectric converting portions (first and second photoelectric converting portions) that can be independently controlled. This segmentation allows selective reading of different portions based on imaging mode, enabling focal point detection and wide dynamic range imaging without requiring all portions to be read sequentially, thus maintaining high frame rate
Solution Approach 2:
The patent implements dynamic gain adjustment where the amplifier operates in different gain modes (first gain mode and second gain mode) depending on the imaging requirements. The controlling unit dynamically switches between gain modes and selects which photoelectric converting portions to read, allowing the system to adapt to different imaging scenarios while maintaining high frame rate performance
2Measurement precision
If signals are read in time-sequential order for focal point detection, then focal point detection capability is improved, but frame rate decreases
Solution Approach 1:
The patent performs preliminary actions by storing noise signals in the sampling and holding capacitor before actual signal reading. The noise signal is read and stored in advance, then used during the actual imaging process to compensate for noise effects. This preliminary noise characterization allows accurate focal point detection without requiring time-sequential reading of all signals, maintaining high frame rate
Solution Approach 2:
The sampling and holding capacitor acts as an intermediary element that temporarily stores signals during the reading process. By using this intermediary storage, the system can read noise signals separately and use them for compensation without requiring time-sequential reading of all photoelectric converting portions, thus maintaining high frame rate while achieving accurate focal point detection
3Measurement precision
If gain adjustment unit processes signals with wide dynamic range, then dynamic range is extended, but frame rate decreases
Solution Approach 1:
The amplifier operates in different gain modes (first gain mode for high gain, second gain mode for low gain) depending on the signal strength and imaging requirements. The controlling unit dynamically switches between gain modes to process signals with wide dynamic range efficiently, avoiding the need to process all signals through the same high-gain path, thus maintaining high frame rate while extending dynamic range
Solution Approach 2:
The patent changes the gain parameter of the amplifier dynamically based on imaging conditions. By switching between different gain modes and adjusting the gain values, the system can process signals across a wide dynamic range without requiring sequential processing of all signals, thereby maintaining high frame rate while achieving extended dynamic range
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 enables suppression of frame rate decrease while maintaining focal point detection and extending dynamic range, with effective noise management and improved image quality.
Implementation Method 1
a first photoelectric converting portion and a second photoelectric converting portion
Data Source
AI summary
An apparatus including: first and second photoelectric converting portions; a charge detecting portion; a transistor outputting a pixel signal; first and second sampling and holding capacitors; an amplifier; and a controlling unit controlling gain in first and second mode. The pixel signal is one of: a first signal at a time of resetting of charge; a second signal including a charge component of the first photoelectric converting portion and a noise component; and a third signal including the first component, a charge component of the second photoelectric converting portion, and a noise component. In the first mode, the controlling unit uses a first gain. In the second mode, the controlling unit uses second gain to the first signal, third gain to the third signal of the first sampling and holding capacitor, and second gain to the third signal of the second sampling and holding capacitor.