Image Sensor High Dynamic Range Spatial Temporal Multiplexing
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Solution Overview
Problem
Conventional image sensors have limited dynamic range, leading to inadequate capture of details in scenes with varying lighting conditions, resulting in images with insufficient contrast and loss of information in shadows or highlights.
Innovation Solution
Combining high dynamic range techniques such as spatial exposure multiplexing, temporal exposure multiplexing, and dual gain operation to generate images with a 20+ bit dynamic range, allowing for improved contrast and reduced motion artifacts and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional image sensors are used, then device simplicity and low cost are maintained, but dynamic range is limited and cannot capture details in high-contrast scenes
Solution Approach 1:
The pixel array is divided into multiple regions, each with different exposure times. Some pixels capture short exposure images while others capture long exposure images simultaneously, allowing the sensor to capture both bright and dark scene details in a single frame without requiring multiple captures or complex mechanical components.
Solution Approach 2:
The patent combines multiple exposure time captures (short and long exposure) into a single composite image. By merging the data from pixels with different exposure times, the sensor achieves extended dynamic range capability while maintaining a simple integrated circuit structure without additional mechanical or optical components.
2Measurement precision
If multiple exposure times are captured sequentially, then dynamic range is improved, but motion artifacts increase and productivity decreases
Solution Approach 1:
The pixel array is segmented into multiple regions with different exposure times that operate simultaneously. This parallel operation allows short and long exposure images to be captured at the same time, maintaining high frame rates while achieving extended dynamic range without the motion artifacts associated with sequential capture methods.
Solution Approach 2:
The sensor maintains continuous operation at a single high frame rate by capturing multiple exposure times simultaneously in different pixel regions. This eliminates the need to alternate between different capture modes, ensuring continuous useful action is performed without interruption or reduction in frame rate.
3Measurement precision
If multiple exposure times are captured sequentially, then dynamic range is improved, but power consumption increases
Solution Approach 1:
The pixel array is divided into regions with different exposure times that operate in parallel. This segmentation allows the sensor to achieve extended dynamic range in a single capture cycle, eliminating the need for multiple sequential captures and thereby reducing overall power consumption while maintaining high measurement precision.
Solution Approach 2:
The sensor performs a single periodic capture cycle that simultaneously obtains multiple exposure times across different pixel regions. This periodic action replaces multiple sequential capture cycles, reducing the total energy required while achieving the same dynamic range improvement.
4Measurement precision
If conventional dynamic range (8-14 bits) is used, then device complexity remains low, but detail capture in diverse lighting conditions is insufficient
Solution Approach 1:
The pixel array is segmented into regions with different exposure times, allowing simultaneous capture of both bright and dark scene details. This segmentation enables the sensor to achieve 20+ bit dynamic range equivalent detail capture through spatial multiplexing, improving measurement precision without requiring complex post-processing or additional hardware components.
Solution Approach 2:
The sensor merges data from multiple exposure time regions within the same frame, achieving high dynamic range detail capture in a single operation. This combining approach eliminates the need for complex sequential processing of multiple images, reducing processing requirements while significantly improving detail capture capability in diverse lighting conditions.
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
Enables the capture of high dynamic range scenes with enhanced detail preservation and reduced power consumption, matching human vision capabilities and meeting requirements for applications like automotive imaging.
Implementation Method 1
CMOS image sensors include an array of pixels, each of which can comprise a photodetector. CMOS image sensors also include circuitry to convert light energy to an analog voltage
Data Source
AI summary
Various technologies described herein pertain to combining high dynamic range techniques to enable rendering higher dynamic range scenes with an image sensor. The image sensor can implement a combination of spatial exposure multiplexing and temporal exposure multiplexing, for example. By way of another example, the image sensor can implement a combination of spatial exposure multiplexing and dual gain operation. Pursuant to another example, the image sensor can implement a combination of temporal exposure multiplexing and dual gain operation. In accordance with yet another example, the image sensor can implement a combination of spatial exposure multiplexing, temporal exposure multiplexing, and dual gain operation. The image sensor can be formed on a single wafer or the image sensor can be a 3D-IC image sensor that includes at least two vertically integrated layers.