Uneven Timing Gap Image Sensor Readout for Ghost Effect Reduction
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Solution Overview
Problem
Current image sensors suffer from degraded image quality due to a uniform timing gap between successive image captures, which is not optimized for varying exposure times, leading to issues like ghost effects.
Innovation Solution
Implementing uneven timing gaps between image captures with different exposure times, such as long, short, medium, and ultra-short exposures, to improve image quality by using a pixel array partitioned into sub-arrays coupled with readout circuitry that includes separate ADC circuits for each exposure type, allowing for parallel readout and high dynamic range imaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a uniform timing gap is used between successive image captures, then the timing structure is simple and consistent, but image quality degrades due to ghost effects when exposure times vary
Solution Approach 1:
The patent applies local quality by making the timing gap between successive image captures variable rather than uniform. Each timing gap is specifically adjusted according to the exposure times of the adjacent frames, creating locally optimized timing structures that prevent ghost effects while maintaining overall system functionality.
Solution Approach 2:
The patent implements dynamics by making the timing gap adaptive and variable based on exposure time ratios. The timing structure transitions from a static uniform gap to a dynamic gap that automatically adjusts according to the specific exposure times of consecutive frames, optimizing image quality for varying capture conditions.
2Productivity
If the number of readout circuits is increased to achieve higher frame rates, then frame rate increases, but device complexity and power consumption increase
Solution Approach 1:
The patent applies segmentation by dividing the pixel array into multiple sub-arrays that can be read out in an interleaved manner. This allows the system to achieve higher effective frame rates by processing different sub-arrays simultaneously through fewer readout circuits, avoiding the need to proportionally increase the number of readout circuits.
Solution Approach 2:
The patent implements periodic action through the interleaved readout scheme where different sub-arrays are read out in alternating sequences. This periodic switching between sub-arrays enables higher frame rates to be achieved by efficiently utilizing the available readout circuits over time, rather than requiring dedicated circuits for each frame rate increment.
3Productivity
If the number of readout circuits is increased to achieve higher frame rates, then frame rate increases, but power consumption increases
Solution Approach 1:
The patent applies segmentation by dividing the pixel array into multiple sub-arrays that can be read out in an interleaved manner. This allows the system to achieve higher effective frame rates by processing different sub-arrays simultaneously through fewer readout circuits, avoiding the need to proportionally increase the number of readout circuits.
Solution Approach 2:
The patent implements periodic action through the interleaved readout scheme where different sub-arrays are read out in alternating sequences. This periodic switching between sub-arrays enables higher frame rates to be achieved by efficiently utilizing the available readout circuits over time, rather than requiring dedicated circuits for each frame rate increment.
4Measurement precision
If a large timing gap is used between short exposure and subsequent image capture, then the exposure time ratio can be maintained, but image quality degrades due to ghost effects
Solution Approach 1:
The patent applies local quality by making the timing gap between successive image captures variable rather than uniform. Each timing gap is specifically adjusted according to the exposure times of the adjacent frames, creating locally optimized timing structures that prevent ghost effects while maintaining overall system functionality.
Solution Approach 2:
The patent implements parameter changes by dynamically adjusting the timing gap parameter based on the exposure time ratio between consecutive frames. This allows the system to maintain the necessary exposure time ratios for high dynamic range imaging while simultaneously optimizing the timing gap to prevent ghost effects and maintain image quality.
Data Source
AI summary
Stacked chip imaging system comprising pixel array partitioned into pixel sub-arrays (PSAs) disposed in first semiconductor die and ADC circuitry including ADC circuits disposed in second semiconductor die. Each PSA is arranged into pixel groups. Each pixel group generates pixel data signals. Pixel array captures image data of first frame with first exposure time, second frame with second exposure time, third frame with third exposure time, and fourth frame with fourth exposure time. First, second, third and fourth exposure times are different. At least one of the pixel groups in each of the pixel sub-arrays is coupled to a different ADC circuit from pixels groups remaining in each of the pixel sub-arrays. ADC circuitry acquires the pixel data signals. For each frame, ADC circuits converts pixel data signal received from pixel groups respectively coupled thereto from analog to digital to generate ADC outputs. Other embodiments are also described.