TDI Sensor Rolling Shutter Pixel Separation Space
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Solution Overview
Problem
Conventional TDI CMOS image sensors using rolling shutter technology suffer from imaging distortion due to uneven integration times across pixels, leading to noise and reduced signal-to-noise ratio (SNR).
Innovation Solution
A TDI CMOS image sensor with a pixel array that includes multiple pixel columns with a separation space between adjacent pixels, calculated as a function of pixel height and line time difference, to compensate for the rolling shutter effect, ensuring that pixel data from the same scene position is integrated in successive frames, thereby enhancing SNR.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If rolling shutter operation is used in TDI CMOS image sensor, then power consumption is reduced and integration speed is improved, but imaging distortion occurs due to uneven integration times across pixels
Solution Approach 1:
The patent applies local quality by introducing a separation space between adjacent pixels in the along-track direction. This separation space is specifically designed to compensate for the line time difference caused by rolling shutter operation, ensuring that pixel data from the same scene position is integrated consistently across successive frames. The local structural modification (separation space) addresses the specific problem of uneven integration times without affecting the overall rolling shutter operation that provides low power consumption.
2Speed
If rolling shutter operation is used in TDI CMOS image sensor, then integration speed is improved, but signal-to-noise ratio is reduced due to imaging distortion
Solution Approach 1:
The separation space between adjacent pixels is specifically designed to compensate for the line time difference, ensuring that pixel data from the same scene position integrates consistently. This local structural adjustment maintains the fast integration speed of rolling shutter while eliminating the imaging distortion that degrades signal-to-noise ratio.
3Manufacturing precision
If physical offset is arranged between adjacent pixels to compensate integration interval, then imaging distortion is reduced, but device complexity increases
Solution Approach 1:
The patent changes the spatial parameter (separation space) between adjacent pixels to compensate for the temporal parameter (line time difference) caused by rolling shutter operation. By adjusting the physical separation distance based on the relationship between pixel height, line time difference, and frame period, the patent achieves consistent integration times without requiring complex control circuits or additional hardware components.
Data Source
AI summary
The present disclosure provides a time delay integration (TDI) sensor using a rolling shutter. The TDI sensor includes multiple pixel columns. Each pixel column includes multiple pixels arranged in an along-track direction, wherein two adjacent pixels or two adjacent pixel groups in every pixel column have a separation space therebetween. The separation space is equal to a pixel height multiplied by a time ratio of a line time difference of the rolling shutter and a frame period, or equal to a summation of at least one pixel height and a multiplication of the pixel height by a time ratio of the line time difference and the frame period. The line time difference of the TDI sensor is changeable without changing the separation space.