Dual-Pixel Image Sensor Staggered Readout for Low-Light Noise
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Solution Overview
Problem
In image capturing devices, increasing the frame rate in low-light conditions leads to high noise levels due to the combination of multiple frames for extended exposure times.
Innovation Solution
An image capturing device with two sets of pixels and a drive unit that reads out signals from these pixels at different timings, allowing for staggered exposure and readout cycles, including a rolling shutter method to manage charge accumulation and signal output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If the frame rate is reduced to increase exposure time in dark places, then the exposure time becomes sufficient for capturing images, but the frame rate decreases leading to lower productivity
Solution Approach 1:
The imaging device is divided into two separate imaging units (first and second imaging units), each capable of independent image capture. This segmentation allows parallel operation where one unit captures during odd intervals and the other during even intervals, effectively doubling the frame rate while maintaining adequate exposure time for each unit individually.
2Productivity
If multiple frames are combined to increase apparent frame rate, then the frame rate increases, but noise influence becomes high deteriorating image quality
Solution Approach 1:
Instead of combining multiple low-quality frames, the patent uses two separate imaging units that each capture high-quality images independently. The segmented architecture allows each unit to maintain optimal exposure settings without noise accumulation from frame combination, while the alternating readout pattern achieves high apparent frame rate.
Solution Approach 2:
The two imaging units operate in continuous alternation (first unit on odd intervals, second unit on even intervals), providing a continuous stream of high-quality images at doubled frame rate. This continuous operation eliminates the need for frame combination while maintaining both high frame rate and low noise levels.
3Productivity
If two sets of pixels are used to increase frame rate, then the frame rate increases, but the device complexity increases
Solution Approach 1:
The second imaging unit is positioned to utilize the same optical path as the first unit, with the second unit receiving light that has passed through the first unit's pixel array. This nested configuration allows both imaging units to share optical components (lens, filters, etc.), reducing overall device complexity while maintaining dual-unit functionality for high frame rate operation.
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 enables increased frame rates without a corresponding increase in noise, allowing for higher quality moving images in low-light environments.
Implementation Method 1
a plurality of first pixels that have a plurality of color components, and that generate first signals by photoelectrically converting incident light
Implementation Method 2
a plurality of second pixels that generate second signals by photoelectrically converting light that has passed through the first pixels
Data Source
AI summary
An image capturing device includes: a plurality of first pixels that have a plurality of color components, and that generate first signals by photoelectrically converting incident light; a plurality of second pixels that generate second signals by photoelectrically converting light that has passed through the first pixels; and a drive unit that reads out the first signals from the first pixels, and that reads out the second signals from the second pixels at timings that are different from timings of reading out the first signals.