Image Sensor Checkerboard Pixels Wide Dynamic Range
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Solution Overview
Problem
Conventional image sensors face challenges in capturing a wide dynamic range of lighting conditions without introducing motion artifacts, as they often require multiple exposures or fixed neutral density filters, which limit dynamic range and introduce artifacts.
Innovation Solution
An image sensor with a checkerboard pattern of pixels, where alternating sub-blocks have different integration times, allowing for continuous adjustment of dynamic range and simultaneous capture of long and short exposure times within a single frame, minimizing motion artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple images are taken with different exposure times, then the dynamic range is improved, but motion artifacts are introduced
Solution Approach 1:
The pixel array is divided into multiple regions, each with different integration times. Specifically, first and second regions are defined within the same pixel array, where pixels in the first region accumulate light for a first integration time while pixels in the second region accumulate light for a second integration time that is longer than the first. This spatial segmentation allows simultaneous capture of multiple exposure times within a single frame, eliminating motion artifacts while maintaining wide dynamic range capability.
Solution Approach 2:
The patent transitions from temporal multiplexing (taking multiple images at different times) to spatial multiplexing (capturing multiple exposure times simultaneously in different spatial regions). By adding the spatial dimension to the exposure time variation, the system can capture long and short exposure data concurrently without the temporal separation that causes motion artifacts.
2Reliability
If multiple sensors are used to simultaneously accumulate different exposures, then motion artifacts are reduced, but device complexity increases
Solution Approach 1:
The patent merges multiple exposure functions into a single pixel array by creating different integration time regions within the same sensor. Instead of using multiple separate sensors to capture simultaneous exposures, the invention combines long exposure and short exposure capabilities in one device by having pixels in different regions accumulate light for different durations, then reads out all regions sequentially to reconstruct the multi-exposure image.
Solution Approach 2:
A single pixel array is designed to perform multiple functions: it can capture both long exposure and short exposure data simultaneously within the same physical sensor. The pixel array serves as both the long exposure region and the short exposure region through temporal control of the integration periods, eliminating the need for separate sensors while maintaining the ability to capture wide dynamic range without motion artifacts.
3Illumination intensity
If neutral density filters are deposited on the sensor, then dynamic range is fixed, but filtering of bright areas is achieved
Solution Approach 1:
The patent implements dynamic control of integration times for different pixel regions, allowing the effective dynamic range to be adjusted based on scene requirements. By controlling the reset timing of pixels in different regions, the system can adaptively set different integration times (first integration time for one region, second integration time for another region) to match varying lighting conditions, providing flexibility that fixed neutral density filters cannot achieve.
Solution Approach 2:
The invention changes the integration time parameter for different pixel regions rather than using fixed optical filters. By varying the integration time parameter (first integration time versus second integration time) across different regions of the same pixel array, the system achieves dynamic range control through temporal parameter adjustment rather than fixed spatial filtering, enabling adaptable response to different lighting scenarios.
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 the capture of a wide dynamic range with negligible motion artifacts and uncompromised resolution, allowing for dynamic range adjustment and improved imaging in varying lighting conditions.
Implementation Method 1
a photoelectric converter converting the light into an electrical signal
Data Source
AI summary
An image sensor, system and method that alternates sub-sets of pixels with long exposure times and pixels with short exposure times on the same sensor to provide a sensor having improved Wide Dynamic Range (WDR). The sub-sets of pixels are reset at different time intervals after being read, which causes the respective integration times to vary. By combining information contained in the both the short and long integration pixels, the dynamic range of the sensor is improved.